CD79A and Diarrhea: On the other hand, most of the genes that were down-regulated with high diarrhoea, compared low diarrhoea, are directly or indirectly involved in the immune response, the regulation of immune response and immune tolerance: ‘antigen processing and presentation’, ‘antigen processing and presentation of peptide or polysaccharide antigen via MHC class II’, ‘intestinal immune network for IgA production’, ‘primary immunodeficiency’ and ‘immune response’.