Open Access

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the “EAACI Molecular Allergology User's Guide” (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Aim: Calcium-activated potassium channels of high conductance (BKCa channels) are important contributors to vascular smooth muscle membrane potential and thus to vascular tone. BKCa channels can promote vasodilation by facilitating vessel responses to NO. BKCa channels may also serve as limiters of the anticontractile effect of NO. However, it is unclear whether BKCa channels act simultaneously as facilitators and limiters in different vascular regions. Therefore, this study tested the hypothesis that BKCa channels both facilitate and limit NO-induced vasorelaxation in multiple vessels. Methods: Contractile responses of rat tail, saphenous, and left and right coronary arteries were studied using wire myography. Results: The NO-donor SNP reduced contractile responses induced by low concentrations of methoxamine or serotonin, respectively, in all arteries tested, both in the absence and in the presence of iberiotoxin. This anticontractile effect of SNP was larger in the presence of iberiotoxin than in its absence, i.e., functionally active BKCa channels limit the anticontractile effect of SNP. In contrast, the anticontractile effect of SNP at high concentrations of methoxamine or serotonin, respectively, in all arteries tested was smaller in the presence of iberiotoxin than in its absence, i.e., functionally active BKCa channels facilitate the anticontractile effect of SNP. Conclusion: BKCa channels simultaneously limit NO-induced vasodilation at lower levels of contractility but facilitate it at higher levels of contractility in multiple vascular beds. Therefore, BKCa channels may play a dual role as facilitators and as limiters of the effect of NO, depending on the level of contractility.