The relationship of renal histopathological lesions to immunoglobulin classes and complement fixation of anti-native DNA antibodies in systemic lupus erythematosus.

The relationship of renal immunohistopathological lesions to the immunoglobulin classes (Ig) and complement fixation (CF) of anti-native DNA antibodies (anti-nDNA) in sea was studied in 20 patients with systemic lupus erythematosus (SLE) on whom renal biopsy was performed. The Ig classes and CF of anti-nDNA were assessed by the indirect immunofluorescent and complement fixation methods employing kinetoplasts of Crithidia luciliae as substrate. The histopathologically active lesions of lupus nephritis showed a significant correlation with the IgG and complement fixation of anti-native DNA antibodies in sera. IgM anti-nDNA superiority was not necessarily observed in patients with inactive histological lesions, but rather in those with thickening of the glomerular basement membrane. The granular deposits of immunoglobulin or complement in the renal glomeruli showed a significant correlation with the presence of IgG and CF of anti-nDNA in sera, while the deposition of C3 in the glomeruli also showed a significant correlation with the CF of anti-nDNA.