Distinct anti-microbial peptides expression patterns and microbiome profiles in skin of Tunisian endemic Pemphigus foliaceus patients.

Pemphigus foliaceus (PF) is a multifactorial skin disease. Substantial evidence for microbiota dysbiosis in skin disorders was gradually revealed. In PF patients' skin lesions, we characterized the profile of microbial communities and the expression of microbial peptides. Using real-time reverse transcriptase PCR and immunohistochemistry, skin lesions were analyzed for gene and protein expression of human β-defensin (hBD) 1, 2, and 3, cathelicidin (LL-37), RNAse-7, and psoriasin. Bacterial 16S rRNA gene sequencing was used for assessing skin microbial communities in 15 samples from PF patients' lesioned skin and 11 PF patients' non-lesioned skin. Gene expression of hBD 2 and 3 and psoriasin were significantly downregulated in skin samples from remittent patients compared to chronic or de novo diagnosed patients. Protein expression of hBD 2, Psoriasin, and LL-37 was increased in skin from de novo patients compared to skin from healthy donors showing markedly different distribution patterns. The skin microbial analysis revealed a substantial difference in microbiome diversity between lesioned and non-lesioned skin of de novo PF patients and, non-lesioned skin of remittent patients. In addition, microbiome diversity within samples of lesioned skin from de novo PF patients showed lower diversity with a lower abundance of specific bacterial genera, namely Dermabacter, Psychrobacter, and Bradyrhizobium. Thus, there is a noticeable over-representation of Staphylococcus and decreased richness in the bacterial communities of PF-active skin lesions. Our data supports the hypothesis that active skin lesions in PF patients exhibit alterations in skin bacterial diversity interlinked with increased expression of AMPs.