NASAL LAVAGE AS TOOL FOR HEALTH EFFECT ASSESSMENT OF PHOTOCHEMICAL AIR-POLLUTION

It is widely accepted that humans exposed to known concentrations of o zone under controlled conditions exhibit reversible changes that affec t the large and small airways as well as the alveolar region of the lu ng. Among the reversible changes, the induction of inflammatory respon ses in the lung are of major concern. Many of the cell types found in the lining of the nasopharyngeal region are similar to cells of the tr acheal and bronchial lining. Therefore, it has been suggested that the cellular responses in the nose to toxicants are likely to be similar to the lower airway at the same dose of the agent. If these pollutants are respiratory irritants, capable of causing cellular damage, effect s may therefore be detected in the nasal passage. Experimental studies have shown that the inflammatory response in the nose may be predicti ve for the situation in the lung. In this paper we described the resul ts of a feasibility study on the use of nasal lavage for epidemiologic al studies. Nasal lavages were performed in 12 volunteers, 5-7 times p er volunteer during 2 months. Polymorph nuclear leukocytes (PMN's), im mune mediators and markers for exudation were monitored in the nasal l avage (NAL). It was found that the procedure of the nasal lavage techn ique was minimally invasive, very well tolerated and no adverse side e ffects were observed. The leukocytes, the proteins myeloperoxidase (MP O), eosinophil cationic protein (ECP) and interleukin-8 (IL-8) were de tectable in NAL of most volunteers, while tryptase IgE and IL-6 were n ot detectable. Exudation markers albumin, urea and uric acid were also detectable. The coefficient of variance (CV) values of the various ce lls and mediators varied between 13% and 137%. It was calculated that, except for the number of leukocytes and the concentration of ECP, it should be possible to detect ozone effects with a study-protocol of 6 repeated measurements among 35 children and an assumed 26% increase in cells or mediators per 100 mu g O-3 per m(3). To measure increase in leukocytes number or in ECP concentration more children are needed. In conclusion, this pilot study has shown that it is possible to measure relevant biomarkers in NAL, and that these assays can be easily incor porated in epidemiological studies