oa Editorial [Hot Topic: Modulation and New Mediators in Inflammation Executive (Guest Editor: Frank A. Redegeld)]

In this special issue, current insights in the pathomechanisms of inflammatory diseases are reviewed by experts in the field. The involvement of mast cells in allergic and inflammatory diseases is discussed by Theoharides and coauthors [1]. Mast cells are known for their key effector role in allergic diseases, but evidence for their contribution to chronic inflammatory, neurologic and autoimmune diseases is emerging. In the review, the potential role of mast cells as therapeutic targets in cardiovascular diseases and obesity is discussed. Mast cells can be activated by numerous antigen-specific and aspecific stimuli. A novel mechanism of antigen-specific activation of mast cells is discussed by Groot Kormelink et al. [2]. Immunoglobulin free light chains can activate mast cells in an antigen-specific -but IgEindependent- manner. Free light chains are found increased under many inflammatory conditions. The possible contribution of this mechanism to the pathogenesis of upper and lower airway disease, food allergy, inflammatory bowel disease and rheumatoid arthritis is discussed. Allergic sensitization and effector responses can be modulated at various stages. Paul Forsythe discusses the role of the nervous system as a critical regulator of immune responses underlying allergy [3]. Sympathetic nerve fibers innervate primary and secondary lymphoid organs extensively and can influence B and T cell activation and regulate antigen presenting cells. Bidirectional neuroimmune signaling systems may contribute to the etiology and pathophysiology of immune disorders and this review provides an overview of major aspects of the interaction between the immune and nervous system and the implications of this relationship to health and disease with particular reference to allergy. Two reviews deal with the mechanism of adjuvant-mediated immune stimulation. Adjuvants are widely used to improve the adaptive immune responses to e.g. vaccinations. Different molecular mechanisms are involved depending on the nature of the adjuvant used. Those containing microbial components stimulate pattern recognition receptors, while aluminum-based adjuvants stimulate the innate arm of the immune system via an endogenous danger signal. Fierens and Kool [4] describe the cellular and molecular mode of action of such adjuvants. Gilles et al. [5] discuss the importance of non-allergenic, adjuvant substances released from pollen. Many compounds and enzymes (NAPDH oxidases, proteases, adenosine, lipid mediators) are associated with pollen and may have an important contribution to the allergenicity of the pollen. The authors propose that systematic comparative studies on non-allergenic, adjuvant substances in different pollens might help to deduce the relevance of such substances for pollen allergenicity and could help to predict possible susceptibility to develop specific pollen allergies by individuals....