Correlative studies of lymphocyte transformation and plasma protein levels in ankylosing spondylitis.

Lymphocyte transformation was studied in 24 patients with ankylosing spondylitis (AS), 21 with rheumatoid arthritis (RA) and 23 control subjects (CS). Enhanced transformation was found in response to phytohemagglutinin (PHA) (p less than 0.01) and human aggregated gamma globulin (p less than 0.025), but not to inulin, for AS patients. Correlation coefficients between the concentrations of each of 8 AS plasma proteins and PHA-induced lymphocyte transformation in autologous plasma showed significance only for C-reactive protein (CRP). However, co-culture experiments with PHA in autologous and allogeneic (AB) plasma, and in CRP-devoid AB serum showed no specific enhancing effect by AS plasma on lymphocyte responses. Although these studied demonstrate that AS is frequently characterized by enhanced in vitro transformation to T lymphocyte dependent mitogens, this response does not appear to be related to the known immunoregulatory properties of CRP.