Latex allergen exposure increases exhaled nitric oxide in symptomatic healthcare workers

Abstract

The objective of this study was to investigate the clinical and diagnostic impact of baseline exhaled nitric oxide (eNO) levels and latex allergen-induced eNO changes in different healthcare worker groups.Healthcare workers, 31 latex-sensitised and 14 nonsensitised, underwent occupational-type challenge tests with powdered allergenic latex gloves.Sensitised as well as nonsensitised healthcare workers developed a significant eNO increase 1 h after challenge. Conversely, only latex-sensitised employees showed a significant eNO increase 22 h after challenge, which showed a significant relationship with bronchial obstruction (specific airway resistance changes). However, there was no difference in either baseline eNO level or eNO increase after 22 h between asthmatic (n513) and rhinitic only (n520) responders. The specificity and sensitivity of a 50% eNO increase after 22 h in responders were 100 and 56%, respectively.These results support the assumption that the whole respiratory tract is involved in a combined allergic rhinitis and asthma syndrome. Smoking healthcare workers showed reduced baseline exhaled nitric oxide levels, but, as shown for the first time, an allergen-induced exhaled nitric oxide increase comparable to that of nonsmokers. Corticosteroid therapy inhibited the allergeninduced exhaled nitric oxide change but not the clinical response in the challenge test. These findings suggest that cigarette smoke and corticosteroids initiate distinct molecular mechanisms influencing nitric oxide concentrations in the airways. KEYWORDS: Allergy, bronchial asthma, latex, nitric oxide E xhaled nitric oxide (eNO) has been described as a marker of allergic airway inflammation in both rhinitic and asthmatic subjects [1][2][3][4][5][6][7]. 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.The present hypothesis is that allergen-induced eNO increases have a clinical and diagnostic impact. Considering the influence of possible confounding factors such as atopy, smoking and corticosteroid therapy, it was investigated whether, in different patient subgroups, baseline eNO concentrations, as well as eNO changes, are associated with: 1) latex-specific immunoglobulin (Ig) E and skin-prick test responses; and 2) clinical responses...

Guidelines for the management of work-related asthma

“…12) In the clinical setting, a finding of normal exhaled nitric oxide fraction cannot be used to exclude occupational asthma (**) [62,[73][74][75].…”

Across-shift changes of exhaled nitric oxide and spirometric indices among cotton textile workers

“…One hour after exposure to latex, FeNO was significantly increased in both sensitized and nonsensitized subjects, but after 24 h this increase remained only in the sensitized subjects. This study has proposed assessment of across-shift changes of FeNO as a screening test in HCWs [36].…”

Specific inhalation challenge in the diagnosis of occupational asthma: consensus statement

“…There have been conflicting data on the changes in FeNO after SIC with occupational agents [87][88][89][90][91][92][93][94][95]. A significant increase in FeNO level was observed only 24 h after positive challenges, while there was a significant increase in sputum eosinophil at 7 h [92,96].…”