A study of 60 patients who had unexplained severe allergic reactions suggests that a compound in meat known as alpha-galactose may be the culprit, according to research presented at a meeting of the American Academy of Allergy, Asthma & Immunology in New Orleans.

They found immune system proteins called IgE antibodies in 25 out of 60 patients who had unexplained allergic reactions.

We believe that the presence of IgE antibody to this sugar is wider spread in the human population as a whole than we had initially expected, Dr. Scott Commins of the University of Virginia, who led the research, said in a telephone interview.

What we're finding is that this traditional notion of allergy to meat being very rare may, in fact, not be true, Commins added.

Alpha-galactose is produced in most mammals but humans and great apes make an antibody to the sugar, Commins said.

So the problem becomes when people make IgE antibody to this sugar and then they eat meat or dairy products that contain the sugar then they get a delayed reaction, Commins said.

The anaphylaxis may seem to appear out of the blue because the meat or dairy may have been eaten four to six hours earlier, Commins said.

The typical scenario has been if you don't react to food within two hours, then it's not the food, in this case that doesn't seem to be true, Commins said.

Typically, anaphylaxis occurs within minutes.

Commins and colleagues screened blood samples from 60 patients, testing for the antibody to alpha-galactose. The people in the study -- 22 at the University of Virginia, 20 at the University of Tennessee and 18 at John James Medical Center in Australia, had anaphylaxis and no apparent cause for it, Commins said.

Twenty-five tested positive for alpha-galactose and no other patterns were found that would have otherwise explained the cause of their anaphylaxis, the researchers said.