Interestingly, the delineation of CYP21 epitopes benefited from interferon-γ (IFNγ, a type-2 IFN) assay in cultures of peripheral blood mononuclear cells challenged with several CYP21 fragments: some patients with APS1 carrying the MHCI HLA-B35 allele were included in these studies. Here, CYP21A2 is linked to autoimmune polyendocrine syndrome type 1.