Burden of infection and fat mass in healthy middle-aged men.

OBJECTIVE: Our aim was to study the effect of exposure to four infections on fat mass. RESEARCH METHODS AND PROCEDURES: This was a cross-sectional study of healthy middle-aged men from the general population (n = 74). Each study subject's serum was tested for specific IgG class antibodies against herpes simplex virus (HSV)-1, HSV-2, enteroviruses, and Chlamydia pneumoniae through the use of quantitative in vitro enzyme-linked immunosorbent assays (ELISAs). A total pathogen burden score based on these seropositivities [Quantitative Seropositivity Index (QSI)] was constructed. Fat mass was measured by bioelectrical impedance. RESULTS: We observed significant relationships between the HSV-1 titer and fat mass and percentage fat mass. The associations were stronger when considering the infection burden. The QSI was significantly associated with fat mass (r = 0.30, p = 0.009) and percentage fat mass (r = 0.27, p = 0.01). Those subjects in the highest tertile of fat mass showed significantly higher QSI (259.5 +/- 74.1 vs. 206.9 +/- 78.2, p = 0.007). In subjects that were seropositive for Enteroviruses, the relationship between the QSI and fat mass was strengthened (r = 0.51, p = 0.02). In a multivariate regression analysis, the QSI, independently of age and C-reactive protein, contributed to 9% of fat mass variance. DISCUSSION: Pathogen burden showed an association with fat mass. Subjects with increased fat mass could be more susceptible to developing multiple infections resulting in a chronic low-grade inflammation. We can not exclude the possibility that exposure to multiple infections leads to increased fat mass.

[Antibodies against Chlamydophila in patients with acute myocardial infarction and coronary risk and their association with mortality]. / Anticuerpos contra Chlamydophila en pacientes con infarto agudo del miocardio y riesgo coronario, y su relación con la muerte.

OBJECTIVE: The primary aim of this study was to determine whether antibodies against Chlamydophila pneumoniae in patients with acute myocardial infarction (AMI) and coronary risk factors are associated with death. MATERIAL AND METHODS: A cross-sectional study was conducted among 100 patients hospitalized in the Coronary Unit of Centro Medico La Raza Hospital of the Mexican Institute of Social Security, between 1999 and 2000. Subjects were males and females older than 18 years, diagnosed with AMI and coronary risk. Antibodies against Chlamydophila pneumoniae, Chlamydophila psitacii and Chlamydia trachomatis were measured using an indirect microinmunofluorescence assay. In addition, blood samples from 33 patients from the original group were taken when the patients were discharged from the hospital,and 3 months after their myocardial infarction. Data analysis consisted of geometric means and standard deviations as well as odds ratios with 95% confidence intervals. RESULTS: Seventy percent of patients presented antibodies against Chlamydophila pneumoniae. Antibodies against Chlamydophila psittaci and Chlamydia trachomatis were not identified. No statistically significant association was found between antibodies and death in these patients with coronary risk factors and AMI. In the subgroup of 33 individuals 25 had antibodies against Chlamydophila pneumoniae and in 83% of them antibodies decreased three months after the AMI event. CONCLUSIONS: Even though patients with coronary risk factors and AMI had an increased seropositivity for Chlamydophila pneumoniae it was not significantly associated with death.

Impact of serological methodology on assessment of the link between Chlamydia pneumoniae and vascular diseases.

We assessed the impact of five serologic tests on the link between Chlamydia pneumoniae and abdominal aortic aneurysms (AAA). The results of the tests were inconsistent. Agreement among the five tests was generally poor. Detection of the link between C. pneumoniae and AAA depends on the serologic methodology chosen.

A prospective study of Chlamydia pneumoniae infection and risk of MS in two US cohorts.

BACKGROUND: Chlamydia pneumoniae (Cpn) has been proposed as a possible etiologic agent in multiple sclerosis (MS). However, previous studies were cross-sectional and could not assess whether Cpn infection preceded the onset of MS. METHODS: The authors conducted a prospective nested case-control study among 3 million US Army personnel and 121,466 members of the Kaiser Permanente Medical Care Program (KPMCP) cohort. Serum samples collected prior to onset of MS symptoms were available for 83 MS cases in the Army and 46 in the KPMCP cohort. Two controls were matched to each case on age, sex, and date of blood collection. Microimmunofluorescence was used to measure serum immunoglobulin M (IgM) and immunoglobulin G (IgG) antibody titers to Cpn; IgG titers > or 1:16 were considered positive for past Cpn infection. RESULTS: Seropositivity for Cpn was not significantly associated with risk of MS in either cohort (Army: OR = 1.0; 95% CI 0.6, 1.8; KPMCP: OR = 1.5; 95% CI 0.7, 3.1) or in the pooled analysis (OR = 1.2; 95% CI 0.8, 1.9). Serum levels of anti-Cpn IgG antibody were also not associated with an increased risk of MS in the Army (OR for a fourfold difference in antibody titers = 0.9; 95% CI 0.7, 1.2) or in the pooled analysis (OR = 1.2; 95% CI 0.9, 1.4), but a significant increase in risk was seen in the KPMCP cohort (OR = 1.7; 95% CI 1.2, 2.5). The difference between these results in the Army and the KPMCP cohort was significant (p = 0.01). CONCLUSIONS: Neither Cpn seropositivity nor serum anti-Cpn IgG antibody titers predicted risk of developing MS. However, due to the heterogeneity of results between cohorts, we cannot exclude the possibility that infection with Cpn may modify the risk of MS.

Performance of five serological chlamydia antibody tests in subfertile women.

BACKGROUND: Micro-immunofluorescence (MIF) is widely used for chlamydia antibody testing (CAT). Recently a species-specific MIF and three enzyme-linked immunosorbent assay (ELISA) tests have been introduced. We compared five commercially available CAT tests, using laparoscopy as a reference, and evaluated whether combinations of tests could improve the predictive value of CAT. METHODS: In a consecutive cohort of 315 subfertile women, results of the five CAT tests were correlated to findings at laparoscopy. Likelihood and odds ratios (OR) were calculated for single tests and for combinations of tests. RESULTS: Of the tests evaluated, MIF Labsystems had the best diagnostic performance (OR 15.7), while pELISA Medac (OR 8.2) was the best of the three ELISA tests. Stepwise logistic regression analysis showed that performance of MIF Labsystems could not be improved by adding a second test. Significant cross-reactivity with C. pneumoniae antibodies was found in all tests evaluated, except in pELISA Medac. CONCLUSIONS: In screening for tubal factor subfertility, MIF Labsystems was superior to the ELISA tests evaluated, and combining two CAT tests did not improve its predictive value. Economic analysis will show whether serial testing by pELISA Medac, and retesting positive samples by MIF Labsystems, is most cost-effective. In CAT, cross-reactivity with C. pneumoniae antibodies is still a major concern.

Assessment of polymerase chain reaction and serology for detection of chlamydia pneumoniae in patients with acute respiratory tract infection.

OBJECTIVE: To study Chlamydia pneumoniae (C. pneumoniae) infection in 110 patients with respiratory tract infection admitted to our hospital from January to December 1995 in Nanjing. METHODS: Sputum and throat swab specimens were taken and C. pneumoniae DNA was detected by using polymerase chain reaction (PCR) with the HM-1-HR-1 primer pair. At the same time, serum samples were taken and immunoglobulin G and M (IgG and IgM) fractions of antibodies to C. pneumoniae were studied by microimmunofluorescence test. RESULTS: Prevalence of specific IgG was 70% in patients with respiratory tract infection. Seventeen patients (15.5%) were serologically diagnosed as having recent C. pneumoniae infections and 12 patients (10.9%) had positive PCR in sputum and/or swab specimens. The total positive rate was 22.7% (25/110) detected by PCR combined with serological tests. Acute infection of C. pneumoniae was common in patients with asthma (57.1%), pneumonia (35.0%), COPD (25.9%) and bronchitis (25.0%). Clinical features between C. pneumoniae infection and non-C. pneumonia infection showed no significant differences. CONCLUSIONS: Chlamydia pneumoniae is an important pathogen that causes infection of the human respiratory tract and attention should be drawn to this special illness.

Chlamydia pneumoniae and atherosclerosis: critical assessment of diagnostic methods and relevance to treatment studies.

A number of studies have found that inflammation of the vessel wall plays an essential role in both the initiation and progression of atherosclerosis and erosion and fissure and the eventual rupture of plaques. Chlamydia pneumoniae is one of the infectious agents that have been investigated as possible causes of this inflammation. Initial studies of the association of C. pneumoniae and cardiovascular disease (CVD) were seroepidemiologic, and these were followed by studies in which the organism was identified in vascular tissue from patients with CVD by electron microscopy, PCR and immunocytochemical staining (ICC). C. pneumoniae has also been isolated by culture from vascular tissue in a small number patients. However, no single serologic, PCR, or ICC assay has been used consistently across all studies. The assays used are also not standardized. Recent studies of serologic and PCR assays for diagnosis of C. pneumoniae infection have suggested that there may be substantial interlaboratory variation in the performance of these tests. It now appears that some of the inconsistency of results from study to study may be due, in part, to lack of standardized methods. Although initial seroepidemiologic studies demonstrated a significantly increased risk of adverse cardiac outcome in patients who were seropositive, subsequent prospective studies found either small or no increased risk. In addition to the lack of consistent serologic criteria, recent evaluations have demonstrated inherent problems with performance of the most widely used serologic methods. Most importantly, we do not have a reliable serologic marker for chronic or persistent C. pneumoniae infection.

[Assessment of sputum culture and serology for detection of chlamydia pneumoniae in patients with symptomatic acute respiratory tract infection].

OBJECTIVE: To evaluate sputum culture and serology for detection of chlamydia pneumoniae (C. pneumoniae) in adult patients with acute respiratory tract infection and normal subjects. METHODS: Microimmunoflorescence (micro-IF) test for IgG and IgM antibodies to C. pneumoniae specific antigen was performed in every subject. Thirty-seven patients also had sputum HEP-2 cell culture tested for C. pneumoniae. RESULTS: Twenty-six patients (29.7%) with micro-IF IgG titres equal to or greater than 1:512 or/and IgM titres equal to or greater than 1:32 indicated recent infection. Eight patients (21.3%) with positive sputum culture of C. pnuemoniae were identified. No similar titer was shown in control normal subjects. CONCLUSIONS: Acute infection of C. pneumoniae was common in symptomatic patients with acute respiratory tract infection and attention should be drawn to this special illness.