Testing a Reduced Conditioning Regimen FB2A2 Preceded by a Fractionated Radio-immunotherapy (RIT) With 90Y-Epratuzumab Before Allogeneic Stem Cell Transplantation for Patients With Lymphocyte B CD22 Positive Acute Lymphoblastic Leukemia

Determination of the maximum tolerated dose (MTD) of fractionated RIT with epratuzumab radiolabeled with yttrium-90 (90Y-epratuzumab) preceding a reduced conditioning regimen FB2A2 before allogeneic stem cell transplantation.

Inclusion Criteria: * Age ≥ 18 * Acute lymphoblastic Leukemia (ALL) CD22 + B-type in RC1 with high risk * B-Cell Acute Lymphoblastic Leukemia (ALL) CD22+ beyond RC1. * Expression of CD22 ≥ 30% in tumor population evaluated by flow cytometry or immunohistochemistry at diagnosis stage or relapse stage. * HLA-identical donor intra family or not, without major HLA mismatch (9 / 10th accepted) without contra-indication for stem cell mobilization * ECOG (Eastern Cooperative Oncology Group) ≤ 2 * Having or not received previously Epratuzumab * Eligible for an allograft with reduced conditioning regimen * With a signed informed consent * Patient in age of children bearing with adequate contraception * Patient affiliated to or beneficiary of the National Health Service Exclusion Criteria: * T-cell ALL * Known hypersensibility to 90Y-DOTA-hLL2 * Immunization against hLL2 for patients having already received one or several injections of this antibody * Patient eligible for myeloablative conditioning regimen * Other prior malignancies must have had at least a 2-year disease-free interval with the exception of successfully treated carcinoma skin cancer or carcinoma in situ of the cervix. * Patient with progressive psychiatric condition. * HIV positive, hepatitis B-antigen positive, or hepatitis C positive patients who need a treatment * Pregnant or breast-feeding women * Women with childbearing potential without effective contraception * Serious concomitant and uncontrolled infection * Usual contraindications in the allogeneic transplant: * Adult patient protected by the French law