Analysis of T-cell receptor genes in malignant lymphocytic disease ; Rearrangement of TcR delta chain gene.

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We analyzed the rearrangement of T-cell receptor(TcR) delta chain gene, reported as fourth TcR gene, in malignant lymphoproliferative disorders. All of 9 acute lymphoblastic leukemias/lymphoblastic lymphomas(ALL/LBL), of which 4 cases have neither beta nor gamma gene rearrangement, had a new rearranged band of TcR delta locus. Of B-ALL/LBL 41% had rearranged band(s) and of that 23% showed the deletion of TcR delta locus. The VD or DD rearrangement in B-lineage and DD, DJ or VDJ in T- lineage ALL/LBL are suggested due to the results of the delta gene rearrangement pattern. The frequency of the new rearranged band(s) and deletion of the delta locus was 10% and 40% in T-lymphomas, 7% and 9% in B-lymphomas, 20% and 40% in AILDs, and 7% and 7% in acute myelocytic leukemias(AML). Any cases with Hodgkin's disease and adult T-cell leukemia/lymphoma(ATL/ATLL) did not have a new rearranged band of delta locus. The frequency of the delta deletion in those diseases were 61% and 83%. It is suggested that ATL/ATLL, T-lymphoma and a part of Hodgkin's disease and AILD are originated from alpha beta-T-cell. Appearance of delta rearranged band in B-lymphoma and AML are suggested as a missprogram of those tumor cells. The analysis of delta chain gene in T-cell lines show that there is pre-alpha beta T-cell subclass in alpha beta T-lineage.Finally, these studies suggest that 1) the delta chain gene rearranges at a very early stage of the T-cell differentiation, prior to the other TcR genes. 2) delta gene analysis is an useful tool to evaluate clonality, particularly for the most immature T-cell leukemia/lymphoma with no lineage-associated markers or rearrangement of the other TcR genes. 3) rearrangement of TcR delta is not lineage specific but useful in evaluating lymphold lineage of ALL/LBL, when used in conjunction with the immunoglobulin heavy chain gene.