Polyunsaturated fatty acids (PUFAs) are metabolized into mediators that exhibit various biological effects. Lipid mediators derived from the omega-6 PUFA arachidonic acid (AA) include leukotrienes (LTs), prostaglandins (PGs), and lipoxins. These mediators are involved in the regulation of many inflammatory disorders. They are synthesized by most leukocytes and stromal cells and released in response to numerous stimuli including microbes, opsonins, pollutants, cytokines, venoms, immune complexes, and danger signals. LTs are classically known for their chemotactic/chemokinetic properties (LTB4) and their bronchoconstrictive activities (cysLTs), but they are also potent mediators of innate and adaptive immunity. LTs promote phagocyte recruitment and activation, as well as antigen presentation by enhancing dendritic cell and T cell responses. Conversely, PGD2, PGE2, and PGI2 display an interesting array of pro- and anti-inflammatory signals that modulate inflammatory responses and host defense. Other AA-derived mediators such as epoxy-eicosanoids, eoxins, lipoxins, hydroxy-eicosanoids and endocannabioids are established and/or emerging immunomodulators. Mediators derived from omega-3 PUFAs include resolvins, protectins and docosatrienes. These present wide-ranging anti-inflammatory and pro-resolution properties that are attributed to inhibition of inflammatory cytokine production; suppression of pro-inflammatory gene and cell adhesion molecule expression; down-regulation of nuclear transcription factor activation; and to induction of inflammatory cell apoptosis and phagocytosis. These events might protect tissues from damage and induce clearance of inflammatory cellular debris, promoting the resolution of inflammation and a return to homeostasis.

In this special issue of Mediators of Inflammation, we are seeking manuscripts highlighting novel aspects of lipids as immunomodulators. We aim to cover key and current trends in immunomodulatory lipids. Review articles that underscore and discuss conflicting or controversial results are welcome. Potential topics include, but are not limited to:

• Biosynthesis and metabolism
• Involvement of lipids in infectious and chronic diseases
• Lipids as mediators of tissue fibrosis and repair
• Regulation and control of innate and adaptive immunity
• Lipid mediators as promising targets for therapeutics

These aspects are important to understand the roles of lipid mediators in animal and human pathophysiology.

Before submission authors should carefully read over the journal's Author Guidelines, which are located at http://www.hindawi.com/journals/mi/guidelines/. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/ according to the following timetable: