Background: Perianal fstulas are a debilitating complication of Crohn’s disease (CD). Due to unknown reasons, CD-associated fstulas are in general more diffcult to treat than cryptoglandular... Show moreBackground: Perianal fstulas are a debilitating complication of Crohn’s disease (CD). Due to unknown reasons, CD-associated fstulas are in general more diffcult to treat than cryptoglandular fstulas (non-CD-associated). Understanding the immune cell landscape is a frst step towards the development of more effective therapies for CD-associated fstulas. In this work, we characterized the composition and spatial localization of disease-associated immune cells in both types of perianal fstulas by high-dimensional analyses. Methods: We applied single-cell mass cytometry (scMC), spectral fow cytometry (SFC), and imaging mass cytometry (IMC) to profle the immune compartment in CD-associated perianal fstulas and cryptoglandular fstulas. An exploratory cohort (CD fstula, n = 10; non-CD fstula, n = 5) was analyzed by scMC to unravel disease-associated immune cell types. SFC was performed on a second fstula cohort (CD, n = 10; non-CD, n = 11) to comprehensively phenotype disease-associated T helper (Th) cells. IMC was used on a third cohort (CD, n = 5) to investigate the spatial distribution/interaction of relevant immune cell subsets. Results: Our analyses revealed that activated HLA-DR+CD38+ effector CD4+ T cells with a Th1/17 phenotype were signifcantly enriched in CD-associated compared with cryptoglandular fstulas. These cells, displaying features of proliferation, regulation, and differentiation, were also present in blood, and colocalized with other CD4+ T cells, CCR6+ B cells, and macrophages in the fstula tracts. Conclusions: Overall, proliferating activated HLA-DR+CD38+ effector Th1/17 cells distinguish CD-associated from cryptoglandular perianal fstulas and are a promising biomarker in blood to discriminate between these 2 fstula types. Targeting HLA-DR and CD38-expressing CD4+ T cells may offer a potential new therapeutic strategy for CD-related fstulas. Show less
Guo, N.N.; Li, N.; Jia, L.; Jiang, Q.Y.; Schreurs, M.; Unen, V. van; ... ; Koning, F. 2023
T he intestine represents the largest immune compartment in the human body, yet its development and organisation during human foetal development is largely unknown. Here we show the immune subset... Show moreT he intestine represents the largest immune compartment in the human body, yet its development and organisation during human foetal development is largely unknown. Here we show the immune subset composition of this organ during development, by longitudinal spectral flow cytometry analysis of human foetal intestinal samples between 14 and 22 weeks of gestation. At 14 weeks, the foetal intestine is mainly populated by myeloid cells and three distinct CD3–CD7+ ILC, followed by rapid appearance of adaptive CD4+, CD8+ T and B cell subsets. Imaging mass cytometry identifies lymphoid follicles from week 16 onwards in a villus-like structure covered by epithelium and confirms the presence of Ki-67+ cells in situ within all CD3–CD7+ ILC, T, B and myeloid cell subsets. Foetal intestinal lymphoid subsets are capable of spontaneous proliferation in vitro. IL-7 mRNA is detected within both the lamina propria and the epithelium and IL-7 enhances proliferation of several subsets in vitro. Overall, these observations demonstrate the presence of immune subset-committed cells capable of local proliferation in the developing human foetal intestine, likely contributing to the development and growth of organized immune structures throughout most of the 2nd trimester, which might influence microbial colonization upon birth. Show less
