Mitogenic Responses to Lipopolysaccharide by B Lymphocytes from Patients with Systemic Lupus Erythematosus

Peripheral blood lymphocytes from 43 patients with systemic lupus erythcmatosus (SLE) and from age- and sex-matched normal controls were cultured with lipopolysaccharide (LPS) to examine the response to the polyclonal B-cell activator. Lymphocytes from active SLE patients incorporated 4840±471 (mean ± SE) cpm in response to LPS, whereas lymphocytes from inactive SLE patients incorporated 6906 ± 897 cpm. In contrast, lymphocytes from normal individuals incorporated 7452 ± 1126 cpm. Ig synthesis of lymphocytes from active SLE in response to LPS stimulation was also less than that of normal individuals. The helper T-cell function of active SLE, as examined by co-culturing irradiated SLE lymphocytes with unirradiated normal lymphocytes, was normal. These results thus suggested that a defect of B lymphocytes exists in active SLE patients. This B-cell defect and T suppressor cells apparently play an important role in the pathogenous of SLE.