TY - JOUR T1 - Mucosal associated invariant T cells in ARDS: MAIT cells set fire to macrophages via cytokines JF - Thorax JO - Thorax SP - 846 LP - 847 DO - 10.1136/thoraxjnl-2022-218696 VL - 77 IS - 9 AU - Dong Hyun Kim AU - Bonah Kim AU - Won-Woo Lee Y1 - 2022/09/01 UR - http://thorax.bmj.com/content/77/9/846.abstract N2 - Mucosal-associated invariant T (MAIT) cells are evolutionarily conserved innate-like T cells that play an important role in the maintenance of homeostasis of mucosal and non-mucosal barriers.1 They are highly abundant in the liver and blood and are also present in mucosal tissues. MAIT cells express a semi-invariant T cell receptor (TCR) recognising precursor derivatives of the riboflavin (vitamin B2) biosynthetic pathway, presented by the evolutionarily conserved, monomorphic major histocompatibility complex (MHC) class I-related protein-1 (MR1).1 Since these derivatives are strictly found in riboflavin-synthesising bacteria and yeasts, MAIT cells mediate a broad and potent antimicrobial reactivity.1 Activated MAIT cells rapidly secret proinflammatory cytokines, such as interleukin-17 (IL-17), interferon-γ (IFN-γ), and tumor necrosis factor (TNF) and exert cytolytic activity against cells presenting bacterial ligands on MR1.2 Additionally, MAIT cells can be activated in a TCR/MR1-independent manner by several cytokines, including IL-12, IL-15, IL-18 and type I interferons.2 3 In this issue of Thorax, Kim and colleagues4 broaden our understanding of the pathological role of MAIT cells in acute respiratory distress syndrome (ARDS). ARDS is an acute respiratory illness featured by bilateral chest radiographical opacities with severe hypoxemia due to non-cardiogenic pulmonary oedema.5 ,6 ARDS occurs most often in the setting of pneumonia, non-pulmonary sepsis, aspiration of gastric contents or severe trauma. The authors demonstrate that the frequency … ER -