Exploring the effect of presence and type of allergen sensitization on fractional exhaled nitric oxide, immunoglobulin E, and interleukins 4, 5, and 13 among asthmatics

OBJECTIVE: Asthma is associated with airway inflammation. Allergen sensitization (atopy) is common in asthma. This study explored the effect of food and/or aeroallergen sensitization; on airway and systemic inflammation using fractional exhaled nitric oxide (FE(NO)) and interleukins (ILs) 4, 5, and 13. METHODS: The study enrolled asthmatics (diagnosed using Global Initiative for Asthma guidelines). Atopy was diagnosed using skin-prick testing (SPT). All subjects underwent testing for FE(NO), blood absolute eosinophil count (AEC), and serum levels of immunoglobulin E (IgE), and ILs 4, 5, and 13. Asthmatics (BA) were classified as atopic (BA-A) and nonatopic (BA-N). Atopic-asthmatics were subclassified as exclusively food allergen (AtAA) or aeroallergen (AtAA); or dually (AtFAA) sensitized. RESULTS: The study enrolled 203 asthmatics (BA) and 50 controls. Among BA, 169 were BA-A and 34 were BA-N. Mean values of AEC, serum IgE and FE(NO), and ILs 4 and 13 were significantly higher in BA-A than BA-N (659 vs. 218/mm(3), 638 vs. 217 IU/ml, 39.2 vs. 20.0 ppb, 14.96 vs. 8.04 pg/ml, and 22.12 vs. 11.64 pg/ml, respectively). Meanwhile, mean IL-5 was higher in BA-A (11.01 vs. 8.76 pg/ml; P = 0.22), but not statistically significant. Subgroup analysis of atopic asthmatics (i.e., AtFA, AtAA, and AtFAA), revealed similar mean values for FE(NO) (31.99 vs. 40.16 vs. 39.46 ppb), AEC (691.00 vs. 653.07 vs. 659.88/mm(3)), IgE (635.60 vs. 630.32 vs. 646.39 IU/ml), IL-4 (12.63 vs. 14.74 vs. 15.44 pg/ml), and IL-13 (18.38 vs. 19.87 vs. 24.57 pg/ml). No difference was observed among subgroups of atopic-asthmatics. CONCLUSION: Subgroups of atopic-asthmatics did not show any consistent difference across all the studied parameters.