Hoping to prevent allergy and autoimmune disease 

As a Wallenberg Scholar, Petter Brodin will be studying blood and faecal samples from newborn babies to find what biological mechanisms are involved in the development of human immune systems

Immediately after birth, the newborn baby is colonised with billions of bacteria and other microbes, and it is up to its immune system to determine which are beneficial commensals to tolerate and which need to be combated. 

This process is believed to be crucial for the development of the immune system and to the risk of developing immune mediated disorders like asthma, allergy and autoimmune disease later in life.

As a Wallenberg Scholar, Petter Brodin will be studying how immune B and T lymphocytes determine which bacteria are to be tolerated and which are to be repelled. To do this, he and his research group have started a unique birth cohort at Karolinska University Hospital, in which they have so far gathered blood and faecal samples from 510 babies, whom they follow up to the age of four.

“The samples enable us to study the gut bacterial flora and the blood’s immune cells and their activity over time early in life,” says Professor Brodin. “We still know little about the biological mechanisms involved in the interactions between the bacterial flora and the immune system, although mouse studies have given us some clues.”

Since it is a complicated matter to collect blood samples from neonates, the researchers have developed special analytical methods that can extract a large amount of data from just a few drops of blood. The data gleaned is then linked to information about the gut flora from the faecal samples and the relationships between these two dynamical systems inferred.

One arm of their research is to compare babies born vaginally or by caesarean section, and babies who have been fed breast milk with those who have received infant formulae. All these factors have proved to be associated with the development of immune-mediated diseases later in life.

Professor Brodin hopes that the results of their research will eventually be able to give all babies a better start in life by ensuring a healthy bacterial flora and beneficial immunological development in accordance with our evolutionary origin and for health. They also have the potential to improve the development of vaccines and other therapeutic interventions, both for babies and for older individuals.