Small bowel histology 5 days after BMT. (A) Allogeneic control mouse, exhibiting severe villus blunting, extensive crypt destruction with no appreciable regenerative response, and a moderate lamina propria inflammatory infiltrate. (B) Allogeneic mouse treated with KGF from day -3 to +5 exhibiting moderate villus blunting, prominent crypt regenerative features, and minimal lamina propria inflammatory infiltrate. Features in syngeneic control mice (not shown) were identical to those in KGF allogeneic animals.