The role of capsule endoscopy in patients with nonresponsive celiac disease.

t n t a p t Celiac disease is a unique autoimmune disease affecting approximately 1% of the population worldwide. The treatment is a gluten-free diet, and adherence to the diet improves symptoms in the majority of patients. However, approximately 7% to 30% of patients experience persistent symptoms while being treated with a gluten-free diet, commonly because of continued gluten ingestion.1 Individuals who are nonresponsive to treatment present a challenge to the clinician and are frequently encountered at tertiary-care referral centers. Symptoms may fail to improve initially or may recur after an extended period of treatment with a gluten-free diet. A systemic approach in evaluating these patients is helpful for excluding causes such as persistent gluten exposure, microscopic colitis, small-intestinal bacterial overgrowth, lactose or fructose intolerance, pancreatic exocrine insufficiency, and autoimmune enteropathy. Consultation with a skilled dietician is crucial, but availability is limited in many areas. Other reasons for persistent symptoms include refractory celiac disease (RCD). RCD, defined as persistent diarrhea and villous atrophy despite adherence to a gluten-free diet for at least 12 months, is divided into two types, depending on the population of intraepithelial T lymphocytes.2 In type I RCD, the intraepithelial lymphocytes have normal surface CD3 and CD8 expression as well as a polyclonal T-cell receptor arrangement, similar to uncomplicated celiac disease. In type II RCD, an aberrant lymphocyte population is expanded with loss of surface CD3 and CD8 expression, retention of CD3 expression within the cell, and a monoclonal T-cell receptor arrangement. Type II RCD has a poor prognosis with increased mortality, often because of the development of enteropathy-associated T-cell lymphoma, an unfortunate complication occurring in over 50% of patients.2-3 Luckily, in the United States, RCD type II appears rare compared with European populations, although the reasons for this are unclear.4 For patients with unresponsive celiac disease or susicion of refractory disease, conventional upper endoscopy s needed to obtain biopsy specimens for immunohistochemstry, flow cytometry, and T-cell receptor polymerase chain eaction studies. Capsule endoscopy is a useful, noninvasive method for xamining the entire small intestine, not only in patients with bscure bleeding but also in celiac disease. The role of apsule endoscopy in the initial evaluation and subsequent