High Frequency of TGM3 Autoantibodies in Subjects Not Suffering from Dermatitis Herpetiformis

Presentation Number: SUN 412
Date of Presentation: April 2nd, 2017

Maribel Aranda Guillen*1, Leonie Versteegh2, Åsa Hallgren1, Daniel Eriksson3, Sophie Bensing4, Olle Kämpe1 and Nils Landegren5
1Centre for Molecular Medicine, Department of Medicine (Solna), Karolinska Institutet, Stockholm, Sweden, 2Centre for Molecular Medicine, Department of Medicine (Solna), Karolinksa Institutet, Stockholm, Sweden, 3Centre for Molecular Medicine, Dept. of Medicine (Solna), Karolinska Institutet, Stockholm, Sweden., 4Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden, 5Karolinska Institutet, Stockholm, Sweden

Abstract

Transglutaminases (TGM) consist of a nine-member family of enzymes that cross-link proteins through bonds between glutamic acid and lysine residues. TGM have been implicated as autoantigens in many autoimmune disorders. TGM2 and TGM6 are known autoantigens of celiac disease and gluten ataxia, respectively. TGM4 was recently described as a novel prostatic autoantigen in APS1 (Landegren, N., et al. Sci. Transl. Med., 2015). Analyses were done to investigate whether TGM1, TGM3 and TGM5 are autoantigens in different skin disorders. TGM3 is recognized as an autoantigen of dermatitis herpetiformis, however, while the results of performed analyses were negative for other cutaneous diseases, antibodies against TGM3 were found in 7% of healthy individuals. Thereby, we investigate the presence of autoantibodies anti-TGM3 in a population not suffering from dermatitis herpetiformis. A radio-ligand binding assay (RLBA) was performed using sera from 794 Addison’s disease patients without dermatitis herpetiformis. TGM3 antibodies were measured by immunoprecipitation, after being incubated with a radioactive TGM3 produced by in vitro transcription and translation. 108 out of 794 (13,6%) Addison’s patients were strongly positive for autoantibodies against TGM3. The reason for this remains unclear. Despite of being described as the specific autoantigen for dermatitis herpetiformis, we confirm the presence of TGM3 autoantibodies in healthy individuals and in patients with Addison’s disease not suffering from dermatitis herpetiformis. Further studies are needed to clarify the role of TGM3 in autoimmune mechanisms, since it could be a potential novel autoantigen.

 

Nothing to Disclose: MA, LV, ÅH, DE, SB, OK, NL