Asthma and allergic diseases: Cross talk of immune system and environmental factors.

Air pollution and immune-related diseases including allergy and asthma are constantly on the rise worldwide. Thus, a comprehensive investigation of environmentally induced immune regulation is required for a deeper understanding of disease pathogenesis, progression as well as prevention. Here, we summarize the current knowledge on environmental factors such as microbiome or geographical locations with harmful or protective effects for human health and their different routes of exposure. This review comprises a brief outline regarding the latest findings on the interaction of environmental factors with innate and adaptive regulation of the immune system, exemplarily for one protective and one harmful environmental factor, respectively.

The Role of Innate Immunity and Bioactive Lipid Mediators in COVID-19 and Influenza.

In this review, we discuss spatiotemporal kinetics and inflammatory signatures of innate immune cells specifically found in response to SARS-CoV-2 compared to influenza virus infection. Importantly, we cover the current understanding on the mechanisms by which SARS-CoV-2 may fail to engage a coordinated type I response and instead may lead to exaggerated inflammation and death. This knowledge is central for the understanding of available data on specialized pro-resolving lipid mediators in severe SARS-CoV-2 infection pointing toward inhibited E-series resolvin synthesis in severe cases. By investigating a publicly available RNA-seq database of bronchoalveolar lavage cells from patients affected by COVID-19, we moreover offer insights into the regulation of key enzymes involved in lipid mediator synthesis, critically complementing the current knowledge about the mediator lipidome in severely affected patients. This review finally discusses different potential approaches to sustain the synthesis of 3-PUFA-derived pro-resolving lipid mediators, including resolvins and lipoxins, which may critically aid in the prevention of acute lung injury and death from COVID-19.