A novel biphenotypic B-cell precursor leukemia cell line (NALM-29) carrying t(9;22)(q34;q11) established from a patient with acute leukemia.

A novel biphenotypic leukemia cell line, NALM-29, was established from a 46-year-old Japanese male patient with acute lymphoblastic leukemia (ALL). The primary leukemic blasts showed a common ALL phenotype with CD19+, CD10+, CD13-, HLA-DR+ and Igs-. NALM-29 cells display biphenotypic characteristics: expression of the intracellular enzyme myeloperoxidase at the mRNA and protein level and cell surface positivity for CD19, CD10, CD13, CD33 and HLA-DR. NALM-29 fulfills EGIL criteria as B-cell precursor (BCP) leukemia B-II type. NALM-29 cells have a lymphoblastic morphological appearance; the immunoglobulin heavy chain gene is rearranged. NALM-29 cells responded significantly to the proliferative stimuli of FLT-3 ligand and IL-7, but not to GM-CSF, IL-3, IL-6, PIXY-321 or SCF. Proliferation of cells was inhibited significantly by IL-4, TNF-alpha or TNF-beta treatment. Cytogenetic analysis revealed the characteristic t(9;22)(q34;q11); expression of the m-bcr e1-a2 BCR-ABL fusion gene (typically found in ALL) was determined by PCR amplification of cDNA. The immunological, cytogenetic and functional characterization of NALM-29 suggests that this cell line may represent a scientifically significant in vitro model for BCP-type leukemia cells with biphenotypic characteristics.