EVALUATION OF THE ALLERGIC IRRITANT POTENTIAL OF AIR-POLLUTANTS - DETECTION OF PROTEINS MODIFIED BY VOLATILE ORGANIC-COMPOUNDS FROM OILSEEDRAPE (BRASSICA-NAPUS SSP OLEIFERA) USING ELECTROSPRAY IONIZATION MASSSPECTROMETRY

Background Upward trends in allergy and asthma rates have been reporte d in most western societies, including the UK, where around 15-20% of the population now suffer from allergy or asthma. Scientific proof of the causes of these increases relies on accurate assessment of exposur e and standardized diagnostic tests, such as for specific IgE in blood serum and skin testing. For many air pollutants it has proven difficu lt to assess an individual's exposure outside an occupational environm ent and reliable test development is hampered by not knowing whether a n allergic or irritant mechanism is involved. These problems are parti cularly evident in the controversial issue of whether airborne release s from oilseed rape can cause health effects. Objective To develop a m ethod for evaluating the allergic/irritant potential of air pollutants and to assess whether the volatile organic compounds emitted by oilse ed rape have this potential. Methods Proteins were exposed in vitro to volatile organic compounds emitted by oilseed rape. Electrospray ioni zation-mass spectrometry was used to detect any resultant protein modi fications. Results Dimethyl disulphide, thiocyanic acid methyl ester a nd 2-methyl-propanenitrile were able to modify human proteins. In addi tion, two isothiocyanates which can be emitted by damaged oilseed rape also have this ability. The major products emitted by undamaged oilse ed rape, terpenes, a sesquiterpene and a terpene alcohol did not have this property, but the possible role of their oxidized products is dis cussed. Conclusion Some of the volatile organic compounds emitted by o ilseed rape have the potential to be allergens/irritants. Standardized modified proteins produced by this method should prove useful for bio monitoring human exposure in molecular epidemiological studies as well as in diagnostic tests. This method should find further application i n investigations into the possible health effects of other environment al pollutants.