Routine early biopsy of allografts with delayed function: correlation of histopathology and transplant outcome

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Abstract
Approximately 25–30% of our cadaveric renal transplant recipients have required post‐transplant dialysis. In an attempt to discern the etiology, routine biopsies were performed 7‐10 d post‐transplant and repeated weekly. All patients received a triple‐therapy cyclosporine‐based regimen with (N=61) or without (N=10) antilymphocyte induction. Rejection was classified as ‘early’ when it appeared on the first biopsy (8.9±0.3 d), ‘delayed’ when it appeared only on the second biopsy (17.9±1.0 d) and persistent when present on both biopsies. Adequate biopsy material was obtained from 71 patients who provided a total of 117 biopsies. Acute tubular necrosis was the most common finding (50%) in the first biopsy, while rejection occured in 30% of biopsies. Rejection on the first biopsy was strongly associated with primary nonfunction (PNF) (8 of 21 vs. 1 of 40, p≤0.0001). In contrast, eight patients without rejection on Biopsy I developed delayed rejection on Biopsy 2; only one was associated with PNF DGF persisted beyond the second week in 38 patients; 17 (38%) of which had rejection. Nine patients had persistent rejection 55% of whom experienced PNF compared to 6% without persistent rejection (p≤0.001). The occurrence of early rejection was associated with pretransplant peak PRA levels >50% (p=0.01). Graft survival for all patients was 79% and 65% at 1 and 2 yr. Rejection influenced 1‐yr graft survival for patients with persistent rejection who had 55% incidence of primary nonfunction and 1‐ and 2‐ yr graft survival rates of 42% and 37%. These data indicate that early biopsies are useful in unmasking rejection during DGF and at predicting primary nonfunction. Based on these data we recommend the routine utilization of biopsies for all patients with DGF.