Small-bowel mucosal transglutaminase 2-specific IgA deposits in coeliac disease without villous atrophy: a prospective and randomized clinical study.

Objective In coeliac disease, autoantibodies directed against transglutaminase 2 are produced in small-bowel mucosa, and they have been found to be deposited extracellularly. The aim of this study was to investigate whether such mucosal IgA deposits are important in the diagnostic work-up of early-stage coeliac disease without small-bowel mucosal villous atrophy. Material and methods Forty-one adults suspected of coeliac disease owing to increased density of mucosal γδ+ intraepithelial lymphocytes but normal villous morphology were randomized to gluten challenge or a gluten-free diet for 6 months. Clinically and histologically verified gluten dependency was compared with existence of small-bowel mucosal transglutaminase 2-specific extracellular IgA deposits and (coeliac disease-type) HLA DQ2 and DQ8; 34 non-coeliac subjects and 18 patients with classical coeliac disease served as controls. Results Of the 41 patients, 5 in the challenge group and 6 in the gluten-free diet group were clinically gluten sensi...