Rearrangements of T-cell receptor beta-chain genes in human leukaemias

Rearrangements of the T-cell receptor (TCR), beta-chain genes and immunoglobulin (Ig) heavy chain genes in several T-cell leukaemias (T-ALL and ATL), and some B-cell and myelogenous leukaemias were investigated. Two out of 15 cases of T-cell leukaemia tested failed to show a rearrangement pattern of TCR beta genes although both expressed mRNA for this gene. The remaining 13 cases showed diverse patterns of rearrangements involving either C beta 1, C beta 2 or both. C beta 1 but not C beta 2 was deleted in some of the T-cell leukaemias. Polyclonal T cells from four normal individuals showed the germ line pattern and an additional two bands in Hind III digested DNA. Except for one, all cases of C-ALL (B-cell leukaemia) showed a rearranged JH locus which was not evident in any of T-cell leukaemias studied. One case of B-cell leukaemia showed a rearrangement of both TCR beta genes and JH genes. The results of these studies suggest that rearrangement of TCR and Ig genes occurs at a very early stage of differentiation of stem cells and does not appear to play a direct role in leukaemogenesis per se.