The epithelial immune microenvironment (EIME) in atopic dermatitis and psoriasis.

Area of Science:

• Dermatology
• Immunology
• Microbiology
• Cell Biology

Background:

• The skin acts as a crucial physical and immunological barrier against external threats.
• Skin's protective mechanisms are finely tuned for pathogen elimination and physical danger response.
• Dysregulation of skin's immune machinery can lead to inflammatory skin diseases.

Purpose of the Study:

• To explore the pathogenesis of atopic dermatitis and psoriasis.
• To examine the role of the epithelial immune microenvironment in these inflammatory skin diseases.
• To elucidate the specific inflammatory loops (IL-4 and IL-17) involved.

Main Methods:

• Discussion of pathogenesis based on existing literature.
• Analysis of the epithelial immune microenvironment components: microbiota, keratinocytes, and sensory nerves.
• Focus on the resulting inflammatory loops in disease development.

Main Results:

• Atopic dermatitis is driven by a defective barrier and microbial dysbiosis, activating an interleukin-4 (IL-4) loop.
• Psoriasis pathogenesis involves disordered keratinocyte signaling and a predisposition to type 17 responses, driving an IL-17 loop.
• Both diseases are characterized by distinct inflammatory loops within the skin's immune microenvironment.

Conclusions:

• Inflammatory skin diseases arise from dysregulated epithelial immune responses.
• Specific inflammatory loops, IL-4 in atopic dermatitis and IL-17 in psoriasis, are central to their pathogenesis.
• Understanding these loops offers insights into therapeutic strategies targeting the skin's immune microenvironment.