Spontaneous production of B cell growth factors by SLE lymphocytes.

Systemic lupus erythematosus blood lymphocytes produce B cell growth factors (BCGF) spontaneously to an extent comparable with pokeweed mitogen-stimulated lymphocytes from normal donors. BCGF production by SLE lymphocytes is not increased by PWM and these cells are refractory to exogenous BCGF. Production requires B cells and irradiated T cells but not accessory cells. The properties of spontaneously synthesized BCGF differ in some respects from those induced by PWM. These findings suggest that the abnormal B cell proliferation characteristic of SLE may result, at least in part, from autostimulatory growth factors.