Objective: To investigate the relation between signs and symptoms of irritation and biomarkers of inflammatory markers in blood in healthy volunteers exposed to different chemical vapours for 2 or 4 hours in an exposure chamber.
Methods: The investigated chemicals were: acetic acid (5 and 10 ppm), acrolein (0.05 and 0.1 ppm), 1,4-dioxane (20 ppm), n-hexanal (2 and 10 ppm), hydrogen peroxide (0.5 and 2.2 ppm), 2-propanol (150 ppm), m-xylene (50 ppm), standard and dearomatised white spirit (100 and 300 mg/m3). C reactive protein (CRP), serum amyloid A protein and interleukin 6 were measured in plasma immediately before and 2 or 4 hours after the exposures. Symptoms were rated from 0 to 100 mm in Visual Analogue Scales and covered 10 questions whereof four related to irritation: discomfort in the eyes, nose and throat and dyspnoea. The effect measurements included blink frequency by electromyography, nasal swelling by acoustic rhinometry and lung function by spirometry.
Results: Logistic quantile regression analyses revealed no significant associations except a negative relation between ratings of irritation and CRP.
Conclusion: The results suggest a down-regulation of CRP after short-term exposure to low levels of vapours of irritating chemicals. This response might be mediated by the cholinergic anti-inflammatory pathway and further studies are recommended in order to refute or confirm this hypothesis.
Keywords: chamber exposure; human volunteers; irritation.
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