Single UM171-expanded cord blood transplant can cure severe idiopathic aplastic anemia in absence of suitable donors.

Haplo-identical donors have been increasingly used as an alternative source of stem cells in patients with severe aplastic anemia in need of an allogeneic transplantation but lack a matched donor. Single cord blood (CB) transplant also offers a curative option for this disease but few adult patients have been reported due to low number of progenitor cells leading to prolonged cytopenias and a high risk of infections. CB stem cell expansion may theoretically solve these pitfalls but has not been used previously in non malignant diseases, likely due to fear of graft rejection and lack of availability of expanded CBs outside clinical trials . We report the first case of an adult patient with severe aplastic anemia who was successfully transplanted with a UM171-expanded CB graft. After a conditioning of rabbit anti-thymocyte globulin, fludarabine, cyclophosphamide and total body irradiation, a UM171 expanded graft of 3.29 x 106 CD34+ cells/kg (a 51 fold increase) was infused. Full donor chimerism was observed on day +14, with neutrophil and platelet engraftment on day +23 and +27. There was no severe infection or graft-versus-host disease. UM171-expanded grafts offer a valuable option for patients with aplastic anemia in need of transplantation but have no suitable donor.