CD40LG and infection: In this article, we purposely discussed patients that do not fulfill the strict criteria for SAD with a diminished antibody response to polysaccharide antigens following vaccination or wild-type infection as the only immunologic pathology (normal levels of IgG, IgA, IgM and IgG subclasses) (12, 13, 20, 22) for the following reasons: SAD is not a genetically distinct IEI.