In fact, there are occasional examples of intractable infections in both APS1 and MG/thymoma patients [8,10,11,21]; it may be relevant that one young child with APS1 who had almost continuous respiratory infections also had neutralising titres of 500–2,000 against IFN-β by age 7–9 y. Here, IFNB1 is linked to autoimmune polyendocrine syndrome type 1.