English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Background Crohn’s disease (CD) and ulcerative colitis (UC) are characterized by intestinal infiltration of pathogenic effector CD4+ T cells. The defects driving loss of T-cell regulation vary between patients and remain undefined. Previously, we have shown that in human intestine, 20–40% of effector (CD62LnegCD4+) T cells express TIGIT (T cell immunoglobulin and ITIM domain), an inhibitory receptor modulating dendritic cell and T-cell function. TIGIT expression is enriched in circulating gut-homing CD38+ effector T cells in healthy controls while in a subgroup of IBD patients with active intestinal inflammation, frequencies of inhibitory TIGIT+CD38+ effector T cells are decreased and associated with earlier relapse of disease. Here we hypothesized that gut-homing effector T cells lacking TIGIT (TIGITneg) are pathogenic mediators of intestinal inflammation in IBD and assessed whether patients with low frequencies have a distinctive disease immunotype. Methods In the Rotterdam PIBD-SETQuality cohort of newly diagnosed pediatric IBD patients (CD: n=50; UC: n=25), patients with suspicion of IBD but negative diagnosis (n=17) and age-matched healthy controls (HC: n=22), we monitored TIGIT+ and TIGITnegCD38+ effector T cells in peripheral blood, collected plasma at diagnosis and during therapy and phenotyped intestinal T cells. Results At diagnosis, 50% of CD patients had strongly reduced frequencies of inhibitory TIGIT+CD38+ effector T cells compared to UC patients and HC. CD patients with reduced frequencies of inhibitory TIGIT+CD38+ effector T cells had higher plasma IFN-γ concentrations and 53% of them experienced a disease relapse by 1 year versus 25% for CD patients with normal TIGIT+CD38+effector frequencies. In keeping with our hypothesis that TIGITneg gut-homing effector T cells are pathogenic, absence of TIGIT expression identified CD38+ effector T cells enriched in recent proliferation and having high expression of chemokine receptors associated with inflammatory non-classical T helper-1 IFNγ highIL-17Alow producing (Th1*) cells. Moreover, intestinal TIGITnegCD4+ T cells of CD patients contained higher frequencies of IFNγ and IL-17A producing cells than TIGIT+CD4+ T cells. In order to identify the factors that drive differentiation of the pathogenic Th1* cells, inhibitory TIGIT+CD38+ effector T cells from HC were exposed to an array of IBD-associated cytokines in vitro. Only IL-12p70, a known driver of IFNγ, could convert inhibitory TIGIT+CD38+ effector T cells into their TIGITneg proinflammatory counterpart. Conclusion We identify TIGITneg gut-homing effector T cells, enriched in Th1* cells, as potential drivers of intestinal inflammation in a subgroup of CD, but not UC patients, with a more severe disease course.

P045 TIGIT expression differentiates regulatory from inflammatory Th1* gut-homing effector CD4+ T cells in inflammatory bowel disease patients