IMPLEMENTATION OF HIGH-RESOLUTION HLA TYPING IN A PUBLIC HEMATOLOGY CENTER REVEALS NOVEL ALLELES AND IMPROVES DONOR REGISTRY REPRESENTATION IN THE BRAZILIAN AMAZON

Human leukocyte antigens (HLA) are pivotal for immune recognition and critically influence outcomes in hematopoietic stem cell transplantation (HSCT), with HLA compatibility being a major determinant of graft success. In this context, we established a high-resolution HLA typing pipeline based on next-generation sequencing (NGS) at the Fundação Hospitalar de Hematologia e Hemoterapia do Amazonas (HEMOAM), aiming to expand regional representation in the Brazilian Bone Marrow Donor Registry (REDOME) and improve patient care. DNA was extracted from whole blood samples of volunteer donors at HEMOAM using the PureLink DNA Kit (Invitrogen). Libraries were prepared with the AllType FastPlex kit (OneLambda) and sequenced on the Illumina MiSeq platform. The TypeStream Visual NGS Analysis Software was used to help identify HLA alleles. To date, 175 individuals have been genotyped and successfully integrated into REDOME. We identified a novel exonic HLA variant, A02NOVO (T > G, Trp→Gly), in a volunteer donor. Additionally, 280 novel intronic variants were detected. HLA-B and HLA-DPB1 emerged as the most polymorphic loci within the cohort, with the latter ranking fifth among South American populations. This implementation enabled the incorporation of advanced immunogenetic technology in a public hematology center and contributed to increasing the genetic diversity of REDOME. The detection of novel alleles underscores the immunogenetic uniqueness of the Amazonian population and highlights the relevance of regionally driven initiatives for enhancing HSCT outcomes, supporting association studies, and informing public health and precision medicine policies.