Circadian and seasonal variations in subcutaneous allergen immunotherapy reactions

Circadian and seasonal rhythms play an important role in many physiological responses involving the immune system and allergic diseases 1 Christ P Sowa AS Froy O Lorentz A The circadian clock drives mast cell functions in allergic reactions. Front Immunol. 2018; 9: 1526 Crossref PubMed Scopus (17) Google Scholar ,2 Paganelli R Petrarca C Di Gioacchino M Biological clocks: their relevance to immune-allergic diseases. Clin Mol Allergy. 2018; 16: 1 Crossref PubMed Scopus (27) Google Scholar and may also have implications in the safety profile of subcutaneous immunotherapy (SCIT). Although rare after administration of conventional SCIT in a clinical setting, systemic reactions (SR) occur in approximately 1 in 1000 injections, with roughly 67% classified as mild, 29% as moderate, and 4% as severe. 3 Epstein TG Liss GM Murphy-Berendts K Bernstein DI Risk factors for fatal and nonfatal reactions to subcutaneous immunotherapy: national surveillance study on allergen immunotherapy (2008-2013). Ann Allergy Asthma Immunol. 2016; 116: 354-359.e2 Abstract Full Text Full Text PDF PubMed Scopus (79) Google Scholar Our study aimed to determine if the time of immunotherapy administration, seasonality, or demographic factors impact the rate of SR after SCIT.