The outcome of renal allograft C4d staining among indicated biopsies in Ramathibodi hospital

Abstract

C4d is a footprint of complement activation and diffusely stained in endothelium of peritubular capillaries (PTC) of renal allograft significantly associated with antibody mediated rejection (AMR). Association with C4d staining and poor graft outcome has been reported but some show little effects. Kidney transplant patients with indicated kidney biopsies in Ramathibodi hospital (151 patients, 181 specimens) during 2010–2012 with follow up durations of 12–30 months were enrolled in this retrospective cohort study. Graft survival/outcome, demographic, clinical and histological data were recorded and correlated with PTC C4d staining and graft survival. PTC C4d deposition was detected in 38.12% of allograft biopsies. AMR was diagnosed in 47 specimens while 107 specimens show minimal histologic change. Univariate analysis shows that pathological factors associated with graft loss are peritubular capillaritis, interstitial fibrosis, tubular atrophy, transplant glomerulopathy, arteriolar hyalinosis and C4d staining. Multivariate analysis of survival analysis shows that C4d deposition associated with graft loss, HR 11.37 (p = 0.021, 95% CI 1.45–89.15). In patients without rejection, C4d deposition was still associated with worse prognosis (10.21 vs 0.62 events/1000 patient-month, p = 0.012). Our study shows C4d positivity in 38% of indicated renal allograft biopsy and its significant association with poor renal allograft function and graft loss.