The aim of this work was to evaluate histopathological and immunohisto- chemical differences between immune originated and degenerative synovitis.
Materials and Methods. The samples of synovial tissue were taken from the joint of 24 patients (11 men, 13 women), that underwent surgical treatment. 12 of these patients had diagnosis of rheumathoid arthritis and other 12 - degenerative synovitis. Further, the samples were prepared for histopathological and immunohisto- chemical analysis.
Results. There was significant histopathological differences between synovial samples. Synovitis of immune ori gin expressed higher blood vessels (p = 0.02899) and fibroblasts proliferaton (p=0.00004), significant edema (p=0.00011), more intence infiltration of immune cells (p=0.00127) and lymphoid follicle formation (p=0.00019), also expressed higher features of fibrosis (p=0.00127) and fibrinoid necrosis (0.00001).
Fol low ing immunohistochemical analysis we determined, that inflammation occured in immune originated as well as in degenerative synovitis, but in the first patients it was more severe, than in the others (p=0.000001). Rheumathoid arthritis patients also had higher TNF-a expression (p=0.038477). Our analys showed, that in both groups of patients expression of TNF-a and IL-6 is more localised in the intima and vessels of synovium, while expression of MMP-8 - in synovial fibroblasts.
Conclusions. Histopathological and immunohistochemical analysis of immune originated and degenerative synovitis showed significant differences in synovial fibroblasts and blood vessels proliferation, inflammation, immune cell infiltration and lymphoid foll icle formation as well as in TNF-a expression. However, there was no diferences in IL-6 and MMP-8 expres i sion between two groups of patients.

