Candida albicans belongs to the normal microbial flora on epithelial surfaces of humans. However, under certain, still not fully understood conditions, it can become pathogenic and cause a spectrum of diseases, from local infections to life-threatening septicemia. We investigated a panel of antimicrobial proteins and peptides (AMPs), potentially involved in mucosal immunity against this pathogen. Out of six studied AMPs, psoriasin was most up-regulated during a mucosal infection, an acute episode of recurrent Candida vulvovaginitis, although candidacidal activity has not been demonstrated. We here show that psoriasin binds to β-glucan, a basic component of the C. albicans cell wall, and thereby inhibits adhesion of the pathogen to surfaces and increases IL-8 production by mucosal epithelial cells. In conclusion, we show a novel mechanism of action of psoriasin. By inhibiting C. albicans adhesion and by enhancing cytokine production, psoriasin contributes to the immune response against C. albicans.Key messages The antimicrobial peptide psoriasin is highly up-regulated during a local mucosal infection, Candida albicans vulvovaginitis.Psoriasin binds to β-glucan in the Candida albicans cell wall and thereby inhibits adhesion of the pathogen.Binding of psoriasin to Candida albicans induces an immune response by mucosal epithelial cells. Electronic supplementary materialThe online version of this article (10.1007/s00109-018-1637-6) contains supplementary material, which is available to authorized users.

Objectives Recurrent vulvovaginal candidiasis (RVVC) causes significant morbidity. Candida albicans is the main pathogen associated with both sporadic and recurrent candidiasis. Due to unsatisfactory treatment effect, the impact of chlorhexidine digluconate and fluconazole alone or in combination on C. albicans and biofilm was investigated.

Nitric oxide is significantly elevated in patients with recurrent vulvovaginal candidiasis during acute episodes of infection and decreases after antifungal treatment. The results illustrate the pronounced inflammatory response in recurrent vulvovaginal candidiasis correlating to symptoms of pain and discomfort.

Background: Infections of the female genital tract are common and have severe impact on the quality of life and sexual health of affected women. The innate immune system is crucial and is involved in the defense of infections. Understanding innate immunity of the vaginal and cervical mucosa is important to enable development of future preventive and therapeutic strategies for genital infections. Objective: The aim of this thesis was to investigate innate immune factors in women with recurrent candida vulvovaginitis (RVVC) and high grade squamous intraepithelial lesions (HSIL) of the cervix, induced by human papilloma virus (HPV). This in order to contribute to the understanding of the innate immune response in these two common infections of the lower female genital tract. Material and Methods: Clinical examinations, measurements of intravaginal nitric oxide (NO) levels and vaginal biopsies were performed in 28 patients with RVVC and 31 healthy controls. Cervical biopsies and vaginal lavage were collected from 19 patients with HPV induced HSIL and 14 controls. Immunohistochemistry (IHC), enzyme-linked immunosorbent assay (ELISA), western blot and reverse transcriptase real time polymerase chain reaction (PCR)) were used to identify and quantify inducible nitric oxide synthase (iNOS), antimicrobial proteins, cytokines and encoding genes. Adhesion and binding assays were performed to evaluate the adhesive capacity of candida and to demonstrate the binding between candida and the antimicrobial protein psoriasin. Transmission electron microscopy was conducted to measure the cell wall thickness in C. albicans affected by psoriasin. To evaluate a new treatment strategy for RVVC, the effect of chlorhexidine digluconate and fluconazole on C. albicans eradication and biofilm was investigated in RVVC and commensal strains, using the crystal violet method and viable count. Results: NO levels were significantly higher in patients during acute infection compared to controls. Levels decreased after fluconazole treatment but remained higher than in controls. Furthermore, increased expression of iNOS was observed in the epithelial basal layer in patients both before and after treatment. There were positive correlations between NO levels, clinical symptoms and examination scores. Findings indicated that C. albicans induces production of psoriasin during mucosal candida infection. Psoriasin was shown to interact with β-glucan in the candida cell wall and inhibit candida adhesion to surfaces. In HPV induced HSIL, psoriasin expression and protein levels increased significantly after surgical treatment and reached similar levels as in controls. The mRNA expression of the proinflammatory cytokine IL-8 was higher before treatment and restored to the same levels as in controls six months after lesions were excised. Chlorhexidine digluconate prevented new biofilm formation and reduced already established C. albicans biofilm. Moreover, the number of candida cells in both planktonic state and within the biofilm were significantly decreased....