Circulating IL-17-producing mucosal-associated invariant T cells (MAIT) are associated with symptoms in children with asthma

IL-17 and mucosal-associated invariant T (MAIT) cells have been involved in asthma pathogenesis. However, IL-17-producing MAIT cells (MAIT-17) were not evidenced. We aimed to determine whether circulating MAIT-17 were detectable in children with asthma, and whether they correlated with asthma symptoms or lung function. Children from the SPASM cohort of preschoolers with severe wheeze were reassessed for asthma at school age, and categorized as exacerbators (1 or more severe exacerbations in the previous 12 months) or non-exacerbators. Nineteen children (10.9 years) were included (9 non-exacerbators, 10 exacerbators). Circulating MAIT-17 were detected by flow cytometry. Their frequency was higher in exacerbators than in non-exacerbators (1.9 [1.01-3.55] vs 0.58 [0.46-1.15], p < 0.01). MAIT-17 correlated with the number of severe exacerbations (r = 0.68, p < 0.001), and correlated negatively with the ACT score (r = − 0.55, p = 0.01). In summary, MAIT-17 are present in children with asthma and associated with asthma symptoms.