Mesenchymal stromal cells (MSCs) are multipotent progenitor cells that can be isolated and expanded from various sources. MSCs modulate the function of immune cells, including T and B lymphocytes, dendritic cells, and natural killer cells. An understanding of the interaction between MSCs and the inflammatory microenvironment will provide critical information in revealing the precise in vivo mechanisms involved in MSCs-mediated therapeutic effects, and for designing more practical protocols for the clinical use of these cells. In this review we describe the current knowledge of the unique biological properties of MSCs, the immunosuppressive effects on immune-competent cells and the paracrine role of soluble factors. A summary of the participation of MSCs in preclinical and clinical studies in treating autoimmune diseases and other diseases is described. We also discuss the current challenges of their use and their potential roles in cell therapies.

The New England Journal of Medicine Gallstone IleusSeven days before admission, nausea and crampy abdominal pain developed in a 65-year-old woman with a history of cholecystitis and cholelithiasis. Two days before admission, the pain became more intense, and she vomited, had no bowel movements, and passed no gas. A posteroanterior radiograph obtained during a barium examination of the small bowel shows an irregular collection of barium in the right upper quadrant (Panel A, arrowheads), representing partial filling of the cystic duct. Both jejunum and ileum are markedly dilated, with dilution of the barium in a pattern consistent with small-bowel obstruction. There is abrupt termination of the barium column at the site of an oval intraluminal filling defect (Panel A, arrow). A view of the end of the barium column shows luminal obstruction by a smooth intraluminal mass (Panel B, arrows) with faint calcification of the peripheral rim. Exploratory laparotomy revealed a foreign body in the terminal ileum that was 4 cm by 4 cm and felt hard (Panel C). A gallstone was extracted through a transverse incision (Panel D). The entire length of the intestine was examined in search of other gallstones, but none were found. The patient recovered uneventfully.