Genotypic and cytogenetic study of acute myelocytic leukemia and chronic myelocytic leukemia in blast crisis: Specific δ rearrangement pattern does not involve J δ gene locus

Abstract

We have analysed the configuration of immunoassociated genes and the karyotypes of 30 patients with acute myelocytic leukemia (AML) and 10 with chronic myelocytic leukemia in blast crisis (CML-BC). In AML, the frequencies of T-cell receptor (TcR) β, γ, and δ chain and immunoglubulin heavy and light chain gene rearrangements were 4.2%, 19%, 8%, 10.7% and 10.5%, respectively. In CML-BC, they were 10%, 20%, 40%, 50% and 0%, respectively. Nine patients had abnormalities in chromosome 2, 7 or 14, upon which immunoassociated genes are located. There seems to be no apparent relationship between these chromosome abnormalities and gene rearrangements. In all patients but one (5/6), the δ rearrangement was accompanied by other immunoassociated gene rearrangements. Molecular size analysis revealed specific δ rearranged band(s) (19.5 kb-BamHI and/or 6.9 kb-EcoRI), as commonly detected in B-acute lymphocytic leukemia (ALL). All the patients with the δ rearranged band, however, had a germline configuration of J δ gene loci, suggesting a DD or V(D)D (probably V δ2(D)D) pattern. This study also indicates that the δ rearrangement is specific in AML or CML-BC and distinct from that in early T leukemia/lymphoma.