B cell hyperactivity in systemic lupus erythematosus: selectively enhanced responsiveness to a high molecular weight B cell growth factor.
To characterize B cell hyperactivity in systemic lupus erythematosus (SLE) patients we studied the early events of B cell activation in 14 patients and controls. We measured B cell proliferation induced by three interleukin (IL) preparations (20-kDa B cell growth factor, BCGF, recombinant IL2 and 50-kDa BCGF) in the absence and in the presence of an anti-mu antibody (Ab). SLE B cells exhibited a markedly enhanced proliferative response to the 50-kDa BCGF in the absence of an anti-mu Ab, while responding normally in the presence of a first signal. This pattern of hyperactivity was observed in 11 out of 14 patients tested, and was absent in control patients. In contrast, SLE B cells behaved like normal B cells for the response to the other two IL tested, and to the anti-mu Ab alone. It should be pointed out that SLE B cells responded normally to recombinant IL2 whereas T cells from the same patients exhibited a decreased response to this IL. The selectively enhanced responsiveness of SLE B cells to the 50-kDa BCGF suggests that the events leading to B cell hyperactivity in this disease affect the early stages of B cell activation.
D000328:Adult; D000906:Antibodies / Q000276:immunology; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D005260:Female; D006133:Growth Substances / Q000494:pharmacology*; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D007376:Interleukin-2; D015847:Interleukin-4; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000494:pharmacology*; D008297:Male; D011994:Recombinant Proteins / Q000494:pharmacology
D000906:Antibodies; D006133:Growth Substances; D007376:Interleukin-2; D008222:Lymphokines; D011994:Recombinant Proteins; D015847:Interleukin-4; D007371:Interferon-gamma