HETEROGENEITY OF V-DELTA-2 TCR DELTA-GENE REARRANGEMENTS IN ACUTE MYELOID-LEUKEMIA

In a previous study, we described the occurrence of T-cell receptor (T CR)delta gene rearrangements in 9/100 acute myeloid leukemia (AML) cas es. In this study, we further characterized these rearrangements by So uthern Blot hybridization using a V delta 2 specific probe and polymer ase chain reaction (PCR). Southern Blot analysis revealed that rearran gements involved the V delta 2 gene segment in four patients. Interest ingly the restriction fragments detected by the V delta 2 probe differ ed markedly in size. PCR analysis revealed a complete V delta 2(Dn)J d elta 1 gene rearrangement, an incomplete V delta 2D delta 3 rearrangem ent and a large amplification product, which cannot be explained with normal VDJ recombinatorial processes, in one case each. Furthermore al though V delta 2 and J delta 1 were rearranged, no comigration of rear ranged fragments was observed and no PCR product was obtained in one c ase. Obtained results in AML differ from findings in acute lymphoblast ic leukemia (ALL) of B-cell lineage, where a more homogeneous pattern of rearrangements has been described. This heterogeneity might be rela ted to the illegitimate occurrence of TCR delta gene rearrangements in AML.