Graft-versus-host disease (GvHD)  is a syndrome, characterized by inflammation in different organs. GvHD is commonly associated with bone marrow transplants and stem cell transplants. White blood cells of the donors immune system which remain within the donated tissue (the graft) recognize the recipient (the host) as foreign (non-self). The white blood cells present within the transplanted tissue then attack the recipients bodys cells, which leads to GvHD. This should not be confused with a transplant rejection, which occurs when the immune system of the transplant recipient rejects the transplanted tissue; GvHD occurs when the donors immune systems white blood cells reject the recipient. The underlying principle (alloimmunity) is the same, but the details and course may differ. GvHD can also occur after a blood transfusion if the blood products used have not been irradiated or treated with an approved pathogen reduction system. Types
In the clinical setting, graft-versus-host disease is divided into acute and chronic forms, and scored or graded on the basis of the tissue affected and the severity of the reaction.In the classical sense, acute graft-versus-host disease is characterized by selective damage to the liver, skin (rash), mucosa, and the gastrointestinal tract. Newer research indicates that other graft-versus-host disease target organs include the immune system (the hematopoietic system, e.g., the bone marrow and the thymus) itself, and the lungs in the form of immune-mediated pneumonitis. Biomarkers can be used to identify specific causes of GvHD, such as elafin in the skin.
A stomach rumble, also known as a bowel sound, peristaltic sound, abdominal sound, bubble gut or borborygmus (pronounced ; plural borborygmi), is a rumbling, growling or gurgling noise produced by movement of the contents of the gastro-intestinal tract as they are propelled through the small intestine by a series of muscle contractions called peristalsis. A trained healthcare provider can listen to these intestinal noises with a stethoscope, but they may be audible enough to be heard with the naked ear as the fluid and gas move forward in the intestines (in the vicinity of, but not actually within the stomach). The lack of bowel sounds is indicative of ileus, intestinal obstruction, or some other serious pathology. Etymology
The scientific name borborygmus is related to the 16th-century French word borborygme, itself from Latin, ultimately from Ancient Greek βορβορυγμός (borborygmós). The Greeks probably onomatopoetically coined the word. Other causes
Other causes of stomach rumbles:

Incomplete digestion of food can lead to excess gas in the intestine. In humans, this can be due to incomplete digestion of carbohydrate-containing foods, including milk and other dairy products (lactose intolerance or the use of α-glucosidase inhibitors by diabetics), gluten (protein in wheat, barley, and rye) (coeliac disease), fruit, vegetables, beans, legumes, and high-fiber whole grains. In rare instances, excessive abdominal noise may be a sign of digestive disease, especially when accompanied by abdominal bloating, abdominal pain, diarrhea or constipation. Some examples of diseases that may be associated with this symptom include carcinoid neoplasm and coeliac sprue. Louder rumbles may occur when one is hungry.