Researchers have identified the link between severe allergies and brain development, by studying mice with asthma-like features.
The study, led by the Center for Neuroscience and Cell Biology of the University of Coimbra (CNC-UC), Portugal, and also involving EARA members the Johannes Gutenberg University of Mainz, Germany, and the University of Manchester, UK, also shed light on how these reactions may lead to characteristics akin to attention deficit hyperactivity disorder (ADHD).
The researchers investigated the effect of a protein involved in the immune response, interleukin-4 (IL-4), on the functioning of the brain’s immune cells, called microglia.
After birth, at low levels of IL-4, the microglia carry out an important function of removing excess neurons (or ‘pruning’) from a brain region known as the cerebellum – a vital part of cerebellum development takes place after birth.
But in mice with induced asthma (as a model for severe allergy), the team saw that with high levels of IL-4 there was defective pruning by the microglia, resulting in the survival of excess neurons and a disrupted cerebellum.
When the pruning failed to occur at all, there were changes in features like hyperactivity, which are linked to ADHD.