Hematopoietic stem cell transplantation (HSCT) is frequently accompanied by severe inflammation-related complications, among which graft-versus-host disease (GVHD) stands out as one of the most common and life-threatening. As a systemic inflammatory disorder, GVHD arises when donor T cells recognize the recipient's alloantigens and initiate an immune attack. Currently, effective second-line treatment options remain scarce for patients with antibiotic-resistant or steroid-refractory GVHD. Mesenchymal stem cells (MSCs) are non-hematopoietic cells widely distributed in fetal and adult tissues and organs, endowed with multipotent differentiation potential and prominent immunomodulatory properties. Emerging evidence suggests that impaired function or apoptosis of MSCs exacerbates HSCT-associated complications and significantly compromises hematopoietic stem cell engraftment. Over the past two decades, leveraging their potent anti-inflammatory and immunomodulatory capacities, MSCs have been rapidly integrated into HSCT research and clinical practice, where they play a pivotal role in promoting hematopoietic engraftment and preventing or treating GVHD. This review elaborates on the molecular basis of MSCs' anti-inflammatory effects and the inflammatory pathological characteristics of HSCT-related complications. We conducted a systematic literature search in PubMed, Web of Science, and Embase databases up to December 2025. The search strategy combined the following terms: ("mesenchymal stem cells" OR "MSCs") AND ("hematopoietic stem cell transplantation" OR "HSCT") AND ("graft-versus-host disease" OR "GVHD") AND ("inflammation" OR "immune regulation"). It systematically analyzes the molecular mechanisms underlying MSCs' anti-inflammatory actions and their application progress in HSCT, aiming to provide a theoretical foundation and translational insights for the rational clinical application of MSCs in HSCT.
Zhu et al. (2026) studied this question.