PEANUT allergy may stem in part from the unusual way in which the proteins responsible are taken up by the gut.
A team led by Claudio Nicoletti at the Institute of Food Research in Norwich, UK, injected predigested roasted peanuts into the guts of anaesthetised mice. Between 15 and 30 minutes later they looked at the gut tissue under a microscope, using antibodies to reveal the presence of the allergenic proteins.
Unexpectedly, most of this protein ended up in specialised cells called M cells, which usually engulf bacteria and viruses and present their proteins directly to the immune system. 鈥淭hey keep the immune system informed about what鈥檚 going on,鈥� Nicoletti says.
Advertisement
Whether this occurs in humans, why it happens at all and why it causes allergy is still not clear. But M-cell transfer does mean that large quantities of peanut proteins are delivered quickly to the immune system, which might explain the massive, sometimes fatal immune response in a few people (Biochemical and Biophysical Research Communications, vol 325, p 1258).
Around 1 in 200 people are allergic to peanuts. Even skin contact can cause a reaction, but it is eating peanuts that can cause the most serious, potentially fatal reaction.
