Leukemia is a complex disease in which mutations and other genomic and epigenomic abnormalities play a role in both its initiation and progression. Acute lymphoid leukemia (ALL) patients with loss of heterozygosity (LOH) in the HLA region before transplantation have been described rarely. In this report, we described two ALL cases with LOH encompassing the HLA, wholly or partly. HLA molecular typing was performed on peripheral blood (PB) and somatic cell. Simultaneously, we performed whole-exome sequencing. Typing results on PB samples collected during blast crisis demonstrated complete or partial homozygosity at the -A, -B, -C, -DR, and -DQ loci. Two somatic samples demonstrated heterozygosity at all loci. LOH at the HLA gene locus may significantly influence the donor search, resulting in misidentification of homozygous donors. We recommend confirming the patients' HLA typing with hematological malignancies when homozygosity is detected at any locus by using somatic samples or alternatively from PB when remission is achieved.

中文翻译：

---

急性淋巴细胞白血病移植前HLA区杂合性缺失2例

白血病是一种复杂的疾病，其中突变和其他基因组和表观基因组异常在其起始和进展中都起作用。移植前 HLA 区域杂合性缺失 (LOH) 的急性淋巴细胞白血病 (ALL) 患者很少被描述。在本报告中，我们描述了两个 LOH 全部或部分包含 HLA 的 ALL 病例。在外周血（PB）和体细胞上进行HLA分子分型。同时，我们进行了全外显子组测序。在爆炸危机期间收集的 PB 样本的分型结果表明，在 -A、-B、-C、-DR 和 -DQ 基因座处完全或部分纯合。两个体细胞样本在所有基因座都表现出杂合性。HLA 基因位点的 LOH 可能会显着影响供体搜索，从而导致对纯合供体的错误识别。