CD40LG and infection: In summary, the fact that the studied patients were not completely agammaglobulinemic, the presence of IgA in almost 88% of the patients, the detectable protective levels of IgA in saliva in some, and the low level of serious infections in these patients (only one patient, who was one of the agammaglobulinemic patients after CART19) may be indicative of the presence of a preserved immune reservoir in some children despite CART19 (those with preserved IgA/IgM levels).