The 1987 ACR classification criteria for rheumatoid arthritis were criticized for their lack of sensitivity in early disease. To overcome this limitation, new criteria have now been developed. The... Show moreThe 1987 ACR classification criteria for rheumatoid arthritis were criticized for their lack of sensitivity in early disease. To overcome this limitation, new criteria have now been developed. The question is how will these criteria be implemented in clinical and basic research, and in daily clinical practice? Show less
Willekes, C.; Post, J. van der; Mol, B.; Roumen, F.; Boers, K.; Delemarre, F.; ... ; Wijnen, E. 2011
Introduction: Mast cells have been implicated to play a functional role in arthritis, especially in autoantibody-positive disease. Among the cytokines involved in rheumatoid arthritis (RA), IL-17... Show moreIntroduction: Mast cells have been implicated to play a functional role in arthritis, especially in autoantibody-positive disease. Among the cytokines involved in rheumatoid arthritis (RA), IL-17 is an important inflammatory mediator. Recent data suggest that the synovial mast cell is a main producer of IL-17, although T cells have also been implicated as prominent IL-17 producers as well. We aimed to identify IL-17 expression by mast cells and T cells in synovium of arthritis patients.Methods: Synovial samples of anticitrullinated protein antibody-positive (ACPA+) and ACPA-negative (ACPA-) RA and osteoarthritis (OA) patients were stained for IL-17 in combination with CD117 (mast cells), CD3 (T cells) and CD68 (macrophages). Concentrations of IL-17 in synovial fluid were determined by ELISA.Results: The number of IL-17+ cells in synovium was comparable in all groups. Although the vast majority of IL-17+ cells are mast cells, no difference in the percentage of IL-17+ mast cells was observed. Nonetheless, levels of IL-17 in synovial fluid were increased in ACPA+ RA patients compared to ACPA-RA and OA patients.Conclusions: The synovial mast cell is the main IL-17+ cell in all three arthritis groups analyzed. These data are relevant for studies aimed at blocking IL-17 in the treatment of arthritis. Show less