T-cell receptor gamma and delta gene rearrangements in T-cell acute lymphoblastic leukemia in Indian patients

T-cell acute lymphoblastic leukemia (T-ALL) is a clonal lymphoid malignancy and junctional sequences of rearranged T-cell receptor (TCR) represent the best suitable marker to study clonality in these patients. A sensitive, no n-radioactive, and rapid approach of PCR coupled with heteroduplex analysis was used to analyse clonality of TCR gamma and delta gene rear rangements in 26 Indian T-ALL patients. Amongst TCR gamma gene family, V gamma I-J gam ma 1.3/2.3 sequences were most utilized (53.9%) while from TCR delta repert oire V delta 1-J delta 1 sequences were preferentially rearranged (23.1%) i n these patients. 19.2% of Indian T-ALL patients demonstrated both clonal T CR gamma and delta gene rearrangements along with surface expression of TCR gamma delta. Although the majority of T-ALL patients showed surface expres sion of TCR alpha beta, the small fraction (19.2%) of TCR gamma delta+ T-AL L represent a distinct subgroup which needs further evaluation.