CD40LG and infection: Regarding serological responses in the acute phase after infection in IEI patients compared with HC, IgG, IgM, and IgA were positive in all HC (100%, 14/14), but only positive in about half of IEI patients: IgG+ 58.8% (10/17) (p=0.009); IgM+ 41.2% (7/17) (p<0.001); IgA+ 52.9% (9/17) (p=0.003) (Figure 2A).