6533b820fe1ef96bd1279ae4

RESEARCH PRODUCT

Characterisation of gd T cells infiltrating colorectal cancer

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We have read with great interest the paper by de Vries et al 1 reporting on the immune landscape of colorectal cancer (CRC) by high-dimensional mass cytometry, flow cytometry and single cell RNA sequencing. Among clusters of immune cells infiltrating CRC, authors have identified two populations of γδ T cells: one programmed cell death protein 1 (PD-1)+ population is almost exclusively found in DNA mismatch repair (MMR)-deficient (d) tumours, constitutes up to 8.4% of CD45+ cells and has an activated phenotype, and a PD-1− counterpart with a resting phenotype, which is also found in colorectal normal mucosa and MMR-proficient (p) tumours. Using deconvolution of transcriptomic datasets and single cell RNA sequencing, we have detected γδ cells in many different human tumours, including CRC,2 3 but it is important to know also their subset distribution, maturation states and functional profiles. In fact, there are two subsets of γδ T cells, those expressing Vδ1 which reside at mucosal sites and those expressing Vδ2 which are found in the blood but are recruited to the tumour site.4 Our previous study5 in tissue specimens of n=70 patients with CRC using flow cytometry has shown that γδ T cells account for around 4.5% of CD45+ cells both in normal and in CRC mucosa, and these data have been confirmed by data-mining of …