Chlamydia pneumoniae Antibody Titers Are Significantly Associated With Acute Stroke and Transient Cerebral Ischemia

Abstract

Background and Purpose —Several studies have implied an association between Chlamydia pneumoniae and atherosclerosis. Our research was designed to investigate the association of this organism with strokes and transient cerebral ischemia. Methods —Antibodies to C pneumoniae were measured in 176 patients with stroke or transient cerebral ischemia and 1518 control subjects with noncardiovascular, nonpulmonary disorders. Acute infection or reinfection was defined by IgG ≥512 or IgM ≥8 or fourfold rise in IgG, and previous infection was defined by IgG 64 to 256 or lgA ≥8. Logistic regression was used to examine the influences of ethnic origin, age, sex, smoking habit, diabetes mellitus, steroid medication, and social deprivation on antibody levels. Some patients underwent CT and carotid ultrasound examinations and cholesterol, triglyceride, fibrinogen, and von Willebrand factor estimations. Results —We found that 13.6% of stroke/transient ischemic attack (TIA) patients and 5.7% of control subjects had antibody titers suggesting acute C pneumoniae (re)infection, while 32.4% of stroke/TIA patients and 12.7% of control subjects had titers suggesting previous infection ( P <.05). Stroke/TIA patients differed from control subjects in their levels of acute and previous infection, with adjusted odds ratios of 4.2 (95% CI, 2.5 to 7.1) and 4.4 (95% CI, 3.0 to 6.5), respectively. These did not differ notably between strokes resulting from major nonhemorrhagic infarcts, small-vessel infarcts, or hemorrhage. Cholesterol, triglyceride, fibrinogen, and von Willebrand factor concentrations showed no apparent association with titers. Conclusions —These data support the association of cerebral vascular disease with previous C pneumoniae infection and the association of stroke and transient cerebral ischemia with recrudescence of infection.