Nitric Oxide Reaction May Trigger Hayfever -- MEDICA - World Forum for Medicine

Hayfever is a major irritation for up to 20% of the population in most economically developed countries. Pollen is the cause of this allergic reaction but the question is what causes it and why. Dr. Jo Bright and Dr. John Hancock of the University of the West of England have found evidence that nitric oxide (NO) and nitrite is released by pollen grains, and they suggest that this could be what triggers the allergic response in the nose. “Our research is the first to show that pollen which is allergenic releases much greater amounts of NO and nitrite than a non-allergenic pollen,” Bright says.

“The discovery of the potential link to hayfever was made almost by accident,” colleague Hancock adds. “Whilst working on a separate project on plant reproduction we found that pollen was producing NO as a by-product. We realised that this might have implications for the allergic response many people have to pollen.”

The current study enabled the scientists to look closely at how the plant produces NO, but they need to carry out further research so they can prove the link between the NO and the allergic reaction, the biologists say. “These findings are very exciting and I believe they could have implications for how we treat hayfever in the future – but there is still a lot of work to do before we can fully establish the link and we are now looking for funding so we can carry on this research,” Hancock hopes.

Previous research indicates that the male parts of the plant (the pollen) may produce NO as a signal to the female parts (the stigma) during reproductive processes. NO and nitrite signalling are also important mechanisms in mammals, Bright and her colleagues intend to investigate what role the pollen-derived NO and nitrite plays in human cell inflammation and irritation during hayfever.; Source: Society for Experimental Biology