CD79A and agammaglobulinemia: Furthermore only 10% had chronic diarrhea compared 20–60% chronic diarrhea in other reports from the literature) [7, 16, 48, 49] The progression of chronic gastrointestinal diseases may still occur in patients with a primary antibody deficiency since IgG substitution will only substitute IgG, while IgA and IgM, the major secretory antibodies at mucosal surfaces are not replaced, and secondly, immune dysregulation and T cell abnormalities may contribute to gastrointestinal disease.