[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Gastrointestinal tract](https://durgical.com/en/general-pathology/areas/gi/) › Coeliac disease

# Coeliac disease

- Lesion

In genetically prone people, gluten from wheat, rye and barley triggers an immune attack that flattens the small-bowel lining.

Updated Nov 12, 2026

## Key points

- HLA-DQ2 in most patients and DQ8 in most of the rest; their absence almost excludes the disease.
- Biopsy from the second part of the duodenum or proximal jejunum.
- Histology: intraepithelial CD8 T lymphocytosis (the most sensitive sign), crypt hyperplasia, villous atrophy; plasma cells, mast cells and eosinophils in the lamina propria.
- Serology: IgA anti-TG2 (most sensitive), IgA anti-endomysial; IgG-based tests in IgA deficiency.
- Associations: dermatitis herpetiformis, type 1 diabetes, thyroiditis, Sjögren syndrome, IgA nephropathy, lymphocytic gastritis and colitis.
- Complications: iron deficiency, osteoporosis, infertility, enteropathy-associated T-cell lymphoma, small-bowel adenocarcinoma, refractory sprue.

## What it is

Coeliac disease is an immune enteropathy requiring three ingredients: gluten, HLA-DQ2 or DQ8, and tissue transglutaminase 2 (TG2). TG2 deamidates gluten peptides, making them bind tightly to DQ2 or DQ8 on antigen-presenting cells; gluten-specific CD4 T cells then produce interferon-γ and IL-21, and IL-15 from epithelium activates cytotoxic intraepithelial CD8 T cells that kill enterocytes. The result is loss of villi and malabsorption that reverses on a gluten-free diet.

## Step by step

- Gluten is digested into proline- and glutamine-rich peptides that resist further breakdown.
- TG2 deamidates glutamine to glutamic acid, giving the peptides a negative charge.
- Deamidated peptides bind HLA-DQ2 or DQ8 and activate gluten-specific CD4 T cells.
- CD4 T cells release IFN-γ and help B cells make anti-TG2 IgA.
- Epithelial IL-15 activates intraepithelial CD8 T cells, which kill enterocytes through NKG2D.
- Villi shorten while crypts proliferate to compensate: malabsorption.

## Marsh–Oberhuber grades, simplified

| Grade | Intraepithelial lymphocytes | Crypts | Villi |
| --- | --- | --- | --- |
| 0 | Normal | Normal | Normal |
| 1 (infiltrative) | Increased | Normal | Normal |
| 2 (hyperplastic) | Increased | Hyperplastic | Normal |
| 3a to 3c (destructive) | Increased | Hyperplastic | Partial, subtotal or total atrophy |

## Markers

- IgA anti-TG2
- IgA anti-endomysial
- HLA-DQ2/DQ8 (negative predictive)
- CD3/CD8 intraepithelial T cells

## Clinical notes

- Adults often present atypically: anaemia, fatigue, bloating; children with diarrhoea, distension and failure to thrive after gluten enters the diet.
- Intraepithelial lymphocytosis and villous atrophy are not specific (viral enteritis, drugs), so histology and serology go together.
- Symptoms returning despite strict diet raise concern for refractory sprue or lymphoma.

## Memory aid

Gluten, a gene (DQ2/8) and a glue enzyme (TG2): three Gs flatten the villi.

## Test yourself

Think of the answer, then tap the question to see it.

## What does tissue transglutaminase do in the pathogenesis of coeliac disease?

It deamidates gluten peptides, increasing their binding to HLA-DQ2 or DQ8 and their presentation to CD4 T cells; it is also the target of IgA autoantibodies.

## What is the most sensitive histological sign of coeliac disease?

Increased intraepithelial T lymphocytes, particularly in the villi.

## Which serological test is most sensitive for coeliac disease?

IgA antibodies against tissue transglutaminase.

## Which skin disease is associated with coeliac disease?

Dermatitis herpetiformis, an itchy blistering eruption.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/general-pathology/coeliac-disease/)

[More Pathology questions →](https://durgical.com/en/practice/?f=pathology)

## Elsewhere in DurgiPedia

- [Small intestine: villi, crypts, enterocytes, Paneth cells; duodenum vs jejunum vs ileum](https://durgical.com/en/histology/small-intestine-villi-crypts-enterocytes-paneth-cells-duodenum-vs-jejunum-vs-ile/)
- [HLA associations with disease](https://durgical.com/en/immunology/hla-associations-with-disease/)
- [Type IV hypersensitivity (delayed, T cells)](https://durgical.com/en/immunology/type-iv-hypersensitivity/)
- [Autoantibodies: the table to know](https://durgical.com/en/immunology/autoantibodies-the-table-to-know/)

## Connections

## Related 6

- [Malabsorption and diarrhoea](https://durgical.com/en/general-pathology/malabsorption-and-diarrhoea/)
- [Gastrointestinal lymphoma](https://durgical.com/en/general-pathology/gastrointestinal-lymphoma/)
- [Uncommon gastritis: eosinophilic, lymphocytic and granulomatous](https://durgical.com/en/general-pathology/uncommon-gastritis-eosinophilic-lymphocytic-and-granulomatous/)
- [Other colitis: microscopic, diversion, GVHD, drug](https://durgical.com/en/general-pathology/other-colitis-microscopic-diversion-gvhd-drug/)
- [Other enteropathies](https://durgical.com/en/general-pathology/other-enteropathies/)
- [Atrophy](https://durgical.com/en/general-pathology/atrophy/)

## Related conditions 7

- [Coeliac disease](https://durgical.com/en/conditions/coeliac-disease/)
- [Dermatitis herpetiformis](https://durgical.com/en/conditions/dermatitis-herpetiformis/)
- [Iron deficiency anaemia](https://durgical.com/en/conditions/iron-deficiency-anaemia/)
- [Non-Hodgkin lymphoma](https://durgical.com/en/conditions/non-hodgkin-lymphoma/)
- [Tropical sprue](https://durgical.com/en/conditions/tropical-sprue/)
- [Type 1 diabetes mellitus](https://durgical.com/en/conditions/type-1-diabetes-mellitus/)
- [Osteoporosis](https://durgical.com/en/conditions/osteoporosis/)

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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Celiac Disease](https://www.ncbi.nlm.nih.gov/books/NBK441900/) (StatPearls (NCBI Bookshelf), 2025); [Celiac disease - sprue: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/000233.htm) (MedlinePlus, US National Library of Medicine, 2025).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/general-pathology/coeliac-disease/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/coeliac-disease/