Autoimmune Mechanisms of Psoriasis: Pathogenic Role of the IL-23/IL-17 Axis

Psoriasis is a chronic, recurrent, immuno-inflammatory disease of the skin and joints associated with significant morbidity and mortality. Psoriasis affects approximately 2-4% of the Caucasian population worldwide. The precise immuno-inflammatory mechanisms leading to skin psoriasis are still to be fully defined. There is emerging evidence supporting the existence of a relationship between changes in cutaneous microbiota and development of psoriasis. Under certain pathologic conditions associated with dysbiosis of the skin microbiome, pathogenic microbes triggering aberrant immuno-inflammatory responses may spark the onset and relapses of psoriasis. Strong association of certain human leukocyte antigens (HLAs) along with the pathogenic role of IL-17 suggests the involvement of autoimmune mechanisms in psoriasis. Multiple clinical trials targeting the IL-17/IL-23 axis in psoriasis are underway. Here, we review the emerging findings suggesting the autoimmune nature of psoriasis and examine new therapeutic approaches for treatment of this chronic immuno-inflammatory disease.