F8 and hemophilia A: Previously, Hofbauer et al. presented proof-of-principle data indicating that the presence of high-affinity FVIII-specific IgG4 antibodies and FVIII inhibitors in patients with severe hemophilia A correlated with the upregulation of pro-inflammatory gene expression signatures in PBMC after short-term in vitro re-stimulation with FVIII [12,13,14].