Retinoids and T-Cell Balance

The accepted paradigm of psoriasis etiology is shifting.

The epidermis of psoriasis hyperproliferates, allegedly driven by an inflammatory infiltrate of T lymphocytes. T cells include at least four subsets: Th1, Th2, T regulatory cells (Tregs), and Th17. The Th1/Th2 paradigm of psoriasis — developed before the two latter types were recognized and promulgated by immunologists, psorologists, and pharmaceutical companies — made sense but required a putative, as-yet-unknown antigen to drive the response. Attention has now shifted to the Treg/Th17 hypothesis. Tregs prevent autoimmunity, whereas Th17 cells promote autoimmunity and inflammation and infiltrate psoriatic plaques. Th17 cells produce IL-22 and IL-23, both of which promote epidermal acanthosis and inflammation. Sequence variations in the gen…

Author

Mark V. Dahl, MD

Disclosures

Consultant / Advisory board Ulthera, Inc.; AuBio LifeSciences, LLC; Paris Therapeutics

Equity Elorac, Inc.; Makucell, Inc.; Paris Therapeutics

Editorial boards UpToDate

Leadership positions in professional societiesNational Rosacea Society (Chairman, Medical Board)

Mark V. Dahl, MD

Disclosures

Consultant / Advisory board Ulthera, Inc.; AuBio LifeSciences, LLC; Paris Therapeutics

Equity Elorac, Inc.; Makucell, Inc.; Paris Therapeutics

Editorial boards UpToDate

Leadership positions in professional societiesNational Rosacea Society (Chairman, Medical Board)