Immunoglobulin-secreting cells in SLE: correlation with disease activity.

Peripheral blood lymphocytes which contain and secret immunoglobulin were identified by fluorescent staining and a reverse hemolytic plaque assay. Significantly increased numbers of these cells were found in patients with active systemic lupus erythematosus compared with patients with rheumatoid arthritis, bacterial infections and normal controls. The increased numbers of these circulating activated B cells closely correlated with clinical and laboratory indices of disease activity, indicating their potential value in the management of lupus patients. However, the demonstration of pseudo-plaques in assays of lymphocytes from some lupus patients emphasizes the need to establish the true secreting nature of the plaques detected.