Non-Responsive and Refractory Celiac Disease
Celiac disease is a serious, genetic autoimmune disorder triggered by consuming a protein called gluten. When a person with celiac eats gluten, the protein interferes with the absorption of nutrients from food by damaging a part of the small intestine called villi. Damaged villi make it nearly impossible for the body to absorb nutrients into the bloodstream, leading to malnourishment and a host of other problems including some cancers, thyroid disease, osteoporosis, infertility and the onset of other autoimmune diseases.
Currently, there are no FDA approved treatments for celiac disease beyond a lifelong gluten-free diet.
Non-Responsive Celiac Disease
Non-responsive celiac disease is defined as continuing to have persistent symptoms, elevated antibodies or small intestinal damage even after following a strict gluten-free diet for six to 12 months.
Some celiac disease patients don’t respond to the gluten-free diet because of conditions unrelated to celiac disease, including bacterial overgrowth and lactose intolerance, but even when these are excluded, a seemingly strict gluten-free diet can inadvertently include enough gluten to trigger symptoms or damage.
A 2007 study by the gastroenterology department at Beth Israel Deaconess Medical Center, Boston, found that 36 percent of patients with non-responsive celiac disease were inadvertently consuming gluten.
In recent years, endoscopy and biopsy studies have shown that non-responsive celiac disease includes a larger group of patients than previously thought. While current scientific literature indicates that about 30 percent of patients have non-responsive celiac disease, there is evidence the number is closer to 50 percent when those who don’t have symptoms but continue to have damage to the intestine, called mucosal atrophy, are included.
Non-responsive celiac disease is common in both children and adults.
Refractory Celiac Disease
Refractory celiac disease is marked by a lack of response to a strict gluten-free diet after six to 12 months, with symptoms, intestinal damage and an abnormal population of white blood cells in the gut.
These cells, called abnormal intraepithelial lymphocytes, are unique immune cells found in the lining of the small intestine. Their presence is the distinguishing and disturbing characteristic of refractory celiac disease because they can be the beginning of cancer.
A patient is classified as having refractory celiac disease Type I or II based on the proportion and characteristics of the intraepithelial lymphocytes. For diagnosis, the cells are counted by a flow cytometer, an instrument that analyzes the chemical and physical properties of particles. Patients with less than 20 percent of the abnormal lymphocytes have Type I refractory celiac disease, and those with more than 20 percent, Type II.
About 1 in 100 celiac disease patients have Type I and 1 in 200 have Type II.
Refractory celiac disease is believed to be independent of gluten since the gluten-free diet is not effective in preventing the lymphocytes from increasing.
Patients with Type II have a greater than 50 percent chance of the abnormal lymphocytes spreading outside the gut, causing a full-blown lymphoma, which has a poor prognosis and high mortality.
Most cases of both types of refractory celiac disease occur in older patients who are not diagnosed until later in life. Typically, they suffer symptoms for many years until severe pain develops and abnormalities such as severe anemia are discovered. Finally, celiac disease is pinpointed as the cause. Refractory celiac disease only appears in patients who have not been on a gluten-free diet or have not followed the diet correctly for decades.
A drug to treat refractory celiac disease, AMG-714, may be available to some patients with diagnosed refractory celiac disease through Amgen’s expanded access to investigational medicines program. More information is available here and here.