Immunologic classification of childhood acute lymphocytic leukemia.

Immunologic approaches to the classification of acute lymphocytic leukemia (ALL) have led to a new awareness of the heterogeneity of this disease. Surface membrane markers including surface membrane immunoglobulin, complement receptors, and sheep erythrocyte (E) receptors have demonstrated at least three subtypes of ALL, which include non-B, non-T, ALL, T-ALL, and B-ALL. In addition, hetero-antisera to Ia-like antigens and ALL-associated antigens have been used to positively identify non-B, non-T ALL, which was previously a diagnosis of exclusion. This paper reports 17 cases of childhood ALL whose lymphoblasts were studied for surface membrane immunoglobulin, sheep erythrocyte receptors, and the presence of four antigens detected by well-characterized heteroantisera. Every non-B, non-T lymphoblast was positively identified by the Ia-like antiserum and/or the ALL antiserum. One T lymphoblast was identified by E receptors and the T antiserum, whereas two did not have E receptors but did react to the T antiserum. None of these three T lymphoblasts reacted with the Ia-like antiserum.