[Antigen-specific T cells as a potential regulator of hematopoietic stem cell clones]

Hematopoietic stem cells (HSCs) are tissue-specific stem cells that are critical for homeostasis and regeneration of the hematopoietic system. Multiple mechanisms exist that help maintain the size and integrity of the HSC pool after exposure to various insults to provide all lineages of blood cells throughout life. Clonal hematopoiesis, an age-related clonal mosaicism detected in the hematopoietic system and governed by aberrant HSC clones with somatic mutations, has recently been identified as an important risk factor for hematological malignancy and cardiovascular disease. Cells with a somatic mutation can present neoantigens via the major histocompatibility complex and can be recognized and eliminated by antigen-specific T cells. However, whether this mechanism also acts to maintain HSC pool integrity remains largely unclear. In this review, I have summarized mechanisms known to support the lifelong maintenance of HSC numbers and function, introduced recent findings that indicate active interaction between HSCs and T cells, and discussed potential effects of its dysregulation on hematological diseases.