Recategorizing childhood acute lymphoblastic leukemia with monoclonal antibodies to human T cells

The lymphoblasts of three patients with childhood acute lymphoblastic leukemia (ALL) were analyzed for their immunologic surface markers. Blasts from two of these patients did not form rosettes with sheep erythrocytes and the third did so marginally, suggesting these patients had non-T-cell leukemia. These blasts were also tested with monoclonal antibodies that detect thymocyte differentiation markers, and all three patients were highly reactive with at least two of these reagents. We anticipate the availability of multiple standardized monoclonal reagents will necessitate a recategorization of ALL phenotypes. Some of these leukemic phenotypes may not correspond to normal stages of lymphoid differentiation. Therefore, we suggest that it may be inappropriate to attempt to identify and categorize leukemic cells by the pathways of normal differentiation.