Anti-C1q autoantibodies from active lupus nephritis patients could inhibit the clearance of apoptotic cells and complement classical pathway activation mediated by C1q in vitro

作者：Pang, Yun; Yang, Xiao-Wei; Song, Yan; Yu, Feng^*; Zhao, Ming-Hui

来源：Immunobiology, 2014, 219(12): 980-989.

DOI：10.1016/j.imbio.2014.07.004

• Anti-C1q autoantibodies
• Apoptosis
• Complements
• Lupus nephritis
• Systemic lupus erythematosus

Anti-C1q antibodies are prevalent in patients with active lupus nephritis and were found to be closely associated with renal involvement and predictive for a flare of nephritis. However, the pathogenesis of anti-C1q antibodies involved in human lupus nephritis remains unclear. C1q, which plays a key role in apoptotic cell and immune complex removal, is a very important functional molecule in the pathogenesis of SLE. The aim of this study was to investigate the influence of anti-C1q autoantibodies from active lupus nephritis patients on the bio-functions of C1q in vitro. We purified IgG autoantibodies against C1q from lupus nephritis patients, and found that they could recognize C1q bound on early apoptotic cells at 30 mu g/ml, and could significantly decrease the phagocytosis by macrophages of early apoptotic cells opsonized by 50 mu g/ml C1q in comparison with normal IgG. Levels of circulating immune complexes of the ten patients were measured by a circulating immune complexes (CIC)-C1q Enzyme Immunoassay Kit. Anti-C1q autoantibodies affinity purified by microtiter plates could significantly inhibit the deposition of C3c on CIC-C1q in a dose dependent manner in comparison with IgG from 10 healthy blood donors. The binding of opsonized immune complexes to RBCs was significantly inhibited by anti-C1q autoantibodies purified by microtiter plates in a dose dependent manner. Our observations suggest that serum anti-C1q autoantibodies from active lupus nephritis patients could interfere with some biological function of C1q in vitro.

• 出版日期2014-12
• 单位中国人民解放军总医院; 北京大学