Ng2 pe

Clinical data was available for 67 diagnostic iMLLr-B-ALLs. Fifty-five of these infants were enrolled in the Interfant treatment protocol.^{28 (link)} Clinico-biological correlations in Figure 1 are based on the Interfant cohort except CNS disease data, which was obtained from 12 iMLLr-B-ALL used for xenotransplantation studies. Table 1 shows the clinico-biological data of the patients contributing samples for the experiments. The Institutional Review Board of the Hospital Clinic of Barcelona approved the study, and all patients’ parents gave written informed consent. Mononuclear cells from patients with >85% of blasts were isolated from diagnostic bone marrow (BM) or peripheral blood (PB) by density gradient centrifugation using Ficoll-Hypaque. Blasts were FACS (fluorescence-activated cell sorter)-immunophenotyped using the monoclonal antibodies CD45-FITC, CD19-APC, CD10-PerCP-Cy5.5, CD34-PE-Cy7 (BD Biosciences, San Jose, CA, USA) and NG2-PE (Beckman, Barcelona, Spain), and NG2⁺ and NG2⁻ blast populations were FACS-sorted (FACS Aria, San Jose, CA, USA) (Figure 2a).

Leukemic samples at presentation were used from n = 5 independent MLLr-B-ALL patients with complete immunophenotypic and molecular/cytogenetic diagnosis. Four patients were t(4;11)/MLL-AF4+, and one patient was t(1;11)/MLL-EPS15+. Patients’ mononuclear cells with >85% CD45^lowCD19⁺CD34⁺CD10⁻NG2⁺ MLLr blasts were isolated by density gradient centrifugation using Ficoll-Hypaque (Amersham Biosciences, Uppsala, Sweden). MLL/(11q23) status was confirmed by fluorescence in situ hybridization [22 (link)]. Blasts were immunophenotyped using the monoclonal antibodies (MoAbs) CD45-FITC, CD19-APC, CD10-PerCP-Cy5.5, CD34-PE-Cy7 (BD Biosciences, San Jose, CA), and NG2⁻PE (Beckman, Barcelona, Spain), and the NG2⁺ and NG2⁻ blast populations were isolated by fluorescence-activated cell sorting (FACS) using a FACSAria cell sorter (BD Biosciences). The Institutional Review Board of the Hospital Clinic of Barcelona approved the study, and all patients’ parents gave written informed consent.