The distinct role and regulatory mechanism of IL-17 and IFN-γ in the initiation and development of plaque vs guttate psoriasis

Psoriasis is a chronic recurrent inflammatory skin disorder characterized by hyperproliferation of keratinocytes and by infiltration of activated Th1 and Th17 cells in the (epi)dermis [1–3]. The majority of T lymphocytes infiltrating psoriatic dermis are CD4+T lymphocytes while CD8+T lymphocytes mainly accumulate in epidermis [4,5]. Psoriasis vulgaris is classified into the guttate and plaque psoriasis according to clinical features, especially the size and distribution of skin lesions. Guttate psoriasis, known to have a better prognosis than plaque psoriasis, shows rapid involution and longer remission.