Association between Chlamydia pneumoniae antibodies and wheezing in young children and the influence of sex.

BACKGROUND: The proposed association between Chlamydia pneumoniae (Cpn) infection and wheezing needs further clarification. METHODS: Serum samples obtained from 1581 children aged 4 years in a population based cohort were tested for antibodies to Cpn and IgE antibodies to common allergens. Data on environmental factors and disease were collected prospectively from birth. RESULTS: The occurrence of IgG antibodies to Cpn at 4 years of age was associated with reported wheezing at different ages; however, these findings were most often not significant. In girls, the occurrence of anti-Cpn IgG was associated with wheezing at the ages of 1, 2, and 4 years (odds ratios (ORs) 3.41 (95% confidence interval (CI) 1.46 to 7.96), 2.13 (95% CI 1.02 to 4.44), and 2.01 (95% CI 1.14 to 3.54), respectively), and even higher ORs were observed for each age category when only high level antibody responses to Cpn were analysed. At the time of blood sampling the association between anti-Cpn IgG and wheezing was restricted to girls without atopic sensitisation (OR 2.39 (95% CI 1.25 to 4.57). No associations with wheezing were detected in boys, in whom IgE sensitisation was inversely associated with the presence of anti-Cpn IgG (OR 0.49 (95% CI 0.26 to 0.90)). CONCLUSIONS: This study suggests an association between evidence of earlier Cpn infection and a history of wheezing in young girls. Infection with Cpn may be an important risk factor for wheezing and possibly for non-atopic asthma, predominantly in girls.

Antibodies to Chlamydia pneumoniae in young Swedish orienteers.

During 1992-93 sera from 1790 Swedish elite orienteers were tested for antibodies to Chlamydia pneumoniae. The reason for this was that a cluster of 16 cases of sudden unexpected cardiac death had occurred among Swedish orienteers and DNA from C. pneumoniae had been found in the myocarditic heart and in the lung in 1 of 2 deceased athletes in whom testing was feasible; in addition, C. pneumoniae IgG was found in all 5 cases where serum was available. Among the orienteers, the prevalence rates of IgG antibodies in males and females were 54% (n = 1194) and 50% (n = 596), respectively. The corresponding figures for 319 male and female blood donors were 60% (n = 169) and 53% (n = 150), respectively. These differences are not statistically significant. Male orienteers had a lower prevalence of IgA antibodies than male blood donors (19% and 26%, respectively; p < 0.05), while no such difference was found in females (16% and 18%). The prevalence of IgM antibodies was < 1% in all groups. Neither the performance level of the orienteers nor the place of residence affected the antibody prevalence. In conclusion, Swedish orienteers do not show a higher prevalence of antibodies to C. pneumoniae than healthy blood donors.

Demonstration of Chlamydia pneumoniae in the adenoid from children with and without secretory otitis media using immunohistochemistry and PCR.

Chlamydia pneumoniae has been found in patients with middle ear inflammation. The adenoid, which has a central role in the development of secretory otitis media (SOM), may act as a reservoir for bacteria causing ear infection. Adenoid tissue was examined for the presence of C. pneumoniae. Twenty children undergoing adenoidectomy because of hyperplastic adenoids, 10 with SOM and 10 without SOM, were examined with nasopharyngeal swabs for routine bacteriological culture, serology for C. pneumoniae and throat swabs for C. pneumoniae PCR. The removed tissues were analyzed for C. pneumoniae using immunohistochemical (IHC) analysis and PCR. In the group of children with SOM samples were also taken from the middle ear fluid for routine bacteriological culture and PCR for C. pneumoniae. C. pneumoniae was found in the adenoid by PCR in 3 cases from each group and from all 20 children by IHC. Four children in each group had increased levels of specific antibodies to C. pneumoniae. Two children with SOM had high antibody titers and a positive PCR from a throat swab. Two children were PCR-positive for C. pneumoniae in fluid from the middle ear. The significance of these findings is not yet clear.

Chlamydia pneumoniae in children undergoing adenoidectomy.

UNLABELLED: Chlamydia pneumoniae is a common respiratory pathogen which is often found in paediatric populations. Little is known about the true colonization rate and the localization of the bacteria in the respiratory tract. In this study, immunohistochemistry was used to examine adenoids from 69 children undergoing elective adenoidectomy. Throat swabs for polymerase chain reaction (PCR) and blood samples for serology were also obtained. Chlamydia pneumoniae was demonstrated in the adenoids by immunohistochemistry in 68 of the children. Five children (7%) had a positive C. pneumoniae PCR test from throat swabs and 14 children (20%) had detectable antibodies by the microimmunofluorescence technique. CONCLUSION: The results suggest that C. pneumoniae is a common finding in the adenoids of children undergoing adenoidectomy. Whether or not C. pneumoniae plays a pathogenic role in this patient population could not be determined from the data obtained in this investigation.

An association between chronic infection with Chlamydia pneumoniae and lung cancer. A prospective 2-year study.

This study assesses a possible relationship between chronic Chlamydia pneumoniae (Cpn) infection and lung cancer (LC). A total of 210 consecutive patients (136 M, 74 F) were diagnosed with LC during a 2-year period. Blood was obtained from 128 M and 70 F patients for Cpn serology. Repeat blood specimens were taken after 3 months. Throat specimens for Cpn DNA analysis by PCR were taken from 110/136 M and 63/74 F Seventy-four cytobrush specimens were taken and also analyzed by polymerase chain reaction (PCR). Fifty (29 M, 21 F) bronchial biopsies and 8 (6 M, 2 F) tumors resected at surgery were analyzed for Cpn by immunohistochemistry (IHC). Males had significantly more often squamous-cell carcinoma (SCC) than females. Other types of LC were more equally distributed between males and females. The difference between males and females regarding smoking history was significant, and male LC patients had significantly higher levels of IgG and/or IgA antibodies than female LC patients. Male and female LC patients had significantly higher prevalences of high antibody titers than controls. A high prevalence of unusually high titers of specific Cpn antibodies was found in male LC patients. This could indicate that LC may be induced by chronic Cpn infection, since stable high titers of Cpn antibodies, especially IgA, are a hallmark of chronic infections.

A new DIG-PCR-EIA method for the detection of Chlamydia pneumoniae DNA in clinical samples.

Chlamydia pneumoniae, a common respiratory pathogen, may also play a role in the pathogenesis of other chronic conditions. For accurate detection of infected persons and verification of results obtained by other PCR methods, a DIG-PCR-EIA method was evaluated. In the DIG-PCR-EIA, a 437 bp DNA sequence was amplified and hybridized with a newly synthesized 229 bp biotin-labeled probe. The end product was detected by an enzyme immunoassay. The sensitivity of DIG-PCR-EIA was compared with Southern blot hybridization and one-step HR/HL PCR, which was the routine method used. DNA was detected to the level of 20 elementary bodies of DIG-EIA-PCR compared to less than 2 by Southern blot, and 200 by HR/HL PCR. Thus a 100-fold increase in sensitivity could be expected by DIG-EIA-PCR compared to the routine method. Throat swabs and adenoid tissue from 22 children with otitis and middle ear secretions from 29 children, as well as throat swabs from 179 blood donors, were analyzed with DIG-EIA-PCR, HL/HR PCR and nested touchdown PCR. 32% of the ear secretions were positive by DIG-EIA-PCR as compared to 5% by the other two methods. Three adenoid tissue samples were positive by all methods applied. Among the child and adult throat samples, 18% and 32%, respectively, were positive by DIG-EIA-PCR and 5% and 10% by HR/HLPCR. The results indicate the suitability of DIG-PCR-EIA for verification of results of HR/HL PCR. DIG-PCR-EIA has a potential for increased sensitivity and adaptation for automation. It should be further evaluated using various types of tissue specimens and DNA extraction methods.

Serological analysis of specific IgA to Chlamydia pneumoniae: increased sensitivity of IgA antibody detection using prolonged incubation and high antigen concentration.

The microimmunofluorescence technique (MIF) is recognized as the only test hitherto allowing discrimination between different Chlamydia species and is considered to be the reference method for serology. This method was developed for the detection of IgG and IgM antibodies only. We investigated the effects of some test parameters on the ability of MIF to detect Chlamydia pneumoniae IgA. These parameters were the time needed for binding of serum IgA to C. pneumoniae antigen and the effect of antigen concentration on the outcome of IgA antibody testing. It was found that the most sensitive MIF tests for the detection of serum IgA antibodies were those in which an overnight incubation of sera with antigen slides containing high concentrations of chlamydial elementary bodies was employed. The number of patients with chronic infections found to have elevated IgA titers was increased by 25% using longer incubation times for the antibody-antigen reaction. Thirty-two sera from patients with coronary artery disease and confirmed chronic C. pneumoniae infection were used to compare antigen slides with low and high concentrations of elementary bodies with respect to IgA levels; 31/32 patients were found to have specific IgA antibodies to C. pneumoniae using the high antigen concentration, as opposed to only 22/32 patients using the low antigen concentration.

Chlamydia pneumoniae seropositivity is associated with carotid artery intima-media thickness.

BACKGROUND AND PURPOSE: Infection may both augment the atherosclerotic process and contribute to later manifestations of overt clinical disease. Chlamydia pneumoniae elementary bodies have been detected in atherosclerotic lesions. The aim of the present study was to investigate whether elevated titers of antibodies and circulating immune complexes to C pneumoniae were associated with ultrasound findings indicating presence of atherosclerosis in the carotid artery. METHODS: Serum titers of antibodies to C pneumoniae (IgM, IgA, IgG, and circulating immune complex) were related to intima-media thickness (IMT) and plaque status measured by B-mode ultrasound in the carotid artery in 113 men with treated hypertension and at least 1 of the following risk factors: hypercholesterolemia, smoking, or diabetes. RESULTS: Any of the titers was elevated in 56 (50%) men, and common carotid artery IMT was thicker in this group compared with the 57 men without any elevated titers (1.00 versus 0.92 mm, P<0.05). There were no accompanying differences in blood pressure, lipid levels, blood glucose, or smoking. Elevation of separate antibody types and circulation immune complex were also associated with increased IMT. In the latter group, systolic blood pressure was higher among seropositive patients compared with those who had no circulating immune complex. Seropositivity was not related to plaque status. CONCLUSIONS: Seropositivity for C pneumoniae was associated with an increased intima-media thickness in the common carotid artery but not plaque status in hypertensive men at high risk for cardiovascular disease.

Chlamydia pneumoniae serology: interlaboratory variation in microimmunofluorescence assay results.

The lack of standardization in chlamydia serology has made interpretation of published data difficult. This study was initiated to determine the extent of interlaboratory variation of microimmunofluorescence (MIF) test results for the serodiagnosis of Chlamydia pneumoniae infections. Identical panels of 22 sera were sent to 14 laboratories in eight countries for the determination of IgG and IgM antibodies by MIF. Although there was extensive variation in the numeric titer values, the overall percentage agreement with the reference standard titers from the University of Washington was 80%. For results by serodiagnostic category, the best agreement was for four-fold rise in IgG titers, while the lowest agreement was for negative or low IgG titers. Agreement for IgM titers was 50%-95%. Four laboratories failed to discern false-positive IgM titers possibly because of the presence of rheumatoid factor. Further studies are underway to determine the source of interlaboratory variation for the MIF test.

Detection of viable Chlamydia pneumoniae in abdominal aortic aneurysms.

OBJECTIVES: to investigate the presence of Chlamydia pneumoniae in the wall of abdominal aortic aneurysms (AAAs) and in the aortas of patients without a history of cardiovascular disease. DESIGN: case-control study. MATERIALS: twenty-six consecutive patients operated for AAA were compared to 17 controls. METHODS: aorta was obtained at surgery or autopsy (controls) and prepared for immunohistochemical (IHC) analysis and culture for C. pneumoniae. Throat swabs from 14/26 patients were analysed by PCR for C. pneumoniae. Blood was obtained from 24/26 patients and from 178 70-year-old males. RESULTS: C. pneumoniae was detected in the aortic aneurysms of 20/26 patients by IHC. C. pneumoniae was cultured from 10 of the 20 IHC-positive patients. Only 1/17 controls was positive for C. pneumoniae by IHC (p=0.0001). PCR was positive for C. pneumoniae in 5/14 patients. Serological analysis by microimmunofluoresence (MIF) showed significantly more high titres of the specific antibodies to C. pneumoniae in patients than in age-matched male controls. CONCLUSIONS: we conclude that C. pneumoniae is often present in AAAs in a viable form and that C. pneumoniae is linked to the pathogenesis of AAA.

Seroprevalence of antibodies to Chlamydia pneumoniae in elderly people: a two-decade longitudinal and cohort difference study.

A gerontological population of 178 men and 249 women was investigated regarding the prevalence of antibodies specific to Chlamydia pneumoniae. A longitudinal substudy was carried out on 22 men and 44 women, age range 70-90 y. Antibodies specific to C. pneumoniae were common. Men had higher prevalences and higher antibody levels than women. More than half of the individuals in the longitudinal study had significant IgG and/or IgA titre changes (> or = 4-fold) between the ages of 70 and 90 y, suggesting that C. pneumoniae infections are common in the elderly population. This is of importance for the treatment of respiratory infections in elderly people.

Comparison of a new commercial EIA kit and the microimmunofluorescence technique for the determination of IgG and IgA antibodies to Chlamydia pneumoniae.

Chlamydia pneumoniae infection is often diagnosed by analyzing specific antibodies to C. pneumoniae in sera. The method which has been used as the reference method, or "gold standard", the microimmunofluorescence test (MIF), demands a high level of experience for proper interpretation. A number of commercial enzyme immunoassay (EIA) tests have been introduced to the market in the past few years. These provide objective reading of titers, but are genus specific and not species specific. The latest EIA introduced, LabSystems EIA for C. pneumoniae, was investigated using several groups of clinically relevant patient sera in a comparison with MIF. It was found that the LabSystems EIA did not discriminate between antibodies to C. trachomatis and C. pneumoniae when tested with sera containing high titers of C. trachomatis antibodies. The correlation between C. pneumoniae EIA and MIF IgG and IgA titers was, however, good in the patient groups not having a high background of C. trachomatis antibodies: hypertensives, n= 199 and patients with chronic C. pneumoniae infections and ischaemic heart disease, n=33. In conclusion, the LabSystems EIA is a method which can be useful for screening populations with low prevalences of C. trachomatis/C. psittaci infection for antibodies to C. pneumoniae. It cannot replace the MIF test due to the lack of discrimination between different chlamydial antibody types.

Chlamydia pneumoniae may be associated with lung cancer. Preliminary report on a seroepidemiological study.

Material from 117 consecutive patients with lung cancer was investigated with respect to serological markers for chronic Chlamydia pneumoniae infection. Specific C. pneumoniae IgA antibodies were found significantly more often in patients with lung cancer than in control groups with coronary heart disease and in healthy controls, even after adjustment for smoking. The results suggest that chronic C. pneumoniae infection is common in patients with lung cancer.

Demonstration of Chlamydia pneumoniae in tissue by immunohistochemistry.

Chronic Chlamydia pneumoniae infection may be difficult to diagnose using routine methods such as culture, antigen detection, serology and polymerase chain reaction (PCR). We describe a method for the immunohistochemical staining of tissue biopsies using a C. pneumoniae-specific monoclonal antibody and a streptavidin/biotin technique. This method provides specific identification of the organism and reveals its actual location in tissues which may or may not be inflamed. Host cells containing C. pneumoniae antigen were easily identified by their bright red color in tissue sections counterstained with hematoxylin.

Bordetella pertussis, Bordetella parapertussis, Mycoplasma pneumoniae, Chlamydia pneumoniae and persistent cough in children.

Material collected during a prospective pertussis vaccine trial in 1992-95 was examined for Bordetella pertussis (culture and serology), Bordetella parapertussis (culture), Mycoplasma pneumoniae and Chlamydia pneumoniae (PCR). From 64% (99/155) of episodes with cough for less than 100 d, 115 aetiological agents were identified in one southern and one northern subset of DT-recipients. The most common single agent was B. pertussis, representing 56%(64/115), with a median cough period of 51 d, followed by M. pneumoniae 26%(30/115), 23 d, C. pneumoniae 17% (19/115), 26 d, and B. parapertussis 2% (2/115). For co-infections, the median duration of cough was about 60 d. Spasmodic cough for 21 d or more (clinical WHO criteria for pertussis) was present in 82% (41/50) of infections with B. pertussis as single agent, 38% (17/45) with B. parapertussis, 38% (5/13) with C. pneumoniae, 26% (5/19) with M. pneumoniae and 30%(17/56) in cases where no aetiology was found. In children with cough for more than 100 d (n = 78) using all vaccine arms, B. pertussis was responsible in 83% (65/78), in 21%(16/78) together with other agents. Acellular vaccines were more efficient against serious disease than whole cell vaccine. Antibiotic treatment was more common at the southern (34%) study site than at the northern one (12%). The findings indicate that diagnosis should rely on laboratory confirmation, both for rational treatment of an individual case and for monitoring outbreaks.

Evidence of 2 waves of Chlamydia pneumoniae infection in Gävle, Sweden, 1990-96.

Chlamydia pneumoniae is a common respiratory tract pathogen. The majority of adults have serological evidence of previous exposure. Most infections are probably asymptomatic or subclinical. Recent studies have implicated C. pneumoniae as a risk factor for the development of cardiovascular disease. It was therefore of interest to study new blood donors collected between the years of 1990 and 1996 for the purpose of delineating the epidemiological situation in the Gävle area of Sweden. Sera from all first time blood donors over a 7 y period were tested for IgG, IgA and IgM antibodies to C. pneumoniae with a microimmunofluorescence test (MIF). Donors were subjectively healthy individuals between 18 and 65 y of age, (913 M, 752 F). Exposure to C. pneumoniae, expressed in terms of specific IgG antibodies in titres of > 1/32, increased for men in 1990-92 and for women in 1990-93. There was a decrease the following year for both sexes, followed by another increase in 1994-95. IgG antibodies in titres of > or = 512, and IgA antibodies in titres of > or = 1/64, were increased in 1990-91 for men and in 1994-96 for both sexes. The prevalence of specific antibodies increased throughout the 7 y period except for women 1995-96. Men had higher antibody titres than women throughout the entire study period. The results indicate that two waves of largely subclinical infection occurred in our area over the years 1990-96.

Chlamydia pneumoniae but not cytomegalovirus antibodies are associated with future risk of stroke and cardiovascular disease: a prospective study in middle-aged to elderly men with treated hypertension.

BACKGROUND AND PURPOSE: Several cross-sectional and prospective studies have indicated that high titers of antibodies to Chlamydia pneumoniae and cytomegalovirus (CMV) are associated with coronary heart disease. The aim of the present study was to examine whether elevated titers of antibodies to these pathogens are predictive of not only coronary but also cerebrovascular disease. METHODS: Serum titers of antibodies to C pneumoniae (IgM, IgG, IgA, IgG immune complex) and CMV (IgG) were determined at baseline (n=130) and after 3.5 years (n=111) in a total sample of 152 men. All individuals had treated hypertension and at least 1 additional risk factor for cardiovascular disease (hypercholesterolemia, smoking, or diabetes mellitus) and constituted 93% of a randomly selected subgroup (n=164) of patients participating in a multiple risk factor intervention study. RESULTS: Elevations of any or both of the IgA or IgG titers to C pneumoniae at entry or after 3.5 years were found in 84 cases (55%). Of those with high titers at entry, 97% remained high at the 3.5 year reexamination. After 6.5 years of follow-up, high titers to C pneumoniae at entry were associated with an increased risk for future stroke (relative risk [RR], 8.58; P=0.043; 95% CI, 1.07 to 68.82) and for any cardiovascular event (RR, 2.69; P=0.042; 95% CI, 1.04 to 6.97). A high serum titer of antibodies to CMV was found in 125 cases (85%), and this was not associated with an increased risk of future cardiovascular events. CONCLUSIONS: Seropositivity for C pneumoniae, but not for CMV, was associated with an increased risk for future cardiovascular disease and, in particular, stroke.

Association of Chlamydia pneumoniae with otitis media in children.

Chlamydia pneumoniae is a common cause of acute and persistent respiratory tract infections. The prevalence of C. pneumoniae was studied using the polymerase chain reaction (PCR) in throat swabs from 85 consecutive children with respiratory tract infections and 86 healthy children. In retrospect, it became evident that this study was conducted in the midst of a local C. pneumoniae epidemic. 38 (45%) of the sick children and 5 (5.7%) of the healthy children were positive for C. pneumoniae by PCR. 26 of the sick children (mean age 6.4 years) were found to have otitis media either at the time of examination or shortly thereafter. Six of 9 children with acute otitis media were PCR positive for C. pneumoniae and 7 of the 9 had specific antibody responses indicating active infection. 10 of 17 children diagnosed as having otitis media with effusion were found to be positive for C. pneumoniae by PCR. Seven children had or developed persistent otitis media with effusion. Chlamydia pneumoniae was demonstrated by PCR from the middle ear fluid in 1 of the children. The results obtained from this study indicate that C. pneumoniae may be involved in the aetiology of otitis media.

The prevalence of chronic Chlamydia pneumoniae infection as detected by polymerase chain reaction in pharyngeal samples from patients with ischaemic heart disease.

AIMS: Cross-sectional serological studies have suggested an association between ischaemic heart disease and infections from Chlamydia pneumoniae and Helicobacter pylori. We therefore sought to find out if patients with ischaemic heart disease had an increased prevalence of C. pneumoniae in the pharynx. As the course of the C. pneumoniae infection remains unclear, both acute and follow-up samples were taken and compared with antibody levels. METHODS AND RESULTS: We studied 282 patients with ischaemic heart disease. One hundred and two subjects without history or symptoms of ischaemic heart disease served as controls. Pharyngeal specimens for polymerase chain reaction detection of C. pneumoniae, and blood samples for C. pneumoniae and H. pylori antibody detection, were collected. In patients with positive polymerase chain reaction or C. pneumoniae IgA titres > or = 32, indicating current infection, convalescent samples were taken at least 6 weeks later. An immunofluorescent antigen detection test was used to confirm the presence of C. pneumoniae elementary bodies in specimens found to be polymerase chain reaction positive. The prevalence of positive polymerase chain reaction tests was 36% among patients and 22% among controls (P<0.05). Forty-seven percent of patients with positive polymerase chain reaction remained positive in the convalescent test. Elevated C. pneumoniae IgG titres > or = 512 were found in 39% of patients and 26% of the controls (P<0.05). IgA titres > or = 32 were found in 46% of the patients and 44% of the controls (ns). Antibody titres remained largely unchanged at convalescent testing. Two patients and none of the controls had IgM titres > 16. There was no link between positive H. pylori serology and positive C. pneumoniae polymerase chain reaction tests. CONCLUSIONS: The high prevalence and persistence of positive pharyngeal C. pneumoniae polymerase chain reaction and elevated antibody titres in patients with ischaemic heart disease indicate a chronic infection. The pharyngeal presence of C. pneumoniae might contribute to a low grade inflammatory activation or be a source for further spread of the bacteria to atherosclerotic vessels.