 - Patients with denuded mucosa caused by GVHD are eligible for enrollment, regardless of prior treatment for acute GVHD; denuded mucosa is defined as loss i.e., erosion or sloughing of the epithelium in: a at least one-third of the surface area in a 30 cm colonic segment i.e., rectosigmoid, descending or transverse colon; or b at least one fifth of the surface area of the second portion of the duodenum, as estimated by endoscopic evaluation; denuded mucosa must be documented by images of the duodenum and colon and by histologic evaluation of the colon 