Association of soluble ST2 with disease activity in pediatric systemic lupus erythematosus

Objective: The aim of this study is to assess soluble ST2 (sST2) as a potential biomarker in pediatric systemic lupus erythematous patients (pSLEs), especially to reveal the association of the sST2 levels with the disease activity and other laboratory tests.Methods: A total of 65 pSLEs and 33 age-and sex-matched healthy controls (HCs) were enrolled in this study between July and December 2022 from Children's Hospital of Fudan University. Serum levels of sST2 were determined and clinical information and laboratory test results were collected.Results: Serum sST2 levels were significantly increased in pSLEs (36.7 ng/mL, IQR 16.6-76.9) compared with HCs (10.4 ng/mL, IQR 6.4-14.8). Patients with moderate to severe disease activities had significantly elevated levels of sST2 compared with those with inactive and mild disease activities. A positive correlation was found between sST2 levels and SLE Disease Activity Index-2000 (SLEDAI-2K) scores. The serum levels of sST2 also showed positive correlations with anti-dsDNA antibody, ALT, AST, GGT, blood urea, and negative correlations with C3, C4, CH50 and ALP. ROC analysis showed that sST2 could discriminate active disease (AUC: 0.959, 95 %CI 0.878-0.992) with an optimal cut-off of 30.2 ng/mL (sensitivity: 89.7 %, specificity: 100 %) and moderate/severe disease activities (AUC: 0.962, 95 %CI 0.883-0.994) with an optimal cut-off of 45.2 ng/mL (sensitivity: 91.7 %, specificity: 90.2 %). Decreased sST2 levels were observed after clinical treatment.Conclusions: Elevated serum sST2 level in pSLEs were observed and were highly associated with disease activity, suggesting sST2 might be a potential biomarker for pSLEs.