Immunohistochemical analysis of the expression of main adhesion molecules and tumor necrosis factors in the synovial membrane of psoriatic arthritis

Objective: To define the expression and pattern of the synovial distribution of adhesion molecules such as E-selectin, ICAM-1 and VCAM-1 and of TNFα and TNFβ cytokines in psoriatic arthritis (PsA), according to the synovitis duration. Methods: Cryostatic sections of the synovial membrane tissue samples were stained for the different antibodies using a standard three-stage-immunoperoxidase-labeling technique. Results: E-selectin grade of staining was higher in those patients with a shorter disease duration compared to longstanding synovitic specimens, as well as ICAM-1 expression. On the contrary a higher VCAM-1 positivity was mainly found in longstanding PsA patients. Anti-TNFa positivity was found almost in all the specimens with no difference among the two groups, while the intensity of anti-TNFβ positivity was globally higher in longstanding cases. Conclusions: Different adhesion molecules may separately participate to the synovitic process in the different phases of PsA, leading to the hypothesis of their different involvement during the disease evolution. Moreover the upregulation of TNFα and TNFβ gives evidence to their local proinflammatory effect within the synovium and to their role in perpetuating the PsA synovitis.