The inflammatory proteome of hidradenitis suppurativa skin is more expansive than that of psoriasis vulgaris

Background Although hidradenitis suppurativa (HS) shares some transcriptomic and cellular infiltrate features with psoriasis, their skin proteome remains unknown. Objective To define and compare inflammatory protein biomarkers of HS and psoriasis skin. Methods We assessed 92 inflammatory biomarkers in HS (n = 13), psoriasis (n = 11), and control skin (n = 11) using Olink high-throughput proteomics. We also correlated HS skin and blood biomarkers using proteomics and RNA sequencing. Results We identified 57 differentially expressed proteins (DEPs) in lesional psoriasis and 64 DEPs in lesional HS skin, compared to healthy controls. Both HS and psoriasis lesional skin demonstrated a significant upregulation of T helper 1 and T helper 17 proteins. Healthy-appearing perilesional HS skin had 63 DEPs compared to healthy controls. Nonlesional HS and psoriasis skin had 24 and 7 DEPs, respectively, compared to healthy controls. Tumor necrosis factor and 8 other proteins were significantly correlated with clinical severity in perilesional HS skin (2 cm from a nodule). Limitations Inclusion of only moderate-to-severe patients and the cohort size. Conclusion HS has a greater inflammatory profile and is more diffusely distributed compared with psoriasis. Proteins correlated with disease severity are potential disease mediators. Perilesional skin is comparably inflamed to lesional skin, suggesting the need to treat beyond skin nodules.