Protooncogene expression in peripheral blood mononuclear cells from patients with systemic lupus erythematosus as an indicator of the disease activity.

In the present study, we examined the various protooncogene expressions in PBMC (peripheral blood mononuclear cell) of systemic lupus erythematosus (SLE) patients to determine if they could be an indicator for the disease activity. We divided SLE patients into "very active," "active," and "remitting" states according to the clinical symptoms in addition to the laboratory data peculiar to SLE. In addition, we determined the amount of circulating immune complex (IC) as one of the representative laboratory indicators for the disease activity. We found a positive correlation with either c-myc or c-myb expression and the amounts of IC and clinical disease activity. The degree of c-myc and c-myb expression was significantly reduced along with or prior to the amelioration of clinical symptoms and improvement as determined by laboratory data under treatment with prednisolone and/or azathioprine administration. The degree of c-myc and c-myb gene expression had no direct relation to the presence of particular clinical sign(s) or autoantibody. The expression of the c-raf gene was found in SLE and other systemic autoallergic patients although it showed no correlation with the disease activity. No significant expression of c-src, c-ras, c-fos, c-fgr, c-fps, c-fes, c-fms, c-yes, c-rel, c-abl, c-mos, c-sis, and c-erb B genes was found in the patients. c-myc and c-myb expression as having pathogenic and clinical significance is discussed.