In a patient with acute leukemia, immunophenotype pattern is CD 19+ve, CD 10+ve. CD33+ve and CD 13+ve. He may probably have which of the following type of leukemia?

Based on the immunophenotype pattern the leukemic cells are expressing both myeloid (CD13, 33) and B lineage antigens (CD10,19). As a result the most likely diagnosis is biphenotypic leukemia. Biphenotypic leukemia is the most common type of mixed phenotype acute leukemia, that contain a morphologically homogenous population of poorly differentiated blasts that uniformly express a mixture of lymphoid (B and/or T cell) associated and myeloid associated antigens. Immunophenotyping pattern found in various leukocytes: Antigen Cell lineage associated with CD1- CD8 T cell CD 10,19,20 to 23 B cell CD 13 to 15, 33 Monocyte, macrophage CD 16, 56 NK cell CD 34 Stem cell and progenitor cell CD 30 Activation markers CD 45 All leukocytes REf: Childhood Leukemias edited by Ching-Hon Pui page 36.