Impact of Red Blood Cell Antigen Matching on Alloimmunization and Transfusion Complications in Patients with Sickle Cell Disease: A Systematic Review.

Red blood cells (RBC) transfusion is critical in managing acute and chronic complications in sickle cell disease (SCD); however, it is complicated by RBC alloimmunization, iron overload, transfusion reactions and infection. Several reports documented an increased incidence of alloantibodies in transfused individuals with SCD, especially for Rh and Kell antigens. As a result, the National Institutes of Health Expert Panel and British Society for Haematology guidelines recommend primary matching for C/c, E/e and K antigens in addition to ABO/RhD for RBC transfusions. However, the evidence supporting these recommendations was cited as limited and understanding of alloimmunization in SCD is evolving. To examine the limitations of the evidence, we undertook a systematic review of evidence behind recommendations for limited and extended serologic and genotypic RBC antigen matching to reduce alloimmunization, autoimmunization and transfusion reactions. Searches of PubMed, Embase, Cochrane, and Web of Science databases using MeSH index and free text terms between 1976 through October 2015 and papers and captured through July 2016 through review references in papers, word of mouth, and ongoing Google Scholar and Medline Alerts identified 303 unique articles. Nineteen articles met inclusion criteria and were classified by the Oxford Centre Evidence Based levels of evidence. Strengthening the Reporting of Observational Studies in Epidemiology checklists were completed for 18 of the 19 studies. There were no prospective randomized controlled trials. Sixteen of the articles were cohort studies, two were cross-sectional studies, and one decision tree model examining costs. Low-quality evidence from observational cohort studies supports that alloimmunization prevalence can be decreased by extending serological RBC antigen matching. Transfusion reactions are generally poorly and inconsistently reported. There was no evidence reporting the effect prophylactic genotypic matching has on alloimmunization, autoimmunization or transfusion reactions. There were no studies comparing prophylactic genotypic matching to serologic matching. High-quality evidence was lacking to support clinical decision making regarding best transfusion practices. Multicenter prospective randomized clinical trials are needed to determine best strategies for reducing the rate of alloimmunization using serologic and genotypic matching.