Follow-Up Comparison of Fluorescence Optical Imaging With Musculoskeletal Ultrasound for Early Detection of Psoriatic Arthritis.

Objectives: Early diagnosis of psoriatic arthritis (PsA) is crucial for a patient outcome but hampered by heterogenous manifestation and a lack of specific biomarkers. We recently showed that fluorescence optical imaging (FOI) can differentiate between patients with confirmed and suspected PsA. This study aims to follow-up (FU) patients with confirmed and suspected PsA focusing on patients with a change from suspected to confirmed PsA by the use of FOI in comparison with musculoskeletal ultrasound (MSUS). Methods: Follow-up examination of patients included in the study performed by Erdmann-Keding et al. in which FOI of both hands was performed in a standardized manner using three predefined phases (p1-p3) and PrimaVista Mode (PVM). The comparison was drawn to grayscale-power Doppler (GS/PD) MSUS of the clinically dominant hand (wrist, MCP, PIP, DIP 2-5) from dorsal or palmar. Results: Patients with a change from suspected to diagnosed PsA showed an increased prevalence of joints with pathological enhancement in FOI (p = 0.046) with an unchanged joint distribution pattern, especially with a dominant involvement of DIP joints. Compared to the baseline, these patients were three times more common to show enhancement in FOI p3 at FU. Newly detected pathologic joints by FOI (PVM, p2) and MSUS at FU were positively associated with the change of diagnosis from suspected to confirmed PsA (FOI: AUC 0.78; GSUS: AUC 0.77). Conclusion: Fluorescence optical imaging appears to be a helpful tool to detect early PsA and to distinguish between acute and chronic disease stages. It could thereby become a suitable tool as a screening method to select psoriasis patients with an indication for further rheumatological evaluation.

Fluorescence optical imaging for the detection of potential psoriatic arthritis in comparison to musculoskeletal ultrasound.

OBJECTIVE: Comparison of fluorescence optical imaging (FOI) with grayscale (GS) and power Doppler ultrasound (PDUS) to detect joint inflammation in patients with confirmed or suspected psoriatic arthritis (PsA). METHODS: Patients (n = 60) with psoriasis and tenderness and/or swelling of joints were separated into two groups: diagnosis confirmed by the treating dermatologist before the start of the study (n = 26), and suspected PsA (n = 34). GS/PDUS of the hand most clinically affected was performed with a dorsal/palmar view (wrist, MCP, PIP, DIP2-5). FOI examination was carried out in a standardized manner by analyzing the predefined Phases 1-3. RESULTS: FOI was found to be more sensitive than ultrasound (US) for detection of inflammation in PIP/DIP joints (p = 0.035). Confirmed PsA patients showed more findings in FOI P2 and P3, while suspected PsA patients showed more findings in P1. In the confirmed PsA group, most involved joints were MCP joints, while in the suspected PsA group, more involved wrist joints and DIP joints (p = 0.006) were detected with FOI. CONCLUSIONS: The differences between the confirmed and suspected groups indicate that FOI is helpful in the detection of early PsA since P1 may correspond to acute inflammation, whereas P2 and P3 enhancement reflect chronic inflammation. Fluorescence optical imaging might therefore be a novel diagnostic tool for early PsA diagnosis.

IL-19 is a component of the pathogenetic IL-23/IL-17 cascade in psoriasis.

Psoriasis is a common chronic inflammatory disease with characteristic skin alterations and functions as a model of immune-mediated disorders. Cytokines have a key role in psoriasis pathogenesis. Here, we demonstrated that out of 30 individually quantified cytokines, IL-19 showed the strongest differential expression between psoriatic lesions and healthy skin. Cutaneous IL-19 overproduction was reflected by elevated IL-19 blood levels that correlated with psoriasis severity. Accordingly, anti-psoriatic therapies substantially reduced both cutaneous and systemic IL-19 levels. IL-19 production was induced in keratinocytes by IL-17A and was further amplified by tumor necrosis factor-α and IL-22. Among skin cells, keratinocytes were found to be important targets of IL-19. IL-19 alone, however, regulated only a few keratinocyte functions. While increasing the production of S100A7/8/9 and, to a moderate extent, also IL-1ß, IL-20, chemokine C-X-C motif ligand 8, and matrix metalloproteinase 1, IL-19 had no clear influence on the differentiation, proliferation, or migration of these cells. Importantly, IL-19 amplified many IL-17A effects on keratinocytes, including the induction of ß-defensins, IL-19, IL-23p19, and T helper type 17-cell- and neutrophil-attracting chemokines. In summary, IL-19 as a component of the IL-23/IL-17 axis strengthens the IL-17A action and might be a biomarker for the activity of this axis in chronic inflammatory disorders.