Celiac disease is an illness where the body's immune system mistakenly attacks the small intestine when gluten is eaten. Gluten is found in foods like bread and pasta. This study will explore how parts of the body, like cells and genes, interact with gluten to cause symptoms and tissue damage in people with celiac disease. We also want to learn why some people heal differently when avoiding gluten.

• Study Length: Participants must have had celiac disease diagnosis for at least 12 months
• Visits Needed: Participants are divided into three groups based on their current diet and symptoms
• Eligibility: Must be 18-75 years old and meet specific health criteria

Participants will be divided into three groups: those who avoid gluten, those who don't, and a control group without celiac disease. People with serious complications or other illnesses, and certain medication users cannot join. The study aims to improve care for those with celiac disease.