The objective of this retrospective study was to evaluate the role of MICA in heart graft acceptance. Pre- and post-transplant sera from 31 patients were evaluated for MICA antibodies by cytotoxicity on recombinant cell lines and soluble MICA (sMICA) concentrations by ELISA. The results demonstrated that the patients with post-transplant anti-MICA antibodies were at a high risk for the development of severe acute rejection (AR) (p