The T-cell receptor gene rearrangements in T-lineage tumors without OKT-3,4,6,8 markers.

Abstract

In the human system, discrete stages (I, II, and III) of intrathymic ontogeny have been defined on the basis of monoclonal antibody probes directed at unique T-lineage-specific surface glycoproteins. We have examined the relationship among T-cell receptor gene rearrangements and cell surface antigen expressions in T-cell malignancies. Twelve of 15 cases had the rearranged T-cell receptor beta chain gene, indicating that they represent cells already committed to the differentiated T-cell lineage at the gene level and are monoclonally proliferating regardless of the variable expression of surface antigens. We examined five cases of the earliest identifiable T-lineage cells (stage I) expressing WT-1 antigen without OKT-3, 4, 6, 8 antigens. Among them, two cases did not reveal the T-cell receptor beta chain gene rearrangements. In contrast, three cases demonstrated the T-cell receptor beta chain gene rearrangements even in stage I by the criteria of surface antigen expressions in contrast to the previous findings. Thus, we conclude that somatic rearrangement of the T-cell receptor gene of the beta chain occurs at the stage I level (early thymocyte) in the T-cell differentiation scheme. The phenotypically defined stage I T-cells consist of two populations with or without rearrangements of the T-cell receptor gene.