Allergic diseases in children may have a common cause. Tests

Allergic diseases affect millions of children around the world, and their incidence is constantly increasing. Scientists “examined” four different allergic diseases, looking for a possible cause of their occurrence in several-year-old children. The study was published in Nature Communications. This is one of the first such studies. Researchers plan to use its results to develop a therapy for intestinal microflora imbalance, which may be the basis of allergic diseases. As a consequence, it will also be possible to prevent their development in children in the future.

The basis of the most common allergic diseases

Researchers from the University of British Columbia and BC Children’s Hospital conducted a study on the occurrence of the four most common allergic diseases in children. It concerned:

• atopic dermatitis,

• asthma,

• hay fever,

• food allergy.

Scientists compared their development with the characteristics of the intestinal microbiome. Although each of these diseases has different symptoms, it turns out that their causes may be common. Researchers found that it is related to the composition of the intestinal microflora. “These are different diagnoses, each with their own list of symptoms, so most researchers consider them individually,” said Dr. Charisse Petersen, co-author of the paper. However, she added that after looking at what happens at the cellular level, they have a lot in common. More research will be needed, but current knowledge allows scientists to better understand how an infant’s gut microbiome may undergo changes that predict and partially explain the future development of childhood allergies.

Researchers analyzed data from 1,115 children. They were monitored from birth until the age of 5. Of this group, 523 children never had any allergy symptoms. In turn, in 592 children the doctor diagnosed one or more allergic disorders. The toddlers’ stool samples were also tested, based on which scientists assessed their intestinal microbiome. They were collected when the children were first 3 months old and then 1 year old.

Development of allergies and intestinal microflora disorders

After analyzing the samples, the researchers noticed a relationship between allergic diseases diagnosed in children and the characteristic features of the microbiome, which indicated an unbalanced intestinal microflora. The results show that four allergic conditions are consistently associated with specific microbiome changes and influences during early childhood. This was probably the result of impaired function of the intestinal mucosa and an increased inflammatory response in the intestines.

“Typically, our bodies tolerate the millions of bacteria living in our gut because they do so much good for our health. We tolerate them, among other things, by maintaining a strong barrier between them and our immune cells and limiting the inflammatory signals that would stimulate these cells to act,” said Courtney Hoskinson, a PhD student and first author of the article. The researcher also added that the breakdown of these mechanisms in children precedes the development of allergies.

What shapes the intestinal microflora of infants?

Many factors may influence the formation of infants’ intestinal microflora. This includes:

• diet,

• type of delivery,

• antibiotics used,

• place of residence (whether it is a city or a village).

The microbiome is formed early in life, immediately after birth, but undergoes many changes as it matures. “Our data show that the use of antibiotics in the first year of life increases the likelihood of later allergic disorders, while breastfeeding for the first six months has a protective effect. This was a universal observation for all the allergic diseases we studied,” explains Dr. Stuart Turvey, professor in the department of pediatrics and one of the study’s lead authors.