The Potential Roles of Mucosa-Associated Invariant T Cells in the Pathogenesis of Gut Graft-Versus-Host Disease after Hematopoietic Stem Cell Transplantation

Abstract Background & Purpose: Gut acute graft-versus-host disease (aGVHD) is a serious complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and associated with high mortality. Mucosal-associated invariant T cells (MAITs) are group of innate-like enriched in the intestine that can be activated by riboflavin metabolites from various microorganisms. However, little known about function or mechanism action MAIT occurrence gut aGVHD human body. Methods Cases: In our study, multiparameter flow cytometry (FCM) was used to evaluate number functional cytokines. 16S V34 region amplicon sequencing analysis analyse intestinal flora transplant patients. vitro stimulation coculture assays were study activation MAITs. The distribution MAITs tissues analysed immunofluorescence technology. We prospectively studied enrolled 150 consecutive patients who underwent allo-HSCT institute. Results: frequency infused grafts lower than those non-gut (Figure). Recipients had higher abundance early post-transplantation period (+14 days). At onset aGVHD, decreased peripheral blood, marker CD69, chemokines CXCR3 CXCR4 transcription factors Rorγt T-bet tended increase. Furthermore, when occurred, proportion MAIT17 MAIT1. non-riboflavin metabolic pathways increase secreted more granzyme B, TNF-α IFN-γ under IL-12/IL-18 (non-TCR signal) most IL-17 CD3/CD28 (TCR signal). inhibited proliferation CD4+ vitro. Conclusions: conclusion, related incidence may affect composition recipients transplantation. metabolism pathway promoted secretion protective humans. Figure 1 1. Disclosures No relevant conflicts interest declare.