Bone Marrow Transplant Plus Cyclophosphamide and Total-Body Irradiation in Treating Patients With Hematologic Cancer

DISEASE CHARACTERISTICS: One of the following hematologic malignancies/disorders: Acute lymphoblastic leukemia In second or subsequent complete remission (CR) In first CR with high-risk features (e.g., Philadelphia chromosome-positive) In first relapse and failed conventional salvage therapy Acute myelogenous leukemia (AML) In second or subsequent CR In early first relapse In full first relapse and failed conventional salvage therapy In first CR with high-risk features, e.g., trisomy 8 or FAB 6/7 Standard-risk AML offered conventional-dose consolidation chemotherapy or autologous bone marrow transplantation Chronic myelogenous leukemia in chronic, accelerated, or second chronic phase No blast crisis Severe aplastic anemia that has failed at least 1 course of immunosuppressive therapy Paroxysmal nocturnal hemoglobinuria with high-risk features (e.g., disseminated intravascular coagulation, thrombotic events) Myelodysplastic syndrome, i.e.: Symptomatic, transfusion-dependent refractory anemia with excess blasts (RAEB) or RAEB in transformation Secondary leukemia in CR following conventional-dose induction chemotherapy Unrelated marrow donor available who is 8 out of 10-, 9 out of 10-, or 10 out of 10-antigen serologically HLA-matched at A, B, C, DRb, and DQB loci by molecular typing No CNS malignancy PATIENT CHARACTERISTICS: Age: 17 to 60 Performance status: Karnofsky 70-100% Life expectancy: No reduction due to other serious illness Hematopoietic: Not specified Hepatic: Bilirubin less than 3 mg/dL AST/ALT no greater than twice normal Renal: Creatinine no greater than 2.0 mg/dL Creatinine clearance greater than 60 mL/min Cardiovascular: Left ventricular ejection fraction at least 45% No severe hypertension Pulmonary: DLCO, FEV_1, and FVC at least 50% Other: HIV negative No active infection at time of transplant No advanced diabetes No significant neurologic deficit No active drug or substance abuse No emotional disorders Able to participate in frequent medical care for at least 1-2 years Willing to comply with National Marrow Donor Program policies PRIOR CONCURRENT THERAPY: Biologic therapy See Disease Characteristics Chemotherapy See Disease Characteristics Endocrine therapy Not specified Radiotherapy Not specified Surgery Not specified