Exhaled and nasal nitric oxide is increased in laboratory animal allergy

Abstract

Background Allergens from rats, mice, guinea pigs or rabbits cause up to 30% of exposed persons to develop specific immunoglobulin E (IgE) responses. Laboratory animal allergy (LAA) is among the highest occupational risks for asthma in the UK. Elevated levels of nitric oxide (NO) are found in exhaled breath in asthma. In LAA symptoms may progress from conjunctivitis, rhinitis to asthma. Health surveillance aims to detect early sensitization. Objective To assess whether an association exists between LAA and exhaled NO. Methods A cross-sectional study was performed in 39 laboratory workers undergoing LAA health surveillance. Volunteers completed two health questionnaires, had skin-prick tests, spirometry, total IgE and RAST tests. Exhaled and nasal NO was measured by chemiluminescence analyser (LR2000, Logan Research, Rochester, UK). Results There were 23 asymptomatic subjects (mean age 29.53 yearss) and 16 symptomatic subjects (29.63 yearss, P ¼ 0.95); 9 early LAA, seven LAA asthma. Exhaled NO was raised in those with LAA symptoms 17.97 ppb Ϯ 1.24 (mean Ϯ SEM) compared with asymptomatics 6.08 ppb Ϯ 1.15, P < 0.05. A trend of increased NO by allergic status was observed; asymptomatic, to early LAA, to asthma. One-way analysis of variance compared differences between groups (F ratio 13.93, P < 0.001). Symptomatic subjects also had raised nasal NO, vs asymptomatic subjects (mean difference 378 ppb, P < 0.05). A trend was again observed by allergic status (F ratio 5.28, P ¼ 0.01). Conclusion Raised NO levels in LAA increasing with symptom severity suggest NO may prove a useful additional tool in monitoring for LAA, and possibly the response to exposure reduction or allergy due to other respiratory sensitizers.

Association between exhaled nitric oxide, ambient air pollution and respiratory health in school children

“…The level of exhaled NO (eNO) can vary considerably between individuals, but is consistently found to be increased in asthmatic patients and atopic subjects [2,5,6,9,16,40]. In addition, eNO may be a sensitive marker for respiratory effects related to air pollution, as we previously showed a positive association (P<0.001) between the level of ambient air pollution and eNO level [38].…”

“…Nevertheless, high eNO values are consistently observed in allergic-asthma patients and atopic individuals [2,5,6,9,16,40], though the physiological meaning of this increase in eNO is still not understood. Increased production and release of NO in the airways might represent a broncho-dilating feedback effect to counteract broncho-constriction in asthma, or might reflect the characteristic pulmonary inflammatory reaction of asthmatic lungs.…”

Latex allergen exposure increases exhaled nitric oxide in symptomatic healthcare workers

“…eNO levels may be elevated in patients before asthmatic symptoms develop [8,9]. HENRIKSEN et al [8] and GRATZIOU et al[9] observed a seasonal rise in eNO levels in pollensensitised subjects with and without rhinitic and/or asthmatic symptoms, with a tendency towards increased concentrations in symptomatic subjects.Despite the considerable number of publications and results indicating relations between baseline eNO level and/or eNO changes on the one hand and symptoms [9][10][11], bronchial hyperresponsiveness [12,13] and inflammatory parameters of the airways [14] on the other, the clinical role of eNO measurements has not been exactly defined. Moreover, the relation between eNO levels and eNO changes following laboratory allergen challenge has so far rarely been compared between subjects with rhinitic and those with asthmatic responses.…”

“…Despite the considerable number of publications and results indicating relations between baseline eNO level and/or eNO changes on the one hand and symptoms [9][10][11], bronchial hyperresponsiveness [12,13] and inflammatory parameters of the airways [14] on the other, the clinical role of eNO measurements has not been exactly defined. Moreover, the relation between eNO levels and eNO changes following laboratory allergen challenge has so far rarely been compared between subjects with rhinitic and those with asthmatic responses.…”

Acute Exudative Inflammation and Nasally Exhaled Nitric Oxide Are Two Independent Phenomena

“…In the present study we investigated the possibility that a potent exudative and vasodilator stimulus like histamine topically given to the nasal mucosa in healthy individuals may increase nasally exhaled NO as seen in allergic rhinitis [5,10,24].…”