Non-myeloablative hematopoietic stem cell transplantation in the treatment of severe idiopathic CD4+ lymphocytopenia.

A 40-year-old man with severe chronic idiopathic CD4+ lymphocytopenia complicated with opportunistic infections was successfully treated with non-myeloablative allogeneic hematopoietic stem cell transplantation. After conditioning with fludarabine plus low dose of total-body irradiation, CD34+ peripheral blood stem cells obtained by leukapheresis from his HLA-identical sister were infused. T cell and myeloid complete chimerism was achieved at day +28 and remained stable during the follow-up period. The patient did not develop infectious complications during the procedure. At 35 months of follow-up, his CD4+ T cell count was 1019 cells per microliter. Non-myeloablative allogeneic hematopoietic stem cell transplantation should be considered a treatment option for patients with severe forms of idiopathic CD4+ lymphocytopenia.