Chronic Lymphocytic Leukemia (CLL) is characterized by accumulation of small mature looking, ineffectual, CD5+ B-cells in the peripheral blood, bone marrow and secondary lymphoid tissues.1 These cells have a characteristic immunophenotype i.e. CD19+, CD20+ and CD23+with relatively low expression of CD22 and CD79b.2 The gene discussed is CD19; the disease is B-cell chronic lymphocytic leukemia.