Thymus histology and concomitant autoimmune diseases in Japanese patients with muscle-specific receptor tyrosine kinase-antibody-positive myasthenia gravis.

Abstract

BACKGROUND AND PURPOSE:

The differences in the characteristics of thymus histology, coexisting autoimmune diseases and related autoantibodies between anti-muscle-specific receptor tyrosine kinase (MuSK)-antibody (Ab)-positive myasthenia gravis (MG) patients, and anti-acetylcholine receptor (AChR)-Ab-positive MG patients are not clearly defined.

METHODS:

The types of thymus histology, coexisting autoimmune diseases and associated Abs in 83 MuSK-Ab-positive patients nationwide were investigated and were compared with those in AChR-Ab-positive patients followed at our institute (n = 83). As for the autoantibodies associated with thymoma, titin Abs were measured.

RESULTS:

Thymoma was not present in any of the MuSK-Ab-positive patients but presented in 21 patients (25.3%) amongst the AChR-Ab-positive patients. Titin Abs were absent in MuSK-Ab-positive patients but positive in 25 (30.1%) of the AChR-Ab-positive patients. Concomitant autoimmune diseases were present in eight MuSK-Ab-positive patients (9.6%) amongst whom Hashimoto's thyroiditis and rheumatoid arthritis predominated, whereas 22 AChR-Ab-positive patients (26.5%) had one or more concomitant autoimmune diseases of which Graves' disease predominated.

CONCLUSIONS:

Differences in frequency of thymoma and thymic hyperplasia, coexisting autoimmune diseases and autoantibody positivity between MuSK-Ab-positive and AChR-Ab-positive MG were indicated, suggesting that, in contrast with AChR-Ab-positive MG, thymus does not seem to be involved in the pathogenic mechanisms of MuSK-Ab-positive MG.

• Authors: R Nakata, M Motomura, T Masuda, H Shiraishi, M Tokuda, T Fukuda, T Ando, T Yoshimura, M Tsujihata, A Kawakami
• Journal: European journal of neurology (Eur J Neurol) Vol. 20 Issue 9 Pg. 1272-6 (Sep 2013) ISSN: 1468-1331 [Electronic] England
• PMID: 23679930 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2013 The Author(s) European Journal of Neurology © 2013 EFNS.

Chemical References

• Autoantibodies
• Autoantigens
• Connectin
• Receptors, Cholinergic
• MUSK protein, human
• Receptor Protein-Tyrosine Kinases

Topics

• Adult
• Asian People
• Autoantibodies (blood, immunology)
• Autoantigens (blood, immunology)
• Autoimmune Diseases (complications)
• Connectin (immunology)
• Female
• Humans
• Male
• Middle Aged
• Myasthenia Gravis (complications, immunology, pathology)
• Radioimmunoassay
• Receptor Protein-Tyrosine Kinases (immunology)
• Receptors, Cholinergic (immunology)
• Thymoma (complications, pathology)
• Thymus Gland (pathology)
• Thymus Hyperplasia (complications, pathology)
• Thymus Neoplasms (complications, pathology)