T-cell Receptor γ and δ Gene Rearrangements in T-cell Acute Lymphoblastic Leukemia in Indian Patients

Abstract

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, non-radioactive, and rapid approach of PCR coupled with heteroduplex analysis was used to analyse clonality of TCR γ and 8 gene rearrangements in 26 Indian T-ALL patients. Amongst TCR γ gene family, Vγ1-Jγ1.3/2.3 sequences were most utilized (53.9%) while from TCRδ repertoire Vδ1-Jδ1 sequences were preferentially rearranged (23.1%) in these patients. 19.2% of Indian T-ALL patients demonstrated both clonal TCR γ and δ gene rearrangements along with surface expression of TCRγδ. Although the majority of T-ALL patients showed surface expression of TCRα β, the small fraction (19.2%) of TCRγδ+ T-ALL represent a distinct subgroup which needs further evaluation.

Key Words:

• T-ALL
• TCR γ and δ genes
• PCR
• Heteroduplex analysis