Aims: 1. Examination of antibodies against Chlamydophilla pneumonie, Chlamydia trachomatis and chlamydial heat shock protein 60 in a cohort of rheumatic patiens; 2. interpretation of sensitivity and specificity of species specific antibodies against Chlamydia trachomatis and chlamydial heat shock protein 60 in patients with uroarthritis. Methods: The first group was represented by sera from patients with reactive arthritis from national register of patients with rheumatic diseases. A total number of 87 sera was analysed. Thirty-six sera were obtained from patients with uroarthritis and 51 sera from patients with enteroarthritis. The second group was represented by sera from patients with other rheumatic diagnoses. The presence of antibodies against species specific antigens of Chlamydia trachomatis, Chlamydiophilla pneumoniae and chlamydial heat shock protein 60 was examined in all patients. On the basis of the results, prevalence of chlamydia infection was evaluated in the cohort of rheumatic patients. Further, sensitivity of serological reactivity against Chlamydia trachomatis and chlamydial heat shock protein in patients with uroarthritis was evaluated. Specificity of these findings to diagnose uroarthritis was statistically assessed by comparing findings in the group of patients with enteroarthritis and group of patients with other rheumatic diagnosis. Results: Prevalence of antibodies against Chlamydophilla pneumoniae in rheumatic cohort ranged between 25-32.32%. Prevalence of antibodies against Chlamydia trachomatis in rheumatic cohort ranged between 13.73-52.78%. Prevalence of antibodies against chlamydial heat shock protein 60 in rheumatic cohort ranged between 11.11-44.44%. Sensitivity of seroreactivity against species specific antigens of Chlamydia trachomatis in patients with uroarthritis was 52.78%. Sensitivity of reactivity of chlamydial heat shock protein 60 was 44.44%. There were nearly 4-times higher levels of antibodies against Chlamydia trachomatis and chlamydial heat shock protein 60 detected in the group of patients with uroarthritis in contrast to patients with enteroarthritis and other rheumatic diseases. Specificity of species specific antibodies and antibodies against chlamydial heat shock protein 60 to diagnose uroarthritis was 73.47% and 74.99%, respectively. Conclusion: Examination of species specific antibodies against Chlamydia trachomatis and antibodies against chlamydial heat shock protein 60 is of an auxiliary significance to diagnose uroarthritis.

        Key words: reactive arthritis, Chlamydophilla pneumoniae, Chlamydia trachomatis, chlamydial heat shock protein 60