Circulating immune complexes in patients with systemic lupus erythematosus.

Abstract

Circulating immune complexes (CIC) were studied in seventy-one patients with systemic lupus erythematosus (SLE) in order to correlate CIC with the clinical manifestations and the disease activity of SLE. C1q-solid phase ELISA (C1q-SP) and microtiter plate Raji cell-ELISA (Raii cell) methods were used for measurement of CIC levels in this study. Patients with elevated CIC had a higher frequency of malar rash, CNS involvement, nephritis, and anti-dsDNA antibodies than those with normal levels of CIC. There were negative associations between CIC detected by the C1q-SP method and C1q, and factor B; while CIC detected by the Raji cell method negatively correalated with C3, C4, CH50, C3c, factor B, and factor H. The CIC levels were well correlated with the disease activity of SLE. The more active the disease, the greater the increase of CIC. These suggest that serial measurement of CIC is helpful in monitoring the disease activity of SLE.