They have identified zonulin as a molecule in the human body called haptoglobin 2 precursor.
Pinpointing the precise molecule that makes up the mysterious protein will enable a more detailed and thorough study of zonulin and its relationship to a series of inflammatory disorders.
Haptoglobin is a molecule that has been known to scientists for many years. It was identified as a marker of inflammation in the body.
While haptoglobin 1 is the original form of the haptoglobin molecule, and is believed to have evolved 800 million years ago, haptoglobin 2 is a permutation found only in humans. It's believed the mutation occurred in India about 2 million years ago.
The study led by Dr Alessio Fasano revealed that zonulin is the precursor molecule for haptoglobin 2 - that is, it is an immature molecule that matures into haptoglobin 2 "While apes, monkeys and chimpanzees do not have haptoglobin 2, 80 percent of human beings have it," said Fasano.
"Apes, monkeys and chimpanzees rarely develop autoimmune disorders. Human beings suffer from more than 70 different kinds of such conditions. We believe the presence of this pre-haptoglobin 2 is responsible for this difference between species.
"This molecule could be a critical missing piece of the puzzle to lead to a treatment for celiac disease, other autoimmune disorders and allergies and even cancer," Fasano added.
The only current treatment for celiac disease is cutting gluten from the diet, but we have confidence.
"We hope pre-haptoglobin 2 will be a door to a better understanding of not just celiac disease, but of several other devastating conditions that continue to affect the quality of life of millions of individuals," said Fasano.
"This is quite a remarkable molecule that was just flying under the radar. We would have never have thought it would be the key. Now that we have identified this molecule, we are able to replicate it in the lab to use for research purposes," Fasano added.
The study appears online in Proceedings of the National Academy of Sciences.