Pollen allergens do not come alone: pollen associated lipid mediators (PALMS) shift the human immue systems towards a T_H2-dominated response

• Main Authors: Gilles Stefanie, Mariani Valentina, Bryce Martina, Mueller Martin J, Ring Johannes, Behrendt Heidrun, Jakob Thilo, Traidl-Hoffmann Claudia
• Format: Article
• Language: English
• Published: BMC 2009-10-01
• Series: Allergy, Asthma & Clinical Immunology
• Online Access: http://www.aacijournal.com/content/5/1/3
• ISSN: 1710-1484; 1710-1492

<p>Abstract</p> <p>Pollen allergy is characterized by a T_H2-biased immune response to pollen-derived allergens. However, pollen-exposed epithelia do not encounter pure allergen but rather a plethora of protein and non-protein substances. We demonstrated that pollen liberate lipids with chemical and functional similarities to leukotriens and prostaglandins - the pollen associated lipid mediators (PALMs). To date, two main groups of PALMs have been characterized: The immunostimulatory PALMs activating innate immune cells such as neutrophils and eosinophils, and the immunomodulatory E₁-phytoprostanes blocking IL-12 production of dendritic cells, resulting in the preferential induction of T_H2 responses. This article reviews our work in the field of PALMs and their effects on cells of the innate and adoptive immune system. From recent results a general picture starts to emerge in which PALMs (and possibly other pollen-associated substances) may - independently from protein allergens - propagate an overall T_H2 favoring micromilieu in pollen exposed tissue of predisposed individuals.</p>