Robert Zeiser's 2022 review in the European Journal of Immunology explores how impaired immunity leads to severe intestinal inflammation in Graft-versus-Host Disease (GVHD), IBD, and primary immunodeficiencies, focusing on the breakdown of the "mucosal firewall". The open-access article highlights the role of the microbiome and innate immune interactions, while discussing regenerative therapeutic strategies like IL-22 and ruxolitinib. Access the full-text PDF at the Wiley Online Library .