The possible contribution of anti-Gal to Graves' disease

Thyroid. 2005 Nov;15(11):1239-43. doi: 10.1089/thy.2005.15.1239.

Abstract

Anti-Gal is a natural antibody specific for the alpha-galactosyl epitope. Previous studies suggested that Graves' disease (GD) patients had elevated anti-Gal titers compared to normal controls, but titers returned to normal after treatment. We developed an anti-Gal enzyme-linked immunosorbent assay (ELISA) using the property of anti-Gal to bind tightly to mouse laminin. We found no significant correlations between anti-Gal and thyroidstimulating immunoglobulin (TSI) or free thyroxine (T(4)) in untreated hyperthyroid GD patients (n = 15) without clinical ophthalmopathy or euthyroid, previously treated GD patients with ophthalmopathy. There was a significant regression between TSI and free T(4) in the hyperthyroid patients (p < 0.01). Addition of total anti- Gal antibody to the regression showed a trend toward improved correlation (p = 0.15 for improved correlation relative to TSI and free T(4) alone), suggesting it may stimulate GD thyroid tissue. However, in contrast to previous studies we found hyperthyroid patients (n = 20) had lower levels of anti-Gal immunoglobulin G (IgG) (18.4 +/- 4.0 vs. 41.8 +/- 8.9) than normals (n = 36 p < 0.05). Interestingly, hyperthyroid patients without clinical ophthalmopathy tended to have lower IgG anti-Gal levels than euthyroid patients with ophthalmopathy (p = 0.1). Hyperthyroidism significantly lowers anti-Gal, but the possible increase of anti-Gal in patients with ophthalmopathy suggests anti-Gal may play a role in ophthalmopathy, or may reflect the euthryoid status of these patients. This trend needs further study.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Enzyme-Linked Immunosorbent Assay
  • Epitopes / genetics
  • Extracellular Matrix Proteins / metabolism
  • Graves Disease / genetics*
  • Humans
  • Immunoglobulin G / genetics
  • Immunoglobulin M / genetics
  • Laminin / metabolism
  • Thyrotropin / genetics
  • Thyroxine / genetics
  • Trisaccharides / genetics*

Substances

  • Epitopes
  • Extracellular Matrix Proteins
  • Immunoglobulin G
  • Immunoglobulin M
  • Laminin
  • Trisaccharides
  • alpha-galactosyl epitope
  • Thyrotropin
  • Thyroxine