1994 Volume 36 Issue 4 Pages 345-354
The serum levels of circulating immune complexes (CIC) measured by three different types of enzyme immunoassay (ETA) using monoclonal anti-C1q and anti-C3d antibodies and C1q as solid phase reagents were compared with clinical disease activity and immunohistological glomerular lesions in 29 SLE patients. Three types of CIC measured by these assays (anti -C1q CIC, anti-C3d CIC and C1q SP CIC) showed significantly higher levels in patients than in controls and were significantly associated with the clinical and serological disease activities . Anti-C1q CIC showed good correlation not only with mesangial IgG depositions (P <0.01), but also with that of C1q (P <0.05). Clq SP CIC also showed a weak correlation with mesangial C1q deposition (P < 0.05). Serum levels of anti-C3d CIC increased with the degree of mesangial IgG and complement depositions . Analysis of the clinical course of a patient with active SLE revealed a more rapid decrease of anti-C1q CIC and anti -C3d CIC along with the improvement of disease activity, including the mesangial lesion, than that of C1q SP CIC. According to these results, the CIC detected with assays using monoclonal antibodies against complement fragments, especially the anti-C1q assay, is likely to provide specific information regarding the clinical, serological and immunohistological disease activity in lupus nephritis.
