226 Non-invasive skin-surface biomarkers for psoriasis monitoring

Abstract

In clinical dermatology there is a need for non-invasive efficient and accurate diagnostic tools that can objectively measure psoriasis (PS) activity and can be used to monitor therapeutic effects of PS treatment. This exploratory study aimed to determine whether non-invasive measurements of proteins from PS lesional skin can be used to assess disease severity and measure treatment efficacy. BM measurements from skin were performed using non-invasive Transdermal Analysis Patch (TAP) capture antibody microarrays detecting IL-1α, IL-1RA, CXCL-1/2, hBD-1 (ng/ml). Captured BM were visualised using spot-ELISA.TAPs were applied to non-lesional (NL) and lesional (L) skin of PS patients (N=30). PASI and local inflammation scores of lesions were documented; thickness of epidermis, dermis, subepidermal lowechogenic band (SLEB) was analysed using ultrasound (US) at the same skin site as TAP measurements and clinical scores. Potential of these skin-surface BM was further studied by monitoring skin lesions of PS patients (N=14) undergoing UVB (311nm) therapy using TAP together with clinical scores for PS severity. Skin surface measurements of PS patients revealed clear differences of IL-1a, IL-1RA, CXCL-1/2 on L skin when compared to NL. Comparing BM expression patterns with clinical scores of PS skin following correlations were observed: between CXCL-1/2 and lesion thickness (p<0.05), between CXCL-1/2 and SLEB thickness (p<0.001) on L; IL-1RA and SLEB thickness (p<0.05) of analysed NL skin. During UVB treatment, clear patterns towards normalisation of IL-1RA and CXCL-1/2 levels were noted on L which was in accordance with clinical parameters. Skin surface analysis of IL-1RA and CXCL-1/2 displayed a different profile than achieved by visual scoring of local inflammation or US - confirming that measuring the ‘molecular root’ of inflammation appears to have value as an objective, non-invasive BM measurement for scoring disease severity in its own right.