Red‐blood‐cell alloimmunization and female sex predict the presence of HLA antibodies in patients undergoing liver transplant

Background Refractoriness to platelet transfusion because of HLA antibodies can jeopardize the outcome of patients who require platelet support during surgery. As routine screening for HLA antibodies would pose a huge burden on presurgical work‐ups, a stratification of patients according to the risk of having HLA antibodies is warranted. Study design and methods Clinical and laboratory data from 1351 patients submitted to liver transplant were analyzed to determine the accuracy of RBC alloimmunization and other patient features to predict the concomitant presence of HLA antibodies. Predictive variables were selected through binary logistic regression and their accuracy to prognosticate HLA alloimmunization was calculated by contingent table methods. Results RBC and HLA antibodies were detected in 70 (5·2%) and 71 (5·3%) patients, respectively. Female sex and RBC alloimmunization were the only patient features associated with HLA aloimmunization. Risk of being HLA immunized increased from male patients without RBC antibodies (n = 842; 1·5% with HLA antibodies) to female patients with RBC alloimmunization (n = 36, 36·2% with HLA antibodies), being of 9·7% in the remaining 473 patients. In women, the positive and negative predictive values of RBC alloimmunization to prognosticate HLA alloimmunization were 36% and 90%, respectively. In male patients, such values were 12% and 99%, respectively. The incidence of HLA immunization decreased after the introduction of universal leukoreduction in 2002. Conclusions RBC alloimmunized female patients that may require platelet support during liver transplant should be preoperatively evaluated for HLA antibodies. Such evaluation is unnecessary in male patients without detectable RBC antibodies. Decision‐making in the remaining patients must be individualized.