CD40LG and typhoid fever: Here we have evaluated IgG, IgM and IgA ELISAs using purified S. Typhi LPS and HlyE using culture-confirmed pediatric bacteremias, including typhoid, iNTS disease, and ‘other’ febrile diseases, as well as healthy Nigerian children, and healthy adults from the U.S. We find LPS-specific IgA and IgA+M ELISA, in particular, are sensitive in diagnosing acute typhoid in these children, and descriminate well between typhoid and healthy, and other febrile bacteremias commonly encountered in Nigeria.