Panhypogammaglobulinemia in systemic lupus erythematosus: in vitro demonstration of multiple cellular defects

Classically, systemic lupus erythematosus (SLE) is a disease of antibody overproduction, whereas the hallmark of acquired immune deficiency is antibody underproduction. Two patients are presented in whom panhypogammaglobulinemia developed during the course of SLE. In both patients, the levels of the major immunoglobulin (Ig) classes did not fall simultaneously. Anti-DNA antibodies were present, and exacerbations of SLE nephritis occurred in both cases 6 to 8 yr after Ig levels became subnormal. One patient still requires immunosuppressive therapy for renal disease; both patients are experiencing recurrent sinopulmonary bacterial infections. In the pokeweed mitogen-stimulated Ig biosynthesis assay, both patients showed abnormal Ig production due to defective function of three cell types: hyporesponsive B cells, excessive T suppression, and subnormal T help. The latter defect is rare in common variable hypogammaglobulinemia. One patient also showed extreme suppression of Ig production by phagocytic mononuclear cells. Thus, despite the similarity in the histories, the cellular function of these two patients was not identical in vitro.