Purpose: To determine the prevalence of antibodies to Chlamydia pneumoniae, C. trachomatis, and C. pneumoniae heat shock protein (Cpn Hsp60) in patients with acute anterior uveitis (AAU) and in sex- and age-matched healthy control subjects.
Methods: Altogether 64 patients with previous AAU were examined at the Helsinki University Eye Hospital from September through December 1999. Serum specimens from the patients and sex- and age-matched healthy control subjects were tested for antibodies to C. pneumoniae and C. trachomatis by a specific microimmunofluorescence test and for antibodies to Cpn Hsp60 by enzyme immunoassay (EIA).
Results: The prevalence of antibodies to C. pneumoniae (69% vs. 72%) and C. trachomatis (11% vs. 6%) did not differ significantly between the patients and control subjects, nor did the level of IgG antibodies to Cpn Hsp60 (median EIA unit, 65 vs. 48). The levels of IgA antibodies to Cpn Hsp60 were significantly higher in the patients with AAU than in the control subjects (median EIA unit, 18 vs. 10; two-tailed Wilcoxon signed rank test, P = 0.0001).
Conclusions: The high frequency of IgA antibodies to Cpn Hsp60 in patients with past AAU indicates that such patients may have persisting or recurrent infections due to C. pneumoniae. This finding suggests that C. pneumoniae may play a role in the pathogenesis of AAU.