Leukemic blasts separated from peripheral blood of three-year-old boy with acute lymphoblastic leukemia (ALL) were tested using indirect immunofluorescence assay with panel of 33 monoclonal antibodies. The results showed that leukemic cells expressed on their surface antigens which reacted with monoclonal antibodies RF-1, 3ACCIa, 4H9, W6/32 and SFR8-B-6. This phenotype indicated that ALL was derived from early differentiation stage of thymocytes. After in vitro incubation of leukemic blasts with 12-0-tetradecanoyl-phorbol-13-acetate (TPA) differentioation into more mature stage of T-cell line was not found.
Acute lymphoblastic leukemia with the phenotype of early thymocytes
