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1.  Toll-Like Receptor 4 Gene (TLR4), but Not TLR2, Polymorphisms Modify the Risk of Tonsillar Disease Due to Streptococcus pyogenes and Haemophilus influenzae▿ †  
Tonsillar disease (recurrent tonsillitis and/or tonsillar hypertrophy) is one of the most common human disorders, with Streptococcus pyogenes (group A beta-hemolytic streptococcus [GAS]) and Haemophilus influenzae representing the most common pathogens. Until now, no study has investigated why some individuals are more susceptible to tonsillar infections caused by specific bacteria than others. The aim of this study was to uncover possible associations between common Toll-like receptor gene (TLR) polymorphisms and tonsillar disease. The TLR2-R753Q, TLR4-D299G, and TLR4-T399I polymorphisms were determined in a cohort of 327 patients subjected to tonsillectomy due to recurrent tonsillitis (n = 245) and tonsillar hypertrophy (n = 82) and 245 healthy bone marrow donors. Associations of the aforementioned polymorphisms with the isolated bacterial strains after tonsillectomy were also investigated. Interestingly, carriers of the TLR4 polymorphisms displayed an approximately 3-fold increased risk for GAS infections (for TLR4-D299G, odds ratio [OR] = 2.81, 95% confidence interval [CI] = 1.16 to 6.79, P = 0.038; for TLR4-T399I, OR = 3.01, 95% CI = 1.29 to 7.02, P = 0.023), and this association was more profound in patients with recurrent tonsillitis. On the contrary, the presence of the TLR4-T399I polymorphism was associated with a 2-fold decreased risk of Haemophilus influenzae carriage (OR = 0.38, 95% CI = 0.15 to 0.96, P = 0.038). In the end, no significant differences were observed, considering the genotype and allele frequencies of the above-mentioned polymorphisms, between patients and controls. Our findings indicate that, regarding tonsillar infections, TLR4 polymorphisms predispose individuals to GAS infection, while they are protective against Haemophilus influenzae infection. This result further elucidates the role that host immune genetic variations might play in the susceptibility to common infections and tonsillar disease.
doi:10.1128/CVI.00460-10
PMCID: PMC3067360  PMID: 21159925
2.  Association of TLR4-T399I Polymorphism with Chronic Obstructive Pulmonary Disease in Smokers 
Tobacco smoking has been considered the most important risk factor for chronic obstructive pulmonary disease (COPD) development. However, not all smokers develop COPD and other environmental and genetic susceptibility factors underlie disease pathogenesis. Recent studies have indicated that the impairment of TLR signaling might play a crucial role in the development of emphysema. For this purpose we investigated the prevalence and any possible associations of common TLR polymorphisms (TLR2-R753Q, TLR4-D299G, and TLR4-T399I) in a group of 240 heavy smokers (>20 pack years), without overt atherosclerosis disease, of whom 136 had developed COPD and 104 had not. The presence of TLR4-T399I polymorphism was associated with a 2.4-fold increased risk for COPD development (P = .044), but not with disease stage or frequency of exacerbations. Considering that infections contribute to COPD and emphysema pathogenesis, our findings possibly indicate that dysfunctional polymorphisms of innate immune genes can affect the development of COPD in smokers. Although this finding warrants further investigation, it highlights the importance of impaired innate immunity towards COPD development.
doi:10.1155/2009/260286
PMCID: PMC2822240  PMID: 20169003

Results 1-2 (2)