Bacterial biofilm is associated with higher levels of regulatory T cells in unaffected hidradenitis suppurativa skin.

Abstract

The role of bacterial biofilm in hidradenitis suppurativa (HS) is highly debated. Less biofilm is found in clinically unaffected axillary perilesional skin of HS patients compared with healthy controls. To study the correlation between biofilm and the phenotypical characterization of the preclinical inflammatory infiltrate. An exploratory comparative study of punch biopsies from unaffected axillary HS skin compared to similarly biopsies from healthy controls underwent standard staining procedures for CD4, CD8, CD25, FoxP3 and IL17. Standard-sized inflammatory histological hotspots were identified manually. Slides were scanned into Leica Biosystems' Digital Image Hub. Number of stained cells per slide and hotspot was found using an algorithm. 12.5% of HS had biofilm compared to 85% of controls. For full slides, HS patients had more CD4+ cells than controls; HS patients with biofilm had higher CD4+ cell number than controls with or without biofilm and HS patients without biofilm. For hotspots, HS patients with biofilm had higher number of CD4+FoxP3+ cells than HS patients without biofilm and controls with biofilm. The association between biofilm and the number of regulatory T cells in HS patients supports the concept of dysbiosis as a factor in the preclinical HS lesions.