[Chlamydia pneumoniae antibody titers in patients with acute ischemic stroke].

To evaluate an association of ischemic stroke and Chlamydia pneumoniae (C. pneumoniae) infection, we investigated specific antibodies to C. pneumoniae by ELISA in sera of 91 patients (male 53, female 38, mean age 73 years) with acute ischemic stroke. We divided the patients under clinical diagnosis into three groups, those with cardiac embolism (E group, n = 35), atherothrombotic infarction (A group, n = 29) and lacunar infarction (L group, n = 27). Carotid ultrasound examination was performed in 79 patients. The active infection, including acute primary infection, reinfection and chronic active infection, was defined by IgG or IgA index being > or = 3.00, while inactive infection, including previous and chronic inactive infection, was defined by IgG index being > or = 1.10 and < 3.00, and IgA index being < 3.00. We found that 20.7% of A group, 2.9% of E group, and 7.4% of L group had indexes suggesting an active infection (A vs. E. p = 0.040, A vs. L, p = 0.254, L vs. E, p = 0.575: Fisher's exact test). The IgG indexes of A group (mean, 1.50) were higher than those of E group (mean, 1.35) and those of L group (mean, 0.93, A vs. L, p = 0.049: unpaired t-test). The patients with carotid plaque (n = 7) had higher IgG indexes (mean, 2.28) than those without carotid plaque (n = 72, mean, 1.11, p = 0.002: unpaired t-test). These data support the association of acute atherothrombotic infarction with chronic active C. pneumoniae infection.