Objective. Identify the clinical, laboratory, and instrumental manifestations of reactive Chlamydophila pneumoniae associated arthritis.

Materials and methods.The clinical, laboratory and instrumental data of 34 patients with reactive Chlamydophila pneumoniae associated arthritis were analyzed.The patients aged 42.0±2.3 years in the average. The average reactive arthritis duration was 12 (6—24) months.Chlamydophila pneumoniae infection was diagnosed by the following methods: real-time PCR in the samples from the oral cavity, urethra, cervical canal, synovial fluid, PCR of the nucleic acids isothermal amplification in the synovial fluid as well as detection of specific antibodies (Ig M, Ig A, Ig G) in the blood by ELISA. The data was processed using the MS Exel and Statistica 10 (serial number BXXR207F383402FA-V) software.

Conclusion. Reactive Chlamydophila pneumoniae associated arthritis usually occurs in women (76.5%) of a young or middle age (91.1%).The disease debuts mainly with arthritis of the lower extremities (81.8%) more often of the knee joints (63.6%). As the reactive arthritis progresses, oligopolyarthritis (82.3%) dominates in the clinical picture occurring usually without fever (76.5%), skin hyperemia over the joints (23.5%) and extra-articular manifestations (91.2%).The periarticular tissues may be involved with enthesis, ligaments and periarticular bags (41.1 %) lesions and persistent myalgia (8.8 %).The reactive Chlamydophila pneumoniae associated arthritis differs from the reactive Chlamydia trachomatis associated arthritis characterized by the polyarthritis prevalence at the disease onset (p=0.019) accompanied by lesions of predominantly small joints of the hands (p=0.011).As the disease progresses, the differences in the clinical picture of reactive arthritis caused by different chlamydial infections disappear.However, in the reactive Chlamydophila pneumoniae associated arthritis, the inflammatory changes in the blood cannot be detected in a larger number of patients.