In Vitro Cell Growth Stimulated by Recombinant Human Cytokines Can Help to Diagnose Transient Leukemia in Neonates

Abstract

In a previous study, we demonstrated that in vitro cell growth stimulated by human placental conditioned medium distinguished between transient leukemia (TL) and congenital acute myeloid leukemia (AML) in neonates. We then sought to determine whether the application can be expanded if in vitro cell growths are stimulated by recombinant human cytokines including granulocyte-macrophage colony-stimulating factor (rhGM-CSF), interleukin-3 (rhIL-3), stem cell factor (rhSCF) and thrombopoietin (rhTPO). Eight neonates with features indistinguishable from AML were studied. Seven patients had Down syndrome and the eighth a normal phenotype. Bone marrow or peripheral blood mononuclear cells (MNC) were cultured in the presence of rhGM-CSF+rhIL-3+rhSCF or of rhTPO alone. After incubation, granulocyte-macrophage colony-forming units (CFU-GM)-derived colonies and clusters were scored on an inverted microscope. Colony-forming units-megakaryocyte (CFU-MK)-derived colonies were counted with an in situ CD61 immunostained dish. Liquid suspension cultures of MNC were stimulated by rhGM-CSF and/or rhTPO. CFU-GM-derived colonies and clusters from bone marrow and peripheral blood MNC revealed normal patterns in seven patients. RhTPO-stimulated megakaryocyte colony formation was normal in one patient. Cytospin smears of liquid suspension cultures all showed good myeloid or megakaryocytic maturation consistent with TL rather than AML. One neonate died on the 2nd day of life, but in the seven remaining patients, blasts disappeared from the peripheral blood within 10 months. Among four patients followed long-term, one developed myelodysplastic syndrome at 21 months. This child was given tailored chemotherapy and had a disease-free survival>20 months. In vitro cell growth stimulated by recombinant human cytokines can help to diagnose TL in neonates.