The roles and clinical applications of mesenchymal stem cells and their exosomes in hematologic diseases

Mesenchymal stem cells (MSCs) are multipotent stem cells with critical functions, including immunomodulation, multidirectional differentiation, anti-inflammatory activity, tissue repair, and regeneration. Recent studies demonstrate that MSCs can enhance hematopoietic stem cell engraftment, mitigate graft-versus-host disease (GVHD), address transplant-related complications, and treat conditions such as immune thrombocytopenia (ITP) and severe aplastic anemia (SAA). These therapeutic effects are largely attributable to the immunomodulatory and anti-inflammatory properties of MSCs. However, in hematologic malignancies, MSCs can exert both pro-tumor and anti-tumor influences. Exosomes, which are extracellular vesicles derived from MSCs (MSC-EVs), not only replicate many MSC functions but also exhibit greater chemical stability and lower immunogenicity. These characteristics make MSC-EVs particularly significant in the context of hematopoietic stem cell transplantation (HSCT). This review provides a detailed overview of the roles and clinical applications of MSCs in hematologic diseases, the properties of MSC-EVs, and their emerging significance in HSCT.