Objective To discuss the clinicopathological characteristics and prognosis of the recurrence of IgA nephropathy (IgAN)after renal transplantation.Methods A total of 1 48 patients,pathologically diagnosed with IgAN which progressed into end-stage renal failure,undergoing renal transplantation in National Clinical Medical Research Center of Kidney Diseases,Nanjing General Hospital of Nanjing Military Command from January 1 996 to April 2009,were included in this study.According to whether IgAN recurred,all patients were assigned into recurrence (n =46)and non-recurrence groups (n =1 02).Urinary red blood cell (U-RBC)count,24 h urinary protein level,renal function including serum creatinine (Scr)and glomerular filtration rate (GFR)at 0,1 ,2,3 and 5 years after renal transplantation were statistically compared between two groups.The incidence of histopathological renal injury and survival rate of transplant kidneys was compared between two groups.Results In recurrence group,U-RBC count and 24 h urinary protein level were gradually elevated and renal function steadily declined.Compared with non-recurrence group,U-RBC count at 2-,3-and 5-year after renal transplantation significantly increased,and renal function was significantly aggravated at postoperative 5 years (all in P<0.01 -0.001 )in recurrence group.Renal pathological findings revealed that compared with non-recurrence group,the incidence of cellular crescent formation,glomerulus adhesion,mesangial cell proliferation,increased mesentery matrix, glomerulosclerosis,segmental glomerulosclerosis,glomerular dysfunction and tubulointerstitial fibrosis was significantly higher in recurrence group (all in P <0.001 ).After renal transplantation,chronic kidney injury index in recurrence group was 7.7 ±2.3,which was significantly higher than 4.6 ±1 .4 in non-recurrence group (P <0.01 ).Compared with non-recurrence group,the incidence of chronic rejection,glomerulopathy of transplant kidney (without IgAN)and positive C4d deposition was significantly higher in recurrence group (P <0.01 -0.001 ).At 1 -and 3-year after renal transplantation, survival rates of transplant kidney did not significantly differ between recurrence and non-recurrence groups (93.8% vs.86.7%,95.6% vs.88.3%,both in P >0.05).However,the survival rate at 5 years after transplantation was 51 .4% in recurrence group,significantly lower compared with 83.8% in non-recurrence group (P <0.001 ).In recurrence group,1 0 patients (22%)presented with renal failure after renal transplantation,and 9 patients (9%)in non-recurrence group.Conclusions After renal transplantation,the recurrence of IgAN characterized by asymptomatic microscopic hematuria, albuminuria and progressive aggravation of renal function reduce long-term survival rate of renal graft and indicate poor prognosis.