Simultaneously increased fraction of exhaled nitric oxide levels and blood eosinophil counts relate to increased asthma morbidity.
We have previously described that fraction of exhaled nitric oxide (Feno) levels and blood eosinophil counts offer additive information in relation to asthma and asthma exacerbations when analyzing data from a large population study.



We sought to investigate increased Feno levels and blood eosinophil counts in relation to lung function, bronchial hyperresponsiveness (BHR), and asthma control in a cohort of young asthmatic patients.



Measurements of Feno levels and blood eosinophil counts were available in 406 subjects (208 women) aged 10 to 35 years. Asthma control was assessed through the Asthma Control Test. Moderate-to-severe BHR was defined as a cumulative dose of methacholine of less than 0.3 mg causing an FEV1decrease of 20%.



Subjects with simultaneously increased Feno levels (≥20-25 ppb) and blood eosinophil counts (≥0.3 × 109/L) had a higher prevalence of uncontrolled asthma (Asthma Control Test score, <20) than subjects with singly increased blood eosinophil counts (40.5% vs 21.1%, P = .01). This difference remained significant (P = .006), and a significant difference was also found between subjects with both increased Feno levels and blood eosinophil counts and subjects with normal Feno levels and blood eosinophil counts (P = .02) after adjusting for confounders. Having increased Feno levels and blood eosinophil counts related to a higher prevalence of moderate-to-severe BHR than having normal Feno levels and blood eosinophil counts or singly increased Feno levels or blood eosinophil counts (85.7% vs 35.8% or 63.3% or 60%, P < .05 all comparisons).



We have shown that simultaneously increased local (Feno) and systemic (blood eosinophil) markers of type 2 inflammation related to a higher likelihood of BHR and uncontrolled asthma in a large cohort of young asthmatic patients.
Department of Medical Sciences: Clinical Physiology, Uppsala University, Uppsala, Sweden. Electronic address: Andrei.Malinovschi@medsci.uu.se.
Andrei
A
Malinovschi
Department of Medical Sciences: Respiratory Medicine and Allergology, Uppsala University, Uppsala, Sweden.
Christer
C
Janson
Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
Magnus
M
Borres
Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
Kjell
K
Alving
D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000097:blood / Q000453:epidemiology / Q000378:metabolism / Q000503:physiopathology; D001944:Breath Tests; D016535:Bronchial Hyperreactivity / Q000097:blood / Q000453:epidemiology / Q000378:metabolism / Q000503:physiopathology; D002648:Child; D004804:Eosinophils; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007958:Leukocyte Count; D008297:Male; D009017:Morbidity; D009569:Nitric Oxide / Q000378:metabolism*; D014797:Vital Capacity; D055815:Young Adult
D009569:Nitric Oxide; D007073:Immunoglobulin E
Exhaled nitric oxide; asthma control; blood eosinophil count; bronchial responsiveness; lung function