Prevalence of Candida species in Psoriasis

Background Psoriasis patients are more frequently colonised with Candida species. The correlation between fungal colonisation and clinical severity is unclear, but may exacerbate psoriasis and the impact of antipsoriatic therapies on the prevalence of Candida is unknown. Objectives To examine the prevalence of C species in psoriasis patients compared to an age- and sex-matched control population, we investigated the influence of Candida colonisation on disease severity, immune cell activation and the interplay on psoriatic treatments. Methods The prevalence of C species was examined in 265 psoriasis patients and 200 control subjects by swabs and stool samples for fungal cultures. Peripheral mononuclear blood cells (PBMCs) were collected from 20 fungal colonised and 24 uncolonised patients and stimulated. The expression of interferon (IFN)-gamma, IL-17A, IL-22 and tumour necrosis factor (TNF)-alpha from stimulated PBMCs was measured by quantitative real-time polymerase chain reaction (qPCR). Results A significantly higher prevalence for Candida was detected in psoriatic patients (p <= .001) compared to the control subjects; most abundant in stool samples, showing Candida albicans. Older participants (>= 51 years) were more frequent colonised, and no correlation with gender, disease severity or systemic treatments like IL-17 inhibitors was found. Conclusions Although Candida colonisation is significantly more common in patients with psoriasis, it does not influence the psoriatic disease or cytokine response. Our study showed that Candida colonisation is particularly more frequent in patients with psoriasis >= 51 years of age. Therefore, especially this group should be screened for symptoms of candidiasis during treatment with IL-17 inhibitors.