Lack of humoral response against Helicobacter pylori peptides homologous to human ZnT8 in Hashimoto’s thyroiditis patients

  • Speranza Masala University of Sassari, Sassari, Italy
  • Davide Cossu University of Sassari, Sassari, Italy
  • Magdalena Niegowska University of Sassari, Sassari, Italy
  • Giuseppe Mameli University of Sassari, Sassari, Italy
  • Daniela Paccagnini University of Sassari, Sassari, Italy
  • Leonardo A Sechi University of Sassari, Sassari, Italy
Keywords: zinc transporter 8, Hashimoto’s thyroiditis, Helicobacter pylori

Abstract

Introduction: The Helicobacter pylori (HP) reinfection rate seems to be higher in developing countries than in developed ones. An increased seroprevalence of HP has also been reported in patients with type 1 diabetes (T1D) and Hashimoto’s thyroiditis (HT). Mycobacterium avium subsp. paratuberculosis (MAP) has been linked to both T1D and HT. Quite a few lines of evidence indicate that autoantibodies against several epitopes belonging to human zinc transporter 8 (ZnT8) cross-recognize the homologous MAP3865c epitopes in both T1D and HT patients. HP may play a role in HT disease, most likely acting through a molecular mimicry mechanism that targets ZnT8 as reported for MAP and the two autoimmune diseases.

Methodology: An enzyme-linked immunosorbent assay (ELISA) has been developed for the detection of antibodies against several epitopes deriving from HP proteins, which are highly homologous to the immunodominant ZnT8 peptides previously identified: ZnT8178–186 and ZnT8186–194.

Results: None of the HP peptides tested were significantly recognized when the humoral responses of 92 HT patients and 91 healthy volunteers were analyzed.

Conclusions: These findings do not support a triggering role for HP (through ZnT8 mimicking) in HT. If a molecular mimicry phenomenon is taking place, it involves a different self-antigen. Moreover, the negative outcome of the experiments performed stresses the fact that sharing stretches of sequence homology is relevant, but not enough to trigger an antibody-mediated cross-recognition.

Published
2015-07-04
How to Cite
1.
Masala S, Cossu D, Niegowska M, Mameli G, Paccagnini D, Sechi LA (2015) Lack of humoral response against Helicobacter pylori peptides homologous to human ZnT8 in Hashimoto’s thyroiditis patients. J Infect Dev Ctries 9:631-634. doi: 10.3855/jidc.6284
Section
Original Articles