Comprehensive characterization of Mucosal-Associated invariant T (MAIT) cells in patients with hepatitis E virus infection

Hepatitis E virus (HEV) gt3 infection causes a self-limiting, usually asymptomatic disease in immunocompetent patients. However, in immunocompromised patients, chronic HEV infection can develop, leading to liver cirrhosis. Since HEV is mainly transmitted orally, the first contact with the virus is through the mucosal barrier, including mucosal-associated invariant T cells (MAIT). Modulation of MAIT cells has been demonstrated in chronic viral hepatitis. Since little information is available on MAIT cells during HEV infection, we investigated the phenotype and function of MAIT cells in HEV-infected immunocompetent and immunosuppressed patients.

PBMCs from 48 HEV patients (17 immunocompetent (no-TX, acute and resolved); 31 immunocompromised (TX, acute, chronic, resolved)) were investigated. MAIT cells were phenotypically characterized and their function was measured after in vitro stimulation with IL12/IL18 or HEV protein.

The frequency of MAIT cells was comparable in the groups studied. A higher frequency of the activation marker CD69 on MAIT cells was observed in HEV-infected TX patients (chronic p < 0.05, acute p=0.06) compared to no-TX patients (acute HEV)). When analyzing PD1 expression on MAIT cells, we observed significantly increased expression in chronic HEV compared to acute HEV, but only in TX patients. Increased functionality (significant for TNF) was observed in chronic TX patients compared no-TX patients following IL12/IL18 stimulation in vitro and likewise after stimulation with HEV protein, the latter mediated via MR1.

MAIT cells showed a distinct phenotype and increased functionality in chronic HEV-infected TX patients, which may contribute to the hepatitis and progression to liver fibrosis observed in these patients.

Poster Visit Session I Basic Hepatology (Fibrogenesis, NPC, Transport)

28/01/2022, 13.55 pm – 14.40 pm

Publication History

Article published online:
26 January 2022