Since no APS1 thymic cells were available, we compared IFN expression (assessed by RT-PCR) by monocytes and immature and mature DCs cultured from blood from a compound heterozygous APS1 patient (with high anti-IFN-α2 and anti-IFN-ω titres). The gene discussed is IFNA2; the disease is autoimmune polyendocrine syndrome type 1.