Autoimmune enteropathy (AIE) is a rare disorder of the immune system condition that affects infants, young children and (rarely) adults causing severe diarrhea, vomiting, and other morbidities of the digestive tract. AIE causes malabsorption of food, vitamins, and minerals often necessitating replacement fluids and total parenteral nutrition.
There are 3 types of autoimmune enteropathy:
Type 1: IPEX syndrome: Immune dysregulation, Polyendocrinopathy, Enteropathy, X – linked syndrome, which is caused by a mutation in the FOXP3 gene. This can only affect boys.
Type 2: IPEX-like, which manifests similarly to IPEX syndrome but without recognizable mutations in the FOXP3 gene. This can affect both genders and includes a variety of manifestations of varying severity.
Type 3: Autoimmune manifestations primarily limited to the GI tract. This can affect both genders and may also be considered IPEX-like.
There is considerable overlap in these disorders, and it is often unclear how to properly distinguish between them as the responsible genes are generally poorly understood at this time.
- Diarrhea (frequent loss of fluids)
- Intestinal inflammation
- Intestinal bleeding
- Difficulty or inability to gain weight
- Rapid weight loss
- Decreased urine output from dehydration
There is a diagnostic test for AIE that looks for an antibody against the enterocyte. The diagnostic test contains the Western Blot which can identify the antibody IgG or IgA and with the immunohistochemistry can localize these antibodies. Endoscopy with biopsies of the colon, small colon, stomach, and other locations may be helpful in diagnosing. This test is done to look at the stomach and small intestines and to see what cells are infiltrating the digestive tract. There are also documented cases of autoimmune enteropathy where the auto-antibodies were undetectable and the diagnosis was made on the basis of clinical presentation and response to treatment.
The first line of treatment are corticosteroids and other medicines used to suppress the immune system such as tacrolimus and sirolimus. A intravenous nutrition such as total parenteral nutrition and/or a special diet may be necessary. Hematopoietic stem cell transplantation may be curative.