Researchers from the Sanquin-LUMC in the Netherlands have concluded that female sex alone is not sufficient to recommend extended crossmatching of red blood cells to prevent alloimmunization. Led by Dr. Esther Verduin, the group conducted a systematic review of 30 observational studies from 1974 through 2011, which assessed a total of 11,034 transfusion recipients with 1,535 cases of alloimmunization. Among adult transfusion recipients with hemoglobinopathies, pooled analysis suggested that females were 22% more likely than males to experience red blood cell alloimmunization. Stratification by hemoglobinopathy demonstrated that transfused females with sickle cell disease were 27% more likely to become alloimmunized than transfused males with sickle cell disease. However, among transfused thalassemia patients, females and males faced similar alloimmunization risks. The pooled analysis also found that among adult patients without hemoglobinopathies and pediatric patients with hemoglobinopathies, there were no significant differences in alloimmunization risk between sexes. The research group suggested that the small increase in alloimmunization risk among female sickle cell patients could be attributed to increased exposure to immunizing events through pregnancy and an increased life expectancy compared to males. Therefore, they proposed that aside from prophylactic c and K antigen matching for fertile women to prevent severe hemolytic disease of the fetus and newborn, extended antigen matching should not be implemented simply based on sex.
1. Verduin EP, Brand A, Schonewille H. Is female sex a risk factor for red blood cell alloimmunization after transfusion? A systematic review. Transfus Med Rev 2012;26: 342-53 e5.