A new paradigm of eosinophil granulocytes: neuroimmune interactions


Ulrike Raap, MD, Department of Dermatology and Allergology, Hannover Medical School, Ricklinger Str. 5, 30449 Hannover, Germany, Tel.: +49 511 9246 230, Fax: +49 511 9246 206, e-mail: raap.ulrike@mh-hannover.de


Abstract:  Eosinophil granulocytes have long been regarded as potent effector cells with the potential to release an array of inflammatory mediators involved in cytotoxicity to helminths and tissue destruction in chronic inflammatory diseases such as asthma. However, it has become evident that eosinophils are also involved in regulatory mechanisms modulating local tissue immune responses. Eosinophils take part in remodelling and repair mechanisms and contribute to the localized innate and acquired immune response as well as systemic adaptive immunity. In addition, eosinophils are involved in neuroimmune interactions modulating the functional activity of peripheral nerves. Neuromediators can also modulate the functional activity of eosinophils, revealing bidirectional interactions between the two cell types. Eosinophils are tissue-resident cells and have been found in close vicinity of peripheral nerves. This review describes neuroimmune interactions between eosinophil granulocytes and peripheral nerves and highlights why eosinophils are important in allergic diseases such as asthma.