Association between anti-C1q antibodies and glomerular tuft necrosis in lupus nephritis

Abstract

Proliferative glomerulonephritis includes various glomerular lesions in patients with systemic lupus erythematosus (SLE) that might have distinct pathogenic mechanisms. The aim of the study was to determine whether anti-C1q antibodies, which are associated with lupus nephritis, were specifically associated with given glomerular histopathological lesions. The presence and titer of anti-C1q antibodies were determined in a retrospective study including 63 SLE patients with biopsy-proven lupus nephritis. We confirmed the correlation between the presence of anti-C1q antibodies with both clinical and immunological markers of disease activity. We showed that the presence of anti- C1q antibodies was significantly associated with glomerular tuft necrosis and crescents, major criteria of active lesions. Additionally, no necrosis was found in patients without anti- C1q antibodies, giving anti-C1q antibodies a 100% negative predictive value for glomerular tuft necrosis. Conversely, there was no difference in the percentage of glomeruli showing endocapillary proliferation or wire loops according to the anti-C1q status. Our data highlight for the first time an association of anti-C1q antibodies with necrotizing forms of lupus nephritis suggesting new insights into the pathogenesis and the treatment of this entity.