Background: Cytokines have been implicated in the acute rejection of solid organ transplantation. Many studies have investigated the association between recipient or donor IL-4 polymorphism and acute rejection, with different studies reporting inconclusive results. Methods: We searched PUBMED and EMBASE until June 2012 to identify eligible studies investigating the association between IL-4 polymorphism with acute rejection after solid organ transplantation. Statistical analysis was performed using STATA10.0. Results: A total of 12 studies were included. Pooled ORs suggested 1) no significant association was detected between recipient or donor IL-4 - 590C/T polymorphism and acute rejection of solid allograft; 2) no significant association was detected between recipient IL-4 - 33C/T polymorphism and acute rejection of solid allograft; 3) when stratified by transplantation type, IL-4 - 590C/T polymorphism was associated with acute rejection of liver transplantation (T/T + C/T vs. C/C: OR = 0.36, 95%CI = 0.14-0.90); 4) significantly decreased risk of acute rejection was detected in recipient IL-4 - 590*T-negative/donor T-positive genotype pairs than all other recipient-donor IL-4 - 590T/C pairs (OR = 0.14, 95%CI = 0.03-0.66). Conclusions: Our meta-analysis suggested that recipient IL-4 - 590C/T polymorphism was associated with acute rejection of liver transplantation, but nor renal or heart transplantation. It was also suggested that combined recipient IL-4 - 590*T-negative/donor T-positive genotype may suffer decreased risk of acute rejection of solid allograft. Further well-designed studies with larger sample size were required to verify our findings, with focus on the association of IL-4 polymorphism with acute rejection in patients with liver transplantation and studies investigating combined recipient-donor genotype. (c) 2012 Elsevier B.V. All rights reserved.