title: Human T cell gamma-chain gene rearrangements in acute lymphoid and nonlymphoid leukemia: comparison with the T cell receptor beta-chain gene.
abstract: Rearrangement of germ-line genes coding for T and B cell antigen receptor molecules is an early event in lymphoid development which eventually leads to the generation of clonal diversity in receptor-positive lymphocytes. Three T cell-associated rearranging genes have been described. Two, T alpha and T beta, code for the two polypeptide chains that form the T cell receptor heterodimer. The function of the third gene, the gamma-gene (T gamma), is not known. To learn more about the behavior of T gamma during lymphoid ontogeny, we compared rearrangement of T gamma and T beta genes in leukemic cells arrested at varied stages of lymphoid and myeloid development. We analyzed 38 fresh cell lines and 15 established cell lines from a total of 53 leukemic patients. Cells were immunophenotyped with a panel of monoclonal antibodies recognizing T-, B-, or myeloid-associated surface markers. Sixteen T-lineage cases were studied; 15 displayed both T beta and T gamma rearrangements. The exception (germ-line for T beta and T gamma) was an immature CD2(T11)+, CD3(T3)-, CD7(3A1)+, CD1(T6)+, CD5(T101)+ phenotype. Fourteen non-T non-B leukemias were analyzed; eight were germ-line for both T beta and T gamma, four had rearrangements involving both T beta and T gamma, and two were germ-line for T beta and rearranged to T gamma. Four cases with acute biphenotypic leukemia were studied; two had rearrangements of T beta and T gamma, and two were germ-line for both genes. Cells from nonlymphocytic leukemias were studied in 19 cases. All were found to be germ-line for both T beta and T gamma. Fifty-one of 53 genomic DNA samples were concordant for T gamma and T beta rearrangement. These results indicate that rearrangement of T gamma can occur in leukemic cells of B cell as well as T cell precursor origin, as has been reported previously for T beta.
mesh_terms: D000951:Antigens, Neoplasm / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis; D001402:B-Lymphocytes / Q000502:physiology; D002454:Cell Differentiation; D005786:Gene Expression Regulation; D005796:Genes; D006801:Humans; D007938:Leukemia / Q000235:genetics*; D015470:Leukemia, Myeloid, Acute / Q000235:genetics; D046911:Macromolecular Substances; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D011995:Recombination, Genetic; D013601:T-Lymphocytes / Q000502:physiology*
chemical_list: D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D046911:Macromolecular Substances; D011948:Receptors, Antigen, T-Cell