Immune response patterns in non‐communicable inflammatory skin diseases

Abstract

Non‐communicable inflammatory skin diseases (ncISD) such as psoriasis or atopic eczema are a major cause of global disease burden. Due to their impact and complexity, ncISD represent a major challenge of modern medicine. Dermatology textbooks describe more than 100 different ncISD based on clinical phenotype and histological architecture. In the last decades, this historical description was complemented by increasing molecular knowledge – and this knowledge is now being translated into specific therapeutics. Combining the enormous advances made in lymphocyte immunology and molecular genetics with clinical and histological phenotyping reveals six immune response patterns of the skin – type I immune cells cause the lichenoid pattern characterized by immune‐mediated cell death of keratinocytes; type II immune cells underlie the eczematous pattern with impaired epidermal barrier, infection and eosinophils as well as the bullous pattern with loss of epithelial integrity; Th17 cells and ILC3 mediate the psoriatic pattern characterized by acanthosis, high metabolic activity and neutrophils; dysbalance of regulatory T cells causes either the fibrogenic pattern with rarefication of cells and dermal thickening or the granulomatous pattern defined by formation of granulomas. With more and more specific therapeutic agents approved, classifying ncISD also according to their immune response pattern will become highly relevant. This review defines the six immune response patterns of ncISD and highlights therapeutic strategies targeting key lymphocyte mediators.

Generalized pustular psoriasis – a model disease for specific targeted immunotherapy, systematic review

“…In summary, evidence suggests that GPP uses immunologic pathways both overlapping and independent from PV, supporting the theory that GPP and PV are siblings, but not twins. Figure displays the main mediators of GPP pathogenesis including targets for immunotherapy …”

Progress in Dermatology and Venereology – Editor's pick of the year 2018

“…This new classification comprises both the clinical appearance, the dermatopathology and immunohistochemistry as well as the individually relevant cytokines to be targeted by specific therapy. Thus, this new classification may be very helpful in the selection of potential new therapeutic strategies …”

IL‐17C amplifies epithelial inflammation in human psoriasis and atopic eczema

“…Specific Th1, Th2 or Th17 deviated immune responses are critical for the control of viral, parasitic, bacterial or fungal infections of the skin. In the context of inflammatory skin diseases (ISD), however, these mechanisms can lead to exaggerated and self‐amplifying skin inflammation, barrier defects and systemic inflammation …”