Babies with hyperactive immune cells at birth are more likely to develop food allergies in early life, new Australian research has found.
The discovery could lead to future treatments to prevent childhood food allergies which have increased dramatically in recent decades.
The research by Dr Yuxia Zhang and Professor Len Harrison from the Walter and Eliza Hall Institute, and Associate Professor Peter Vuillermin from Barwon Health, Deakin University and the Murdoch Childrens Research Institute, is published in the journal Science Translational Medicine.
Professor Harrison told AAP the findings of the study of more than 1000 Victorian babies were important and gave very clear results.
"We found a link between children who had hyperactive immune cells at birth and the development of allergies to milk, eggs, peanuts, wheat and other common foods in their first years of life," Professor Harrison said.
Those with activated immune cells at birth, detected in the babies' cord blood, were "much more likely" to have the food allergy, raising the next question of the reason for this.
"In at-risk babies, immune cells called monocytes were activated before or during birth," said Dr Zhang.
"Signals from these cells encouraged the development of immune responses by specialised immune cells called T cells that were predisposed to cause allergic reactions to some foods."
Associate Professor Vuillermin said they had shown that the immune systems of babies who develop food allergy are in a sense "primed" for allergic disease by the time they are born.
Describing the hyperactive cells as a "signature of risk" of allergy, Professor Harrison said researchers would now try to identify why the babies had the cells.
"Are the immune cells inherently activated because of the baby's genes or do they become activated at the time of birth or earlier in pregnancy, and how?" he said.
"This study really emphasises how critical it is to look at pregnancy and early life to really understand why chronic immune and inflammatory disorders such as allergies develop in childhood and later."
Associate Professor Vuillermin said there had been a threefold increase in food allergy anaphylaxis.
Part of the puzzle for the team of Victorian scientists, is whether allergies are triggered through a combination of genetic and environmental interactions.
“It's there when the baby's born, but is it occurring during the birthing process, is it occurring in the last weeks of pregnancy, is it occurring in the first weeks?” Associate Professor Vuillermin said.
Researchers hope they can now work towards discovering a treatment by deciphering what they've called a new immune signature.
“[It has] certainly become much more common and is now placing a major burden on the kids, on the families, and on the community,” he said.
Mother of three, Melinda Hopper was part of the study.
Her twins, Evie and Noah were born perfectly healthy, but at eight months of age, Noah had a reaction to banana bread.
“I thought he was choking, he started to go funny around the mouth, and swell around the mouth, his eyes started to swell,” she said.
When Ms Hopper took Noah to the doctor, an egg allergy was discovered. A few months later, the family confirmed Evie, too, was allergic to eggs.
Suddenly the family had to be a lot more vigilant about the food the twins consumed.
“Outside of the house, it did become quite difficult,” said Ms Hopper. “Playgroup and things like that.”
“It means that you're constantly reading packets and things like that.”
And the twins aren't alone.
Ms Hopper said she took part in the study in the hope future generations could be better protected.
“It might not make any difference now for my children, but for their children, my grandchildren, hopefully they won't go on to develop food allergies,” she said.
- with AAP
