A study published in Science Advances has revealed that while genetics play a significant role in shaping children's immune systems, environmental factors also influence key immune responses, offering opportunity for preventing allergic diseases.
Led by Dr Jonatan Leffler at the Wal-yan Respiratory Centre and The Kids Research Institute Australia, the research examined immune profiles of 93 twin pairs aged 7 to 13, providing rare insight into how genes and environment interact to influence the development of atopy - a predisposition to allergic sensitisation and disease.
Using advanced immune profiling and statistical modelling, the team found that certain immune cells, such as B cells and basophils, are strongly influenced by genetics. These cells were more abundant in children who were atopic, particularly among genetically identical twins. However, the study also showed that how the immune system responds to external stimuli - such as bacterial components or allergens - is largely shaped by environmental or individual exposures.
“What’s exciting is that we’ve shown different parts of the immune system are governed by different mechanisms," Dr Leffler said.
"Some traits are hardwired by genetics, but others, especially how the immune system reacts to allergens, can be shaped by the environment.”
One of the study’s most intriguing discoveries was how the IgE receptor — central to triggering allergic reactions — is regulated differently depending on the immune cell type.
On basophil cells, which help drive allergic symptoms, the receptor’s expression was largely determined by genetics. But on dendritic cells, which help shape immune responses, its expression was influenced by environmental exposures.
This dual regulation suggests that while some allergic mechanisms are inherited, others may be shaped, and potentially modified, by the environments children grow up in.
“This opens the door to explore the possibility of targeted interventions.
“By identifying which immune traits are environmentally regulated, we may be able to reduce allergy risk, even in children with a genetic predisposition.”
The findings suggest that even children with a strong genetic predisposition may benefit from tailored environmental interventions, such as exposure to diverse microbiomes or reduced pollutants, to reduce their risk.
The study also highlighted the value of using twin cohorts in childhood. Because the children were still living at home, they shared similar environments, allowing researchers to more precisely isolate genetic and environmental influence, an advantage rarely available in adult twin studies.
“This is a relatively unique cohort. Many twin studies are done in adults, but these children still shared their home environment.
"That gives us a much clearer picture of what’s inherited and what’s shaped by surroundings.”
This research reframes the allergy conversation: while genetics set the stage, the environment may write the script. For families and clinicians, that means there could be actionable steps to reduce risk, even when predisposition is high.
The findings pave the way for future research into environmental factors that could help prevent allergic diseases. Dr Leffler’s team hopes to uncover more through future projects involving the twin cohort.
This research was supported by the Australian National Health and Medical Research Council, The University of Western Australia, and The Kids Research Institute Australia. The project would not have been possible without the participating families and researchers who established this cohort in early 2000.