Establishing the diagnosis of subclinical or clinical celiac disease is of potential importance to rheumatologists for several reasons, including the danger of developing malignancy, the presence of unsuspected nutritional deficiencies, and the occurrence of autoimmune disorders. Some studies have found that the prevalence of autoimmune diseases is related to the duration of undetected celiac disease and may reach more than 30 percent of patients diagnosed after age 20.
The importance of recognizing celiac disease was the topic of Monday’s Celiac Disease & Its Relationship With Autoimmune Diseases and a presentation by Maureen Leonard, MD, MMSc, Clinical Director of the Center for Celiac Research and Treatment at MassGeneral Hospital for Children and Instructor of Pediatrics at Harvard Medical School in Boston.
“Celiac disease is a unique model of autoimmune disease in that it’s the only autoimmune disease for which we know the trigger, which means that if we identify these patients and we put them on a gluten-free diet, they will go into remission with that alone,” Dr. Leonard said. “For research purposes, that means we can also turn on and off the disease in order to study it by giving gluten to patients with celiac disease and then removing it to monitor how they go into remission.”
Dr. Leonard said that much has been learned over the past decade about the genetics and the pathophysiology of celiac disease.
“We know that in order to develop celiac disease, patients must carry the HLA-DQ2 and/or HLA-DQ8 genes, which are directly involved in the pathogenesis of celiac disease,” she said. “These genes encode for a receptor on antigen-presenting cells that happen to bind gluten extremely tightly and allow it to be presented to the immune system for the inflammatory cascade to ensue. This is something we can test for pretty easily, and if the test comes back negative, we know that patient does not have the potential to develop celiac disease in the future.”
Approximately 30-40 percent of the population carry a variant of the HLA-DQ2 or HLA-DQ8 genes, Dr. Leonard said, but only about two percent of that population go on to develop celiac disease.
“In order to trigger the immune response, the gluten must go from the lumen of the small intestine across the single layer of intestinal epithelial cells and into the lamina propria, where it interacts with the immune system,” she said. “Because we know so much about celiac disease, we hope that whatever we learn from it we can apply to other autoimmune disorders for which we know less.”
Dr. Leonard said recent studies have demonstrated a higher prevalence of celiac disease in patients with rheumatic disease, so it is important for rheumatologists to understand and recognize the signs and symptoms of celiac disease. “We now think of celiac disease as a truly systemic disorder that can affect any tissue and any organ in the body,” Dr. Leonard said. “It may present with skin rashes, or with liver inflammation, or with fractures, anxiety, depression, or even no symptoms at all, so you really have to have a high clinical suspicion and take a detailed history in order to suspect celiac disease.”