Escape hematopoiesis by HLA-B5401-lacking hematopoietic stem progenitor cells in men with acquired aplastic anemia

Leukocytes that lack HLA class I alleles derived from hematopoietic stem and progenitor cells (HSPC) that undergo copy number-neutral loss of heterozygosity of the short arm of chromosome 6 (6pLOH) or HLA allelic mutations are often detected in patients with aplastic anemia (AA). The presence of HLA class I allele-lacking leukocytes provides compelling evidence that cytotoxic T-lymphocytes (CTL) are involved in the development of AA,^1-5 but the precise mechanisms underlying HLA lack and clonal hematopoiesis by such HLA(−) HSPC is unknown.Leukocytes that lack HLA class I alleles derived from hematopoietic stem and progenitor cells (HSPC) that undergo copy number-neutral loss of heterozygosity of the short arm of chromosome 6 (6pLOH) or HLA allelic mutations are often detected in patients with aplastic anemia (AA). The presence of HLA class I allele-lacking leukocytes provides compelling evidence that cytotoxic T-lymphocytes (CTL) are involved in the development of AA,^1-5 but the precise mechanisms underlying HLA lack and clonal hematopoiesis by such HLA(−) HSPC is unknown.