Platts-Mills began to work with cetuximab's distributor to investigate the blood of the symptomatic patients and find out what they had in common. It turned out to be antibodies for alpha gal – the sugar found in meat. Cetuximab is full of the sugar, as it is derived from genetically modified mice.
Eventually, Platts-Mills discovered what made the patients so sentive to alpha-gal: 80 percent of the allergic patients reported being bitten by a tick. It was the lone-star tick that had caused the allergy in the first place.
Platts-Mills has since shown that bites from the lone star tick lead to a 20-fold increase in alpha gal antibodies. Researchers are currently trying to figure out why saliva from the ticks cause the immune system to attack alpha-gal as a foreign body, but they say it's early days yet.
“There’s a lot we don’t know about the allergy,” Dave Neitzel, an epidemiologist with the Minnesota Department of Health, told the Herald Review. “It’s too early to really say anything definitive.”
Some people who get bitten by the ticks don't develop the allergy either, making the cause even more difficult to find.
“There’s something really special about this tick,” Jeff Wilson, an asthma, allergy, and immunology fellow in Platts-Mills’ group, told Wired. “Just a few bites and you can render anyone really, really allergic."
Whilst the team investigate why the tick causes a meat allergy, the only way to protect yourself against getting it is to use DEET in areas where the lone star tick dwells.