Rearrangements in the human T-cell-receptor α-chain locus in patients with adult T-cell leukemia carrying translocations involving chromosome 14q11

We describe 5 cases of adult T-cell leukemia (ATL) carrying translocations at chromosome 14q11, where the genes for α- and δ-chains of the T-cell receptor (TCR α/δ) reside (Croce et al., 1985; Isobe et al., 1988). Since the TCR α/δ locus is the region where several types of chromosome translocations occur in T-cell tumors, rearrangements of the TCR α/δ locus in those ATL cases were studied as a first step to characterize these translocations at the molecular level. For this purpose we have generated an extensive series of probes to define the specificity and the diversity of rearrangement occurring at the widely spanned Jα-Cα locus and the complex Dδ-Jδ-Cδ-Vδ2 locus. Using a set of probes, we have found the deletion of the TCR δ locus in all ATL cases, and at least 2 rearrangements in the Jδ locus in each case of ATL. It is possible that translocations in the TCR α locus may be involved in ATL.