Function of IFNAR1 variants in the patients’ fibroblasts. (A) Intracellular FACS staining of phosphorylated STAT1 in SV40-fibroblasts stimulated with IFN-α2a (1,000 U/ml), IFN-ω (1 ng/ml), IFN-β (100 U/ml), or IFN-γ (1,000 U/ml) for 15 min, for two healthy controls and patients with IFNAR1 variants. (B) Fold-change in HLA class I levels analyzed by flow cytometry with extracellular staining in SV40-fibroblasts stimulated with IFN-α2a, IFN-ω, IFN-β, or IFN-γ for 48 h. Graphs depict the mean ± SEM of two independent experiments.