The effect of acute rejection on long-term renal graft survival is mainly related to initial renal damage

Abstract

It has been suggested that poor long-term prognosis of acute rejection is due to hyperfiltration-mediated injury secondary to the initial renal damage, rather than to ongoing immunological mechanisms. A total of 953 renal transplant recipients was reviewed to examine the effect of acute rejection episodes on graft function and survival; 40 % had no rejections, 45 % one, 12 % two and 3 % three. Rejection episodes adversely affected short- and long-term prognosis (5-year survival for no rejections, 62 %; one, 34 %; two, 26 %; three, 19 %, P < 0.001) and creatinine clearance at one year (cl 1) (none, 56.7 ml/min; one, 51.1; two, 52.9; three, 35.2, P < 0.01). This was mainly due to increased graft loss, but patient survival was also reduced (5-year survival for no rejections, 77 %; one, 76 %; two, 63 %; three, 53 %, P < 0.05). There was no overall effect of rejection number, independently of cl 1. However, subgroup analysis showed a detrimental effect of rejection number on grafts with high residual function, i. e. cl 1 > 60 ml/min (5-year graft survival none and one, 87 %; two and three, 71 %, P < 0.01). Late initial rejection episodes adversely affected prognosis (5-year survival 1–7 days, 34 %; 8–60, 31 %; 60–300, 21 %, P < 0.05) and residual graft function (cl 1 1–7 days, 56.2 ml/min; 8–60, 48.7; 60–300, 44.6, P < 0.01). In conclusion, the poor long-term prognostic effect of rejection episodes is mainly, but not entirely, related to initial graft destruction. Late (> 2 months after transplantation) initial rejection is an important independent risk factor for graft loss.