MPIG6B and digestive system infectious disorder: Moreover SARS-CoV-2 intestinal infection induces a change in the gut immunological barrier [60, 61], since IgA molecules synthesized by immune cells in the lamina propria are likely to predominate the secretions of intestinal mucous membranes, promoting virus transcytosis towards the apical membranes after interaction with the polymeric immunoglobulin receptor [62].