Polyunsaturated fatty acid-induced metabolic exhaustion and ferroptosis impair the anti-tumour function of MAIT cells in MASLD.

Background & Aims: Mucosal-associated invariant T (MAIT) cells constitute a highly abundant innate-like T-cell population in the human liver that is critical for immune surveillance of hepatic cancers. However, MAIT cells are often dysfunctional in human hepatocellular carcinoma (HCC), for reasons that remain unclear. Here, we aimed to identify the mechanisms driving MAIT cell dysfunction in metabolic dysfunction-associated steatotic liver disease (MASLD), a chronic liver condition that predisposes patients to HCC.

Mucosal-Associated Invariant T (MAIT) Cells Are Highly Activated and Functionally Impaired in COVID-19 Patients.

Coronavirus disease 2019 (COVID-19), caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), comprises mild courses of disease as well as progression to severe disease, characterised by lung and other organ failure. The immune system is considered to play a crucial role for the pathogenesis of COVID-19, although especially the contribution of innate-like T cells remains poorly understood. Here, we analysed the phenotype and function of mucosal-associated invariant T (MAIT) cells, innate-like T cells with potent antimicrobial effector function, in patients with mild and severe COVID-19 by multicolour flow cytometry.