Elafin, an elastase specific protease inhibitor, is well described to be upregulated in lesional psoriatic skin. Elastase is active in antimicrobial defence but is also involved in proteolysis of tissue components. The role of this protease – protease inhibitor pair is not well understood in the pathogenesis of psoriasis. We analysed the protein expression of neutrophil elastase (NE) and elafin in epidermal samples and serum of psoriasis patients affected by plaque psoriasis (epidermal n=28, serum n = 20) or psoriasis with psoriatic arthritis (PsA) (n=34, serum = 94) in addition to healthy controls (n=25) and patients with osteoarthritis (n=58). PsA was confirmed by a rheumatologist in patients with psoriasis fulfilling the CASPAR classification criteria. Herein, we here show that the ratio between NE and elafin largely differs between psoriasis patients affected by different disease manifestations. Specifically, elafin was found reduced in epidermal samples and serum of psoriasis patients with PsA as compared to plaque psoriasis only patients (for epidermal samples p < 0.002 for lesional skin and p < 0.0001 for non lesional skin; for serum p < 0.001). The same cohort of PsA patients also showed increased NE expression as measured in serum (compared to psoriasis only patients: p < 0.005). We conclude that PsA patients show reduced capacity to neutralise NE compared to those with plaque psoriasis. The difference in elafin expression between skin psoriasis and those with added PsA was most pronounced in non-lesional skin. These findings need further exploration in order to elucidate their potential as predictive biomarker for those psoriasis patients at risk of developing PsA.

ESDR404 - Plaque Psoriasis patients with Psoriatic Arthritis demonstrate a reduced capacity to neutralise neutrophil derived elastase compared to plaque psoriasis patients without arthritis.

The scientific meeting of the European Society for Dermatological Research (ESDR) is held yearly, usually in September. With an international attendance of more than 1000 skin scientists from around the globe, the four-day event includes short oral presentations from peer-reviewed abstracts, keynote lectures from international experts, sponsored symposia, satellite programs, educational events as well as an important focus on posters, networking and building collaborations amongst scientists. For more information about this year’s meeting visit our website.