iPSC-derived modeling of HLA-lacking hematopoiesis reveals clonal diversity in eltrombopag response in acquired aplastic anemia

Acquired aplastic anemia aplastic anemia: (ay-PLASS-tik uh-NEE_mee-uh) A rare and serious condition in which the bone marrow fails to make enough blood cells - red blood cells, white blood cells, and platelets. The term aplastic is a Greek word meaning not to form. Anemia is a condition that happens when red blood cell count is low. Most… (AA) is an immune-mediated bone marrow failure bone marrow failure: A condition that occurs when the bone marrow stops making enough healthy blood cells. The most common of these rare diseases are aplastic anemia, myelodysplastic syndromes (MDS) and paroxysmal nocturnal hemoglobinuria (PNH). Bone marrow failure can be acquired (begin any time in life) or can be… in which cytotoxic T lymphocytes (CTLs) target hematopoietic stem cells stem cells: Cells in the body that develop into other cells. There are two main sources of stem cells. Embryonic stem cells come from human embryos and are used in medical research. Adult stem cells in the body repair and maintain the organ or tissue in which they are found. Blood-forming (hemapoietic) stem… (HSCs). Approximately 30% of AA patients develop immune escape clones lacking specific HLA HLA: See human leukocyte antigen. class I alleles (HLA[-]) through loss of heterozygosity in chromosome 6p (6pLOH) or somatic loss-of-function mutations. Eltrombopag Eltrombopag: What are the possible side effects of eltrombopag (Promacta)? Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat. Stop using eltrombopag and call your doctor at once if you have: … (EPAG), a thrombopoietin receptor agonist (TPO-RA), demonstrates clinical efficacy in AA in combination with immunosuppressive therapy immunosuppressive therapy: Immunosuppressive drug therapy lowers your body's immune response. This prevents your immune system from attacking your bone marrow, allowing bone marrow stem cells to grow, which raises blood counts. For older patients with acquired aplastic anemia, immunosuppressive drug therapy is the… ; however, its impact on HLA(-) HSCs and hematopoietic progenitor cells (HPCs) remains poorly understood. In this study, we evaluated the hematopoietic effects of EPAG using umbilical cord blood-derived HPCs and a humanized hematopoiesis hematopoiesis: (hi-mat-uh-poy-EE-suss) The process of making blood cells in the bone marrow. model in immunodeficient (BRGS) mice. Furthermore, we established induced pluripotent stem cell (iPSC)-derived hematopoietic models encompassing five wild-type (WT) clones and seven HLA-lacking clones, differentiated them into HPCs, and assessed their responses to EPAG. EPAG selectively conferred a proliferative advantage to specific hematopoietic fractions in HLA(-) HPCs, distinct from that observed in WT HPCs. Molecular analyses revealed clone clone: To make copies. Bone marrow stem cells clone themselves all the time. The cloned stem cells eventually become mature blood cells that leave the bone marrow and enter the bloodstream. -dependent differences in CD110 expression and downstream effectors, including phosphorylated STAT5, FOXM1, and E2F1, indicating differential activation of TPO receptor-mediated signaling pathways among clones. These findings highlight the functional diversity of HLA(-) hematopoiesis and suggest that the hematopoietic response to EPAG is governed by clone-intrinsic signaling programs. Furthermore, our results provide new insights into how eltrombopag modulates clonal competition and hematopoietic recovery in immune-escape hematopoiesis, with potential implications for optimizing therapeutic strategies and predicting clinical response in patients with acquired AA.