Serologic, endoscopic, and histologic features before (A) and after (B) 2 intravenous infusions of autologous bone marrow–derived mesenchymal stromal cells (MSCs) 2 weeks apart. 1, Immunofluorescent pattern of class A antienterocyte autoantibodies showing the strong positivity (A) (original magnification ×25) and negativity (B) (original magnification ×25) of the brush border on cryostat section of monkey jejunum. 2, Endoscopic appearance of duodenal mucosa before MSC infusions (A) showing flattening of intestinal folds with visualization of the underlying vascular pattern and after MSC infusions (B) showing the presence of islets of normal duodenal mucosa. 3, Histologic features of duodenal mucosa before MSC treatment (A) showing villous atrophy with crypt hyperplasia and heavy inflammatory infiltrate and after MSC treatment (B) indicating the recovery of normal architecture and disappearance of the infiltrate (hematoxylin-eosin, original magnification ×100). 4, Immunohistochemical characterization of the inflammatory infiltrate with anti-CD3 antibody (Clone PS1; Novocastra, Newcastle, UK) showing the presence of a heavy lymphocytic infiltrate at the lamina propria and epithelium levels before MSC infusions (A), which returned to normal levels after MSC infusions (B) (original magnification ×100).