Study of the CD3-associated T-cell receptors reveals further differences between T-cell acute lymphoblastic lymphoma and leukemia

Abstract

We show further differences between two clinically related entities, T-cell acute lymphoblastic leukemia (T-ALL) and lymphoblastic lymphoma (T-LL), by using several monoclonal antibodies (MoAbs) reacting with either constant or variable regions of T-cell receptors (TcR) αβ and γδ or with various CD molecules. We analyzed a panel of 15 T-ALL and 15 T-LL selected for their cell surface expression of the CD3 molecules. The results indicated that TcR γδ is more frequently used than TcR αβ in T-ALL (10 of the 15 patients tested). This is in contrast to the results obtained with T-LL where the vast majority expressed TcR αβ (13 of the 15 patients). These findings suggest that the leukemic cells could have a different origin in these two diseases. In addition, analysis of TcR variable regions expressed by the leukemic blasts showed that, in most cases, they had rearranged functional Vol gene segments (8 of 11 patients), whereas in a unique case Vδ2 gene segment was used. Together, these results and those indicating that T-ALL cells coexpress the CD1a, b, and c molecules strengthen the possibility that although these leukemic cells express the CD3-TcR complex at their cell surface, their normal counterparts are not found in peripheral blood. © 1990 by The American Society of Hematology.