Background Psoriasis (Pso) is one of the most common chronic inflammatory skin diseases in Europe. Psoriatic arthritis (PsA) is closely associated to Pso; the skin manifestation appears usually years before PsA-related symptoms emerge. Up to 40% of Pso patients develop PsA. Biomarkers for its early detection are missing by reasons of its distinct clinical manifestations. In early PsA manifestations, changes in synovial vascularisation combined with increased expression of proangiogenic factors appear first. Therefore, imaging biomarkers for detection of changes in vascularisation can be useful for early detection of joint disease. Fluorescence-optical imaging (FOI) is a new method to detect changes in microvascularisation of the hands.
Methods Sensitivity of FOI as imaging biomarker for detection of subclinical signs of inflammation of PsA is observed in a prospective multicentre study (XCITING) in Germany including patients with dermatological confirmed Pso. This is the first interims analysis of 116 enrolled Pso patients (89 complete data sets) without diagnosis of PsA and risk factors for the development of PsA (nail psoriasis and/or joint pain or swelling within the last 6 months). Clinical examination (CE; swollen (66), tender (68) joint count, enthesitis, dactylitis) and standardised ultrasound (US) assessment was performed by a qualified rheumatologist at one time point to assess PsA symptoms. Additionally, FOI was performed. Data was analysed in focus on increased vascularisation of musculoskeletal structures of both hands as marker of inflammation. In cases of discrepant results (positive FOI and negative results for CE and US), MRI was performed to prove the findings.
Results 35% of the Pso patients (mean age 46.9 years, 55% male, baseline PASI 5.2, mean duration of Pso 14.9 years) with risk factors for PsA were diagnosed positive as PsA either by CE/US or FOI. In 22% of these patients neither in CE/US nor in FOI any signs of musculoskeletal inflammation could be detected. 30% of the patients showed increased fluorescence signal in FOI whereas in CE/US no inflammatory signs were detected by rheumatologic assessments (Table 1). In 5.6% of the patients suspected inflammation by FOI was confirmed by a MRI scan. In 23.6% of the patients with negative findings for CE/US the MRI scan was also without pathological findings whereas FOI showed positive signs of inflammation.
Conclusions In this cohort of Pso patients without PsA, more than 40% of the patients were classified as PsA by CE/US only. In another 30% signs of inflammation were detected by FOI while MRI scan was only positive in 5.6%. FOI has the potential for early detection of musculoskeletal involvement in patients with Pso. Its possible high sensitivity in the detection of inflammation needs to be further validated; patients with positive FOI and negative MRI will be reevaluated in a follow up study.
Disclosure of Interest M. Koehm Grant/research support from: Pfizer, AbbVie, T. Rossmanith Grant/research support from: Pfizer, H.-E. Langer: None declared, M. Backhaus Consultant for: AbbVie, Chugai, MSD, Pfizer, Roche, UCB, Speakers bureau: AbbVie, Berlin Chugai, MSD, Pfizer, Roche, UCB, U. Kaesser: None declared, C. Kneitz Grant/research support from: Pfizer, Consultant for: AbbVie, Chugai, Pfizer, Roche, Speakers bureau: AbbVie, Berlin Chemie, Chugai, MSD, Pfizer, Roche, UCB, S. Wassenberg Grant/research support from: Pfizer, Roche, Chugai, Consultant for: MSD, Pfizer, UCB, Janssen, Novartis, Speakers bureau: Pfizer, AbbVie, Roche, Chugai, Janssen, H. Burkhardt Grant/research support from: Pfizer, Roche, Abbvie, Consultant for: Abbvie, Pfizer, Novartis, Chugai, UCB, Janssen, Morphosys, Speakers bureau: Abbvie, Pfizer, Novartis, Chugai, UCB, Janssen, Roche, F. Behrens Grant/research support from: Pfizer, Roche, Abbvie, Chugai, Consultant for: Abbvie, Pfizer, Celgene, Novartis, Chugai, Astra Zeneca, Lilly, Janssen, Merck, Morphosys, Speakers bureau: Abbvie, Pfizer, Celgene, Novartis, Chugai, UCB, Astra-Zeneca, Janssen, Roche, Lilly