• Preoperative high blood HSPC ratio is a potential biomarker for predicting acute rejection after liver transplantation.
• Alloresponse triggers mobilization of both recipient- and donor-derived HSPCs into peripheral blood and migration to target tissues during AR and GVHD episodes.
• Tacrolimus-based immunosuppression is associated with myeloid-biased differentiation of HSPCs in LTx recipients.
• Blood HSPC levels decline after successful treatment of rejection or GVHD, suggesting a dynamic response to alloresponse.