IL17A and psoriasis: However, several clinical studies show that psoriasis patients treated with anti-IL-17 antibodies get more mucous Candida infections [7,8,9] because IL-17 plays an important role in innate and adaptive responses against Candida; this was observed in individuals with genetic deficiencies that impair IL-17-related immune responses (e.g., chronic mucocutaneous candidiasis) [10].