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1.  Unexpected Decrease with Age of Helicobacter pylori Seroprevalence among Swedish Blood Donors 
Journal of Clinical Microbiology  2003;41(9):4038-4042.
Blood donors are often used as proxies for the general population in studies of Helicobacter pylori epidemiology. Our aim was to test if the age-specific seroprevalence rates among blood donors match with the corresponding rates in a random population sample. This descriptive study was based on sera obtained from 3,502 blood donors representing all Swedish counties and cities. An age-stratified random population sample of 1,030 from Stockholm County served as comparison. Sera were analyzed by an in-house enzyme-linked immunosorbent assay for H. pylori immunoglobulin G antibodies. In the population sample, we found the expected increase with age in the seroprevalence of H. pylori infection. This was true also among young blood donors, while the prevalence-by-age curve showed a deflection downward among blood donors who are ≥ 50 years of age. In this age group, the probability of being seropositive was reduced by 73% (95% confidence interval [CI], 63 to 81%) relative to the population sample. Overall, the adjusted odds ratio for H. pylori seropositivity among blood donors was decreased by 43% (95% CI, 28 to 55%). Thus, it appears that blood donors who are H. pylori seropositive selectively disappear from the blood donor cohort. We speculate that H. pylori-seropositive blood donors may tolerate repeated bleedings less well than do noninfected individuals and/or that the general well-being among those who are infected may be somewhat impaired. Our unexpected observation indicates that blood donors may be less suitable as proxies for the general population in analytic studies of H. pylori infection and that the underlying cause needs further study.
PMCID: PMC193826  PMID: 12958222
2.  A European Multicenter Study of Immunoblotting in Serodiagnosis of Lyme Borreliosis 
Journal of Clinical Microbiology  2000;38(6):2097-2102.
A European multicenter study of immunoblotting for the serodiagnosis of Lyme borreliosis showed considerable variation in results obtained from tests with a panel of 227 serum samples. Six laboratories used different immunoblot methods, and a wide range of bands was detected in all the assays. Multivariable logistic regression analysis of data from individual laboratories was used to determine the most discriminatory bands for reliable detection of antibodies to Borrelia burgdorferi sensu lato. These bands were used to construct individual interpretation rules for the immunoblots used in the six laboratories. Further analysis identified a subset of eight bands, which were important in all the laboratories, although with variations in significance. Possible European rules, all closely related, were formulated from these bands, although there was no single rule that gave high levels of sensitivity and specificity for all the laboratories. This is a reflection of the wide range of methodologies used, especially the use of different species and strains of B. burgdorferi sensu lato. The panel of European rules provides a framework for immunoblot interpretation which may be adapted in relation to the characteristics of Lyme borreliosis in local areas.
PMCID: PMC86736  PMID: 10834959
3.  Seroepidemiology of Helicobacter pylori infection in a cohort of children monitored from 6 months to 11 years of age. 
Journal of Clinical Microbiology  1997;35(2):468-470.
A cohort of Swedish children was monitored from 6 months to 11 years of age. Immunoglobulin G (IgG) and IgA antibodies to Helicobacter pylori were measured in 1,857 serum samples, drawn at the ages of 6, 8, 10, 18 months and 2, 4, and 11 years. Of the 294 children, 40 (13.6%) were found to have been infected at some time. However, at 11 years of age, only 6 of 201 (3%) children were seropositive. The highest seroprevalence of positive results, 10%, was found at 2 years of age, and the highest incidence of 13.3% could be calculated for the period between 18 months and 2 years of age. There were no confirmed additional cases for children between 4 and 11 years of age. Infection with H. pylori thus occurs at an early age in a developed country (as well as in developing countries), and spontaneous clearance seems to be common.
PMCID: PMC229601  PMID: 9003617
4.  Enzyme-linked immunosorbent assay-based inhibition test for neutralizing antibodies to polioviruses as an alternative to the neutralization test in tissue culture. 
Journal of Clinical Microbiology  1995;33(11):2927-2930.
A poliovirus-binding inhibition test (PoBI test) was established for the quantitative determination of antibodies to polioviruses and was evaluated in comparison with the conventional neutralization test (NT). The first step of the PoBI test is an incubation of serial dilutions of test samples with inactivated poliovirus followed by the detection of free viral epitopes by a double antibody sandwich enzyme-linked immunosorbent assay with type-specific capture polyclonal antisera and type-specific neutralizing monoclonal indicator antibodies. A comparison of the PoBI test with the conventional NT for antibodies to all three types in 100 human serum samples showed excellent correlations (r > 0.95) over a wide range of antibody concentrations. The PoBI test, not necessitating live virus and tissue culture facilities, could be a simple alternative to the NT, and the principle of the assay is potentially applicable to other microbial systems.
PMCID: PMC228608  PMID: 8576347
5.  Dysmorphic features in offspring of alcoholic mothers. 
Archives of Disease in Childhood  1992;67(6):712-716.
The frequencies of 60 minor physical anomalies and various craniofacial measurements in 52 children with alcohol exposure of various durations in utero were determined and compared with 48 non-exposed healthy children at a mean age of 27 months. Compared with non-exposed children a significantly higher total minor physical anomaly count was observed in those children exposed prenatally to alcohol throughout pregnancy. Binge drinking was not associated with an increased minor physical anomaly count. During the first year of life facial features were judged according to subjective impression: 10 children had typical facial features of fetal alcohol syndrome (FAS) and 19 children were judged to have possible fetal alcohol effects on their face. Only six of them fulfilled the strict craniofacial criteria for diagnosis of FAS at the age of 27 months. Our results stress the importance of recognising also the subtle dysmorphic facial features associated with prenatal alcohol exposure: 22 of 29 (76%) of exposed children judged to have typical or possible features of FAS during the first year showed signs of central nervous system dysfunction at the age of 27 months.
PMCID: PMC1793822  PMID: 1378259
6.  Enzyme-linked immunosorbent assay to evaluate the immunogenicity of a polyvalent Klebsiella capsular polysaccharide vaccine in humans. 
Journal of Clinical Microbiology  1988;26(11):2257-2261.
A highly sensitive enzyme-linked immunosorbent assay was developed for Klebsiella capsular polysaccharide (CPS) and used to evaluate the immunoglobulin G (IgG) antibody response to a 24-valent CPS vaccine in seven adult volunteers. The median rise in titer to all vaccine antigens in samples from the volunteers was significant (twofold or greater). Significant IgG responses to 11 immunologically related serotypes not included in the vaccine were also noted. The mean cross-reacting IgG titer of 127.2 was only slightly lower than the mean titer of 175.7 to the serotypes in the vaccine (P less than 0.05). The mean 29.9-fold increase in titer to the serotypes in the vaccine was significantly higher than the mean 13.5-fold increase in titer to the additional antigens (P less than 0.001). The difference was partly because of the significantly lower (P less than 0.01) natural antibody titers in the preimmune sera to the serotypes in the vaccine, compared with those to serotypes not included in the vaccine. The selection of vaccine serotypes was based on the frequency of serotype isolation from cases of Klebsiella bacteremia. The above findings, which show low levels of natural antibody to these serotypes, support the hypothesis that anti-CPS antibody is protective against bacteremic disease.
PMCID: PMC266871  PMID: 3235653
7.  Evaluation of serologic assays for diagnosis of whooping cough. 
Journal of Clinical Microbiology  1988;26(9):1818-1823.
An enzyme-linked immunosorbent assay (ELISA) for the immunoglobulin G (IgG), IgM, and IgA response to Bordetella pertussis filamentous hemagglutinin (FHA) and pertussis toxin (PT) and a neutralization test (NT) in a microplate tissue culture assay for neutralizing antibodies to PT were evaluated in paired sera from 90 patients with culture-confirmed pertussis. Eighty patients were children (age, less than 15 years), and 6 of 80 children had been immunized with three doses of diphtheria-tetanus-pertussis vaccine as infants. A significant titer rise (greater than or equal to twofold), determined by ELISA, of IgG, IgM, and IgA to FHA was recorded in 75 (83%), 28 (31%), and 47 (52%) of the patients, respectively. A significant titer rise to PT in IgG was found in 83 (92%), IgM in 29 (32%), and IgA in 44 (49%) of the patients. A significant titer rise to FHA or PT in IgG was found in 88 (98%) of the patients, in combination with a significant rise in the titer of IgA to FHA. These data were obtained in a single serum dilution of 1:500. Titrations performed later showed that the titer rise to FHA in IgG was a mean of 6.5-fold, which was significantly lower than the mean 67.0-fold rise in IgG to PT (P less than 0.001). The mean titer of IgG to FHA in convalescent-phase serum was 270, which was also significantly lower than the mean PT titer of 2,943 (P less than 0.001). A significant rise (greater than or equal to fourfold) in PT titer by NT was found in 58 of 83 (70%) of the patients. The NT was significantly less sensitive than the ELISA for the determination of the IgG titer to PT ( P< 0.001). Results showed that a 100% (90 of 90) sensitivity in terms of titer rises was achieved in the serologic diagnosis of pertussis by ELISA in a single-point determination of the IgG and IgA responses to FHA and of the IgG response to PT.
PMCID: PMC266723  PMID: 2903178
8.  Specific immunoglobulin A to Bordetella pertussis antigens in mucosal secretion for rapid diagnosis of whooping cough. 
Journal of Clinical Microbiology  1988;26(5):869-874.
Specific immunoglobulin A (IgA) to Bordetella pertussis filamentous hemagglutinin (FHA) and pertussis toxin (PT) was determined in mucosal secretions by an enzyme-linked immunosorbent assay (ELISA). It took 3 to 4 h to complete the ELISA. The upper limits of normal values for age were determined in nasopharyngeal (NPH) secretions from 23 patients with viral infections and in 10 healthy adults working with pertussis patients or cultures. A significant IgA response to FHA was found in 38 of 54 (70%) and to PT in 28 of 54 (52%) NPH secretions from patients with pertussis confirmed by culture, serology, or both. The rate of positive responses to either antigen (44 of 54 [81%]) was significantly higher than that by culture alone (29 of 54 [54%]; P less than 0.01). The rate of positive responses increased from 65% in patients with symptoms for 1 week or less to 87 to 92% in patients with symptoms for 2 or more weeks. The specific IgA response to PT was found in 100% of NPH samples from 17 unimmunized children less than 3 years of age and in only 30% of adults and immunized children greater than 3 years of age. A response to FHA was found in 65 to 73% of the NPH secretions in all age groups. Saliva samples were found to contain specific IgA to FHA and PT in all age groups, but these were of diagnostic value in 50% (11 of 22) of the adult patients. The specificity of the ELISA was 100% (10 of 10 negatives) in NPH secretions from patients with pertussis-like cough who had negative cultures and serology. The results indicate that determination of specific IgA to PT and FHA in NPH aspirates represents a sensitive and rapid diagnostic method for the detection of pertussis.
PMCID: PMC266476  PMID: 2898484
9.  Serum antibodies to pneumolysin in patients with pneumonia. 
Journal of Clinical Microbiology  1988;26(1):96-100.
Serum antibodies to purified pneumolysin were determined by enzyme-linked immunosorbent assay (ELISA) in paired samples from 406 adult patients with community-acquired pneumonia and in samples from 184 healthy controls. A high sensitivity (83%) was obtained in patients with blood culture-confirmed pneumococcal pneumonia. In patients with a tentative pneumococcal diagnosis based on culture of samples from the sputum or the nasopharynx, 45% were positive by ELISA. The difference likely reflected the different relevance of cultural findings for the diagnosis of pneumococcal pneumonia. A significant rise in ELISA titer was found in 17% of the patients. When the diagnosis was also based on high titers, 25% were positive. Pneumococcal pneumonia diagnosed by the pneumolysin ELISA was significantly more common in the patients with a more severe disease and who required hospitalization (21 versus 5% for outpatients). Younger patients were more often positive for pneumococci as determined by high titers, while older patients showed titer rises. Mixed infections with other infectious agents were not uncommon. The finding of low titers in acute-phase samples from positive patients and in the youngest and oldest age groups of healthy controls were unexpected, indicating that further studies on the role of pneumolysin in pneumococcal disease are warranted.
PMCID: PMC266201  PMID: 3343319
10.  Prospective study of serum antibodies to Pseudomonas aeruginosa exoproteins in cystic fibrosis. 
Journal of Clinical Microbiology  1987;25(10):1868-1874.
Serum immunoglobulin G to four purified antigens from Pseudomonas aeruginosa, phospholipase C, alkaline protease, exotoxin A, and elastase, were determined in 62 patients with cystic fibrosis by enzyme-linked immunosorbent assay. The patients were followed for 12 to 24 months in a prospective study. Increased titers, i.e., titers more than 2 standard deviations above those of normal controls, were exclusively found in patients chronically colonized with P. aeruginosa and not in patients harboring only Staphylococcus aureus. The frequencies of elevated titers of antibody to the different antigens varied from 100% (phospholipase C) to 58% (alkaline protease and exotoxin A) to 15% (elastase) in the chronically colonized patients. Mean serum titer levels, expressed as multiples of the age-correlated upper normal limit (=1), were significantly higher to phospholipase C in patients with dual colonization with P. aeruginosa and S. aureus than in those colonized only with P. aeruginosa (P less than 0.001). Conversely, the other three antigens showed significantly higher serum antibody titer levels in patients harboring only P. aeruginosa (P less than 0.001). In five patients who became colonized with P. aeruginosa during the study period, serum antibodies to phospholipase C and exotoxin A increased first. Exceptions to the general pattern of antibody responses were found in three patients chronically colonized with Escherichia coli. They showed a delayed enhancement of anti-phospholipase C titers after the chronic P. aeruginosa colonization. Serum titers were not influenced by exacerbations of pulmonary infection or by antimicrobial therapy. The determination of titers of serum antibody to phospholipase C seems to be a valuable indicator of a chronic colonization with P. aeruginosa. The results further suggest that bacterial metabolism and interactions may influence the antibody response.
PMCID: PMC269358  PMID: 3117842
11.  Immunoglobulin class and immunoglobulin G subclass enzyme-linked immunosorbent assays compared with microneutralization assay for serodiagnosis of mumps infection and determination of immunity. 
Journal of Clinical Microbiology  1987;25(9):1653-1658.
Total immunoglobulin G (IgG) and IgG subclass reactivities with purified mumps glycoproteins (GP) and nucleoprotein (NP), measured in enzyme-linked immunosorbent assays (ELISAs), were compared with titers in a mumps microneutralization assay (NT). For determination of mumps immunity, the sensitivity of both ELISAs was 100% in comparison with the NT and the specificity was 90%. IgG1 was the dominant subclass against the two antigens found in seropositive healthy individuals. In samples from patients with clinical mumps infections and positive mumps IgM, titer rises of total IgG against NP were invariably seen before GP titer rises. Significant but often late titers rises in NT were found in all patients. Changes of IgG1 levels against both antigens followed the changes of total specific IgG. High levels of IgG3 against NP were diagnostic for mumps infection. In parainfluenza infections, titer rises in the mumps ELISAs and NT were found, but mumps IgM, NP IgG3, and the high ratio between the NP and GP titers found in early samples from patients with mumps infection were not observed.
PMCID: PMC269301  PMID: 3654938
12.  Prospective study of serum staphylococcal antibodies in cystic fibrosis. 
Archives of Disease in Childhood  1987;62(9):905-911.
Serum IgG antibodies to teichoic acid and alpha toxin from Staphylococcus aureus were measured in 62 patients with cystic fibrosis by enzyme linked immunosorbent assays. The patients were followed up for 12-24 months in a prospective study. Raised titres were found exclusively in patients chronically colonised with S aureus. Patients colonised with both S aureus and Pseudomonas aeruginosa had significantly higher titres against teichoic acid than those carrying S aureus alone. Titres were significantly higher when there were clinical signs of low grade infection in the patients chronically colonised with S aureus alone, and in those with both S aureus and P aeruginosa. Significant reduction in titres occurred after antimicrobial treatment given either orally or intravenously in patients with normal erythrocyte sedimentation rates and white cell counts. Measurement of staphylococcal antibody titres may be valuable in monitoring pulmonary infection and antimicrobial treatment in patients with cystic fibrosis.
PMCID: PMC1778603  PMID: 3118820
13.  Diagnosis of pneumococcal pneumonia by enzyme-linked immunosorbent assay of antibodies to pneumococcal hemolysin (pneumolysin). 
Journal of Clinical Microbiology  1987;25(2):226-229.
An enzyme-linked immunosorbent assay (ELISA) with a highly purified pneumolysin as the antigen was evaluated for serological diagnosis of pneumococcal pneumonia. One hundred four healthy controls were tested, and the specificity of the test was set to 95%. In samples from patients with bacteremic pneumococcal pneumonia, 82% (18 of 22) were positive, i.e., at least one serum sample had a titer above the upper normal limit or at least a twofold rise in antibody titers was noted. In nonbacteremic pneumococcal pneumonia, 45% (21 of 47) of samples were positive. All sera were negative for patients with pneumonia caused by Haemophilus influenzae, Legionella pneumophila, Chlamydia psittaci, and influenza A virus. However, in patients with a diagnosis of Mycoplasma pneumoniae infection, 8 of 25 (32%) samples were positive for antibodies to pneumolysin. All sera, including those from patients with mycoplasma infection, were negative to a protein control antigen by ELISA. Serum immunoglobulin G response to pneumolysin as measured by ELISA might thus be an aid in the laboratory diagnosis of pneumococcal pneumonia. This assay may also help to further elucidate the occurrence of dual infections with pneumococci.
PMCID: PMC265872  PMID: 3818919
14.  Diagnosis of spirochetal meningitis by enzyme-linked immunosorbent assay and indirect immunofluorescence assay in serum and cerebrospinal fluid. 
Journal of Clinical Microbiology  1985;21(5):819-825.
The antibody response against a spirochetal strain isolated from Swedish Ixodes ricinus ticks was determined by enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence assay of cerebrospinal fluid (CSF) and serum specimens from 45 patients with chronic meningitis. Samples of CSF, serum, or both from patients with various infections of the central nervous system, multiple sclerosis, syphilis, or infectious mononucleosis and from healthy individuals served as control samples. Probable spirochetal etiology could be demonstrated for 41 of 45 (91%) patients with clinical symptoms of chronic meningitis. Approximately 25% of the patients had significantly elevated titers of antibody to the spirochete in CSF but not in serum. The highest diagnostic sensitivity, 91%, was demonstrated by measurement of CSF antibodies and calculation of a spirochetal CSF titer index, which is the ratio of (ELISA titer in CSF/ELISA titer in serum) to (albumin in CSF/albumin in serum) and which also considers the degree of blood-CSF barrier damage. The highest specificity, 98%, was obtained by calculation of a CSF titer index. Patients with short duration of disease were especially prone to be antibody negative in serum but positive in CSF. Significant rise in serum antibody titers was seldom demonstrated in patients treated with antibiotics. It is concluded that measurement of CSF antibodies, especially by ELISA, is a highly sensitive and specific method for the immunological diagnosis of spirochetal meningitis.
PMCID: PMC271789  PMID: 3889049
15.  Serum folate concentrations during pregnancy in women with epilepsy: relation to antiepileptic drug concentrations, number of seizures, and fetal outcome. 
Serum folate concentrations, blood counts, and antiepileptic drug concentrations were measured during 133 pregnancies of 125 women with epilepsy. There was an inverse correlation between serum folate concentrations and concentrations of phenytoin and phenobarbitone. The number of epileptic seizures during pregnancy showed no association with serum folate concentrations. No cases of maternal tissue folate deficiency or fetal damage attributable to low maternal serum folate were observed. Maternal serum folate concentrations for infants with structural birth defects, "fetal hydantoin syndrome," or perinatal death were similar to those for healthy babies. A low dose (100 to 1000 micrograms daily) of folate supplement appeared sufficient for pregnant women with epilepsy despite the antifolic action of antiepileptic medication. Monitoring folate concentrations in pregnant women with high serum concentrations of phenytoin or phenobarbitone is recommended.
PMCID: PMC1549018  PMID: 6411231
16.  Enzyme-linked immunosorbent assay for antibodies against teichoic acid in patients with staphylococcal infections. 
Journal of Clinical Microbiology  1983;17(4):640-646.
A highly purified teichoic acid preparation was used in an enzyme-linked immunosorbent assay to measure the specific immunoglobulin G (IgG) and IgM response in staphylococcal disease. Antibody determination in a normal population, showing a difference of up to 20-fold in the mean IgG titers between the youngest children and adults, was used to establish age-correlated upper normal values. IgM antibodies were found to be of little diagnostic value since their response was often low or absent. Increased IgG titers were found in 24 of 27 (89%) patients with endocarditis, in 11 of 14 (79%) with complicated septicemia, and in 10 of 20 (50%) with uncomplicated septicemia with serum samples drawn between days 7 and 30 of disease. With paired samples, the numbers of patients with increased IgG titers were 17 of 17, 3 of 4, and 6 of 7, respectively, in the same patient groups. Increased IgG titers were less often demonstrated in patients with chronic osteomyelitis (7 of 22). The enzyme-linked immunosorbent assay for teichoic acid antibodies was found to be a sensitive and specific method for diagnosing staphylococcal endocarditis and septicemia. For optimal results, both the substantial age-correlated variation in normal titers and the importance of adequately spaced samples should be considered.
PMCID: PMC272709  PMID: 6853691
18.  Perinatal cytomegalovirus infection in man. 
Archives of Disease in Childhood  1977;52(5):354-359.
In a prospective study of 148 children from urbanized southern Finland 3 were found to be congenitally and 48 perinatally infected with cytomegalovirus (CMV), while 6 developed "late" infection during the first year of life. During pregnancy and the first year after delivery 23 of the mothers had no CMV antibodies; none of the children of these seronegative mothers developed any type of CMV infection. Fresh blood exchange transfusions did not increase the risk of CMV infection. The data support the hypothesis that the mother is the source of perinatal CMV infection. Children with a low birthweight not due to prematurity, and first children seem to run a greater risk of acquiring perinatal CMV infection. If the child is breast fed up to the age of 2 months the risk seems to be increased. Perinatal CMV infection gave rise to no symptoms or signs and had no effect on growth or on motor and psychosocial development during the first year of life.
PMCID: PMC1544578  PMID: 194539

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