Microscopic enteritis: novel prospect in coeliac disease clinical and immuno-histogenesis. Evolution in diagnostic and treatment strategies.

The diagnosis of coeliac disease has traditionally depended on symptoms and intestinal biopsies; nowadays, the diagnosis has been expanded to include an array of serological markers and subtle microscopic lesions. The most important advance in classifying mucosal lesions in coeliac disease was forwarded by Marsh (1992), who provided the biological explanation of how the small bowel reacts to a variety of environmental antigenic challenges including gluten. In the modified version of this classification (Arnhem 1998-1999) autoantibodies have integrated into Marsh's histopathological scheme. As a large part of the coeliac 'iceberg' remains unrecognised, the difficulties in diagnosis continue to challenge clinicians and researchers. Advances in immuno-histochemistry and discovery of the other sensitive markers have acquainted us with so-called Microscopic enteritis, the distinctive subtle abnormalities behind the atypical gluten sensitivity symptoms that often remain unrecognised. Current diagnostic pathways do not always include facilities for looking for this common histological feature in atypical cases. This is essential since improving of the detection rate has been shown to be directly proportional to recognition of cases with milder or minimal mucosal abnormalities. In this revision, we will define and characterise microscopic enteritis as the entity behind a wide range of unexplained gastrointestinal symptoms. Screening for this subtle and distinctive presentation in small bowel pathology will open a new prospect in recognising the most common but unrecognised atypical forms of symptomatic gluten related enteropathies.