Comparison of T cell receptor α, β, and γ gene rearrangement and expression in T cell acute lymphoblastic leukemia

Abstract

We have analyzed the configuration of the T cell receptor (TCR) α gene using newly developed genomic joining region (Jα) probes, which cover ~80 kb of the Jα region upstream from the constant region in 19 patients with T cell acute lymphoblastic leukemia (T-ALL) and in three CD3- leukemic T cell lines (HSB2, CEM, and MOLT4). In parallel, transcription of the TCR-α, β, and γ genes was examined in 11 of these patients and in the T cell lines. All T-ALL and the three T cell lines exhibited both TCR-γ and β gene rearrangements. 8 of 10 T-ALL and all T cell lines expressed TCR-γ transcripts. All samples tested expressed both TCR-β and CD3-γ transcripts. TCR α transcripts were only observed in CD3+ T-ALL but not in CD3- T-ALL or the CD3- cell lines. Among the CD3+ T-ALL, eight had TCR-α gene rearrangements. In addition, TCR-α gene rearrangements were detected in one CD3- T-ALL and all three T cell lines. These leukemic cells may represent a transient stage between rearrangement and expression and provide an opportunity for analyzing the mechanism regulating the expression of the TCR-α gene.