IL17A and psoriasis vulgaris: Research has revealed a close immunopathological link between GPP and plaque psoriasis, and some biologics used for treating plaque psoriasis, such as anti-TNF-α antibodies, anti-IL-17A antibodies, and anti-IL-12/23 p40 antibodies, have also shown efficacy in treating GPP and have been included in the recommended treatment guidelines for GPP in Japan.1