THE SPECIFIC ANTIBACTERIAL PROLIFERATION OF REACTIVE ARTHRITIS SYNOVIAL T-CELLS IS NOT DUE TO THEIR HIGHER PROPORTION OF CD45RO-BLOOD( CELLS COMPARED TO PERIPHERAL)

Objective. To determine the role of synovial fluid (SF) compared to pe ripheral blood (PB) CD45RO+ T cells in patients with reactive arthriti s (ReA) and undifferentiated oligoarthritis. Methods. We examined SF a nd PB of 8 patients with a specific lymphocyte proliferation to Yersin ia enterocolitica (n = 5) and Chlamydia trachomatis (n = 3). After dep letion of the CD45RA+ T cell subset by dynabeads, the remaining T cell s (> 95% CD45RO+) from PB and SF of these patients were again stimulat ed with these bacterial antigens. Results. The mean stimulation index (SI) of these 8 patients with ReA (n = 5) and undifferentiated oligoar thritis (n = 3) was 30.3 +/- 21.86 in SF compared to 1.36 +/- 0.75 in PB. The enrichment of CD45RO+ cells influenced the antigen specific pr oliferative response of T cells neither in PB (SI = 1.75 +/- 1.35) nor in SF (26.1 +/- 24.05); the initial difference remained unchanged. Co nclusion, Our findings suggest that the antigen specific lymphocyte pr oliferation obtained with SF cells is not due to abundance of nonspeci fic CD45RO+ T cells but can rather be taken as an indication of specif ic recognition of local bacterial antigens in ReA.