Psoriatic arthritis and HLA antigens.

HLA groups including the characteristics of 25 antigens were determined in 108 patients suffering from psoriatic arthritis. These included 18 patients with central forms (pelvospondylitis), and 90 patients with peripheral forms (polyarthritis with or without sacroiliitis). Analysis of the results leads to the following conclusions: central psoriatic arthrisis is strongly associated with B27 and BW38, less closely with B13 and slightly with BW17. Peripheral psoriatic arthritis has the same relationship with the HLA system as has psoriasis without arthropathy.