TOKYO -- A recent study from Japanese researchers has uncovered the biological mechanisms linking psychological stress to heightened allergy symptoms. Published in the Journal of Allergy and Clinical Immunology, the research identifies how stress affects immune cells, specifically macrophages, which typically reduce inflammation.
When under stress, macrophages can lose their ability to perform effectively, resulting in prolonged allergy symptoms that may last up to a week post-stress. The study focused on allergic skin inflammation triggered by IgE antibodies, which react excessively to benign substances like pollen and pet dander.
Laboratory mice subjected to stress exhibited significantly more severe allergic reactions compared to unstressed mice, with a notable increase in eosinophils—white blood cells that can cause tissue damage during allergic responses.
The sympathetic nervous system's release of norepinephrine during stress hampers macrophages' anti-inflammatory functions, particularly their role in clearing dead cells. This deficiency leads to inflammation, creating a cycle that worsens allergic reactions.
Blocking macrophages' response to norepinephrine prevented the stress-induced exacerbation of allergies. The study's findings indicate that stress can leave a lasting impact on immune cells, referred to as 'stress memory,' potentially influencing disease development.
Researchers also noted that inhibiting an enzyme called caspase-1 could reduce inflammation in stressed mice, suggesting a new therapeutic avenue. Dr. Soichiro Yoshikawa from Juntendo University emphasized the study's implications for understanding how stress exacerbates various diseases, including cancer and autoimmune disorders.
These findings highlight the importance of managing stress for both mental health and immune system function.