Exhaled 3-nitrotyrosine is associated with non-allergic asthma in adults from the EGEA study

The role of exhaled 3-nitrotyrosine (3-NT) beyond the severe asthma phenotype remains largely unexplored. Associations of exhaled 3-NT with allergy and with various asthma characteristics were studied in 792 adults from the French Epidemiological study on the Genetics and Environment of Asthma (EGEA, 40% current asthmatics, 56% allergic, 36% adult-onset asthma). Asthma characteristics were defined using questionnaires, and allergy by a positive skin prick test. 3-NT was analyzed as categorical, continuous and ratio (3-NT/tyrosine) variables. Cross-sectional analyses showed that high 3-NT levels were associated with an increased risk of current asthma (adjusted(a)OR [95%CI] = 1.61 [1.09-2.38], particularly in non-allergic asthma (aOR = 2.19 [1.09-4.41]), and no association was found with allergy. Results were consistent across all 3-NT expressions. Longitudinal analyses showed that high 3-NT levels were associated with persistent current asthma at 10-year follow-up. Our results advance understanding of the mechanisms underlying asthma phenotypic heterogeneity, thereby opening new perspectives in its management.