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.

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.

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.

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.

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.

Chlamydia pneumoniae in children attending day-care centers in Gävle, Sweden.

BACKGROUND: The epidemiology of Chlamydia pneumoniae in healthy children has not been established. METHODS: This investigation used polymerase chain reaction (PCR) to study the epidemiology of C. pneumoniae in presumed healthy children. Four hundred fifty-three children and 142 personnel at 9 day-care centers were investigated for carriage of C. pneumoniae. Children found to be positive by PCR were also investigated with serology, and their family members were tested with PCR. RESULTS: One hundred and three (22.7%) children had a positive PCR, as had 33 (23.2%) personnel. Fourteen percent of the children younger than 3 years had a positive PCR test compared with 26% of the older children (P < 0.01). No correlation was found between respiratory symptoms and carriage of C. pneumoniae. Mothers were more often positive in the PCR test as compared with fathers (relative risk, 2.59; 95% confidence interval, 1.16 to 5.78). Antibodies to C. pneumoniae were found in 27 of 97 PCR-positive children; only 2 of whom were younger than 3 years. CONCLUSION: C. pneumoniae can be commonly found in young children attending day care. Most of the youngest children did not develop specific antibodies. Children may have subclinical infections with C. pneumoniae. The organism seems to be easily communicable among individuals living in close proximity.

Increased fibrinogen levels are associated with persistent Chlamydia pneumoniae infection in unstable coronary artery disease.

AIM: Increased levels of acute phase proteins, e.g., fibrinogen, are related to a poor outcome in unstable coronary artery disease, but the cause of inflammation is unknown. We therefore investigated the prevalence of persistent Chlamydia pneumoniae infection, and its relationship to inflammation in this condition. METHODS AND RESULTS: In 256 patients participating in the FRISC trial, evaluating the effects of dalteparin (a low molecular weight heparin) in unstable angina or non-Q wave myocardial infarction, Chlamydia pneumoniae IgA antibody titres and levels of fibrinogen, C-reactive protein and troponin T were determined at inclusion. Increased C. pneumoniae IgA antibody titres were significantly more common in the patients (36%) than in a reference population of similar age (19%); P < 0.001. Raised titres were associated with male gender, increasing age, smoking, and elevated concentrations of fibrinogen, C-reactive protein and troponin T. The association between persistent C. pneumoniae infection and increased fibrinogen levels was independent of other risk factors evaluated in multivariate analysis (P = 0.009). CONCLUSION: Persistent C. pneumoniae infection is common in unstable coronary artery disease. The independent association between increased C. pneumoniae IgA antibody titres and fibrinogen levels indicates that chronic infection could be of importance for disease activity.

Chlamydia pneumoniae in children with acute respiratory tract infections.

Children seeking medical attention for acute respiratory tract infections were investigated for evidence of Chlamydia pneumoniae infection. Blood samples were obtained from 367 children. Nasopharyngeal or throat swabs for PCR analysis (polymerase chain reaction) were taken from 360 children. Serology was found to be useful for diagnosis of infection only in children aged > 5 y. Using PCR, a prevalence of 8 and 10% of C. pneumoniae was found in male and female children aged < 2 y; 17 and 19%, respectively, in the age group 2-4 y and 32 and 21%, respectively, in the age group 5-16 y. We conclude that Chlamydia pneumoniae is a common finding in young children with respiratory tract infections. Younger children were more often found to have a moderate disease, but may have been ill for a long period.

Helicobacter pylori serology in elderly people: a 21-year cohort comparison in 70-year-olds and a 20-year longitudinal population study in 70-90-year-olds.

AIMS: (i) to compare Helicobacter pylori serology in two 70-year-old cohorts in Gothenburg, Sweden, born 21 years apart, (ii) to study H. pylori serology in a 70-year-old cohort over 20 years. POPULATION AND METHOD: H. pylori serology at the age of 70 was investigated in 98 men and 132 women born in 1901/02 and in 77 men and 113 women born in 1922. In 21 men and 40 women Helicobacter serology was monitored longitudinally with examinations at 70, 81, and 90 years of age. The analyses were performed on frozen samples by use of an in-house enzyme immunoassay with a sensitivity of 0.99, specificity of 1.00 and positive and negative predictive values of 0.96 and 1.00, respectively. Absorbance values <0.500 were interpreted as negative; values of > or = 0.700 were interpreted as positive, and values in between as inconclusive. RESULTS: The 70-year-old cohort, born in 1922, showed a significantly lower proportion of subjects with positive H. pylori serology in both men (57.1% vs 80.6%) and women (48.7% vs 75.8%) compared with 70-year-olds born in 1901/02. There were no significant sex differences in either cohort. No longitudinal increase or decrease could be demonstrated in those who were examined at 70, 81 and 90 years of age. CONCLUSIONS: The difference in H. pylori prevalence between the two cohorts may reflect a rapid change in socio-economic conditions in Sweden during this 20-year period.

Chlamydia pneumoniae infection associated with multi-organ failure and fatal outcome in a previously healthy patient.

Chlamydia pneumoniae has been associated with respiratory infections and with cardiovascular disease. We describe here a patient with multi-organ failure and fatal outcome in whom C. pneumoniae was implicated as a causative agent. Serological analysis for C. pneumoniae was done by immunofluorescence. Immunohistochemistry was carried out with avidin-biotin peroxidase staining. The patient had pneumonia I month prior to death. C. pneumoniae was detected in the heart and lungs by immunohistochemistry at autopsy. The patient had an antibody pattern suggestive of current or chronic C. pneumoniae infection. Serological analysis for Legionella sp., Mycoplasma pneumoniae, CMV, EBV, enteroviral agents and markers for autoimmune disease were negative. The findings suggest C. pneumoniae as the aetiological agent in this case of multi-organ failure.

Prevalence of Chlamydia pneumoniae in healthy children and in children with respiratory tract infections.

BACKGROUND: Chlamydia pneumoniae causes respiratory tract infections in adults, but little is known about its significance for acute or persistent respiratory tract infections in children. METHODS: We studied the prevalence of C. pneumoniae by polymerase chain reaction in children younger than the age of 11: 85 consecutive children with respiratory tract infections; and 93 children presumed to be healthy. Throat swabs for PCR analysis were taken from all children, and serology was done for 54 of the 85 sick children and from all but one of the presumed healthy children positive for C. pneumoniae by PCR. RESULTS: PCR was positive in 38 (45%) of the sick children and in 5 (5.7%) of the healthy children. All but 2 of 19 sick children with serologic findings suggesting recent or ongoing infection with C. pneumoniae were positive by PCR. Most children positive for C. pneumoniae by PCR had upper respiratory tract infections. Four children had recurrent respiratory tract infections and otitis media with effusion treated by tubal insertion. CONCLUSION: The findings suggest that C. pneumoniae is common among children with respiratory tract infections.