In vitro lymphocyte response in early rheumatoid arthritis.

Streptokinase-streptodornase (SK-SD) skin tests and peripheral blood mononuclear stimulation to purified SK-SD delayed skin reactor (DSR) and phytohemagglutinin (PHA) was assessed in 41 patients with rheumatoid arthritis (RA) and 17 controls. Lymphocyte response to DSR correlated directly with the diameter of SK-SD-induced erythema, and PHA stimulation decreased with age. RA patients did not show significant depression by either test or did hyporesponsiveness predict rheumatoid disease activity or prognosis. Six patients without medication demonstrated increased PHA responsiveness and a direct rather than inverse correlation with age.