Immunological studies on synovial joint membranes in psoriatic arthritis.

Psoriatic arthritis (PA) is included in the seronegative arthritis group, though it is now generally considered to represent a clinical entity. In PA, in contrast to psoriasis vulgaris and to other types of rheumatoid arthritis, only a few immunological studies have been reported. In the present report synovial joint membranes from patients with PA and control groups have been studied for the presence of (a) vascular changes, (b) fibrin, (c) immunoglobulins and complement factor C3.