1) baseline (BL) : WBC30G/L in B-lineage, CNS involvement, MLL-AF4 and E2A-PBX fusions, haploidy/near-triploidy; 2) early response (ER) : corticoresistance after prophase (CsR), chemoresistance at Day 8 (ChR); all CsR and/or ChR patients are planned to receive higher doses of cyclophosphamide (HyperC) at Day 15 of induction; 3) induction response (IR) : no CR or Ig-TCR minimal residual disease (MRD) 10-2 after standard or HyperC induction. Allogeneic stem cell transplantation is proposed to patients with a donor and at least one BL, ER, or IR factor.