Aberrant Expression of a T-Cell and a Monocytic Antigen in a Newly Diagnosed Precursor B-Cell Acute Lymphoblastic Leukaemia

Abstract

Background: Aberrant expression of antigens/or loss of some antigens on leukemic cells is sometimes seen. Such expressions may or not affect prognosis of leukaemia. Aberrant co-expression of CD5 and CD64 on precursor B-cell ALL leukemic cells is found first time.Objective: To report a novel case of precursor B-cell ALL which co-expressed a T-cell lineage (CD5) and a monocytic lineage (CD64) antigens.Methods: Bone marrow immunophenotyping was performed using FACSCalibur (a four-color flowcytometer) and acute leukaemia panel of antibodies.Case Presentation: A 4-year old boy with circulating small sized blasts. Immunophenotyping data revealed expression of CD45, CD19, CD79a, TdT, CD34, CD10, CD5 and CD64 while absence of CD3, MPO, CD13, CD33, CD4, CD7 and CD8 antigens. Conclusion:A diagnosis of precursor B-cell ALL with aberrant CD5 and CD64 expression was made.