Prevalence and Clinical Features of Selective Immunoglobulin A Deficiency in Coeliac Disease: an Italian Multicentre Study. Italian Society of Paediatric Gastroenterology and Hepatology (SIGEP) and "Club Del Tenue" Working Groups on Coeliac Disease

Background: Selective immunoglobulin A (IgA) deficiency (SIgAD) is associated with coeliac disease (CD).

Aim: 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 (7/54, 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.