Peripheral blood gamma-delta T cells in advanced-stage cancer patients

Abstract  Gamma-delta T (γδ T) cells form a subgroup which has been reported to play a role in both natural and acquired immunity. Their levels have been found to increase in some tumour tissues. The aim of this study was to investigate the ratio of γδ T cells to all T cells in the peripheral blood of advanced-stage cancer patients; the level of γδ T cells expressing the Vδ2-T-cell receptor (TCR) chain; NKG2D receptor expression; and apoptotic (Annexin-V) γδ T-cell levels. Twenty patients with advanced-stage cancer and 13 healthy controls were included. No statistical differences were found between control and patient groups in terms of the γδ T/total T-cell ratio (P=0.53), the Vγ2-TCR expressing γδ T-cell ratio (P=0.19) or the Annexin-V ratio (P=0.48). However, NKG2D expression in γδ T cells was significantly different between the control and patient groups (P=0.014). In summary it was shown that the levels of NKG2D receptors, which are responsible for the cytolytic effect of γδ T cells, were lower in cancer patients than in healthy adults. However, no significant differences were observed in the other parameters studied between groups.