CD4 and digestive system infectious disorder: Gastrointestinal infections with rotavirus, adenovirus, enterovirus, parechovirus, and orthoreovirus in early childhood may also play an important role in the development of celiac disease either by damaging the mucosal barrier for transfer of gluten or by activating dendritic cells that act as antigen-presenting cells for CD4-positive gluten-reactive T cells in the presence of transglutaminase-modified gluten peptides.