Mitogens of B and T cells from peripheral blood in rheumatoid arthritis.

Patients with rheumatoid arthritis (RA), 36 cases, and normal subjects, 49 cases were studied by lymphocyte cultures stimulated by phytohemagglutinin (PHA), Concanavalin A (Con A), pokeweed mitogen (PWM) and Con A convalently bound to Sepharose 4 B (Con A-S). The comparisons between the two groups showed a significant difference between the RA lymphocytes and the control lymphocytes stimulated by PHA and Con A. However, no statistical difference was found between the two lymphocyte populations stimulated by PWM and Con A-S. In order to determine the lymphocyte population stimulated by each mitogen, separation of B and T cells from peripheral blood was performed according to the ability for the T cell population to bind the sheep red blood cells (rosette-forming cells). The T cell-rich population was only stimulated by PHA, Con A and PWM. Although the T cell-depleted population showed no response to these mitogens, a response to Con A-S was elicited.