Treatment of acute lymphoblastic leukemia in children with the BFM protocol: a cooperative study and analysis of prognostic factors

PreB1 (CD10-) acute lymphoblastic leukemia: immunophenotypic and genomic characteristics, clinical features and outcome in 38 adults and 26 children. The Groupe dEtude Immunologique des Leucémies

The less differentiated stage (CD10-) of B-lineage acute lymphoblastic leukaemia (ALL) described as preB1-ALL in the GEIL nomenclature, accounts for less than 10% of ALL. It is classically considered to be associated with translocation (4;11)(q21;q23), and to have a poor prognosis. We report an extensive immunophenotypic, genomic and clinical study of a series of 64 preB-1 ALL patients, representing 6.3% of a cohort of consecutive ALLs. The engagement of preB1-ALL cells in the B-lineage was confirmed by their B-lineage score, equal to or higher than 2. In addition, more than 90% of the cases tested showed rearranged IGH genes. Translocation (4;11) was the most frequent karyotypic anomaly seen, but only accounted for 24% of the preB1-ALL cases tested. Expression of the myeloid associated antigen CD15 was also found with high incidence in this subset. Clinical and biological features at presentation showed more significant differences between preB1- and T-ALL than between preB1- and preB2-ALL (CD10+). However, outcome characteristics of the 22 children with preB1-ALL confirmed the worse prognosis of this entity.

Cerebrospinal fluid drug levels of leukemic children receiving intravenous 5 g/m2 methotrexate

A multicenter prospective study was conducted in 114 children with acute lymphoblastic leukemia receiving 4 intravenous methotrexate (MTX) courses (5 g/m2 as a 24 hour-infusion) to determine the diffusion of MTX in cerebrospinal fluid (CSF) and to correlate the drug levels to central nervous system (CNS) relapse occurrence. Serum and CSF levels were measured at the end of 446 MTX courses. A significant correlation was found between CSF and serum MTX concentration. CSF MTX level was greater than 1 mumol/l in 66% of the courses. Twelve patients (11%) failed to achieve this potentially cytotoxic drug level at the end of the 4 consecutive MTX courses: only one CNS relapse was observed and the mean age of these children was lower than that of the others. To date 9 (7.8%) children had CNS relapse and no difference was observed in terms of CSF MTX levels when compared to data of children free of CNS relapse. With a median follow up of 32 months, pharmacokinetic data during high-dose MTX therapy do not seem to be an exclusive predictive factor of CNS relapse.