The DAU Allele and Anti-D Alloimmunization Present With High Frequency in Brazilian Sickle Cell Disease Patients

BACKGROUND: Antigens DIIIa, DAR and DAU are common in people of African descent and are involved in anti-D alloimmunization. Sickle cell disease (SCD) patients frequently need blood therapy and are vulnerable to alloimmunization. METHODS: The study included SCD patients from the Brazilian state of Bahia, which has the highest incidence of the disease in Brazil; 241 SCD patients and 220 healthy individuals were studied. Alleles were characterized by PCR-RFLP and PCR-SSP techniques. RESULTS: The DAU allele was found in 22.3% (43/193) of the SCD patients. Two (1%) patients had the DIIIa/D wild-type genotype, one (0.5%) had the DIIIa/D- genotype, 11 (5.7%) had the DAR/D wild-type genotype and three (1.6%) had the DAR/D- genotype. Two patients were positive for the 667T>G mutation and the 1136C>T mutation, one (0.5%) had the genotype DIIIa/DAU, and one (0.5%) had the genotype DAR/DAU. CONCLUSION: There was statistical significance when the allele frequencies were evaluated among SCD, sickle cell anemia (HbSS) patients and healthy individuals. The frequencies of the DIIIa, DAR and DAU alleles among SCD patients differ from those of healthy individuals from the same population, and a high frequency of the DAU variant was associated with anti-D alloimmunization in these patients.