Vulval lichen sclerosus and the microbiome

Summary: Abstract Body: Female genital lichen sclerosus (FGLSc) is a common, scarring inflammatory dermatosis associated with significant morbidity and a small risk of squamous cell carcinoma. The role of the microbiome in FGLSc has received limited attention. 16S rRNA next-generation sequencing was performed to determine the microbiome of the vulva, vagina and urine of 30 patients with active, untreated FGLSc and 30 healthy controls, and to assess the impact of treatment. Women with immunocompromise and recent (~4 weeks) topical or systemic antibiotics were excluded. Preliminary statistical analyses have demonstrated a reduction in alpha diversity at all three sites for patients with active FGLSc, with significance demonstrated in vulval samples (p=0.041). Permutational multivariate analysis of variance revealed a significant difference in beta diversity between cases and controls in the vulva(p=0.001), vagina(p=0.019) and urine(p=0.021). There was no significant difference in beta diversity between samples before and after treatment of FGLSc. Compared with healthy controls, samples from patients with active FGLSc had a higher abundance of Lactobaccillus, though this did not achieve statistical significance, and a lower abundance of Streptoccus (p=0.01, 0.02 and 0.06 respectively for vulval, vaginal and urine samples). Smaller differences were seen in Corynebacterium (p=0.04) and Staphylococcus (p = 0.05) in vaginal swabs, Actinomyces (p=0.05) and Mobiluncus (p=0.03) in vulval swabs and Mobiluncus (p=0.03) in urine, where abundances of these bacteria were lower in the FGLSc group. These findings demonstrate potential dysbiosis in the FGLSc; further studies to explore causality are justified. Ashley Spencer^{1, 7, 4}, Ellen H. van den Munckhof², Aarthy Uthayakumar¹, Joy Jonkers¹, Richard E. Watchorn^{3, 7}, Elaine L. Palmer⁴, Randa Akel⁴, Maurits de Koning², Asif Muneer⁶, Georgios Kravvas⁷, L. Claire Fuller⁴, Fiona Lewis⁵, Chris B. Bunker⁷ 1. Dermatology, Imperial College Healthcare NHS Trust, London, England, United Kingdom. 2. Cerba Research, Amsterdam, Netherlands. 3. Beaumont Hospital, Dublin, Leinster, Ireland. 4. Dermatology, Chelsea and Westminster Hospital NHS Foundation Trust, London, England, United Kingdom. 5. Dermatology, Guy's and St Thomas' NHS Foundation Trust, London, England, United Kingdom. 6. Urology, University College London, London, England, United Kingdom. 7. Dermatology, University College London Hospitals NHS Foundation Trust, London, England, United Kingdom. Innate Immunity, Microbiology, and Microbiome