title: Enrichment of Inflammatory IL-17 and TNF-α Secreting CD4(+) T Cells within Colorectal Tumors despite the Presence of Elevated CD39(+) T Regulatory Cells and Increased Expression of the Immune Checkpoint Molecule, PD-1.
abstract: T cell infiltration into colorectal tumors has been shown to correlate with improved patient outcomes. However, more detailed information on the makeup and relationships between the infiltrating T cell subsets is lacking. We therefore correlated the extent of immune infiltration into colorectal tumors with the frequencies of various T cell subsets. We prospectively recruited 22 patients at the time of surgical resection for colorectal cancer. The Klintrup-Mäkinen (KM) score was used to estimate the extent of immune infiltration into colorectal tumors. The frequencies of CD4 and CD8 T cells that produced cytokines or expressed the inhibitory molecule programed cell death 1 (PD-1) were determined by flow cytometry in colorectal tumor and matched uninvolved colonic tissue. In addition, the frequency of CD4 regulatory T cell (Treg) subsets was determined. An increased frequency of CD4 T cells producing IL-17 (Th17 cells) was observed in colorectal tumor tissue compared with adjacent uninvolved tissue. These Th17 cells mostly coproduced TNF-α, but not IFN-γ. IL-17 expression correlated positively with TNF-α and IL-10. Increased expression of the immune checkpoint molecule PD-1 was found in colorectal tumors compared with adjacent uninvolved tissue. There was a negative correlation between expression of PD-1 and IFN-γ, but not IL-17, for both CD4(+) and CD8(+) T cells. CD4(+)CD25(+)CD127(lo) and CD4(+)CD25(+)CD127(lo)FoxP3(+)CD39(+) Treg cells were enriched in colorectal tumors. A positive correlation between KM score and percentage CD4(+)CD25(+)CD127(lo) Treg cells was observed in tumors, suggesting that increased immune infiltration is associated with an increased proportion of Treg cells. In addition, there was a negative correlation between the frequency of CD4(+)CD25(+)CD127(lo) Treg cells and the expression of IFN-γ and IL-2, but not IL-17, in tumors. Taken together, these data suggest that both PD-1 expressing T cells and Treg cells within the tumor may have a suppressive effect on T cells secreting IFN-γ, IL-2, or TNF-α, but not Th17 cells.
authors.affiliation: School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland; School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland.
authors.forename: Margaret R
authors.initials: MR
authors.lastname: Dunne
authors.affiliation: Department of Pathology, St. Vincent's University Hospital , Dublin , Ireland.
authors.forename: Ciara
authors.initials: C
authors.lastname: Ryan
authors.affiliation: Centre for Colorectal Disease, Education and Research Centre, St. Vincent's University Hospital, Dublin, Ireland; School of Medicine, University College Dublin, Dublin, Ireland.
authors.forename: Bláthnaid
authors.initials: B
authors.lastname: Nolan
authors.affiliation: Centre for Colorectal Disease, Education and Research Centre, St. Vincent's University Hospital, Dublin, Ireland; School of Medicine, University College Dublin, Dublin, Ireland.
authors.forename: Miriam
authors.initials: M
authors.lastname: Tosetto
authors.affiliation: Department of Pathology, St. Vincent's University Hospital , Dublin , Ireland.
authors.forename: Robert
authors.initials: R
authors.lastname: Geraghty
authors.affiliation: Centre for Colorectal Disease, Education and Research Centre, St. Vincent's University Hospital, Dublin, Ireland; School of Medicine, University College Dublin, Dublin, Ireland.
authors.forename: Des C
authors.initials: DC
authors.lastname: Winter
authors.affiliation: Centre for Colorectal Disease, Education and Research Centre, St. Vincent's University Hospital, Dublin, Ireland; School of Medicine, University College Dublin, Dublin, Ireland.
authors.forename: P Ronan
authors.initials: PR
authors.lastname: O'Connell
authors.affiliation: Centre for Colorectal Disease, Education and Research Centre, St. Vincent's University Hospital, Dublin, Ireland; School of Medicine, University College Dublin, Dublin, Ireland.
authors.forename: John M
authors.initials: JM
authors.lastname: Hyland
authors.affiliation: Centre for Colorectal Disease, Education and Research Centre, St. Vincent's University Hospital, Dublin, Ireland; School of Medicine, University College Dublin, Dublin, Ireland.
authors.forename: Glen A
authors.initials: GA
authors.lastname: Doherty
authors.affiliation: Department of Pathology, St. Vincent's University Hospital, Dublin, Ireland; Centre for Colorectal Disease, Education and Research Centre, St. Vincent's University Hospital, Dublin, Ireland; School of Medicine, University College Dublin, Dublin, Ireland.
authors.forename: Kieran
authors.initials: K
authors.lastname: Sheahan
authors.affiliation: Centre for Colorectal Disease, Education and Research Centre, St. Vincent's University Hospital, Dublin, Ireland; School of Medicine, University College Dublin, Dublin, Ireland.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Ryan
authors.affiliation: School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland; School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland.
authors.forename: Jean M
authors.initials: JM
authors.lastname: Fletcher
keywords: PD-1; T cells; Th17 cells; colorectal cancer; immunophenotyping; immunotherapy; regulatory T cells