STUDY OF THE RISK FACTORS OF ACUTE REJECTION AFTER LIVE DONOR RENAL TRANSPLANTATION:A SINGLE EGYPTIAN CENTER EXPERIENCE Ayman M Nagib¹, Ahmed S Elsaied¹, Ahmed F Donia¹, Amir M Elokely², Mohamad E Mohamed², Ahmed H Neamattalla¹, Ahmed A Shokeir¹ From the ¹ Department of Dialysis and Transplantation, The Urology and Nephrology Center, Mansoura University, Mansoura; and the ² Department of Nephrology, Zagazig University, Zagazig, Egypt Introduction 023 Kidney P241 Results Objectives Methods Conclusions References we can conclude that old donors, presence of acute tubular necrosis post-transplantation, renal transplant recipients who not received immunosuppression induction and recipients who not received rapamycin as primary maintenance immunosuppression are at high risk for occurrence of acute rejection episodes post- transplantation. This work aimed to evaluate the risk factors of acute rejection among renal allograft recipients, and its impact on both graft and patient survival among Egyptian live-donor renal allo-transplant recipients in Urology and Nephrology Centre, Mansoura University. This retrospective single Center study included 2227 kidney transplant recipients who were transplanted at Mansoura urology & nephrology Centre between 1976& 2013, the patients divided into three groups according to number of acute rejection episodes. (Group1) 963 patients who had no acute rejection episode post-transplantation. (Group2) 714 patients who had one episode of acute rejection post-transplantation. (Group3) 600 patients who had more than one episode of acute rejection post- transplantation. Comparing the three groups of renal allograft recipients to determine the risk factors of acute rejection using both univariate and multivariate analyses. Patient and Graft survival will also be studied in each group. 1.Yoo SW, Kwon OJ, Kang CM. Preemptive living-donor renal transplantation outcome and clinical advantages. Transplantation Proceedings. 2009; 41(1): Nankivell BJ, Stephen I Alexander. Rejection of the Kidney Allograft. N Engl J Med. 2010: 363: Journal Article, Name of Journal 3.Journal Article, Name of JournaMeier HU, Ojo AO, Hanson JA, et al: Increased impact of acute rejection on chronic allograft failure in recent era. Transplantation. 2000; 70: l 4.Matas AJ. Acute rejection is a major risk factor for chronic rejection. Transplant Proc. 1998; 30: Kyll¨onen L, Koskimies S, and Salmela K: Renal transplant recipients with graft survival longer than 20 years. Report on 107 cases. Transplantation proceedings. 2001; 33(4): Wang W, Li XB, Yin H, et al: Factors affecting the long term renal allograft survival. Chinese medical journal. 2011: 124(8): Renal transplantation represents the optimal treatment for patients with ESRD. When compared with dialysis, a successful renal transplant not only offers improved quality of life, better social rehabilitation, and less economic cost, even in high risk patients, but also allows a longer life expectancy (1). Rejection has always been the major obstacle. Transplantation of tissues or cells from a donor who differs genetically from the graft recipient induces an immune response in the recipient against alloantigens of the donor graft. If not controlled, this response will destroy the graft. (2). Acute rejection is a complex process of injury to the allograft caused by Infiltrating cells of host immune system, it lead to multiple responses within graft and is major risk factor for chronic rejection and loss of graft (3). Acute rejection episodes are a major determinant of renal allograft survival and still a major challenge for contemporary transplantation (4). Several studies implicated acute rejection as a major risk factor for chronic allograft failure (5). A previous report showed that an episode of acute rejection reduce the kidney graft half-life from 12.5 to 6.6 years (6) Figure (1) There was a statistically significant difference among the three groups regarding (10 years) graft survival (p-value <0.001). Figure (2) There was a statistically significant difference among the three groups regarding (10 years) patient survival (p-value <0.001) We found that donor age was statistically significant in both univariate and multivariate analyses with (p-value 0.002). As regard induction therapy, a highly statistical significance was found between there groups regarding presence and type of induction therapy (p-value <0.001). As regard maintenance immunosuppression, High statistically significant results were found regarding rapamycin between three groups (p value <0.001)in both univariate and multivariate analyses. Acute tubular necrosis post-transplantation was statistically significant in both univariate and multivariate analyses with (p-value< 0.001). Multi-variate analysis Regression estimate(B) S.E.EXP(B) P-value Donor age Immunosuppression induction No Yes <0.001 ATN No Yes <0.001 Rapamycin <0.001