SP850ACUTE KIDNEY INJURY IN RENAL TRANSPLANT PATIENTS. CLINICAL AND HISTOLOGICAL PARAMETERS OF DISMAL RENAL OUTCOME

Abstract

Introduction and Aims: Recognition of acute rejection (AR) episodes in patients with renal transplant is crucial for their outcome. Therefore, in any acute clinical unexplained deterioration of renal function a quick diagnosis is needed. Renal biopsy, still represents the gold standard for this recognition. Aiming for Clinical and Histological evaluation of Acute Kidney Injury in patients with renal transplant, we retrospectively analyzed our data on such cases. Methods: In forty seven (47) patients (31 men), of mean age 53±13 years who presented with acute decline of renal function 9.6 months (median value, range 0.6-216 m), after the date of transplant, a renal biopsy was performed. Delayed graft function (DGF)suffered 42 pts (89%). In 19 patients (40%) the allograft was from extended criteria donors (ECD) All patients were on triple immunosuppressive treatment (CNI's, steroids, MPA). Estimated GFR immediately before AKI was 34±24 ml/min, while during the acute phase of decline of renal function eGFR was 24±14 ml/min Results: In 27 patients (57%), acute rejection episode was the cause of acute deteriortaion of renal function (cellular rejection 23, humoral 1, mixed 3). C4d positivity was present in 12 patients. From the rest, seven pts presented histological findings of chronic allograft nephropathy(IFTA-banff 5) and 13 suffered from other disorders (interstitial nephritis, CNI toxicity). Acute rejection was treated with steroids (23 pts), with anti-thymocyte globulin (ATG) (4 pts) while in the rest, treatment modification strategies were adopted (course of steroids, switch to everolimus, RAAS inhibitors, CNI minimization etc.). After therapy, improvement of renal function was noticed in 21 pts (eGFR 30±20), stabilization in 15 while 11 entered to end stage renal disease in a period of 0.6±0.5 years. In six pts CMV disease was developed that was treated successfully and 17 developed urinary infections treated without complications. There were no deaths of pts during the follow up. Statistical analysis showed that HLA mismatch, gender, donor and recipient age and the presence of infection, were not correlated to the dismal renal survival of these pts. On the other hand, humoral and mixed type rejection, C4d positivity, the presence of glomerular and vascular sclerotic changes led to reduced GFR and ESRD (p=0.002, 0.003, 0.01 respectively). The histological changes were higher in allografts from extended criteria donors with delayed graft function. Conclusions: In these patients with the high incidence of delayed graft function, acute kidney injury was mainly the result of acute rejection episode. Dismal outcome of renal survival (reduced GFR, ESRD) was related to acute humoral and mixed rejection type, C4d positivity and glomerular and vascular sclerotic changes, the later mainly attributed to allografts from extended criteria donors and to the high incidence of DGF which is known to be related to decreased future GFR of allografts. Hence caution is needed for the allocation of such grafts.