Frequent transfusion and specific HLA-DRB1 alleles correlate independently with Miltenberger blood group alloimmunization in dialysis patients.

Anti-"Mi " is the most frequent irregular RBC antibody in Taiwan due to high prevalence of Miltenberger antigens. Dialysis patients, a special patient group that needs frequent transfusions of RBCs, may have the greatest risk for developing anti-"Mi " antibodies. The aim of this study was to investigate the association between specific HLA-DRB1 alleles and Mi alloimmunization among dialysis patients. A cohort of 267 maintenance dialysis patients who had ever received at least one RBCs transfusion was enrolled. Anti-"Mi " was identified in patients' serum using the manual polybrene technique and HLA-DRB1 genotyping was carried out using polymerase chain reaction and sequence-specific oligonucleotide probe nonradioactive hybridization. Twenty-one (7.9%) of patients had positive anti-"Mi " tests and had received significantly more units of RBC transfusions than those without anti-"Mi " antibodies (11.3 ± 14.5 U vs 4.5 ± 10.1 U, P = .005). DRB1*04, *07, and 09 alleles were also more prevalent in patients with anti-"Mi " compared to those without Mi III alloimmunization. The multivariate logistic regression analysis showed that the number of RBC transfusions and the presence of DRB104, *07, and 09 phenotypes correlated independently with Mi III immunization (Odds ratios [OR] 1.05 (P = .001) for each unit of RBCs transfused; ORs 4.80 (P = .006), 12.29 (P = .005), and 5.42 (P = .003) for presence of DRB104, *07, and *09, respectively). This study is the first to demonstrate markedly high prevalence of Mi III alloimmunization in dialysis patients of Taiwan. Extending Mi III matching for RBC transfusions in susceptible dialysis patients may help to reduce the risk of Mi III alloimmunization in this patient population.