Significance of subclinical rejection in early renal allograft biopsies for chronic allograft dysfunction

To determine the significance of early subclinical rejection of renal allografts, we reviewed 127 biopsy specimens obtained soon after transplantation. Histological finding was categorized according to a modification of the Banff scheme as: acute rejection (AR), borderline changes (BL); non-specific inflammatory changes, (NI) and no rejection (NR). Subclinical rejection was defined as AR, BL or NI. Patients with BL or NI were divided into two groups; one was treated with high-dose methylprednisolone (MP), the other remained untreated. Freedom from chronic allograft dysfunction (defined as non-doubling of serum creatinine 5 yr after transplantation) was significantly more frequent in the NR group (89%) than in the BL (70%) and AR (64%) groups. At 1 yr after transplantation, mean serum creatinine had increased significantly only in the untreated group (p < 0.05), and re-biopsy showed that interstitial fibrosis had developed to a significantly greater extent in the untreated group than in the treated group (p < 0.01). Subclinical rejection in the early protocol biopsies correlated closely with subsequent allograft dysfunction. High-dose MP treatment for early subclinical rejection may be effective in suppressing the development of interstitial fibrosis at 1 yr after transplantation.