Abstract
Background: The fraction of nitric oxide in exhaled air (FeNO) is increased in allergic asthma and the degree of IgE sensitisation to aeroallergens relates to FeNO levels. An additional IgE sensitisation to food allergens is known to increase asthma risk, but the relation between IgE sensitisation to food allergens and FeNO has been little studied previously.
Aim: To investigate in an ongoing asthma study if the presence of food allergy influences the levels of exhaled NO and which food allergens appear to be important.
Methods: Within the frame of an industry-academy collaboration on minimally-invasive diagnostics (MIDAS), measurements of FeNO and specific IgE (sIgE) against the allergens included in ImmunoCAP Phadiatop and fx5 (Phadia AB, Sweden) were done in 170 patients with physician-diagnosed asthma.
Results: Asthmatic subjects with IgE sensitisation to both aero- and food allergens (n=77) had higher FeNO levels than subjects sensitised to only aeroallergens (n=93) (21.2 ppb (18.4, 24.4) vs 15.6 ppb (13.2, 18.6), p=0.006). This difference was confirmed (p=0.03) in a multiple linear regression model after adjustments for sex, height, lung function and age. The sIgE levels to aeroallergens were higher in subjects also sensitised to food allergens (p<0.001). Peanut sensitisation was most common (63/77 subjects) and peanut IgE levels were independently associated with increased FeNO, even after adjustment for the sum of sIgE to aeroallergens.
Conclusion: Peanut sensitisation was independently associated with increased airways inflammation in allergic asthma. A possible mechanism might be a further enhanced Th2 cytokine-driven inflammation related to peanut IgE sensitisation.
- © 2011 ERS