Education Celiac disease occurs when someone’s immune system responds abnormally to gluten. Efforts to improve celiac disease diagnosis are ongoing. A study recently published in Gastroenterology evaluated the effectiveness of using a blood test that measures the cytokine interleukin-2 to diagnose celiac disease. The study’s results indicated that the test to be highly effective for celiac disease diagnosis, even for people following a gluten-free diet. The test could offer another option to