CD8A and autoimmune thrombocytopenic purpura: Hypoxia-inducible factor-1α (HIF-1α) is a key transcription factor in cellular responses to hypoxia, closely associated with the regulation of hematopoietic stem cells (HSCs) and essential for megakaryocyte growth, and it modulates CD8 + T cell involvement in immune responses, and studies indicate reduced HIF-1α expression in ITP [99–102].