J. T. Grayston

Detection of Chlamydia pneumoniae in aortic lesions of atherosclerosis by immunocytochemical stain.

Recent evidence has shown the presence of Chlamydia pneumoniae antigens and nucleic acid in coronary artery atheromas from autopsy patients in South Africa. In this study, the immunocytochemical technique was used to demonstrate C pneumoniae antigens in atheromas of the aorta in autopsy patients from retrospective aortic atherosclerosis studies at the University of Washington. The patients were 34 to 58 years old. Immunoperoxidase staining using Chlamydia-specific monoclonal antibodies showed one of four fatty streaks and six of 17 fibrous plaques were positive for C pneumoniae antigens; four control aortic tissues were negative. Two of the positive plaques were from the same patient. Double-label immunocytochemical staining using Chlamydia- and tissue type-specific monoclonal antibodies demonstrated the antigens in the cytoplasm of macrophages and smooth muscle cells in the atheromatous lesion. This study suggested a wider involvement of C pneumoniae organisms in atherosclerotic lesions of the arterial system than has previously been documented.

Chlamydia pneumoniae strain TWAR antibody and angiographically demonstrated coronary artery disease.

A recent case-control study from Finland reported a strong association between high antibody titers to Chlamydia pneumoniae, strain TWAR, and both chronic coronary heart disease and acute myocardial infarction. The current case-control study investigated the relation between C. pneumoniae immunoglobulin G antibody titers and angiographically diagnosed coronary artery disease. Cases (n = 461) were angiography patients with at least one coronary artery lesion occupying at least 50% of the luminal diameter. Controls (n = 95) were angiography patients with no demonstrable coronary artery disease. After standardization for age and gender, the geometric mean antibody titer was higher for cases than for controls (30.0 versus 24.0, p = 0.04). The estimated risk of coronary artery disease, adjusted for age and gender, was greater among subjects with high (greater than or equal to 1:64) antibody titers than among subjects with low (less than or equal to 1:8) antibody titers (relative risk, 2.0; 95% confidence interval, 1.0-4.0). The risk associated with a high antibody titer was particularly great for coronary artery disease with five or more lesions (relative risk, 2.8; 95% confidence interval, 1.2-7.0). The results of this cross-sectional study support an association between infection with C. pneumoniae and coronary artery disease.

Respiratory infection with Chlamydia pneumoniae in middle-aged and older adult outpatients.

This study was undertaken to characterize the epidemiology and clinical presentation of infection withChlamydia pneumoniae in a population composed primarily of middle-aged and older adults. Pharyngeal swabs and acute and convalescent phase sera were obtained from outpatients presenting with signs and symptoms of an acute respiratory infection. Sera were examined using the micro-immunofluorescence (MIF) test to detect antibody toChlamydia pneumoniae and complement fixation tests to detectMycoplasma pneumoniae, influenza A virus, influenza B virus, respiratory syncytial virus and adenovirus. Pharyngeal swab specimens were cultured forChlamydia pneumoniae and tested forChlamydia pneumoniae by the polymerase chain reaction (PCR). A total of 743 patients with a mean age of 40.5 ± 16.1 years were enrolled in the study. Twenty-one patients were serologically positive for acuteChlamydia pneumoniae infection in the MIF test. PCR was positive in 15 of the 20 serologically positive patients tested. AcuteChlamydia pneumoniae infection was identified in 3 % (2/76) of subjects with pneumonia, 5 % (12/247) of those with bronchitis, 5 % (3/61) of those with sinusitis only and 2 % (2/103) of those with pharyngitis only. Of the 21 patients withChlamydia pneumoniae infection, seven (mean age of 33 years) had an antibody pattern suggesting a primary infection while 14 (mean age of 54 years) had a reinfection pattern. Patients with reinfection had milder disease than those with primary infection. PCR testing in the current study confirms the previously proposed serologic criteria of acuteChlamydia pneumoniae infection.

Current Knowledge of Chlamydia TWAR, an Important Cause of Pneumonia and Other Acute Respiratory Diseases

This article reviews current knowledge of the TWAR strain, a newly recognized chlamydia organism that causes acute respiratory infection, especially atypical pneumonia. Information is presented under the following topics: introduction and history of the organism; microbiology and classification, including the proposal for a new chlamydia species, Chlamydia pneumoniae; laboratory diagnosis by isolation and serology; endemic TWAR disease and evidence for etiology, including studies in university students, in hospitalized pneumonia patients in three cities, and in a health maintenance organization from 1963 to 1974 and from 1985 to 1987; epidemic TWAR disease both country-wide in Denmark, Norway and Sweden 1981–1983, and localized in Finland and other countries; treatment including laboratory determination of antibiotic and sulfa drug sensitivity of the TWAR organism; population TWAR antibody prevalence; and studies by other investigators.