The value of interleukin-6 in predicting disease relapse for Takayasu arteritis during 2-year follow-up

Objective: To evaluate the value of interleukin-6 (IL-6) in predicting long-term disease prognosis for Takayasu arteritis (TA). Methods: Sixty-seven TA patients, who had IL-6 levels detected at the first visit and had a regular follow-up of at least 2 years, were enrolled. Data recorded up to March 31, 2019, including clinical presentations, laboratory indices, treatments, and radiological images were collected and used for analysis. The value of IL-6 in predicting disease relapse and imaging progression was analyzed. Results: IL-6 levels were positively related with disease activity index, including Kerr scores, C-reactive protein (CRP) levels. Patients were divided into three groups according to baseline serum IL-6 levels: low group (< 5.4 pg/mL, n = 29), medium group (5.4–11.5 pg/mL, n = 20), and high group (> 11.5 ng/mL, n = 18). Patients in the medium and high group had higher disease activity than those in the low group (p < 0.01). Baseline IL-6 levels were correlated with luminal stenosis (p < 0.05), although no significant correlations with long-term imaging progression were observed. Patients with more than 2 episodes of disease relapses were most commonly seen in the medium group (p < 0.05). Multivariate Cox proportional hazard regression analysis indicated that medium and high IL-6 levels were positive predictors for disease relapse (HR 4.3, 95%CI 1.3–18.7 p = 0.07 for medium group; HR 2.1, 95% CI 0.7–48.9, p = 0.19 for high group) with disease status and treatment adjusted. Conclusions: IL-6 may be a valuable predictor of TA disease relapse during long-term follow-up. Treatments targeted at IL-6 pathways might reduce disease relapse and have better prognostic effects for TA.• Positive relationships between IL-6 levels and disease activity index, including Kerr scores, C-reactive protein (CRP) levels, etc. were indicated.• Medium and high baseline IL-6 levels were valuable for predicting disease relapse during the 2-year follow-up.• Baseline IL-6 levels were positively correlated with luminal stenosis on imaging.