In this study we aimed to determine the prevalence, alloimmunization risk factors, antigenic exposure, and evaluation of antigen- (C, c, E, e, Mi<sup>a</sup> ) matched RBC transfusion.
However, although distinct alloantigens reside on the RBC surface at different levels, most alloantigens also represent completely different structures, making it difficult to separate the potential impact of differences in Ag density from other alloantigen features that may also influence RBCalloimmunization.
These findings raise the possibility that patients with IFN-α/β-mediated conditions, including autoimmunity and viral infections, may have an increased risk of RBCalloimmunization and may benefit from personalized transfusion protocols and/or targeted therapies.
Because of the high risk of alloimmunization of these patients and the labor-intensive nature of adsorption techniques, we decided to evaluate the feasibility of selecting antigen-matched units on the basis of RBC genotyping.
Alleles DRB1*04 and DRB1*15, as well as haplotypes DRB1*04-DQB1*03:02 and DRB1*15-DQB1*06:02 can be considered as risk factors, while allele DQB1*02 and haplotype DRB1*03-DQB1*02:01 have a protective role in Fy<sup>a</sup> alloimmunization.
Performing RHD genotyping for pregnant women with a weak D phenotype enables to clearly identify weak D type 1, 2 or 3 from the other variants at risk of alloimmunization.
The aim of the present study was to determine the relationship between HLA-DRB1*15:03, HLA-DRB1*11 and HLA-DRB1*09:01 alleles and alloimmunisation in Iranian thalassemia patients.
Frequencies of HLA-DRB1 alleles in individuals with antibodies against clinically relevant antigens were compared to a large population cohort to calculate odds ratios (ORs) for alloimmunization to different RBC antigens.
The D antigen includes category D, partial D, and weak D types, which are important because anti-D alloimmunization can occur in some but not all persons that express a variant RHD allele.
Our results suggest a strong association of alloimmunization with a cluster of HLA DR molecules sharing a particular polymorphic amino acid sequence at position 69-70 (Glu-Asp encoded by GAA-GAC nucleotide sequence) of the DR beta 1 chain (RR = 2.95, RR = 5.70 when patients were homozygous for this sequence), and a negative association with the DRB1*0301 allele (2.1% vs. 28%; RR = 0.08).