Alloimmunization and genotype-predicted Rh antigen expression among chronically transfused patients with thalassemia receiving prophylactic C, E, and Kmatched red cells. (A) Antibody specificities detected among 40 chronically transfused patients with thalassemia. Columns for each specificity indicate patients’ corresponding antigen status (positive or negative) as reported by standard serologic typing methods. RHD and RHCE genotype-predicted Rh antigen expression among 5 Black (B) and 35 non-Black (C) patients with thalassemia. Partial antigens predicted from genotypes associated with alleles that result in Rh epitope(s) missing and absence of conventional antigen. RHD*DAU0 or RHCE*ce48C has not been shown to encode Rh proteins lacking epitopes and is considered altered antigens.