Increased synovial and entheseal fibroblast activation detected by 68Ga-FAPI-PET/CT is associated with the development of psoriatic arthritis in psoriasis patients with arthralgia

Corte G, Atzinger A, Noversa de Sousa R, Mutlu MY, Temiz A, Bayat S, Raimondo MG, Ramming A, Sticherling M, Schmidkonz C, Kuwert T, Schett G, Tascilar K, Fagni F (2026)


Publication Type: Journal article

Publication year: 2026

Journal

Book Volume: 12

Journal Issue: 1

DOI: 10.1136/rmdopen-2025-006567

Abstract

OBJECTIVES: To assess the clinical and imaging characteristics associated with fibroblast activation detected by 68Gallium-labelled fibroblast activation protein inhibitor positron emission tomography/CT (68Ga-FAPI-PET/CT) in patients with psoriasis and whether 68Ga-FAPI uptake correlates with the risk of progression to psoriatic arthritis (PsA). METHODS: Psoriasis patients with arthralgia underwent 68Ga-FAPI-PET/CT and were followed up prospectively. 68Ga-FAPI uptake was assessed at 71 articular sites and patients with ≥1 joint with 68Ga-FAPI uptake and PET/CT Joint Index≥2 were considered FAPI positive. The associations between FAPI uptake and clinical and ultrasound (US) findings were investigated. Survival analyses were conducted to assess the association between 68Ga-FAPI uptake and progression to PsA. RESULTS: 45 patients with psoriasis were enrolled, 37 of whom (82%) were FAPI positive. FAPI-positive psoriasis patients had significantly higher body mass index (BMI) (p=0.036) and Disease Activity Score 28-C reactive protein (p=0.033) compared with FAPI-negative patients. 68Ga-FAPI uptake was most frequent in large joints and mechanically stressed sites and was more likely in the presence of low-grade synovial hyperplasia (OR: 1.77, 95% CI 1.08 to 2.89), entheseal Power Doppler (OR: 3.80, 95% CI 1.66 to 8.72) and concomitant osteoarthritis (OA). FAPI-positive patients showed a higher risk of progression to PsA compared with FAPI-negative patients (HR 7.1, 95% CI 0.9 to 53.6) (log-rank p=0.028). Only 1/8 patients with psoriasis (12.5%) without 68Ga-FAPI uptake developed PsA, as opposed to 18/37 (49%) of FAPI-positive patients. CONCLUSIONS: In psoriasis patients with arthralgia, 68Ga-FAPI uptake, indicating fibroblast activation, is associated with higher BMI, more pain, subclinical US changes and concomitant OA. Pathological 68Ga-FAPI uptake at articular sites was indicative of higher risk of progression to PsA in our cohort, suggesting fibroblast activation as a crucial step to develop PsA.

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APA:

Corte, G., Atzinger, A., Noversa de Sousa, R., Mutlu, M.Y., Temiz, A., Bayat, S.,... Fagni, F. (2026). Increased synovial and entheseal fibroblast activation detected by 68Ga-FAPI-PET/CT is associated with the development of psoriatic arthritis in psoriasis patients with arthralgia. RMD Open, 12(1). https://doi.org/10.1136/rmdopen-2025-006567

MLA:

Corte, Giulia, et al. "Increased synovial and entheseal fibroblast activation detected by 68Ga-FAPI-PET/CT is associated with the development of psoriatic arthritis in psoriasis patients with arthralgia." RMD Open 12.1 (2026).

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