Prevalence and clinical features of selective immunoglobulin A deficiency in coeliac disease: An Italian multicentre study

Background - Selective immunoglobulin A (IgA) deficiency (SIgAD) is associated with coeliac disease (CD). Aims - To make a retrospective study of the association of SIgAD with CD in Italy. Methods - Hospital medical records of 2098 patients consecutively diagnosed as having CD were reviewed. Results - Of 2098 patients with CD, 54 (2.6%) had SIgAD, representing a 10-16-fold increase over that in the population in general. This increase was not influenced by age or geographical factors. Patients with SIgAD had a higher incidence of silent forms (7/54, 13%), recurrent infections (16/54, 29.6%), and atopic diseases (7154, 13%) than those without. The association with autoimmune and malignant diseases and the outcome after eating a gluten free diet were similar in patients with or without SIgAD. In all patients with SIgAD, antibodies for IgA gliadin and endomysium were absent, but serum levels of IgG anti-gliadin antibodies were high in almost all of them (51/54). Conclusions - Serum IgA should be measured in order to be able to interpret negative results for IgA anti-gliadin antibodies and anti- endomysial antibodies in patients being screened for CD. Since some patients with CD and SIgAD may be negative for IgG anti-gliadin antibodies, an intestinal biopsy should be performed in all suspected cases.