Serum S100A8 as a potential biomarker for diagnosis of antiphospholipid syndrome and risk stratification among aPL carriers

BACKGROUND: Current diagnosis of antiphospholipid syndrome (APS) relies on antiphospholipid antibodies (aPL) testing, but false-positive aPL results and asymptomatic aPL carriers pose significant clinical challenges. The importance of S100A8 in thrombosis has been demonstrated, yet its potential role in APS has received little attention. This study aimed to assess serum S100A8 for APS diagnosis and risk stratification among aPL carriers. METHODS: Serum S100A8 levels were measured by ELISA in healthy controls (HCs), aPL carriers without manifestation and patients with APS. Receiver operating characteristic curves were used to evaluate the diagnostic performance of APS. Logistic regression was performed to identify independent variables associated with obstetric morbidity among female aPL carriers. RESULTS: The study enrolled 120 HCs, 57 aPL carriers and 114 patients with APS. Serum S100A8 levels were significantly higher in aPL carriers (median 44.3 (IQR 35.6-75.4) ng/mL, p