Lymphoblasts with both T and B markers in childhood leukemia and lymphoma

A modification of the double rosette method of Mendes et al. was used to examine lymphoblasts from 22 children with acute lymphoblastic leukemia and 1 child with lymphoblastic lymphoma. This method was used since it directly and simultaneously detected T, B, and null lymphocytes as well as monocytes. In addition it detected the D lymphocyte which has both Tand Bcell surface markers. Based on surface characteristics, lymphoblasts from the patients studied could be divided into three groups: (1) null cells with no detectable markers; (2) cells with T-cell markers; or (3) D or double cells with both the T-cell receptor for sheep erythrocytes and the B-cell receptor for activated complement. No lymphoblasts were found which had easily detectable surface immunoglobulins or complement receptors alone. Eighteen patients had null-cell lymphoblasts; four patients, including the child with lymphoma, had two lymphoblast populations, T and D cells. No circulating D lymphoblasts were detected when these patients went into remission. This simple, reproducible method utilizes easily prepared, stable reagents for surface-marker detection and has the advantage of detecting directly another lymphoid subpopulation, the D cell.