Clinical analysis of anti-neutrophil cytoplasmic antibody-associated vasculitis with low serum complement C3 levels

XIE Lijiao; ZHANG Rui; HE Jianghua; TANG Sha; WANG Weili; LIU Xing; ZHANG Jun; LI Furong; ZHANG Jingbo

doi:10.13431/j.cnki.immunol.j.20170073

Abstract：To investigate the clinicopathological features and outcomes of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) with low serum complement C3 (sC3) levels,total of 54 patients with AAV underwent renal biopsy were analyzed by retrospective observational study in our department from January 2011 to March 2016.The sC3 levels of AAV patients were determined by immunoturbidimetric method,then the patients were divided into two groups of the low sC3 group (sC3＜0.9 g/L) and the normal sC3 group (sC3≥0.9 g/L)based on the lower limit of sC3 normal range.The patients were compared in baseline variables,laboratory data,clinical symptoms,histological features and therapeutic outcomes after treatments.Data showed that patients with lower sC3 presented a higher level of initial serum creatinine than patients with normal sC3 (P=0.008).The levels of c-reactive protein and eGFR were significant lower in low sC3 group than those in normal sC3 group (P＜0.001,0.012,respectively).Furthermore,the incidences of rapid progressive renal failure and renal replacement therapy at diagnosis were higher significantly in the low sC3 group than those in normal sC3 level group (P=0.035,0.014,respectively).However,the incidence of remission was lower in the low sC3 level group than that in normal sC3 level group (P＜0.001).The low sC3 group showed worse renal survival than normal sC3 level group (log-rank=10.197,P=0.001) confirmed by Kaplan-Meier analysis.Our results indicated that AAV patients with low sC3 levels tend to have severe renal impairment with a rapid progression and poor prognosis.