No evidence of increased anti-M3 muscarinic acetylcholine receptor autoantibodies in SSA-positive connective tissue disease patients

Hatipoğlu E., Mikkelsen J. H., Korsholm T., Hvid M., Deleuran B., Dahl M. L. N.

APMIS, vol.131, no.10, pp.552-555, 2023 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 131 Issue: 10
  • Publication Date: 2023
  • Doi Number: 10.1111/apm.13349
  • Journal Name: APMIS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, BIOSIS, CAB Abstracts, EMBASE, MEDLINE, Veterinary Science Database
  • Page Numbers: pp.552-555
  • Keywords: Anti-M3R, anti-SSA, connective tissue disease, immunology, muscarinic receptor type 3
  • Hacettepe University Affiliated: Yes


Anti-muscarinic type 3 receptor autoantibodies (M3R) and anti-SSA antibodies are both related to salivary secretion. The presence of M3R antibodies in Sjögren's syndrome is previously demonstrated; nevertheless, the relationship between the anti-SSA antibodies and M3R fragment antibodies, namely the N terminal, first, second, and third extracellular loops, remains to be elucidated. In this study, we analyzed the antibodies against the M3R epitopes in healthy controls and anti-SSA antibody-positive connective tissue disease patients through ELISA method. Antibodies against the first, second, and third extracellular loop (M3R211–230) were not increased in anti-SSA positive patients compared to healthy controls. Indeed, antibodies against the N terminal (M3R1–33) were found to be high in healthy controls. High levels of M3R1–33 in healthy controls are a novel original finding; further research is needed for the clinical significance. There is no significant difference between SSA-positive patients and healthy controls in terms of autoantibodies against the remainder of the linear M3R fragments.