Serum levels and renal deposition of C1q complement component and its antibodies reflect disease activity of lupus nephritis

摘要

Background Lupus nephritis is considered to be a principal cause of morbidity and mortality in SLE. Few studies focus on the association between anti-C1q antibodies in circulation and renal C1q deposition in human lupus nephritis. In this study, we detected the serum levels of C1q, presence of anti-C1q antibodies in circulation, renal C1q deposition and further analyzed their associations with clinical and pathological activity in a large cohort of Chinese lupus nephritis patients. Methods Sera and renal biopsies from 218 consecutive patients with lupus nephritis with long-term follow up data were studied. Sera were tested for levels of C1q and anti-C1q autoantibodies. Associations of levels of C1q, anti-C1q autoantibodies with renal deposition of C1q, clinical and histopathological data and renal outcome were further investigated. Results The levels of serum C1q were significantly lower in lupus nephritis than that in normal controls [33.81?±?20.36 v.s. 61.97?±?10.50?μg/ml (P?P?, P?=?0.012, respectively), renal total activity indices scores (P??0.001, P?P?P?P?=?0.203). Conclusion Anti-C1q autoantibodies were closely associated with serum levels of C1q and glomerular deposition of C1q. Kidney is at least one of the target organs of anti-C1q autoantibodies.