Positive association of DRB1*04 and DRB1*15 alleles with Fya immunization in a Southern European population
Résumé
BACKGROUND: Anti-Fya has been implicated in hemolytic transfusion reactions. However, not all Fy(a-) patients develop anti-Fya after transfusion with 1 unit of blood [Fy(a+)]. This study was designed to identify HLA-DRB1 alleles associated with a predisposition to Fya immunization after blood transfusion. STUDY DESIGN AND METHODS: To identify HLADRB1 alleles prone to immunization after blood transfusion or pregnancy, HLA-DRB1 genotyping using polymerase chain reaction with sequence-specific oligonucleotide nonradioactive probe/sequence-specific priming methods was performed on blood samples from 67 immunized patients and 200 unrelated controls from the same southern European population in a casecontrol retrospective study. RESULTS: Ninety-six percent of patients with anti-Fya had at least one HLA-DRB1*04 or HLA-DRB1*15 allele compared to 34% of controls (pc < 0.001). Furthermore HLA-DRB1*04 and HLA-DRB1*1501 frequencies were significantly increased in Fya-immunized patients (35% vs. 12%, pc < 0.001; and 30% vs. 19%, pc < 0.001, respectively). Among HLA-DRB1*04 allelic subtypes, DRB1*0401 and DRB1*0403 alleles were more strongly correlated with Fya immunization (51% vs. 24% and 19% vs. 9%; pc < 0.001, respectively). CONCLUSIONS: This study indicated that HLADRB1* 04 and DRB1*1501 are overrepresented in Fyaimmunized patients. The correlation between these alleles and Fya immunization could be due to a particular presentation of the Fya peptide in HLA-DRB1 molecules.
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