Background: 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.
Methods: The presence and titer of anti-C1q antibodies were determined in a retrospective study including 63 SLE patients with biopsy-proven lupus nephritis.
Results: 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.
Conclusion: 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.