Can histopathological findings in early renal allograft biopsies identify patients at risk for chronic vascular rejection?

Abstract

In order to assess the prognostic value of renal transplant biopsies for identifying patients at risk for chronic vascular rejection (CVR), 99 biopsies performed at 6 months after renal transplantation were evaluated as part of a prospective study. A chronic graft damage (CGD) score was calculated from the scores of vascular intimal hyperplasia, glomerular mesangial changes, focal lymphocytic infiltration, focal and diffuse interstitial fibrosis, and tubular atrophy, features compatible with CVR. The mean score for the whole patient population was 4.7±2.9 (range 0‐11). There was a strong association between the CGD score at 6 months and the risk of graft loss up to 2 and 3 years following transplantation. Patients with a CGD‐score of ≥6 had a higher graft loss rate at 2 years than those with a score of <6 (6/35 vs 2/54; p=0.037). In patients with a functioning graft at 2 years, the CGD‐score at 6 months correlated with graft function at 2 years. In addition to higher serum creatinine (p= 0.003) and lower GFR (p=0.01), patients with a CGD‐score of ≥6 at 6 months also had a higher degree of albuminuria (p=0.008) at 2 years as compared with patients with a CGD‐score of <6. At 3 years 10/35 patients with a CGD score of ≥6 and 2/54 patients with a CGD‐score of <6 had lost their grafts (p=0.002). The relative risk for graft loss associated with a CGD‐score of ≥6 was 7.65. In patients with a functioning graft there was still a significant positive correlation between graft function at 3 years and the CGD‐score at 6 months (p=0.003). In conclusion, the histopathological picture at 6 months is a prognostic indicator of graft function and graft loss at 2 and 3 years after transplantation. Patients with a high CGD‐score, as indicated here ≥6, may benefit from pharmacological or other interventional measures directed towards the progression of CVR.