Hidradenitis suppurativa (HS) is a chronic inflammatory disorder of apocrine gland-bearing skin. It is associated with alterations in innate immunity and frequent bacterial infections.

We investigated the expression of innate defense antimicrobial peptides in patients with HS and different grades of severity.

Skin biopsy specimens and sweat were collected from 36 patients with HS and 57 healthy control subjects for analysis of epithelial antimicrobial peptides by real-time reverse transcription–polymerase chain reaction, immunohistochemistry, enzyme-linked immunosorbent assay, and surface-enhanced laser desorption ionization time-of-flight mass spectrometry.

We provide evidence that human β-defensin-3 expression is induced in lesional HS skin on transcriptional and protein levels, yet, this up-regulation was not detectable in patients with severe HS (Hurley grade III). In contrast, messenger RNA expression of ribonuclease 7 was significantly diminished in lesional HS skin specimens irrespective of HS severity. Overall levels of dermcidin/dermcidin-derived peptides in sweat and messenger RNA expression of psoriasin in skin biopsy specimens did not differ between patients with HS and healthy control subjects.

The relatively small number of samples, in particular in the group of patients with HS and Hurley grade III, is a limitation.

Deficient constitutive production of ribonuclease 7 and, in severe HS, reduced human β-defensin-3 induction may contribute to impaired immunity within the hair follicle and thereby boost HS inflammation and severity.