The administration of interleukin-3, or IL-3 for short, can have a positive effect on chronic inflammatory respiratory disease, according to research from Universitätsklinikum Erlangen (Germany). The messenger substance interleukin-3 produced by the body was previously considered to be pro-inflammatory in bronchial asthma.

Researchers investigated the production of the messenger substance in healthy preschool children and those affected by asthma who had participated in the European PreDicta pediatric asthma study. They found that children whose asthma was considered controlled by inhaled corticosteroid therapy had higher interleukin-3 production caused by blood cells known as activated peripheral blood lymphocytes. There was also a positive correlation between IL-3 in nasal fluid and the anti-inflammatory soluble form of the ST2 receptor. This suggests that IL-3 may contribute to alleviating asthma, researchers say.

Using mice models induced with asthma, the researchers also investigated whether intranasal administration of interleukin-3 during asthma provocation could actually improve asthma symptoms. They discovered that IL-3 has a regulatory effect on the immune system and induces certain immune cells called regulatory T cells, which are believed to play a role in relieving bronchial asthma. Administration of IL-3 also decreased the number of pro-inflammatory eosinophil cells and reduced mucus production in the lungs of asthmatic mice.

Interleukin-3 also resulted in decreased activation of inflammatory innate lymphoid type 2 cells. These immune cells secrete substances that can participate in the development of allergic diseases. They showed lower cell surface expression of the pro-inflammatory bound receptor ST2, which is important for activation of this cell type, when IL-3 was administered. According to researchers, this clearly shows that IL-3 also has immunoregulatory properties that can improve symptoms in bronchial asthma.