Microbiota in Skin and Mucosa of Patients With Inflammatory Skin Diseases

Background and aim The pathogeneses of many inflammatory diseases are not completely understood, yet, dysregulation of the human microbiota is increasingly being investigated as a possible contributing factor. The human microbiota includes bacteria, archaea, viruses and fungi. In general, little is known about the fungal colonization in inflammatory skin diseases although Candida species in oral mucosa, skin and feces seem to be increased in patients with psoriasis and atopic dermatitis. Inflammation is also an important part of the pathogenesis in other skin diseases such as hidradenitis suppurativa, acne, vasculitis and inflammatory ulcers. Possibly, increased fungal colonization may be present in many inflammatory skin diseases, yet, this has not previously been investigated. Studies of inflammatory diseases involving other body areas such as systemic lupus erythematosus, Sjögren's disease, multiple sclerosis, and spondyloarthritis have also demonstrated increased colonization with Candida species. However, it is unclear, whether colonization with Candida is a cause or a result of inflammatory disease. Treatment of inflammatory diseases with systemic immune-modulating drugs or recurrent antibiotic therapy may also affect yeast colonization. Emergence of biological therapies that directly or indirectly modulates the Interleukin (IL) 17-pathway emphasizes the need for further knowledge, since the IL-17 pathway is involved in the defense against yeast infections in healthy individuals. Until now, investigations of yeast colonization have primarily focused on Candida and Malassezia. Whether other species of yeasts may be of interest is still uncertain.

This study aims to examine the prevalence of microbiome and infection in skin and oral mucosa of a variety of patients and healthy volunteers visiting the Dermatological outpatient clinic.

Methods Study execution The project is carried out as a collaboration between Dermatological Department, Roskilde University Hospital and Statens Serum Institut (SSI) under the leadership of primary investigator, Senior Doctor in Dermatology, PhD, Ditte Marie Lindhardt Saunte. The project is supported by Medical Doctor in Dermatology, PhD Elisabeth Hjardem Taudorf, Dermatological study nurse Helle Anette Jensen, and the established research group at the Dermatological Department. The samples will be analyzed at SSI at the Dpt. of bacteria, parasites, and fungi under PhD Henrik Vedel Nielsen and Head of Microbial Bioinformatics, Department of Bacteria, Parasites and Fungi, PhD Marc Stegger.

Study design A case-control study comparing the incidence of yeast colonization or infection in skin and oral mucosa of patients with different skin diseases and healthy volunteers. Patients with selected skin diseases, staff at Zealand University Hospital in Roskilde, relatives to staff and students with relation to the Dermatologic Department will be asked to fill out a short questionnaire and have swaps taken from oral mucosa, as well as skin scrapings and tape strips from lesional skin (only patients) and non-lesional skin (all).

Swaps will be examined at Dept. of Microbial Bioinformatics, Department of Bacteria, Parasites and Fungi, Statens Serum Institut. The subgroup of patients initiating systemic therapy for their skin disease at the first examination will be asked to repeat the questionnaire, swaps, skin scrapings and tape strips after approximately three months.