Long-term complete autologous reconstitution following cyclophosphamide and allogeneic marrow infusion in a case of severe aplastic anemia.

A 23 year old man with severe idiopathic aplasia, who had previously been unsuccessfully treated with oxymetholone for a period of 6 months, received two intravenous (IV) infusions of bone marrow cells from his HLA identical brother. He was given 200 mg/kg anti-lymphocyte globulins (ALG) IV, followed by a first infusion of 13 X 10(9) nucleated cells IV, but no improvement was observed. Three months later, he was treated with cyclophosphamide (25 mg/kg over 4 days) followed by a second infusion of 18 X 10(9) nucleated cells IV of the same donor. Within a four month period there was evidence of complete marrow reconstitution, and the patient has experienced no relapse of the disease during the subsequent 13 years follow up period. The mechanism of the recovery is unclear: no evidence of graft acceptance could be established. The respective roles of ALG, cyclophosphamide and/or bone marrow infusions are discussed.