Impaired immunomodulatory ability of bone marrow mesenchymal stem cells on CD4+ T cells in aplastic anemia

Aplastic anemia (AA) is a marrow failure syndrome mediated by aberrant T-cell subsets. Mesenchymal stem cells (MSCs) play an important role in maintaining immune homeostasis through modulating a variety of immune cells. However, little is known about the immunomodulation potential of bone marrow MSCs (BM-MSCs) in AA. Here, we reported that BM-MSCs from AA patients were reduced in suppressing the proliferation and clonogenic potential of CD4⁺ T cells and the production of tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), which was associated with decreased prostaglandin E₂ (PGE₂). Meanwhile, BM-MSCs from AA patients were defective to promote CD4⁺CD25⁺FOXP3⁺ regulatory T cells expansion through reduced transforming growth factor-β (TGF-β). No significant difference between AA and normal BM-MSCs was observed in affecting the production of interleukins (IL)-4, IL-10 and IL-17. Our data indicate that BM-MSCs were impaired in maintaining the immune homeostasis associated with CD4⁺ T cells, which might aggravate the marrow failure in AA.