Circulating immune complexes in systemic lupus erythematosus. Association with other immunologic abnormalities but not with changes in renal function.

In a study of the usefulness of two widely performed tests for immune complexes (IC) in the assessment of disease activity of lupus nephritis the Raji cell assay detected IC in sera of 14 of 32 patients and the monoclonal rheumatoid factor (MRF) test in only five. There was a close correlation of levels of IC with number of organ systems showing disease activity and with serum complement levels and a somewhat less significant correlation with serum levels of anti-DNA. Although in a few patients levels of IC closely paralleled improvement in renal function with treatment, there was no overall correlation of changes of levels of IC with changes in creatinine clearance. Measurement of circulating IC in lupus nephritis cannot at present be justified as a worthwhile clinical measurement in the management of such patients.