Relation of Chlamydia pneumoniae infection to documented coronary artery disease in Shiraz, Southern Iran

The possibility that infectious agents may trigger a cascade of reactions leading to inflammation, atherogenesis, and vascular thrombotic events has recently been raised. Chlamydia pneumoniae is one of those that have received the most investigative attention with respect to coronary artery disease (CAD). This study was undertaken for the first time in Shiraz, Iran to determine this relationship. A case-control study was conducted in 167 subjects (81 women and 86 men) who underwent coronary angiography at cardiac catheterization laboratories of Shiraz University of Medical Sciences Hospitals. Immunoglobulin G (IgG), and IgA antibodies to C. pneumoniae antigen were estimated in baseline serum samples from 109 patients (mean age 57 years) experiencing a coronary event and from their matched controls (n = 58, mean age 50 years) by ELISA method. The prevalence of IgG and IgA antibodies to C. pneumoniae did not show any case-control differences (82.6% vs 74.1% and 22% vs 15.5%, respectively). These results suggest that although C. pneumoniae was highly prevalent among these patients, it did not appear to be associated with angiographically documented CAD and cannot be regarded as a positive predictor for the development of acute coronary syndrome.     

Chlamydia pneumoniae and future risk in patients with coronary heart disease

AIM: To evaluate the association between previous exposure to Chlamydia pneumoniae and future coronary risk in patients with coronary heart disease. METHODS: A prospective, nested, case-control design was used. The patient sample was derived from a trial study of bezafibrate for the treatment of coronary heart disease. Anti-Chlamydia pneumoniae antibodies (IgG and IgA) in the baseline sera of 136 patients who had coronary events during follow-up (mean 6.2 years) were compared with those in 136 age- and gender-matched patients from the same trial without subsequent coronary events. RESULTS: Mean titers of IgG and IgA antibodies were similar in cases and controls. The relative odds of future coronary events in patients who were seropositive at baseline were 1.0 (95% CI, 0.54-1.84) for IgG and 0.74 (95% CI, 0.41-1.31) for IgA. The relative odds did not change after adjustment for multiple confounding variables. The risk of future coronary events did not increase with increasing anti-Chlamydia pneumoniae antibody titers. CONCLUSIONS: Prior exposure to Chlamydia pneumoniae in patients with chronic coronary heart disease is not associated with increased risk of recurrent coronary events.     

Chlamydia pneumoniae infection is associated with coronary artery disease but not implicated in inducing plaque instability

BACKGROUND: Many authors have shown an association between Chlamydia pneumoniae (C. pneumoniae) infection and coronary artery disease. However, whether C. pneumoniae infection plays an important role in triggering an acute coronary event remains to be elucidated. METHODS: Sixty-four consecutive patients with unstable angina (group A), 56 consecutive patients with stable exertional angina (group B) and 74 control subjects (group C) were studied. The IgM, IgG and IgA anti-C. pneumoniae titers were assessed (microimmunofluorescence test Labsystem), values > or =1:16, > or =1:32 and > or =1:16 being respectively considered positive. RESULTS: IgM antibodies were found in 10.9% of group A and 12.5% of group B patients, whereas no subject of group C showed IgM titers (A vs. B, p=ns; C vs. A and B, p<0.05). Positive IgG titers were found in 76.6%, 82% and 44.6% in groups A, B and C, respectively (A vs. B, p=ns; C vs. A and B, p<0.05). Positive IgA titers were found in 62.5%, 61% and 31.1% in groups A, B and C, respectively (A vs. B, p=ns; C vs. A and B, p<0.05). Acute infection was observed in 10.9% and 12.5% of patients in groups A and B, respectively (p=ns); reinfection in 17% and 11%; no patient of the control group had signs of acute infection or reinfection. Chronic infection was observed in 34.4% and 37.5% in group A and B, respectively (p=ns). CONCLUSION: C. pneumoniae infection is associated with coronary artery disease, but no difference in serology is present between unstable and stable angina. Therefore, it does not seem implicated in triggering an acute coronary event.     

Autoimmunity to human heat shock protein 60, Chlamydia pneumoniae infection, and inflammation in predicting coronary risk

Heat shock protein 60 (Hsp60) and Chlamydia pneumoniae infection have both been associated with cardiovascular diseases. Our aim was to study the role of Hsp60 antibodies as coronary risk predictors and their association with C pneumoniae infection and inflammation. This was a prospective, nested, case-control study. The cases consisted of 239 middle-aged Finnish men who developed myocardial infarction or coronary death during the follow-up. Baseline levels of IgA and IgG antibodies to human-specific and C pneumoniae-specific Hsp60 were measured by enzyme immunoassay. Human Hsp60 IgA, but not IgG or C pneumoniae Hsp60, antibodies were a significant risk factor for coronary events (odds ratio 2.0, 95% CI 1.1 to 3.6, when the fourth and first quartiles are compared). When an elevated human Hsp60 IgA antibody level (above the second quartile) was present simultaneously with a high C pneumoniae IgA antibody level (the third quartile) and an elevated C-reactive protein level (the second quartile), compared with all factors at low levels, the risk was 7.0 (95% CI 2.6 to 19.1) without adjustment and 5.0 (95% CI 1.8 to 14.2) when adjustment was made for age and smoking. In conclusion, an elevated human Hsp60 IgA antibody level was a risk factor for coronary events, especially when it was present together with C pneumoniae infection and inflammation.     

The proatherogenic properties of lipoprotein(a) may be enhanced through the formation of circulating immune complexes containing Chlamydia pneumoniae-specific IgG antibodies.

AIMS: To investigate a possible relationship between the atherogenic properties of lipoprotein(a) (Lp(a)) and Chlamydia pneumoniae infections. METHODS AND RESULTS: The study population was nested within the V?sterbotten Intervention Program or the WHO MONICA project. In this incident case-control study, 78 patients who had suffered acute myocardial infarction and 156 matched controls were included. The contents of circulating immune complexes were analysed for C. pneumoniae IgG antibodies and Lp(a). A significantly larger proportion of cases than controls had >/=13 mg. l(-1)Lp(a) and a C. pneumoniae specific IgG antibody titre >/=1/2 in circulating immune complexes (odds ratio=3.8). CONCLUSION: The proatherogenic effects of Lp(a) may be enhanced and/or partly mediated through the formation of circulating immune complexes containing C. pneumoniae -specific IgG antibodies. The connection between chronic C. pneumoniae infections and atherosclerosis may, at least in part, be explained by an interaction with Lp(a) through the formation of circulating immune complexes.     

Chlamydia pneumoniae IgA titres and coronary heart disease; prospective study and meta-analysis.

AIMS: To examine associations between Chlamydia pneumoniae IgA titres and incident coronary heart disease, and to compare them with associations previously reported between C. pneumoniae IgG titres and coronary heart disease. METHODS AND RESULTS: We measured serum concentrations of C. pneumoniae IgA antibodies in 502 coronary heart disease cases and in 1005 age- and town-matched controls 'nested' in a community-based prospective study of 5661 British men (mean follow-up in controls, 16 years), and conducted a meta-analysis of published prospective studies to place our findings in context. Two hundred and twenty-one (44%) of the cases were in the top third of C. pneumoniae IgA titres compared with 336 (33%) of the controls, yielding an odds ratio for coronary heart disease of 1.84 (95% confidence interval 1.40-2.43) which was largely unchanged after adjustment. In aggregate, the present study and nine previously reported prospective studies of C. pneumoniae IgA titres involved 2283 cases, yielding a combined odds ratio for coronary heart disease of 1.25 (1.03-1.53), with no significant heterogeneity among the ten studies (chi(2)9=7.8; P>0.1). This combined odds ratio is compatible with that previously reported for C. pneumoniae IgG titres and coronary heart disease (1.15, 0.97-1.36). CONCLUSION: Neither C. pneumoniae IgA titres nor IgG titres are strongly predictive of coronary heart disease in the general population.     

Detection of specific circulating antigen, immune complexes and antibodies in human hydatidosis from Turkana (Kenya) and Great Britain, by enzyme-immunoassay

Circulating antigen, specific immune complexes (IgG and IgM) and specific antibodies (IgG, IgM, IgE and IgA) were detected by enzyme-linked immunosorbent assay (ELISA) in the sera of hydatid (Echinococcus granulosus) patients from Turkana (Kenya) and the UK. Specific IgG and IgM antibodies predominated in current UK hydatid infections, while all classes of specific antibodies were lower in the Turkana patients. Circulating antigen, detected in 3% polyethylene glycol (PEG) precipitated complexes, using peroxidase conjugated hyperimmune human hydatid IgG (Fab) was more specific in ELISA than either antibody or immune complex assays where peroxidase conjugated anti-human IgG was used. Anti-human immunoglobulin ('rheumatoid' factor) was not detected in hydatid sera. Serum antigen, specific IgM immune complexes and specific IgM antibodies were associated with UK cases of current hydatid infection in contrast to patients with previous histories of hydatidosis. In 3 hydatid patients (from UK) levels of circulating antigen and specific IgM immune complexes rapidly declined within 1-4 months after surgical cyst removal. The detection of specific IgG and antigen in PEG precipitated immune complexes from false-negative/low responder Turkana hydatid sera, suggests that antibody 'mopping' by specific antigen may be occurring. After SDS-PAGE/immunoblotting analysis, antigen of mol. wt 67 000, present in hydatid cyst fluid and protoscoleces, was identified as putative circulating antigen in 3% PEG precipitates of sera from albendazole treated hydatid patients.     

Changes in antibody titers against Chlamydia pneumoniae after coronary angioplasty

OBJECTIVES: The potential role of common infectious agents in the pathogenesis and progression of atherosclerosis has been studied increasingly over the last decade. The evidence for Chlamydia pneumoniae as a potential causative agent is strong and is based on the findings of numerous sero-epidemiological studies, examination of atheromatous plaque specimens, in vitro animal models. We performed a prospective study in percutaneous transluminal coronary angioplasty (PTCA) patients to investigate whether the angioplasty procedure influenced the specific humoral immune response reaction against C. pneumoniae antigens. METHODS: We studied 76 patients who successfully underwent PTCA for de novo lesions. Blood samples were drawn immediately before PTCA and 1 month after PTCA. IgG and IgA antibodies against C. pneumoniae (strain CDC/CWL-029) were determined by an in-house developed enzyme immunoassay. RESULTS: At the time of angioplasty 75% and 34% of the patients had seropositive antibodies to elementary bodies (EBs) of classes IgG and IgA, respectively. Mean titers of IgG antibodies before and 1 month after PTCA were 46+/-31 and 50+/-28 relative units (RU/ml) (P>0.05). One month after PTCA, 97% and 34% of the patients had seropositive antibodies to EBs of classes IgG and IgA, respectively. We divided our patients into two groups on the basis of IgG seropositivity (group I: Chlamydia antibody IgG seronegative patients, group II: Chlamydia antibody IgG seropositive) before PTCA. Significant increase in the antibody titers of IgG (12+/-5 vs. 40+/-18, P<0.001) and IgA (0.6+/-0.33 vs. 1.15+/-0.83, P=0.007) was observed in group I patients 1 month after PTCA and 88% of them gained IgG seropositivity. There were no significant changes in IgG and IgA antibody levels in group II after PTCA. CONCLUSION: We have demonstrated a statistically significant rise in C. pneumoniae antibodies (especially IgG) induced by PTCA in patients previously seronegative.     

Relation of Chlamydia pneumoniae infection in Taiwan to angiographically demonstrated coronary artery disease and to the presence of acute myocardial infarction or unstable angina pectoris.

Reports of the association of Chlamydia pneumoniae (C. pneumoniae) infection with coronary artery disease (CAD) are scarce in the Oriental population. We therefore conducted a case-control study to explore this issue in Taiwan. There were 242 consecutive subjects (166 men and 76 women) who underwent cardiac catheterization at the National Taiwan University Hospital Cardiac Catheterization Laboratory. Patients with CAD (n = 156) had > or = 1 coronary artery lesion of > 50% diameter stenosis on angiography. Controls (n = 86) had no demonstrable CAD angiographically. Antibodies to C. pneumoniae were tested by using an enzyme-linked immunosorbent assay. The prevalence of antibodies to C. pneumoniae was as follows: immunoglobulin-G (IgG), 50% (122 of 242 patients); immunoglobulin-A (IgA), 72% (176 of 242 patients); and either IgG or IgA, 79% (192 of 242 patients ). The odds ratio (OR) for CAD with either IgG or IgA was 1.4 (95% confidence interval [CI] 0.7 to 2.7, p = 0.31). After adjusting for the known CAD risk factors, the OR decreased to 0.8 (95% CI 0.3 to 2.1, p = 0.60). The OR for unstable angina or acute myocardial infarction with the presence of either IgG or IgA was 0.5 (95% CI 0.2 to 1.1, p = 0.08) and 0.4 ( 95% CI 0.1 to 1.0, p = 0.049) after adjusting for other risk factors. These results suggest a high prevalence of C. pneumoniae infection in Taiwan. However, C. pneumoniae infection is not associated with angiographically documented CAD, and, in contrast, is a negative predictor for the development of acute coronary syndromes.     

Specific and early detection of IgG, IgA and IgM antibodies to Mycobacterium tuberculosis 38kDa antigen in pulmonary tuberculosis

The objective was to apply the purified 38kDa protein antigen of Mycobacterium tuberculosis in ELISA to estimate the IgG, IgA and IgM antibody levels in sera and circulating immune complexes of tuberculosis patients. Sera from smear and culture positive tuberculosis patients were positive for anti 38kDa IgG, IgA and IgM antibodies, with a sensitivity of 61%, 30% and 10%, respectively, and with a specificity of 100% for IgG. The sensitivity of the test improved to a level of 68% for IgG+IgA and of 71.4% for IgG+IgA+IgM without significantly compromising the specificity (IgG of 100%, IgG+IgA of 96%, IgG+IgA+IgM of 90%). Among the smear, culture-negative but X-ray-positive cases, 60% were serum positive for IgG antibody, while in smear-negative but culture-positive cases, 54% were positive for IgG antibody. Measurement of 38kDa antibodies showed a greater than 95% sensitivity in smear and culture-positive, and smear-negative and culture-positive patients, through a combination of assays for serum IgG and circulating immune complex antibodies, while the specificity was 100%.     

Chlamydia pneumoniae seropositivity and systemic and renovascular atherosclerotic disease

BACKGROUND: Patients with hypertension may be vulnerable to vascular Chlamydia pneumoniae and/or cytomegalovirus (CMV) infection because of increased expression of adhesion molecules. OBJECTIVE: To determine whether C pneumoniae or CMV is associated with the presence of atherosclerotic lesions in hypertensive patients. METHODS: Ninety-six angiographic studies on 100 consecutive patients with of clinical signs or symptoms suggestive of renovascular hypertension were reviewed for the presence or absence of atherosclerotic lesions at the level of the renal arteries as well and abdominal aorta. Also, the presence of a hemodynamically notable renal artery stenosis and antibodies to C pneumoniae (IgG and IgA) and CMV (IgG and IgM) was determined, and all classic risk factors were recorded. RESULTS: Atherosclerotic lesions were documented in 67 patients (70%), and in 49 patients (51%) such lesions were present at the level of the renal artery. In the univariate analysis, significant associations between IgG (odds ratio, 3.8; 95% confidence interval, 1.2-11.7; P =.02) as well as IgA (odds ratio, 2.6; 95% confidence interval, 1.1-6.7; P =.03) antibodies to C pneumoniae and the presence of atherosclerosis were found for both the aorta and the renal arteries. Seroprevalence (IgG) to C pneumoniae in the 23 patients with a hemodynamically notable renal artery stenosis was 100% and differed (P =.01) from those without a notable renal artery stenosis (78%). In the multivariate analysis, IgG seropositivity to C pneumoniae was significantly associated with atherosclerosis (odds ratio, 6.0; 95% confidence interval, 1.33-27.5; P =.02), and age. There was no association between CMV seropositivity and atherosclerosis. CONCLUSION: The presence of antibodies to C pneumoniae was significantly associated with atherosclerosis and renovascular disease in hypertensive patients in whom a renal artery stenosis was strongly suspected.     

Association between chlamydial infection and coronary artery disease

Recent epidemiological studies have demonstrated the association between Chlamydia pneumoniae infection and coronary atherosclerosis. However, the relationship is less clear in the Japanese population. Serum IgA and IgG antibodies to Chlamydia-specific lipopolysaccharide were measured by enzyme-linked immunosorbent assay in 152 consecutive patients(112 males, 40 females, mean age 57 years)who underwent coronary angiography. Patients(n = 123)with coronary artery disease(CAD)were defined as having more than 50% diameter stenosis in at least one major coronary artery. The control group(n = 29) had normal coronary angiograms. In the CAD group, there was a high tendency of prevalence of IgA(20% vs 7%, p = 0.08)and IgG(54% vs 34%, p = 0.052). Prevalence of either IgA or IgG was significantly higher (59% vs 38%, p = 0.045) compared with the control group. Although the index of IgA antibody was not significantly different between the CAD and control groups(median 0.52 vs 0.36, p = 0.19), the index of IgG antibody was significantly higher in the CAD group than in the control group(median 1.29 vs 0.82, p = 0.026). The odds ratios for CAD were 3.4[95% confidence interval(CI)0.6-18.7]for the prevalence of IgA, 2.3(95% CI 0.9-5.2)for the prevalence of IgG, and 2.3(95% CI 1.0-5.2)for the prevalence of either IgA or IgG. Patients with CAD tended to have high prevalence of antibodies to Chlamydia spp, and these findings suggest an association between chlamydial infection and coronary atherosclerosis in the Japanese population.     

Antibodies to Chlamydia pneumoniae in blood serum of patients with ischemic heart disease and presence of complicated lesions in coronary arteries

Levels of IgM, IgG and IgA antibodies to Chlamydia pneumoniae were measured in 107 patients (age 33-75 years) with documented coronary atherosclerosis and 39 subjects with intact coronary arteries. Rates of seropositivity to C. pneumoniae were 77.6 and 25.6% in patients and "healthy" subjects, respectively (p<0.05). Seropositive (n=83) compared with seronegative (n=24) patients had higher prevalence of complicated lesions (p<0.05).     

Antibody response to the 60-kDa heat-shock protein of Chlamydia pneumoniae in patients with coronary artery disease

Serum specimens from 752 individuals undergoing coronary arteriography were examined for antibodies to Chlamydia pneumoniae. Patients with coronary artery disease (CAD) were more likely to have IgG antibodies to C. pneumoniae than were individuals without CAD (60% vs. 52%; P=.007; odds ratio, 1.8; 95% confidence interval, 1. 17-2.77). Antibodies to recombinant hsp60 of C. pneumoniae were found with nearly the same frequency in patients with CAD and individuals without CAD (29% vs. 30%; P=.751). There was no association between chlamydial hsp60 antibodies and the severity of CAD or a previous myocardial infarction. Patient sera reacted most frequently to C. pneumoniae proteins of 17, 38, 40, 58, and 60/62 kDa. Reactivity to these proteins was not different between patients with and without CAD. Study results indicate that neither antibodies to chlamydial hsp60 nor antibodies to other C. pneumoniae proteins are useful for discriminating between seropositive patients with and without CAD.     

Prevalence of chlamydia pneumoniae in Japanese rural districts; association of smoking and physical activity with Chlamydia pneumoniae seropositivity

OBJECTIVE: We conducted a large-scale cross-sectional study to assess the prevalence of Chlamydia pneumoniae and clarify the association between seropositivity and risk factors, such as smoking status, physical activity and body mass index in Japanese rural districts. METHODS: A total of 1,063 men and 1,573 women aged 18-94 years participated in 1999. Serum index values (ID) of IgA and IgG antibodies to C. pneumoniae were measured by ELISA. Index values were categorized as "negative" (ID < 1.10), "positive" (ID > or = 1.10) and "high positive" (ID > or = 3.00). Logistic regression analysis was performed to estimate the crude and adjusted odds ratios for C. pneumoniae seropositivity. RESULTS: The overall prevalence of C. pneumoniae IgA seropositivity was 52.5%, and that of IgG was 55.2%. Each seropositivity significantly increased with age. The prevalence among men was significantly higher than in women in C. pneumoniae IgG "high positive" subjects. Compared with never-smokers, the adjusted odds ratio of current smokers was 2.00 (95% CI: 1.45-2.77) for C. pneumoniae IgA seropositivity. The adjusted odds ratio of the higher tertiles of physical activity for C. pneumoniae IgG seropositivity was 1.42 (1.12-1.80) compared with the lower tertiles. In "high positive" subjects, smoking was associated with both immune complexes. CONCLUSION: We confirmed a high prevalence of C. pneumoniae seropositivity among healthy Japanese adults. The results indicated that smoking and high physical activity were associated with C. pneumoniae infection.     

Chlamydia pneumoniae antibodies and angiographically demonstrated coronary artery disease in a sample population from Italy.

Recent reports suggest an association between Chlamydia pneumoniae and chronic coronary heart disease. This case-control study investigates the relationship between the presence of immunoglobin G (IgG) and immunoglobin A (IgA) when measured by means of microimmunofluorescence (MIF) and angiographically diagnosed coronary disease. Cases (n = 150) were angiography patients with at least one coronary artery lesion occupying at least 50% of the luminal diameter. Controls (n = 49) were angiography patients with no detectable signs of coronary artery disease and patients (n = 56) without signs or symptoms of coronary disease and with normal ECG results. No significant differences were revealed between the seroprevalence of IgG and IaA and geometric mean titers (GMT) as measured in cases and controls. When cases were compared with controls whose angiographic results were normal, after adjusting for established risk factors (cholesterol, smoking, hypertension, diabetes, age, gender and family history), the estimated risk of coronary artery disease was 0.79 (95% confidence interval (C.I.), 0.31-1.99) for the presence of IgG and was 0.94 (95 C.I., 0.37-2.39) for IgA. When cases were compared with controls with normal ECG results, the adjusted odds ratio (O.R.) for coronary artery disease was 1.17 (95%, C.I., 0.52-2.62) for the presence of IgG and 0.82 195% C.I., 0.36-1.86) for the presence of IgA. These results do not support an association between C. pneumoniae infection and coronary disease.     

Association of seropositivity for antibody to Chlamydia-specific lipopolysaccharide and coronary artery disease in Japanese men

Recent studies suggest an association between Chlamydia pneumoniae infection and coronary artery disease (CAD). To examine this relationship in Japanese men, serum IgA and IgG antibodies to Chlamydia-specific lipopolysaccharide were measured by enzyme-linked immunosorbent assay in 507 patients with CAD and 200 age-matched controls. CAD patients were divided into (1) 269 patients with myocardial infarction (MI) and (2) 238 patients with chronic coronary heart disease (CCHD). Compared with the control group, the CAD group did not differ in the prevalences of both antibodies (IgA: 23.7 vs 18.0%, p=0.10; IgG: 52.7 vs 51.0%, p=0.6). The index of IgG antibody was not significantly different between CAD and control groups (median 1.19 vs 1.18, p=0.3), whereas the index of IgA antibody was significantly higher in CAD than control group (median 0.60 vs 0.46, p<0.0001). Compared with the control group, the MI group had a significantly higher prevalence of IgA antibody (28.6 vs 18.0%, p=0.007); however, there was no difference in the prevalence of IgG antibody (58.0 vs 51.0%, p=0.13). The CCHD group did not differ in the prevalences of both antibodies (IgA: 18.1 vs 18.0%, p=0.9; IgG: 45.6 vs 51.0%, p=0.2). After the adjustment for coronary risk factors, odds ratios (ORs) of seropositive antibodies for CAD were 1.59 [95% confidence interval (CI): 0.88-2.87, p=0.12] for IgA seropositivity and 0.92 (95%CI: 0.58-1.47, p=0.7) for IgG seropositivity in all cases. In the MI and control groups, ORs of seropositive antibodies for MI were 2.67 (95%CI: 1.32-5.38, p=0.007) for IgA seropositivity, and 1.36 (95%CI: 0.79-2.36, p=0.2) for IgG seropositivity. This study discovered that IgA antibody to Chlamydia was significantly associated with CAD, especially with MI, in Japanese Men and the findings suggest that chronic infection of Chlamydia may be linked to the pathogenesis of MI.     

Case of infectious mononucleosis with suspected primary coinfection with Chlamydophila (Chlamydia) pneumoniae and Epstein-Barr virus

A 26-year-old male was hospitalized with fever and pharyngeal pain. Liver dysfunction and an increase in the percentage of atypical lymphocytes in the peripheral blood were detected. Computed tomography showed pneumonia involving the right lung and synpneumonic pleural effusion. Serum immunological tests showed positive results for Epstein-Barr virus (EBV) viral capsid antigen (VCA) IgM and IgG antibodies and Chlamydophila (Chlamydia) pneumoniae (C. pneumoniae) IgM and IgA antibodies on admission. The pneumonia and pleural effusion were no longer detectable after a week of treatment with starting azithromycin. At 7 weeks after admission, the liver function test results returned to within normal limits, the serum became negative for EBV VCA IgM antibody, the C. pneumoniae IgM antibody titer decreased, and the C. pneumoniae IgA and IgG antibody titers increased. This case was suspected to have infectious mononucleosis caused by primary coinfection with C. pneumoniae and EBV.     

Chlamydia pneumoniae and newly diagnosed asthma: a case-control study in 1 to 6-year-old children

OBJECTIVE: The aim of the study was to evaluate the association between antibodies to Chlamydia pneumoniae and the onset of asthma in children. METHODOLOGY: In 1996-2000, 122 children aged 1-6 years, who were treated for new asthma as inpatients or outpatients in our hospital, were recruited. For each patient, two controls, matched by age, sex and municipality, were randomly selected from the same population. In 2000, 104 serum samples were available from patients (85%) and 120 from controls (49%) for microimmunofluorescence (MIF) assay for C. pneumoniae and C. trachomatis antibodies, and for enzyme immunoassay (EIA) for C. pneumoniae antibodies. RESULTS: In EIA, the median IgG concentrations were 20 EIU (EIA units) in the patients, and 16 EIU in the controls. IgG was positive (> 30 EIU) in 37 (36%) patients and in 36 (31%) controls. IgA was positive (> 12 EIU) in four (4%) patients and in eight (7%) controls. In MIF, four (4%) patients and seven (6%) controls were IgG positive, and seven were also IgA positive. IgM antibodies were detected in four children by EIA, and in none by MIF. CONCLUSION: IgG antibodies to C. pneumoniae, though common in 1 to 6-year-old children as detected by EIA, did not differ between newly diagnosed asthma patients and controls in this case-control study.     

Evaluation of diagnostic tests for HIV infection in infants born to HIV-infected mothers in Switzerland

Children born to HIV-infected women in Switzerland were tested every 3 months for HIV-reactive serum immunoglobulin (Ig) G, IgM and IgA antibodies by Western blot, viral antigen, virus replicating in T-lymphocyte cultures, and immunologic and clinical parameters. At birth, 27% were isolation-positive, 68% had IgM, 48% IgA and 10% circulating antigen. The proportion of IgM and IgA declined to about 18 and 27%, respectively, during the first 2 years. Detection of circulating antigen was less frequently positive than virus isolation in all age and disease groups. Clinical symptoms were only seen in infants or children who were or had been positive for IgM and/or IgA, but only 39% of children positive for these markers have developed disease so far. Clinical symptoms combined with signs of immunodeficiency were seen only in children who were isolation-positive or had evidence of HIV-reactive IgA or child-produced IgG. Absorption studies showed that Western blot-detected IgM and IgA antibodies were of two types: 42% were directed against various HIV proteins, while the rest represented rheumatoid-factor-like IgM or IgA binding to HIV-specific IgG. HIV-specific IgG antibodies were detected in all samples up to the age of 12 months and were still found in 83% of infants 13-18 months old. We observed weak HIV-specific IgG above the age of 15 months with no other signs of HIV infection, suggesting that the demonstration of antibodies in children beyond this age does not necessarily indicate HIV infection.