CD79A and agammaglobulinemia: However, we observed a significantly stronger positive association between AGA antibody production and total serum IgG and IgA titers in CD19−/− mice (ANCOVA, p<0.001) which we interpret to mean that CD19−/− mice are more responsive to dietary gluten antigens (or food antigens in general) despite their antibody deficiency (Figure 7B).