IFNG and congenital rubella syndrome: Ferritin, an ARP, is increased in many inflammatory states, and it may serve as a biomarker for CRS, HLH in hematologic disorders, but when used as a predictor of infection, ferritin is affected by a variety of factors including IL-6, IL-10, IL-18, and IFNγ (Karakike and Giamarellos-Bourboulis, 2019).