Could coeliac disease be caused by the patient injecting on the stomach? When the blood test shows weakly positive, why must a biopsy be done?

It is not biologically plausible that injecting into the abdominal skin is associated with coeliac disease and although almost none of our 400 patients inject there, we have several patients with coeliac disease. The association with diabetes is via the auto-immune mechanism of disease where the immune system – for reasons unknown – attacks ‘self’ cells. In coeliac disease the protein gluten is the catalyst but it is not understood what starts this process.

The presence of antibodies is only a screening test rather than providing a diagnosis, hence the need for a biopsy. The whole area of biopsies in patients with no symptoms has been controversial but undiagnosed coeliac disease can cause problems with growth, anaemia etc., and can, at least in theory, increase the long term risk of malignancy.

KJR