Mucosal associated invariant T cells in patients with recurrent urinary tract infection exhibit an activated and cytotoxic profile

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

Thursday 14 march 2019

13:19 - 13:21h at Tropentheater

Categories: Klinisch/Basaal, Parallelsessie

Parallel session: Parallelsessie XV – Basaal / Klinisch 2

Background: Mucosal associated invariant T (MAIT) cells are innate-like T-cells involved in the antibacterial response by recognizing bacterial riboflavin metabolites. They comprise ~10% of the T-cell population in human blood, are highly abundant at mucosal barrier sites and respond to a wide range of bacteria. Urinary tract infection (UTI) is a common complication after renal transplantation and can, especially in case of frequent recurrence, lead to damage of the allograft and eventually allograft failure. Although animal studies have indicated that MAIT cells play a role in the defense against UTI, there are currently no human data on the role of MAIT cells in (recurrent) UTI.

Methods: 

We used a fluorescently-labelled MR1-tetramer in conjunction with 14-color flowcytometry to identify and characterize MAIT cells in blood from women with recurrent urinary tract infections (RUTI) (n=10) and in healthy controls (n=10).

Results: There was no significant difference in the amount of MAIT cells between RUTI patients and healthy controls. Characterization of MAIT cells revealed that in RUTI patients, the percentage of MAIT cells expressing the proliferation marker Ki67 was significantly higher (p<0.01), just as the percentage of MAIT cells expressing the cytotoxic markers granzyme B, granzyme K and perforin (respectively p<0.01, p<0.01, p<0.05). The percentage of MAIT cells expressing the transcription factors T-bet and Eomes was also significantly higher among the RUTI patients (respectively p

Conclusions: MAIT cells in blood from women with RUTI display an activated and cytotoxic profile. This suggests that MAIT cells are involved in the defense against uropathogens. Currently it is unclear whether MAIT cells are able to migrate to the urogenital tract or whether also (lower) UTI may be accompanied by ascending bacteria and bacterial metabolites, which would lead to activation of MAIT cells in the bloodstream. Further research is warranted to determine what the exact role is of MAIT cells during UTI, also in renal transplant recipients with R(UTI).