Donor-specific Allogeneic Hematopoietic Cell Transplantation for Acute Lymphoblastic Leukemia (ALL)

Inclusion Criteria: * Patients with ALL who achieve CR after induction chemotherapy. * Patients with recurrent ALL that went into second CR after salvage chemotherapy, except those who had undergone allogeneic HCT previously. * Patients should be 15 years of age or more, and 75 years of age or less. * The performance status of the patients should be 70 or over by Karnofsky performance scale. * Patients should have adequate hepatic function (bilirubin less than 2.0 mg/dl, AST less than three times the upper normal limit). * Patients must have adequate renal function (creatinine less than 2.0 mg/dl). * Patients must have adequate cardiac function (ejection fraction \> 40% on MUGA scan). * Patients must sign informed consent. Exclusion Criteria: * Presence of significant active infection * Presence of uncontrolled bleeding * Any coexisting major illness or organ failure * Patients with psychiatric disorder or mental deficiency severe as to make compliance with the treatment unlike, and making informed consent impossible * Nursing women, pregnant women, women of childbearing potential who do not want adequate contraception * Patients with a diagnosis of prior malignancy unless disease-free for at least 5 years following therapy with curative intent (except curatively treated nonmelanoma skin cancer, in situ carcinoma, or cervical intraepithelial neoplasia)