Binding by serum IgA antibodies from patients with coeliac disease to monkey heart tissue

Background: The recently reported increased prevalence of coeliac disease in heart transplant candidates and in patients with autoimmune myocarditis may suggest an autoimmune process towards antigenic components of both myocardium and small bowel. The objective of this study was to determine the possible presence of IgA antibodies directed against heart tissue in sera from patients with coeliac disease. Methods: Sera samples from 28 biopsy- proven coeliac disease patients and 81 controls ( both healthy and diseased) were assessed by indirect immunofluorescence, with fluorescein isothiocyanate labelled rabbit anti- human IgA, on commercial monkey cardiac muscle sections. Results: A strong fluorescence around heart muscle fibres was found in 13 out of 15 untreated patients but none in either those treated for coeliac disease or in controls. Pretreatment with tissue transglutaminase, a prominent coeliac auto- antigen, abolished the typical fluorescent pattern almost completely. Conclusions: Our study demonstrates that in untreated coeliac disease there is a reaction of IgA antibodies sera, yielding a strong fluorescence, with monkey heart structures, and that tissue transglutaminase is the target antigen in this reaction.