Expression of cytolytic protein-perforin in synovial tissue and synovial fluid lymphocytes in rheumatoid arthritis

Rheumatoid arthritis (RA) is considered to be an autoimmune disease with the significant participation of T cells. In the synovial fluid of patients with RA increased number of CD8+ lymphocytes was found with the cytotoxic rather than the supressor function. The aim of this study was to add to the understanding of the role of cytolytic molecule perforin (P), located in the granules of cytotoxic lymphocytes, in the pathogenesis and mechanisms which are responsible for joint and soft tissue destruction in patients with rheumatoid arthritis. Using direct and indirect immunoflorescence we measured the percentages of CD3, CD4, CD8, CD16, CD56, CD25 and P+ cells in peripheral blood, synovial tissue, and synovial fluid of patients in acute phase of RA. The phenotypic analysis included estimation of double (P and sufrace antigen) positive cells. The results were compared with those obtained from patients with traumatic knee injuries. Analysing double positive cells we found higher percentages of all examined double positive cells in the joint (local level) in comparison with double positive cells in peripheral blood (systemic level) in patients with acute RA. The only exception was observed in expression of CD25 molecule which was almost equal on systemic and local level. The percentages of all examined double positive cells on both levels in RA patients were higher than in patients with traumatic knee injuries. These results provide the evidence implicating cytolytic lymphocytes in the pathogenesis of RA and suggest that the perforin and P+ cells are included in possible mechanisms of joint and tissue destruction.