Human kidneys contain tissue-resident Mucosal Associated Invariant T-cells

M.L. Terpstra, M.J. Sinnige, E.B.M. Remmerswaal, M.C. van Aalderen, J. Kers, S.E. Geerlings, F.J. Bemelman

Wednesday 13 march 2019

14:26 - 14:28h at Koningin Máximazaal

Categories: Basaal, Parallelsessie

Parallel session: Parallelsessie III - Basaal I

Background: Mucosal associated invariant T (MAIT) cells are innate-like T-cells involved in the antibacterial response by recognizing bacterial riboflavin metabolites. They are present in human blood but are particularly abundant in the liver, lungs and intestines. Currently it is unclear whether MAIT cells are present in human kidneys.

Methods: We used a fluorescently-labelled MR1-tetramer in conjunction with 14-color flowcytometry to identify and characterize MAIT cells in normal renal tissue (n=5), in renal allografts explanted after allograft failure (n=13) and in peripheral blood mononuclear cells (PBMCs) from healthy donors (n=21). We performed an additional analysis of the allografts that clinically failed due to recurrent urinary tract infections (RUTI) (n=5).

Results: MAIT cells were present in each of the measured renal samples. Both the absolute T-cell counts and the MAIT cell counts were significantly higher in the explanted allografts than in the normal kidneys (p+MAIT cell population that encompassed a substantial CD69⁺and CD69⁺/CD103⁺‘tissue-resident’ subset. MAIT cells in the allografts less often expressed CD161 and displayed a different phenotype consisting of an increased expression of T-bet and granzyme B and a lower expression frequency of CD27 and IL-7Rαthan circulatory MAIT cells. Further analyses of MAIT cells in allografts that failed due to RUTI, revealed that these MAIT cells displayed a less cytotoxic phenotype.

Conclusions: MAIT cells are present in human kidneys and comprise a CD69⁺CD103⁺tissue-resident population. MAIT cells in renal allografts display a distinct effector profile. Remarkably, in allografts that failed due to RUTI, MAIT cells display a less cytotoxic profile than in allografts that failed for other reasons.