Cotransplantation of haploidentical hematopoietic and umbilical cord mesenchymal stem cells for severe aplastic anemia: Successful engraftment and mild GVHD

• In China, searching for HLA-matched donors is usually unsuccessful because no siblings are available for almost all young people.
• Mesenchymal stromal cells (MSCs) can support hematopoiesis, enhance the engraftment of HSCs, and reduce the incidence of GVHD following HSCT.
• Our data demonstrate that haplo-HSCT combined with UC-MSCs for patients with SAA was safe and feasible.(4) Haplo-HSCT combined with UC-MSCs were effective for the improvement of donor engraftment and the lessening of severe GVHD.

Haploidentical hematopoietic stem-cell transplantation (haplo-HSCT) is associated with an increased risk of graft failure and severe graft-versus-host disease (GVHD). Mesenchymal stromal cells (MSCs) have been shown to support in vivo normal hematopoiesis and to display potent immunesuppressive effects. We cotransplanted the culture-expanded third-party donor-derived umbilical cord MSCs (UC-MSCs) in 21 young people with severe aplastic anemia (SAA) undergoing haplo-HSCT without T-cell-depleted. We observed that all patients had sustained hematopoietic engraftment without any adverse UC-MSC infusion-related events. Furthermore, we did not observe any increase in severe aGVHD. These data suggest that UC-MSCs, possibly thanks to their potent immunosuppressive effect on allo-reactive host T lymphocytes escaping the preparative regimen, reduce the risk of graft failure and severe GVHD in haplo-HSCT.