(18)F-Fluorodeoxyglucose positron emission tomography and serum cytokines and matrix metalloproteinases in the assessment of disease activity in Takayasu's arteritis

Objective: To evaluate (18)F-fluorodeoxyglucose ((18)F-FDG) uptake on positron emission tomography-computed tomography (PET-CT) and serum levels of different cytokines and matrix metalloproteinases (MMPs) in patients with Takayasu arteritis (TA) and associations with disease activity.

Methods: Serum levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-2, IL-6, IL-8, IL-12, IL-18, MMP-3 and MMP-9 were measured in 36 TA patients and 36 controls. Maximum standard uptake value (SUVmax) of (18)F-FDG in arterial walls was determined by PET-CT scans. TA patients were classified as active disease, inactive disease and possible active disease.

Results: Serum IL-6 and MMP-3 levels were higher in TA patients than in controls (p<0.001). Serum IL-6 was higher in patients with active disease and in patients with possible active disease than in inactive disease (p<0.0001). Patients with active disease had higher serum TNFα levels than patients with inactive disease (p=0.049) while patients with possible active disease presented higher IL-18 levels than patients with inactive disease (p=0.046). Patients with active disease had higher SUVmax values than those with inactive disease (p=0.042). By receiver operating characteristic (ROC) curve SUVmax was predictive of active disease in TA and values ≥1.3 were associated with disease activity (p=0.039). Serum TNF-α levels were higher in patients with SUVmax≥1.3 than <1.3 (p=0.045) and controls (p=0.012). Serum IL-6 levels were higher in patients with SUVmax≥1.3 than in controls (p<0.001). No differences regarding other biomarkers were found between TA patients and controls.

Conclusions: Higher serum IL-6 and TNFα levels as well as higher (18)F-FDG uptake in arterial wall are associated with active TA.