Consultant Pediatric Gastroenterologist, KKCTH,
SMF and Apollo Hospitals, Chennai. *
Autoimmune Enteropathy (AIE) is a distinct entity of protracted diarrhea in young infants and children associated with circulating gut auto antibodies and in most patients with extraintestinal disease and a host of various auto immune markers. This disorder is a syndrome of generalized uncontrolled immune activation with the intestine as its primary target. AIE is rare and constitutes about 25 to 29% of protracted diarrhea of infancy.
The majority of children present after 8 weeks of life and within the first 2 years. There are reports in older children and adults. Boys have a more predilection than girls.
AIE is classified into 3 types:
Classic form of AIE which is identical to IPEX syndrome
AIE without extraintestinal manifestations and
AIE in girls
- AIE type 1: The full blown form of AIE type 1 is very akin to IPEX syndrome (immune dysregulation, polyendocrinopathy, enteropathy and X linked syndrome)
A specific mutation on the FOXP3 gene resulting in the dysfunction of immune specific FOXP3 DNA binding protein (scurfin) has been identified which results in abnormal T cell activity and uncontrolled inflammatory reaction.
Clinical features: Large volume secretory diarrhea often occurs within the first 3 months of life occasionally with blood and mucous. Protein losing enteropathy, hypoalbuminemia and dyselectrolytemia can occur.
Extra-intestinal manifestations such as atopic dermatitis, chronic hepatitis, diabetes, food intolerance, growth retardation, glomerulonephritis, hemolytic anemia, interstitial pneumonitis and lymphadenopathy can occur.
Diagnosis: AIE is characterized by a marked infiltration of activated T lymphocytes in the lamina propria of both small and large intestine. Villous atrophy is seen with massive infiltration of the lamina propria by lymphocytes. The peripheral blood lymphocyte count including the T cell and B cell subsets, CD4 and CD8 are within the normal range. IgE levels are raised.
Auto-antibodies: Anti-enterocyte and anticolonocyte antibodies are present in the vast majority though in some it may be negative. These antibodies do not play a role in the pathogenicity of the disease and are an epi-phenomenona of intestinal inflammation. Anti goblet cell antibody and AIE 75 have also been isolated.
- AIE without extra-intestinal manifestation: AIE can present with isolated gut involvement without any extra-intestinal manifestation.
- AIE in girls: This type is rare and seen in girls with thyroiditis and diabetes.
Differential Diagnosis: AIE should also be differentiated from congenital microvillous inclusion disease and tufting enteropathy. AIE in an older infant or child should be differentiated from celiac disease. The main difference is the distribution of the T lymphocytes. In AIE it is seen in the lamina propria in celiac disease it is intra epithelial.
Management: Nutritional support in the form of parenteral or enteral nutrition. The use of steroids alone or in combination with azathioprine, cyclosporine A or Tacrolimus has been encouraging. Infliximab has also been tried. In children resistant to therapy allogenic BMT has been attempted.
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|Sathiyasekaran M.. Available From : http://www.pediatriconcall.com/fordoctor/ Conference_abstracts/report.aspx?reportid=187|