Inflammatory cells in nasal specimens of workers exposed to wood dust

Background:Exposure to wood dust in theworkplace may lead to inflammatory andirritant effects in the respiratory tract andmay cause the onset or the exacerbation ofbronchial asthma, chronic bronchitis andchronic rhinitis. The study of nasal cytol-ogy obtained by scraping is a non-invasivemethod to assess inflammation of the nasalmucosa. The aim of this study is to evalu-ate the nasal inflammatory pattern relatedto occupational wood dust exposure bynasal cytology.Method:48 workers of an industry thatproduces pre-finished plywood flooringwere studied. All the workers were male,of which 10 exposed to wood dust concen-tration >1 mg/m3, 31 exposed to wooddust concentration <1 mg/m3and 7 unex-posed. All subjects underwent to a ques-tionnaire, spirometry, skin prick tests tocommon aeroallergens and to the study ofnasal cytology, obtained by nasal scraping.Result:Workers exposed to wood dustconcentration >1 mg/m3reported morefrequently respiratory symptoms (20%versus14.3% in non-exposed) and workexacerbated rhinitis (50%versus16.7% innon-exposed). Spirometry and skin pricktests showed no significant differencesbetween exposed and unexposed. Thestudy of nasal cytology showed a slightincrease in neutrophils in exposed to wooddust concentration > 1 mg/ m3(27.7%)than those not exposed (17.6%). This dif-ference was more relevant among thosewho had a nasal bacterial colonization(exposed > 1 mg/m3: 34.3%; Non-exposed2.7%).Conclusion:These results propose neu-trophils involvement behind the nasaleffects of wood dust exposure, suggesting adirect irritant effect rather than an eosino-philic/allergic activation. Moreover, thepossible role of bacterial contamination onnasal inflammation needs to be furtherevaluate by microbiological analysis ofnasal specimens and wood samples.