Coeliac disease
How gluten peptides, tissue transglutaminase and HLA-DQ2 or DQ8 switch on a T-cell attack on the small-intestinal lining, flattening the villi and causing malabsorption, anaemia and effects beyond the gut.
By the end, you can
- Describe how villi, crypts and the brush border make the small intestine an absorbing surface.
- Explain how gliadin, tissue transglutaminase and HLA-DQ2 or DQ8 activate gluten-specific T cells.
- Relate intraepithelial lymphocytes and cytokines to villous atrophy and crypt hyperplasia.
- Link the site of damage to iron, folate, calcium and fat malabsorption.
- Recognise the classic biopsy appearances, the Marsh–Oberhuber grades and the antibody and genetic tests of coeliac disease, and explain how the gluten-free diet and other treatments act on the mechanism.
What it is
Coeliac disease is an immune-mediated disease of the small intestine triggered by gluten in genetically susceptible people, in which T-cell inflammation flattens the villi and impairs absorption. It differs from wheat allergy, an IgE-mediated reaction, and from non-coeliac gluten sensitivity, in which the villi are normal.
US spelling: coeliac → celiac.
Normal function
An absorbing surface that renews itself
The small intestine absorbs almost all digested food. Its surface is multiplied many times by circular folds, by finger-like about 0.5–1 mm tall, and by microvilli on each absorptive cell (enterocyte). The microvilli form the brush border, which carries digestive enzymes such as lactase.
Between the villi lie the . Stem cells near their bases divide continuously; new cells migrate up the villus and are shed from its tip within about three to five days. add mucus, and the in each villus core holds capillaries, a lacteal and immune cells. A few lymphocytes normally sit between the enterocytes (intraepithelial lymphocytes).
Different nutrients are absorbed in different places: iron and calcium mainly in the duodenum, folate in the jejunum, and vitamin B12 and bile salts in the terminal ileum.
Underlying change · Step 1 of 4
Gluten peptides meet a susceptible immune system
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 2 of 4
Lymphocytes attack the epithelium
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 3 of 4
Villi flatten and crypts deepen
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Consequences · Step 4 of 4
Malabsorption and its effects
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Symptoms and signs
Symptoms, signs and findings
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Exam detail
Exam detail
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Treatment
How treatment works
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Recap
Recap
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Self-check
Check your understanding
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .