S100A8 and autoimmune polyendocrinopathy: Multivariate logistic regression revealed that S100A8 positivity was independently associated with increased obstetric APS risk among aPL carriers (OR 3.335, 95% CI 1.010 to 11.012, p=0.048).<h4>Conclusion</h4>S100A8 may serve as a complementary biomarker for the diagnosis and risk stratification of APS, especially in female aPL carriers at risk of obstetric morbidity.