Cyclophosphamide and Anti-thymocyte Globulin Followed By Methotrexate and Cyclosporine in Preventing Chronic Graft-Versus-Host Disease in Patients With Severe Aplastic Anemia Undergoing Donor Bone Marrow Transplant

Inclusion Criteria: * Any patient who has aplastic anemia with marrow failure involving 2 of the three following criteria: granulocytes \< 500/uL; a corrected reticulocyte count of \< 1%; platelet count of \< 20,000/uL * Availability of an human leukocyte antigen (HLA)-matched family member * DONOR: Family member who is HLA-matched * DONOR: If more than one HLA-matched family member is available, priority will be given to a donor who is genotypically HLA-identical, of appropriate cytomegalovirus (CMV) serology, ABO compatible, and, in case of a female donor, non-parous Exclusion Criteria: * Severe disease other than aplastic anemia that would severely limit the probability of survival during the graft procedure: * Patients who have developed clonal cytogenetic abnormalities or myelodysplastic syndrome (preleukemia) * Patients with Fanconi's anemia * Aplasia secondary to radiation or cytotoxic chemotherapy * Patients with paroxysmal nocturnal hemoglobinuria who have not developed aplastic anemia * Severe organ toxicities: * Cardiac insufficiency requiring treatment or symptomatic coronary artery disease; * Severe hypoxemia , partial pressure of oxygen (pO2) \< 70 mm Hg, with decreased diffusion capacity of carbon monoxide (DLCO) \< 70% of predicted; or mild hypoxemia, pO2 \< 80 mm Hg with severely decreased DLCO \< 60% of predicted; * Impaired renal function (creatinine \> 2 times upper limit of normal or estimated creatinine clearance \< 60 ml/min) * Fungal infections with radiological progression after receipt of amphotericin B or active triazole for greater than 1 month * Human immunodeficiency virus (HIV)-positive patients * Females who are pregnant or breast-feeding * DONOR: Donors who have increase anesthetic risk and are not able psychologically and medically to tolerate the procedure * DONOR: HIV-positive donors