Pathology

The hallmark of coeliac disease is morphological changes in the small intestinal mucosa. These are most severe proximally, and become progressively less marked distally.

The primary mucosal lesion is partial or subtotal villous atrophy with compensatory crypt hyperplasia. Atrophy is due to premature enterocyte destruction. At first, the villi are replaced by short ridges - partial villous atrophy; later, the mucosa becomes completely flat - subtotal villous atrophy. Enterocyte damage may precede any change in villous architecture. The crypts (of Lieberkuhn) are elongated and show pronounced mitotic activity.

Other notable features include:

• increased prominence of intra-epithelial lymphocytes
• leukocytic infiltration of lamina propria - mainly, of plasma cells, but also, neutrophils, eosinophils, and macrophages

A comparable histological picture is seen in:

• tropical sprue except that the lesions tend to be more mild and more widely distributed throughout the small intestine
• immune-deficient enteropathy, e.g. HIV, IgA deficiency or hypogammaglobulinaemia