Clinical importance of lymphoblasts with T markers in childhood acute leukemia.

Of 48 children with acute lymphocytic leukemia 11 had blast cells with receptors for sheep erythrocytes in their initial bone-marrow aspirates and 37 did not. A comparison of selected clinical features indicated striking differences between the two groups. Leukemia with the receptors was associated with a high proportion of older children, predominantly boys, a thymic mass, and a high white-cell count at diagnosis. In contrast, the 37 children with leukemia without the receptors were generally less than five years of age, with a nearly equal distribution of boys and girls; all but one had normal chest roentgenograms, and only one had a white-cell count greater than 100,000. Thus, the presence or absence of lymphoblasts with sheep erythrocyte receptors--a T-cell marker--distinguishes two forms of childhood acute lymphocytic leukemia, each with a distinct distribution of age and sex as well as other characteristic clinical features.