Psoriasis is a chronic inflammatory skin disease characterized by immune dysregulation, where treatments like IL-23 inhibitors have shown promising results. However, the broader effects of such treatments on the skin’s microbial ecosystem, particularly the mycobiome (the fungal component of the microbiome), are not well understood.
Researchers in this study aims to investigate how systemic IL-23 inhibition impacts the skin and mucosal mycobiome in psoriasis patients, focusing on moist, oily, and mucosal areas of the body.
Methods
Paired pre- and post-treatment skin and mucosal samples were collected from 15 psoriasis patients undergoing IL-23 inhibitor therapy. Samples were taken from three key areas: the moist skin of the antecubital fossa, the oily post-auricular region, and the tongue’s mucosal surface. Swab samples were subjected to DNA sequencing to identify and quantify fungal genera. The study compared fungal diversity (α diversity) and genus-level changes in the mycobiome before and after treatment.
Key Findings:
- Moist Skin Mycobiome (Antecubital Fossa)
- A significant reduction in α diversity (Simpson’s diversity index) was observed in the moist skin area after treatment with IL-23 inhibitors (p = 0.0120).
- Post-treatment, fungal DNA amplification failed in 6/15 patients, indicating undetectable fungal reads in some samples (p = 0.0554).
- Genus Malassezia was dominant before treatment (29.3%), but its prevalence dropped significantly after treatment (p = 0.0137). Pre-treatment species of Malassezia were largely M. restricta (75.3%), which remained the most common post-treatment.
- Oily Skin Mycobiome (Post-Auricular Area)
- No significant difference in α diversity was found in the post-auricular samples before and after IL-23 inhibitor treatment.
- Genus Malassezia remained dominant pre- (70.9%) and post-treatment (61%), with only minor shifts in other genera.
- Mucosal Mycobiome (Tongue Surface)
- There was no significant change in α diversity after treatment on the mucosal surface of the tongue.
- Candida remained the most prevalent genus before (37.0%) and after treatment (38.7%), with minimal variation in the other fungal genera.
These findings highlight the complexity of microbial changes induced by systemic immunosuppressive therapy. While the results suggest that IL-23 inhibitors may alter skin fungal communities, further research is needed to understand the clinical implications and broader effects on the bacterial microbiome and long-term patient outcomes.
Link to the study: https://l1nq.com/RDif7
