PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-25 (1387604)

Clipboard (0)
None

Related Articles

1.  Active or Passive Exposure to Tobacco Smoking and Allergic Rhinitis, Allergic Dermatitis, and Food Allergy in Adults and Children: A Systematic Review and Meta-Analysis 
PLoS Medicine  2014;11(3):e1001611.
In a systematic review and meta-analysis, Bahi Takkouche and colleagues examine the associations between exposure to tobacco smoke and allergic disorders in children and adults.
Please see later in the article for the Editors' Summary
Background
Allergic rhinitis, allergic dermatitis, and food allergy are extremely common diseases, especially among children, and are frequently associated to each other and to asthma. Smoking is a potential risk factor for these conditions, but so far, results from individual studies have been conflicting. The objective of this study was to examine the evidence for an association between active smoking (AS) or passive exposure to secondhand smoke and allergic conditions.
Methods and Findings
We retrieved studies published in any language up to June 30th, 2013 by systematically searching Medline, Embase, the five regional bibliographic databases of the World Health Organization, and ISI-Proceedings databases, by manually examining the references of the original articles and reviews retrieved, and by establishing personal contact with clinical researchers. We included cohort, case-control, and cross-sectional studies reporting odds ratio (OR) or relative risk (RR) estimates and confidence intervals of smoking and allergic conditions, first among the general population and then among children.
We retrieved 97 studies on allergic rhinitis, 91 on allergic dermatitis, and eight on food allergy published in 139 different articles. When all studies were analyzed together (showing random effects model results and pooled ORs expressed as RR), allergic rhinitis was not associated with active smoking (pooled RR, 1.02 [95% CI 0.92–1.15]), but was associated with passive smoking (pooled RR 1.10 [95% CI 1.06–1.15]). Allergic dermatitis was associated with both active (pooled RR, 1.21 [95% CI 1.14–1.29]) and passive smoking (pooled RR, 1.07 [95% CI 1.03–1.12]). In children and adolescent, allergic rhinitis was associated with active (pooled RR, 1.40 (95% CI 1.24–1.59) and passive smoking (pooled RR, 1.09 [95% CI 1.04–1.14]). Allergic dermatitis was associated with active (pooled RR, 1.36 [95% CI 1.17–1.46]) and passive smoking (pooled RR, 1.06 [95% CI 1.01–1.11]). Food allergy was associated with SHS (1.43 [1.12–1.83]) when cohort studies only were examined, but not when all studies were combined.
The findings are limited by the potential for confounding and bias given that most of the individual studies used a cross-sectional design. Furthermore, the studies showed a high degree of heterogeneity and the exposure and outcome measures were assessed by self-report, which may increase the potential for misclassification.
Conclusions
We observed very modest associations between smoking and some allergic diseases among adults. Among children and adolescents, both active and passive exposure to SHS were associated with a modest increased risk for allergic diseases, and passive smoking was associated with an increased risk for food allergy. Additional studies with detailed measurement of exposure and better case definition are needed to further explore the role of smoking in allergic diseases.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
The immune system protects the human body from viruses, bacteria, and other pathogens. Whenever a pathogen enters the body, immune system cells called T lymphocytes recognize specific molecules on its surface and release chemical messengers that recruit and activate other types of immune cells, which then attack the pathogen. Sometimes, however, the immune system responds to harmless materials (for example, pollen; scientists call these materials allergens) and triggers an allergic disease such as allergic rhinitis (inflammation of the inside of the nose; hay fever is a type of allergic rhinitis), allergic dermatitis (also known as eczema, a disease characterized by dry, itchy patches on the skin), and food allergy. Recent studies suggest that all these allergic (atopic) diseases are part of a continuous state called the “atopic march” in which individuals develop allergic diseases in a specific sequence that starts with allergic dermatitis during infancy, and progresses to food allergy, allergic rhinitis, and finally asthma (inflammation of the airways).
Why Was This Study Done?
Allergic diseases are extremely common, particularly in children. Allergic rhinitis alone affects 10%–30% of the world's population and up to 40% of children in some countries. Moreover, allergic diseases are becoming increasingly common. Allergic diseases affect the quality of life of patients and are financially costly to both patients and health systems. It is important, therefore, to identify the factors that cause or potentiate their development. One potential risk factor for allergic diseases is active or passive exposure to tobacco smoke. In some countries up to 80% of children are exposed to second-hand smoke so, from a public health point of view, it would be useful to know whether exposure to tobacco smoke is associated with the development of allergic diseases. Here, the researchers undertake a systematic review (a study that uses predefined criteria to identify all the research on a given topic) and a meta-analysis (a statistical approach for combining the results of several studies) to investigate this issue.
What Did the Researchers Do and Find?
The researchers identified 196 observational studies (investigations that observe outcomes in populations without trying to affect these outcomes in any way) that examined the association between smoke exposure and allergic rhinitis, allergic dermatitis, or food allergy. When all studies were analyzed together, allergic rhinitis was not associated with active smoking but was slightly associated with exposure to second-hand smoke. Specifically, compared to people not exposed to second-hand smoke, the pooled relative risk (RR) of allergic rhinitis among people exposed to second-hand smoke was 1.10 (an RR of greater than 1 indicates an increased risk of disease development in an exposed population compared to an unexposed population). Allergic dermatitis was associated with both active smoking (RR = 1.21) and exposure to second-hand smoke (RR = 1.07). In the populations of children and adolescents included in the studies, allergic rhinitis was associated with both active smoking and exposure to second-hand smoke (RRs of 1.40 and 1.09, respectively), as was allergic dermatitis (RRs of 1.36 and 1.06, respectively). Finally food allergy was associated with exposure to second-hand smoke (RR = 1.43) when cohort studies (a specific type of observational study) only were examined but not when all the studies were combined.
What Do These Findings Mean?
These findings provide limited evidence for a weak association between smoke exposure and allergic disease in adults but suggest that both active and passive smoking are associated with a modestly increased risk of allergic diseases in children and adolescents. The accuracy of these findings may be affected by the use of questionnaires to assess smoke exposure and allergic disease development in most of the studies in the meta-analysis and by the possibility that individuals exposed to smoke may have shared other characteristics that were actually responsible for their increased risk of allergic diseases. To shed more light on the role of smoking in allergic diseases, additional studies are needed that accurately measure exposure and outcomes. However, the present findings suggest that, in countries where many people smoke, 14% and 13% of allergic rhinitis and allergic dermatitis, respectively, among children may be attributable to active smoking. Thus, the elimination of active smoking among children and adolescents could prevent one in seven cases of allergic rhinitis and one in eight cases of allergic dermatitis in such countries.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001611.
The UK National Health Service Choices website provides information about allergic rhinitis, hay fever (including personal stories), allergic dermatitis (including personal stories), and food allergy (including personal stories)
The US National Institute of Allergy and Infectious Disease provides information about allergic diseases
The UK not-for-profit organization Allergy UK provides information about all aspects of allergic diseases and a description of the atopic march
MedlinePlus encyclopedia has pages on allergic rhinitis and allergic dermatitis (in English and Spanish)
MedlinePlus provides links to further resources about allergies, eczema, and food allergy (in English and Spanish)
doi:10.1371/journal.pmed.1001611
PMCID: PMC3949681  PMID: 24618794
2.  Variation in Uteroglobin-Related Protein 1 (UGRP1) gene is associated with Allergic Rhinitis in Singapore Chinese 
BMC Medical Genetics  2011;12:39.
Background
Uteroglobin-Related Protein 1 (UGRP1) is a secretoglobulin protein which has been suggested to play a role in lung inflammation and allergic diseases. UGRP1 has also been shown to be an important pneumoprotein, with diagnostic potential as a biomarker of lung damage. Previous genetic studies evaluating the association between variations on UGRP1 and allergic phenotypes have yielded mixed results. The aim of this present study was to identify genetic polymorphisms in UGRP1 and investigate if they were associated with asthma and allergic rhinitis in the Singapore Chinese population.
Methods
Resequencing of the UGRP1 gene was conducted on 40 randomly selected individuals from Singapore of ethnic Chinese origin. The polymorphisms identified were then tagged and genotyped in a population of 1893 Singapore Chinese individuals. Genetic associations were evaluated in this population comparing 795 individuals with allergic rhinitis, 718 with asthma (of which 337 had both asthma and allergic rhinitis) and 717 healthy controls with no history of allergy or allergic diseases.
Results
By resequencing the UGRP1 gene within our population, we identified 11 novel and 16 known single nucleotide polymorphisms (SNPs). TagSNPs were then genotyped, revealing a significant association between rs7726552 and allergic rhinitis (Odds Ratio: 0.81, 95% Confidence Interval: 0.66-0.98, P = 0.039). This association remained statistically significant when it was analyzed genotypically or when stratified according to haplotypes. When variations on UGRP1 were evaluated against asthma, no association was observed.
Conclusion
This study documents the association between polymorphisms in UGRP1 and allergic rhinitis, suggesting a potential role in its pathogenesis.
doi:10.1186/1471-2350-12-39
PMCID: PMC3070627  PMID: 21410962
3.  Investigating highly replicated asthma genes as candidate genes for allergic rhinitis 
BMC Medical Genetics  2013;14:51.
Background
Asthma genetics has been extensively studied and many genes have been associated with the development or severity of this disease. In contrast, the genetic basis of allergic rhinitis (AR) has not been evaluated as extensively. It is well known that asthma is closely related with AR since a large proportion of individuals with asthma also present symptoms of AR, and patients with AR have a 5–6 fold increased risk of developing asthma. Thus, the relevance of asthma candidate genes as predisposing factors for AR is worth investigating. The present study was designed to investigate if SNPs in highly replicated asthma genes are associated with the occurrence of AR.
Methods
A total of 192 SNPs from 21 asthma candidate genes reported to be associated with asthma in 6 or more unrelated studies were genotyped in a Swedish population with 246 AR patients and 431 controls. Genotypes for 429 SNPs from the same set of genes were also extracted from a Singapore Chinese genome-wide dataset which consisted of 456 AR cases and 486 controls. All SNPs were subsequently analyzed for association with AR and their influence on allergic sensitization to common allergens.
Results
A limited number of potential associations were observed and the overall pattern of P-values corresponds well to the expectations in the absence of an effect. However, in the tests of allele effects in the Chinese population the number of significant P-values exceeds the expectations. The strongest signals were found for SNPs in NPSR1 and CTLA4. In these genes, a total of nine SNPs showed P-values <0.001 with corresponding Q-values <0.05. In the NPSR1 gene some P-values were lower than the Bonferroni correction level. Reanalysis after elimination of all patients with asthmatic symptoms excluded asthma as a confounding factor in our results. Weaker indications were found for IL13 and GSTP1 with respect to sensitization to birch pollen in the Swedish population.
Conclusions
Genetic variation in the majority of the highly replicated asthma genes were not associated to AR in our populations which suggest that asthma and AR could have less in common than previously anticipated. However, NPSR1 and CTLA4 can be genetic links between AR and asthma and associations of polymorphisms in NPSR1 with AR have not been reported previously.
doi:10.1186/1471-2350-14-51
PMCID: PMC3653682  PMID: 23663310
Allergic rhinitis; Association; Asthma; Case–control; Replication
4.  Case-control study of IL13 polymorphisms, smoking, and rhinoconjunctivitis in Japanese women: the Kyushu Okinawa Maternal and Child Health Study 
BMC Medical Genetics  2011;12:143.
Background
Six previous studies have examined the relationships between single nucleotide polymorphisms (SNPs) in the IL13 gene and allergic rhinitis, but the results have been inconsistent. However, a recent meta-analysis using data from these 6 studies has shown that the A allele of IL13 SNP rs20541 was associated with an increased risk of allergic rhinitis, whereas no such relationship existed between IL13 SNP rs1800925 and allergic rhinitis. We investigated the associations between IL13 SNPs rs1800925 and rs20541 and the risk of rhinoconjunctivitis in Japanese women.
Methods
Included were 393 cases who met the criteria of the International Study of Asthma and Allergies in Childhood (ISAAC) for rhinoconjunctivitis. Control subjects were 767 women without rhinoconjunctivitis according to the ISAAC criteria, who had also not been diagnosed with allergic rhinitis by a doctor. Adjustment was made for age, region of residence, presence of older siblings, smoking, family history of allergic rhinitis, and education.
Results
Compared with the GG genotype of IL13 SNP rs20541, the AA genotype, occurring in 7.1% of control subjects, was significantly positively related to the risk of rhinoconjunctivitis: the adjusted odds ratio was 1.65 (95% confidence interval: 1.05 - 2.60). SNP rs1800925 was not associated with rhinoconjunctivitis. The haplotype comprising the rs1800925 C allele and the rs20541 A allele was significantly positively related to rhinoconjunctivitis. The multiplicative interactions between the two SNPs under study and smoking on the risk of rhinoconjunctivitis were not statistically significant. Based on the recessive model, however, the additive interaction between SNP rs1800925, but not rs20541, and smoking was significant.
Conclusions
This study suggests that the minor genotype of IL13 SNP rs20541 and the CA haplotype are significantly positively associated with the risk of rhinoconjunctivitis. In addition, a new pattern of biological interaction that affects the risk of rhinoconjunctivitis is described between SNP rs1800925 and smoking.
doi:10.1186/1471-2350-12-143
PMCID: PMC3214177  PMID: 22023794
5.  Association Pattern of Interleukin-1 Receptor-Associated Kinase-4 Gene Polymorphisms with Allergic Rhinitis in a Han Chinese Population 
PLoS ONE  2011;6(6):e21769.
Objective
Interleukin-1 receptor-associated kinase-4 (IRAK-4) encodes a kinase that is essential for NF-kB activation in Toll-like receptor and T-cell receptor signaling pathways, indicating a possible crosstalk between innate and acquired immunities. We attempted to determine whether the polymorphisms in the Interleukin-1 receptor-associated kinase-4 (IRAK-4) gene are associated with allergic rhinitis (AR) in the Han Chinese population.
Methods
A population of 379 patients with AR and 333 healthy controls was studied. Blood was drawn for DNA extraction and total serum immunoglobulin E (IgE). A total of 11 single nucleotide polymorphisms (SNPs) in IRAK-4 were selected and individually genotyped.
Results
Significant allelic differences between cases and controls were obtained for the SNP of rs3794262 in the IRAK-4 gene. In the stratified analysis for gender, two SNPs (rs4251431 and rs6582484) in males appeared as significant associations. Subgroup analysis for the presence of different allergen sensitivities displayed associations only in the house dust mite-allergic cohorts (rs3794262, rs4251481). None of the selected SNPs in IRAK-4 was associated with total IgE level. The haplotype analyisis indicated GCCTGCGA was significantly associated with AR. The SNP-SNP interaction information analysis indicated that the selected sets of polymorphisms had no synergistic effect.
Conclusions
Our findings did not support the potential contribution of the IRAK-4 gene to serum IgE levels. However, the results demonstrated a gender- and allergen-dependant association pattern between polymorphisms in IRAK-4 and AR in Chinese population.
doi:10.1371/journal.pone.0021769
PMCID: PMC3128076  PMID: 21738793
6.  Comprehensive evaluation of genetic variation in S100A7 suggests an association with the occurrence of allergic rhinitis 
Respiratory Research  2008;9(1):29.
Background
S100A7 is a calcium-binding protein with chemotactic and antimicrobial properties. S100A7 protein levels are decreased in nasal lavage fluid from individuals with ongoing allergic rhinitis, suggesting a role for S100A7 in allergic airway inflammation. The aims of this study were to describe genetic variation in S100A7 and search for associations between this variation and allergic rhinitis.
Methods
Peripheral blood was collected from 184 atopic patients with a history of pollen-induced allergic rhinitis and 378 non-atopic individuals, all of Swedish origin. DNA was extracted and the S100A7 gene was resequenced in a subset of 47 randomly selected atopic individuals. Nine polymorphisms were genotyped in 184 atopic and 378 non-atopic individuals and subsequently investigated for associations with allergic rhinitis as well as skin prick test results. Haplotypes were estimated and compared in the two groups.
Results
Thirteen polymorphisms were identified in S100A7, of which 7 were previously undescribed. rs3014837 (G/C), which gives rise to an Asp → Glu amino acid shift, had significantly increased minor allele frequency in atopic individuals. The major haplotype, containing the major allele at all sites, was more common in non-atopic individuals, while the haplotype containing the minor allele at rs3014837 was equally more common among the atopic individuals. Additionally, heterozygotes at this site had significantly higher scores in skin prick tests for 9 out of 11 tested allergens, compared to homozygotes.
Conclusion
This is the first study describing genetic variation, associated with allergy, in S100A7. The results indicate that rs3014837 is linked to allergic rhinitis in our Swedish population and render S100A7 a strong candidate for further investigations regarding its role in allergic inflammation.
doi:10.1186/1465-9921-9-29
PMCID: PMC2335106  PMID: 18373864
7.  Genome-Wide Association Study for Atopy and Allergic Rhinitis in a Singapore Chinese Population 
PLoS ONE  2011;6(5):e19719.
Allergic rhinitis (AR) is an atopic disease which affects about 600 million people worldwide and results from a complex interplay between genetic and environmental factors. However genetic association studies on known candidate genes yielded variable results. The aim of this study is to identify the genetic variants that influence predisposition towards allergic rhinitis in an ethnic Chinese population in Singapore using a genome-wide association study (GWAS) approach. A total of 4461 ethnic Chinese volunteers were recruited in Singapore and classified according to their allergic disease status. The GWAS included a discovery stage comparing 515 atopic cases (including 456 AR cases) and 486 non-allergic non-rhinitis (NANR) controls. The top SNPs were then validated in a replication cohort consisting of a separate 2323 atopic cases (including 676 AR cases) and 511 NANR controls. Two SNPs showed consistent association in both discovery and replication phases; MRPL4 SNP rs8111930 on 19q13.2 (OR = 0.69, Pcombined = 4.46×10−05) and BCAP SNP rs505010 on chromosome 10q24.1 (OR = 0.64, Pcombined = 1.10×10−04). In addition, we also replicated multiple associations within known candidates regions such as HLA-DQ and NPSR1 locus in the discovery phase. Our study suggests that MRPL4 and BCAP, key components of the HIF-1α and PI3K/Akt signaling pathways respectively, are two novel candidate genes for atopy and allergic rhinitis. Further study on these molecules and their signaling pathways would help in understanding of the pathogenesis of allergic rhinitis and identification of targets for new therapeutic intervention.
doi:10.1371/journal.pone.0019719
PMCID: PMC3098846  PMID: 21625490
8.  Association Study on ADAM33 Polymorphisms in Mite-Sensitized Persistent Allergic Rhinitis in a Chinese Population 
PLoS ONE  2014;9(4):e95033.
Background
The ADAM33 gene has been identified as a potentially important asthma candidate gene and polymorphisms in this gene have been shown to be associated with asthma and seasonal allergic rhinitis.
Objective
To assess whether the ADAM33 polymorphisms are associated with persistent allergic rhinitis (PER) due to house dust mites in a Chinese population.
Methods
In a hospital-based case-control study of 515 patients with mite-sensitized PER and 495 healthy controls, we genotyped seven single nucleotide polymorphisms (SNPs) in ADAM33. Serum levels of eosinophil cationic protein, total IgE and allergen-specific IgE against Dermatophagoides pteronyssinus and Dermatophagoides farinae were measured by the ImmunoCAP assays.
Results
In the single-locus analysis, three polymorphisms, rs3918392 (F1), rs528557 (S2) and rs2787093, were significantly associated with mite-sensitized PER. SNP S2 was associated with significantly increased risk both of asthmatic and nonasthmatic mite-sensitized PER. In the combined genotypes analysis, individuals with 2–4 risk alleles had a significantly higher risk of mite-sensitized PER (adjusted OR = 1.99, 95% CI = 1.50–2.62) than those with 0–1 risk alleles. Haplotype-based association analysis revealed that the ACAGCCT haplotype might have potential to protect against mite-sensitized PER (adjusted OR = 0.67; 95% CI = 0.49–0.90).
Conclusions
Polymorphisms in the ADAM33 gene may contribute to susceptibility of mite-sensitized PER in this Chinese population.
doi:10.1371/journal.pone.0095033
PMCID: PMC3994017  PMID: 24751681
9.  Poor Reproducibility of Allergic Rhinitis SNP Associations 
PLoS ONE  2013;8(1):e53975.
Replication of reported associations is crucial to the investigation of complex disease. More than 100 SNPs have previously been reported as associated with allergic rhinitis (AR), but few of these have been replicated successfully. To investigate the general reproducibility of reported AR-associations in candidate gene studies, one Swedish (352 AR-cases, 709 controls) and one Singapore Chinese population (948 AR-cases, 580 controls) were analyzed using 49 AR-associated SNPs. The overall pattern of P-values indicated that very few of the investigated SNPs were associated with AR. Given published odds ratios (ORs) most SNPs showed high power to detect an association, but no correlations were found between the ORs of the two study populations or with published ORs. None of the association signals were in common to the two genome-wide association studies published in AR, indicating that the associations represent false positives or have much lower effect-sizes than reported.
doi:10.1371/journal.pone.0053975
PMCID: PMC3559641  PMID: 23382861
10.  Impact of Allergic Rhinitis on Quality of Life in Patients with Bronchial Asthma 
Allergy and asthma can reduce HRQOL as a result of profound physical and psychosocial complications. Most patients with asthma also suffer from rhinitis, which also impairs quality of life. However, the impact of allergic rhinitis on asthmatic patients has not been investigated.
Objective
To assess Quality of life (QOL) in asthmatic patients and assess relative burden of allergic rhinitis on asthmatics’ QOL.
Patients and Methods
we analysed HRQOL questionnaire (SF-36) answers of 219 patients (118 allergic rhinitis, 79 asthma and 22 asthma with allergic rhinitis) and controls (30 healthy individuals), in addition to analysis of questionnaire scores according to patients’ characteristic including gender, BMI and duration of symptoms. Moreover, pulmonary function test were done for all patients and control.
Results
HRQOL parameters were significantly lower in females more than males and in patients with BMI>25 if compared with those with BMI<25. Moreover, HRQOL was significantly lower in all 3 patients’ groups if compared with control group (P<0.001) in all parameters except mental health and role emotional. Significantly higher scores (SF-36 sub-scales for physical functioning, role-physical, bodily pain) were found among allergic rhinitis patients compared with asthmatics with or without allergic rhinitis. Although, quality of life was worse in asthmatic patients compared to patients with rhinitis alone, no significant difference was found between asthmatics and those with both diseases. Both PCS and MCS scores are significantly lower in patients’ groups compared with the control (p<0.05). Asthmatic patients with or without rhinitis tended to have lower PCS and MCS scores than subjects with isolated allergic rhinitis, the difference between the groups was statistically significant only for PCS scores. Moreover, highly significant positive correlation between PCS score and FEV1 in asthmatics with or without allergic rhinitis was detected denoting that PCS score is markedly affected by severity of asthma. (r=0.949, P<0.001).
Conclusions
Allergic rhinitis has a limited role in reduction of HRQOL. HRQOL is markedly reduced in patients with asthma with or without rhinitis than in those with allergic rhinitis only; this could be related to the severity of asthma more than the presence of associated allergic rhinitis. These findings indicated that allergic rhinitis does not seem to further impair quality of life in subjects with asthma. We recommend that patients with bronchial asthma with or without allergic rhinitis in need of great help from physicians and social workers to improve their physical and mental health. Moreover, further studies with larger populations and longer duration are needed in order to determine the extent to which asthma and rhinitis comorbidities are associated in HRQOL.
PMCID: PMC3616948  PMID: 23580898
asthma; allergic rhinitis; HRQOL; SF-36 questionnaire
11.  Allergic rhinitis and genetic components: focus on Toll-like receptors (TLRs) gene polymorphism 
Allergic rhinitis represents a global health issue affecting 10% to 25% of the population worldwide. Over the years, studies have found that allergic diseases, including allergic rhinitis, are associated with immunological responses to antigens driven by a Th2-mediated immune response. Because Toll-like receptors (TLRs) are involved in both innate and adaptive immune responses to a broad variety of antigens, the association between polymorphisms of TLRs and allergic diseases has been the focus in many animal and human studies. Although the etiology of allergic rhinitis is still unknown, extensive research over the years has confirmed that the underlying causes of allergic diseases are due to many genetic and environmental factors, along with the interactions among them, which include gene–environment, gene–gene, and environment–environment interactions. Currently, there is great inconsistency among studies mainly due to differences in genetic background and unique gene–environment interactions. This paper reviews studies focusing on the association between TLR polymorphisms and allergic diseases, including allergic rhinitis, which would help researchers better understand the role of TLR polymorphisms in the development of allergic rhinitis, and ultimately lead to more efficient therapeutic interventions being developed.
doi:10.2147/TACG.S8380
PMCID: PMC3681168  PMID: 23776356
allergic rhinitis; allergic diseases; Toll-like receptors
12.  FCRL3 Gene Polymorphisms Confer Autoimmunity Risk for Allergic Rhinitis in a Chinese Han Population 
PLoS ONE  2015;10(1):e0116419.
Background
Heredity and environmental exposures may contribute to a predisposition to allergic rhinitis (AR). Autoimmunity may also involve into this pathologic process. FCRL3 (Fc receptor-like 3 gene), a novel immunoregulatory gene, has recently been reported to play a role in autoimmune diseases.
Objective
This study was performed to evaluate the potential association of FCRL3 polymorphisms with AR in a Chinese Han population.
Methods
Five single-nucleotide polymorphisms of FCRL3, rs945635, rs3761959, rs7522061, rs10489678 and rs7528684 were genotyped in 540 AR patients and 600 healthy controls using a PCR-restriction fragment length polymorphism assay. Allele, genotype and haplotype frequencies were compared between patients and controls using the χ2 test. The online software platform SHEsis was used to analyze their haplotypes.
Results
This study identified three strong risk SNPs rs7528684, rs10489678, rs7522061 and one weak risk SNP rs945635 of FCRL3 in Chinese Han AR patients. For rs7528684, a significantly increased prevalence of the AA genotype and A allele in AR patients was recorded. The frequency of the GG genotype and G allele of rs10489678 was markedly higher in AR patients than those in controls. For rs7522061, a higher frequency of the TT genotype, and a lower frequency of the CT genotype were found in AR patients. Concerning rs945635, a lower frequency of the CC genotype, and a higher frequency of G allele were observed in AR patients. According to the analysis of the three strong positive SNPs, the haplotype of AGT increased significantly in AR cases (AR = 38.8%, Controls = 24.3%, P = 8.29×10-14, OR [95% CI] 1.978 [1.652~2.368]).
Conclusions
This study found a significant association between the SNPs in FCRL3 gene and AR in Chinese Han patients. The results suggest these gene polymorphisms might be the autoimmunity risk for AR.
doi:10.1371/journal.pone.0116419
PMCID: PMC4296936  PMID: 25594855
13.  TLR7 single-nucleotide polymorphisms in the 3' untranslated region and intron 2 independently contribute to systemic lupus erythematosus in Japanese women: a case-control association study 
Introduction
The Toll-like receptor 7 (TLR7) gene, encoded on human chromosome Xp22.3, is crucial for type I interferon production. A recent multicenter study in East Asian populations, comprising Chinese, Korean and Japanese participants, identified an association of a TLR7 single-nucleotide polymorphism (SNP) located in the 3' untranslated region (3' UTR), rs3853839, with systemic lupus erythematosus (SLE), especially in males, although some difference was observed among the tested populations. To test whether additional polymorphisms contribute to SLE in Japanese, we systematically analyzed the association of TLR7 with SLE in a Japanese female population.
Methods
A case-control association study was conducted on eight tag SNPs in the TLR7 region, including rs3853839, in 344 Japanese females with SLE and 274 healthy female controls.
Results
In addition to rs3853839, two SNPs in intron 2, rs179019 and rs179010, which were in moderate linkage disequilibrium with each other (r2 = 0.53), showed an association with SLE (rs179019: P = 0.016, odds ratio (OR) 2.02, 95% confidence interval (95% CI) 1.15 to 3.54; rs179010: P = 0.018, OR 1.75, 95% CI 1.10 to 2.80 (both under the recessive model)). Conditional logistic regression analysis revealed that the association of the intronic SNPs and the 3' UTR SNP remained significant after we adjusted them for each other. When only the patients and controls carrying the risk genotypes at the 3' UTR SNPpositionwere analyzed, the risk of SLE was significantly increased when the individuals also carried the risk genotypes at both of the intronic SNPs (P = 0.0043, OR 2.45, 95% CI 1.31 to 4.60). Furthermore, the haplotype containing the intronic risk alleles in addition to the 3' UTR risk allele was associated with SLE under the recessive model (P = 0.016, OR 2.37, 95% CI 1.17 to 4.80), but other haplotypes were not associated with SLE.
Conclusions
The TLR7 intronic SNPs rs179019 and rs179010 are associated with SLE independently of the 3' UTR SNP rs3853839 in Japanese women. Our findings support a role of TLR7 in predisposition for SLE in Asian populations.
doi:10.1186/ar3277
PMCID: PMC3132023  PMID: 21396113
14.  Filaggrin gene defects and risk of developing allergic sensitisation and allergic disorders: systematic review and meta-analysis 
Objective To investigate whether filaggrin gene defects, present in up to one in 10 western Europeans and North Americans, increase the risk of developing allergic sensitisation and allergic disorders.
Design Systematic review and meta-analysis.
Data sources Medline, Embase, ISI Science Citation Index, BIOSIS, ISI Web of Knowledge, UK National Research Register, clinical trials.gov, the Index to Theses and Digital dissertations, and grey literature using OpenSIGLE.
Study selection Genetic epidemiological studies (family, case-control) of the association between filaggrin gene defects and allergic sensitisation or allergic disorders.
Data extraction Atopic eczema or dermatitis, food allergy, asthma, allergic rhinitis, and anaphylaxis, along with relevant immunological variables relating to the risk of allergic sensitisation as assessed by either positive skin prick testing or increased levels of allergen specific IgE.
Data synthesis 24 studies were included. The odds of developing allergic sensitisation was 1.91 (95% confidence interval 1.44 to 2.54) in the family studies and 1.57 (1.20 to 2.07) in the case-control studies. The odds of developing atopic eczema was 1.99 (1.72 to 2.31) in the family studies and 4.78 (3.31 to 6.92) in the case-control studies. Three studies investigated the association between filaggrin gene mutations and allergic rhinitis in people without atopic eczema: overall odds ratio 1.78 (1.16 to 2.73). The four studies that investigated the association between filaggrin gene mutations and allergic rhinitis in people with atopic eczema reported a significant association: pooled odds ratio from case-control studies 2.84 (2.08 to 3.88). An overall odds ratio for the association between filaggrin gene mutations and asthma in people with atopic eczema was 2.79 (1.77 to 4.41) in case-control studies and 2.30 (1.66 to 3.18) in family studies. None of the studies that investigated filaggrin gene mutations and asthma in people without atopic eczema reported a significant association; overall odds ratio was 1.30 (0.7 to 2.30) in the case-control studies. The funnel plots suggested that publication bias was unlikely to be an explanation for these findings. No studies investigated the association between filaggrin gene mutations and food allergy or anaphylaxis.
Conclusions Filaggrin gene defects increase the risk of developing allergic sensitisation, atopic eczema, and allergic rhinitis. Evidence of the relation between filaggrin gene mutations and atopic eczema was strong, with people manifesting increased severity and persistence of disease. Filaggrin gene mutations also increased the risk of asthma in people with atopic eczema. Restoring skin barrier function in filaggrin deficient people in early life may help prevent the development of sensitisation and halt the development and progression of allergic disease.
doi:10.1136/bmj.b2433
PMCID: PMC2714678  PMID: 19589816
15.  Association between Polymorphisms of the IL-23R Gene and Allergic Rhinitis in a Chinese Han Population 
PLoS ONE  2013;8(5):e63858.
Objective
Polymorphism of the interleukin-23 receptor gene corresponds with susceptibility to several immune-related diseases. For the terminal differentiation of IL-17-producing effector T-helper cells in vivo, the interleukin-23 receptor gene is of vital importance. As shown recently, Th17 cells probably have a great influence on the pathogenesis of allergic airway diseases. Our intention was to establish an association between polymorphisms in the IL-23R gene and allergic rhinitis (AR) in the Chinese Han population.
Methods
We included 358 AR patients and 407 control Chinese subjects in a case-control comparison. The study involved obtaining blood samples for DNA extraction genotyping and determination of 4 selected single-nucleotide polymorphisms in IL-23R by performing PCR restriction fragment length polymorphism analysis (PCR-RFLP).
Results
A substantially growing prevalence of the homozygous rs7517847 GG genotype and G allele appeared in the AR patients unlike that observed in the control individuals (P<0.001). In addition, substantially high frequencies of the GGCA and GGCG haplotypes were observed in the AR patients, unlike that observed in the control individuals (P<0.05). The results suggest that the AGTG haplotype may provide protection against AR (P<0.001).
Conclusions
To the best of our knowledge, this is the first study to demonstrate an important association between polymorphisms in IL-23R and AR in the Chinese Han population. A strong association between rs7517847 in a SNP of IL-23R, and AR was identified.
doi:10.1371/journal.pone.0063858
PMCID: PMC3655942  PMID: 23696856
16.  233 The Evaluation of Allergen Sensitivity in Allergic Rhinoconjunctivitis and Allergic Asthma Patients in Antalya, Turkey 
The World Allergy Organization Journal  2012;5(Suppl 2):S93-S94.
Background
Allergic rhinitis is a common health problem which has 2 forms; seasonal and perennial. The prevalence and etiology of allergic rhinitis varies from region to region and affect 10 to 20% of the population approximately. The prevalences of asthma, allergic rhinitis and allergic eye disease were detected as 8.2%, 10.8% and 7.5% respectively in Antalya, the south coast of Turkey.
Methods
The study was conducted in Antalya between 10th of November 2009 and 20th of September 2010. 866 of 2862 patients who had allergic rhinoconjunctivitis and asthma were enrolled in the study due to having high total IgE levels in blood conducted at the Allergy-Immunology Division of Antalya Research and Training Hospital. Allergen-spesific subcutaneous immunotherapy was given 626 of 866 patients.
Results
Of the 866 patients studied, 66.1 % were females. Most of the cases had declaired that the rhinitis symptomes were due to pollens and house dust the second most common irritant. Also the cases have said that their symptoms got worse with exposure to dust, smoke, heavy odors, perfumes, and detergents. Most of the patients have said that air pollution was the most important factor that exacerbated the symptoms of rhinitis and asthma. While there is a comparison between the age and SPT positivity, Aspergillus fumigatus and Dpteronyssinus sensitivity was statistically different in the mites and fungal mixture dermal test groups. As a result, in the study group of 866 allergic rhinitis patients, only the Plantagolanceolata, Corylusavellana, Aspergillus fumigatus, Dpteronyssinus and cockroach sensitivity was significantly varies with the age.
Conclusions
In allergic diseases; we all know that allergens may have regional variations. That's why; the allergen profiles of the regions must be determined and the dermal Prick tests must be prepared accordingly. Mostly grass and cereal mixtures and mites are responsible from the allergic rhinitis cases due to our observations in our clinic. The other important allergens that are linked to the flora and climate of the region are olive and the cockroaches. High asthma prevalence in people living in shanties and in housewives may be due to exposure to house dust mites.
doi:10.1097/01.WOX.0000411990.41169.0a
PMCID: PMC3512677
17.  Variants of thymic stromal lymphopoietin and its receptor associate with eosinophilic esophagitis 
Background
The genetic etiology of eosinophilic esophagitis (EE) has been largely unexplored until a recent genome-wide association study identified a disease susceptibility locus on 5q22, a region that harbors the thymic stromal lymphopoietin (TSLP) gene. However, it is unclear whether the observed genetic associations with EE are disease-specific or confounded by the high rate of allergy in EE patients. In addition, the genetic contributions of other allergy associated genes to EE risk have not been explored.
Objective
We aimed to delineate single nucleotide polymorphisms (SNP)s that associated with EE apart from allergy.
Methods
We utilized a custom array containing 738 SNPs in 53 genes implicated in allergic and/or immune responses to genotype 220 allergic or 246 non-allergic controls and a discovery cohort of 170 EE patients. We replicated a statistically significant SNP association in an independent case-control cohort and examined the induction of the candidate gene in primary esophageal epithelial cells.
Results
A single SNP residing in the TSLP gene reached Bonferroni LD adjusted significance and only when EE cases were compared with allergic controls (rs10062929, P = 4.11 × 10−5, odds ratio = 0.35). A non-synonymous polymorphism in the TSLP receptor on Xp22.3 and Yp11.3 was significantly associated with disease only in male EE patients. Primary esophageal epithelial cells expressed TSLP mRNA following Toll-like receptor 3 (TLR3) stimulation.
Conclusion
These data collectively identify TSLP as a candidate gene critically involved in EE susceptibility beyond its role in promoting Th2 responses.
doi:10.1016/j.jaci.2010.04.037
PMCID: PMC2904342  PMID: 20620568
Eosinophilic esophagitis; thymic stromal lymphopoietin; single nucleotide polymorphism; allergy; cytokine receptor-like factor 2; Toll-like receptor 3
18.  Absence of the toll-like receptor 4 gene polymorphisms Asp299Gly and Thr399Ile in Singaporean Chinese 
Toll-like receptor 4 (TLR4) is the transuding subunit of lipopolysaccharide receptor and an important intracellular signal pathway of the innate immune response. Published data about the relationship between TLR4 mutations and atopy/asthma are not consistent. This study was performed to detect two commonly reported Asp299Gly and Thr399Ile polymorphisms in TLR4 gene in Singaporean Chinese and their possible association with atopy-related phenotypes. A total of 117 unrelated Singapore residents were randomly selected for this study. Among them, atopy was evident in 66 subjects while 61 had allergic rhinitis. Twenty-one patients had concomitant asthma and 17 were atopic. In all subjects, neither the Asp299Gly nor Thr399Ile polymorphism was found by DNA sequencing. This discrepant result could be due to the ethnic variation of allelic distribution in TLR4 gene. Although it is still debatable whether there is any role of TLR4 polymorphisms on atopy-related phenotypes, one needs to develop an appropriate model to investigate the interactions between genetic variations and environmental factors that contribute to the complex traits in allergic diseases.
PMCID: PMC1661622  PMID: 18360565
TLR4 polymorphisms; Singaporean Chinese; atopy
19.  Polymorphisms in the Tlr4 and Tlr5 Gene Are Significantly Associated with Inflammatory Bowel Disease in German Shepherd Dogs 
PLoS ONE  2010;5(12):e15740.
Inflammatory bowel disease (IBD) is considered to be the most common cause of vomiting and diarrhoea in dogs, and the German shepherd dog (GSD) is particularly susceptible. The exact aetiology of IBD is unknown, however associations have been identified between specific single-nucleotide polymorphisms (SNPs) in Toll-like receptors (TLRs) and human IBD. However, to date, no genetic studies have been undertaken in canine IBD. The aim of this study was to investigate whether polymorphisms in canine TLR 2, 4 and 5 genes are associated with IBD in GSDs. Mutational analysis of TLR2, TLR4 and TLR5 was performed in 10 unrelated GSDs with IBD. Four non-synonymous SNPs (T23C, G1039A, A1571T and G1807A) were identified in the TLR4 gene, and three non-synonymous SNPs (G22A, C100T and T1844C) were identified in the TLR5 gene. The non-synonymous SNPs identified in TLR4 and TLR5 were evaluated further in a case-control study using a SNaPSHOT multiplex reaction. Sequencing information from 55 unrelated GSDs with IBD were compared to a control group consisting of 61 unrelated GSDs. The G22A SNP in TLR5 was significantly associated with IBD in GSDs, whereas the remaining two SNPs were found to be significantly protective for IBD. Furthermore, the two SNPs in TLR4 (A1571T and G1807A) were in complete linkage disequilibrium, and were also significantly associated with IBD. The TLR5 risk haplotype (ACC) without the two associated TLR4 SNP alleles was significantly associated with IBD, however the presence of the two TLR4 SNP risk alleles without the TLR5 risk haplotype was not statistically associated with IBD. Our study suggests that the three TLR5 SNPs and two TLR4 SNPs; A1571T and G1807A could play a role in the pathogenesis of IBD in GSDs. Further studies are required to confirm the functional importance of these polymorphisms in the pathogenesis of this disease.
doi:10.1371/journal.pone.0015740
PMCID: PMC3009732  PMID: 21203467
20.  Developmental Profiles of Eczema, Wheeze, and Rhinitis: Two Population-Based Birth Cohort Studies 
PLoS Medicine  2014;11(10):e1001748.
Using data from two population-based birth cohorts, Danielle Belgrave and colleagues examine the evidence for atopic march in developmental profiles for allergic disorders.
Please see later in the article for the Editors' Summary
Background
The term “atopic march” has been used to imply a natural progression of a cascade of symptoms from eczema to asthma and rhinitis through childhood. We hypothesize that this expression does not adequately describe the natural history of eczema, wheeze, and rhinitis during childhood. We propose that this paradigm arose from cross-sectional analyses of longitudinal studies, and may reflect a population pattern that may not predominate at the individual level.
Methods and Findings
Data from 9,801 children in two population-based birth cohorts were used to determine individual profiles of eczema, wheeze, and rhinitis and whether the manifestations of these symptoms followed an atopic march pattern. Children were assessed at ages 1, 3, 5, 8, and 11 y. We used Bayesian machine learning methods to identify distinct latent classes based on individual profiles of eczema, wheeze, and rhinitis. This approach allowed us to identify groups of children with similar patterns of eczema, wheeze, and rhinitis over time.
Using a latent disease profile model, the data were best described by eight latent classes: no disease (51.3%), atopic march (3.1%), persistent eczema and wheeze (2.7%), persistent eczema with later-onset rhinitis (4.7%), persistent wheeze with later-onset rhinitis (5.7%), transient wheeze (7.7%), eczema only (15.3%), and rhinitis only (9.6%). When latent variable modelling was carried out separately for the two cohorts, similar results were obtained. Highly concordant patterns of sensitisation were associated with different profiles of eczema, rhinitis, and wheeze. The main limitation of this study was the difference in wording of the questions used to ascertain the presence of eczema, wheeze, and rhinitis in the two cohorts.
Conclusions
The developmental profiles of eczema, wheeze, and rhinitis are heterogeneous; only a small proportion of children (∼7% of those with symptoms) follow trajectory profiles resembling the atopic march.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Our immune system protects us from viruses, bacteria, and other pathogens by recognizing specific molecules on the invader's surface and initiating a sequence of events that culminates in the death of the pathogen. Sometimes, however, our immune system responds to harmless materials (allergens such as pollen) and triggers allergic, or atopic, symptoms. Common atopic symptoms include eczema (transient dry itchy patches on the skin), wheeze (high pitched whistling in the chest, a symptom of asthma), and rhinitis (sneezing or a runny nose in the absence of a cold or influenza). All these symptoms are very common during childhood, but recent epidemiological studies (examinations of the patterns and causes of diseases in a population) have revealed age-related changes in the proportions of children affected by each symptom. So, for example, eczema is more common in infants than in school-age children. These findings have led to the idea of “atopic march,” a natural progression of symptoms within individual children that starts with eczema, then progresses to wheeze and finally rhinitis.
Why Was This Study Done?
The concept of atopic march has led to the initiation of studies that aim to prevent the development of asthma in children who are thought to be at risk of asthma because they have eczema. Moreover, some guidelines recommend that clinicians tell parents that children with eczema may later develop asthma or rhinitis. However, because of the design of the epidemiological studies that support the concept of atopic march, children with eczema who later develop wheeze and rhinitis may actually belong to a distinct subgroup of children, rather than representing the typical progression of atopic diseases. It is important to know whether atopic march adequately describes the natural history of atopic diseases during childhood to avoid the imposition of unnecessary strategies on children with eczema to prevent asthma. Here, the researchers use machine learning techniques to model the developmental profiles of eczema, wheeze, and rhinitis during childhood in two large population-based birth cohorts by taking into account time-related (longitudinal) changes in symptoms within individuals. Machine learning is a data-driven approach that identifies structure within the data (for example, a typical progression of symptoms) using unsupervised learning of latent variables (variables that are not directly measured but are inferred from other observable characteristics).
What Did the Researchers Do and Find?
The researchers used data from two UK birth cohorts—the Avon Longitudinal Study of Parents and Children (ALSPAC) and the Manchester Asthma and Allergy Study (MAAS)—for their study (9,801 children in total). Both studies enrolled children at birth and monitored their subsequent health at regular review clinics. At each review clinic, information about eczema, wheeze, and rhinitis was collected from the parents using validated questionnaires. The researchers then used these data and machine learning methods to identify groups of children with similar patterns of onset of eczema, wheeze, and rhinitis over the first 11 years of life. Using a type of statistical model called a latent disease profile model, the researchers found that the data were best described by eight latent classes—no disease (51.3% of the children), atopic march (3.1%), persistent eczema and wheeze (2.7%), persistent eczema with later-onset rhinitis (4.7%), persistent wheeze with later-onset rhinitis (5.7%), transient wheeze (7.7%), eczema only (15.3%), and rhinitis only (9.6%).
What Do These Findings Mean?
These findings show that, in two large UK birth cohorts, the developmental profiles of eczema, wheeze, and rhinitis were heterogeneous. Most notably, the progression of symptoms fitted the profile of atopic march in fewer than 7% of children with symptoms. The researchers acknowledge that their study has some limitations. For example, small differences in the wording of the questions used to gather information from parents about their children's symptoms in the two cohorts may have slightly affected the findings. However, based on their findings, the researchers propose that, because eczema, wheeze, and rhinitis are common, these symptoms often coexist in individuals, but as independent entities rather than as a linked progression of symptoms. Thus, using eczema as an indicator of subsequent asthma risk and assigning “preventative” measures to children with eczema is flawed. Importantly, clinicians need to understand the heterogeneity of patterns of atopic diseases in children and to communicate this variability to parents when advising them about the development and resolution of atopic symptoms in their children.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001748.
The UK National Health Service Choices website provides information about eczema (including personal stories), asthma (including personal stories), and rhinitis
The US National Institute of Allergy and Infectious Diseases provides information about atopic diseases
The UK not-for-profit organization Allergy UK provides information about atopic diseases and a description of the atopic march
MedlinePlus encyclopedia has pages on eczema, wheezing, and rhinitis (in English and Spanish)
MedlinePlus provides links to further resources about allergies, eczema, and asthma (in English and Spanish)
Information about ALSPAC and MAAS is available
Wikipedia has pages on machine learning and latent disease profile models (note that Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
doi:10.1371/journal.pmed.1001748
PMCID: PMC4204810  PMID: 25335105
21.  ALLERGIC RHINITIS AMONG ADULT BRONCHIAL ASTHMATIC PATIENTS IN LAGOS, NIGERIA  
Abstract
Background
Allergic rhinitis (AR) and asthma are different manifestations of allergic disease of the airway. Both can exist together or as separate disease entity in an individual. However, it is not known if the coexistence of the two diseases can make asthmatic control difficult or not in the black population.
Objective
To determine the prevalence of allergic rhinitis in asthmatics and its effects on bronchial asthmatic control among adult Nigerians..
Design
A prospective case-control study.
Setting
Lagos University Teaching Hospital, Lagos, Nigeria.
Subjects
Cases were 160 adult patients with confirmed bronchial asthma and controls were 160 subjects without bronchial asthma.
Methods
Structured questionnaire adapted from the European Community Respiratory Health Survey was applied. Allergic rhinitis was clinically diagnosed if watery rhinorrhea, nasal blockage, and excessive bout of sneezing, itching of eye, ear, nose or throat were present
Results
Amongst the asthmatics, 133 (83%) had concomitant allergic rhinitis while 30 (19%) controls had allergic rhinitis(x2=137.81, p<0.001). Seventy eight (59%) cases with allergic rhinitis had uncontrolled asthma while 9 (33%) cases without allergic rhinitis had uncontrolled asthma (x2 = 8.8731, p=0.012).
Conclusion
The prevalence of allergic rhinitis among adult asthmatics was high and the co-existence of allergic rhinitis was significantly associated with poor asthmatic control.
PMCID: PMC4220476  PMID: 25453016
Allergic Rhinitis; Bronchial Asthma ; Poor asthma control; Lagos ; Nigeria
22.  SNPs in the FCER1A Gene Region Show No Association with Allergic Rhinitis in a Han Chinese Population 
PLoS ONE  2010;5(12):e15792.
Background
Immunoglobulin E (IgE) is a central player in the allergic response, and raised total IgE levels are considered as an indicator of atopy or potential development of atopy. A recent genome-wide scan in a German population-based cohort of adults identified the gene encoding the alpha chain of the high affinity receptor for IgE (FCER1A) as a susceptibility locus influencing total serum IgE levels. The aim of this study was to investigate whether the polymorphisms in the FCER1A gene are associated with allergic rhinitis (AR) in a Han Chinese population.
Methodology/Principal Findings
A population of 378 patients with AR and 288 healthy controls was studied. Precise phenotyping of patients was accomplished by means of a questionnaire and clinical examination. Blood was drawn for DNA extraction and total serum immunoglobulin E (IgE) measurement. A total of 16 single nucleotide polymorphisms (SNPs) in FCER1A were selected and individually genotyped. None of the SNPs in the FCER1A showed an association with AR. Similarly, the lack of association was also evident in subgroup analysis for the presence of different allergen sensitivities. None of the selected SNPs in FCER1A was associated with total IgE level.
Conclusions
Although FCER1A presents itself as a good candidate for contributing to total serum IgE, this study failed to find an association between SNPs in the FCER1A gene region and IgE level or AR susceptibility.
doi:10.1371/journal.pone.0015792
PMCID: PMC3013135  PMID: 21209833
23.  Toll-Like Receptor 4 Promoter Polymorphisms: Common TLR4 Variants May Protect against Severe Urinary Tract Infection 
PLoS ONE  2010;5(5):e10734.
Background
Polymorphisms affecting Toll-like receptor (TLR) structure appear to be rare, as would be expected due to their essential coordinator role in innate immunity. Here, we assess variation in TLR4 expression, rather than structure, as a mechanism to diversify innate immune responses.
Methodology/Principal Findings
We sequenced the TLR4 promoter (4,3 kb) in Swedish blood donors. Since TLR4 plays a vital role in susceptibility to urinary tract infection (UTI), promoter sequences were obtained from children with mild or severe disease. We performed a case-control study of pediatric patients with asymptomatic bacteriuria (ABU) or those prone to recurrent acute pyelonephritis (APN). Promoter activity of the single SNPs or multiple allelic changes corresponding to the genotype patterns (GPs) was tested. We then conducted a replication study in an independent cohort of adult patients with a history of childhood APN. Last, in vivo effects of the different GPs were examined after therapeutic intravesical inoculation of 19 patients with Escherichia coli 83972. We identified in total eight TLR4 promoter sequence variants in the Swedish control population, forming 19 haplotypes and 29 genotype patterns, some with effects on promoter activity. Compared to symptomatic patients and healthy controls, ABU patients had fewer genotype patterns, and their promoter sequence variants reduced TLR4 expression in response to infection. The ABU associated GPs also reduced innate immune responses in patients who were subjected to therapeutic urinary E. coli tract inoculation.
Conclusions
The results suggest that genetic variation in the TLR4 promoter may be an essential, largely overlooked mechanism to influence TLR4 expression and UTI susceptibility.
doi:10.1371/journal.pone.0010734
PMCID: PMC2873976  PMID: 20505764
24.  Allergic rhinitis: evidence for impact on asthma 
BMC Pulmonary Medicine  2006;6(Suppl 1):S4.
Background
This paper reviews the current evidence indicating that comorbid allergic rhinitis may have clinically relevant effects on asthma.
Discussion
Allergic rhinitis is very common in patients with asthma, with a reported prevalence of up to 100% in those with allergic asthma. While the temporal relation of allergic rhinitis and asthma diagnoses can be variable, the diagnosis of allergic rhinitis often precedes that of asthma. Rhinitis is an independent risk factor for the subsequent development of asthma in both atopic and nonatopic individuals. Controlled studies have provided conflicting results regarding the benefits for asthma symptoms of treating comorbid allergic rhinitis with intranasal corticosteroids. Effects of other treatments for comorbid allergic rhinitis, including antihistamines, allergen immunotherapy, systemic anti-IgE therapy, and antileukotriene agents, have been examined in a limited number of studies; anti-IgE therapy and antileukotriene agents such as the leukotriene receptor antagonists have benefits for treating both allergic rhinitis and asthma. Results of observational studies indicate that treating comorbid allergic rhinitis results in a lowered risk of asthma-related hospitalizations and emergency visits. Results of several retrospective database studies in the United States and in Europe indicate that, for patients with asthma, the presence of comorbid allergic rhinitis is associated with higher total annual medical costs, greater prescribing frequency of asthma-related medications, as well as increased likelihood of asthma-related hospital admissions and emergency visits. There is therefore evidence suggesting that comorbid allergic rhinitis is a marker for more difficult to control asthma and worsened asthma outcomes.
Conclusion
These findings highlight the potential for improving asthma outcomes by following a combined therapeutic approach to comorbid allergic rhinitis and asthma rather than targeting each condition separately.
doi:10.1186/1471-2466-6-S1-S4
PMCID: PMC1698497  PMID: 17140422
25.  Genome-Wide Analysis in German Shepherd Dogs Reveals Association of a Locus on CFA 27 with Atopic Dermatitis 
PLoS Genetics  2013;9(5):e1003475.
Humans and dogs are both affected by the allergic skin disease atopic dermatitis (AD), caused by an interaction between genetic and environmental factors. The German shepherd dog (GSD) is a high-risk breed for canine AD (CAD). In this study, we used a Swedish cohort of GSDs as a model for human AD. Serum IgA levels are known to be lower in GSDs compared to other breeds. We detected significantly lower IgA levels in the CAD cases compared to controls (p = 1.1×10−5) in our study population. We also detected a separation within the GSD cohort, where dogs could be grouped into two different subpopulations. Disease prevalence differed significantly between the subpopulations contributing to population stratification (λ = 1.3), which was successfully corrected for using a mixed model approach. A genome-wide association analysis of CAD was performed (ncases = 91, ncontrols = 88). IgA levels were included in the model, due to the high correlation between CAD and low IgA levels. In addition, we detected a correlation between IgA levels and the age at the time of sampling (corr = 0.42, p = 3.0×10−9), thus age was included in the model. A genome-wide significant association was detected on chromosome 27 (praw = 3.1×10−7, pgenome = 0.03). The total associated region was defined as a ∼1.5-Mb-long haplotype including eight genes. Through targeted re-sequencing and additional genotyping of a subset of identified SNPs, we defined 11 smaller haplotype blocks within the associated region. Two blocks showed the strongest association to CAD. The ∼209-kb region, defined by the two blocks, harbors only the PKP2 gene, encoding Plakophilin 2 expressed in the desmosomes and important for skin structure. Our results may yield further insight into the genetics behind both canine and human AD.
Author Summary
Humans and dogs are both affected by the allergic skin disease atopic dermatitis (AD), caused by an interaction between genetic and environmental factors. The German shepherd dog (GSD) is a high-risk breed for canine AD (CAD), also affected by low serum IgA levels. A Swedish cohort of GSDs was used as a model for human AD in this study. We performed a genome-wide association analysis where a region associated with CAD was identified. IgA levels were included in the model due to strong correlation with CAD. Also, age at sampling was included in the model due to correlation with IgA levels. The associated region, consisting of eight genes, was further fine-mapped with sequencing and additional genotyping. Haplotype association analysis from the fine-mapping data indicates association of the gene, plakophilin 2 (PKP2), known to be important for skin structure. We detected a division of the GSD breed into two subpopulations where one is more prone to develop CAD and to have lower serum IgA levels compared with the other. Here, we present methods for performing genome-wide association analyses when the study population is complex and when the trait is affected by additional parameters. The PKP2 gene found within the associated region became an interesting target for further study of its importance both in canine and human AD.
doi:10.1371/journal.pgen.1003475
PMCID: PMC3649999  PMID: 23671420

Results 1-25 (1387604)