The possible contribution of anti-Gal to Graves' disease.
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.
Fullmer
Joseph
J
Department of Neuroscience, University of Minnesota, Minneapolis, USA.
Lindall
Arnold
A
Bahn
Rebecca
R
Mariash
Cary N
CN
D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D006111:Graves Disease / Q000235:genetics*; D006801:Humans; D007074:Immunoglobulin G / Q000235:genetics; D007075:Immunoglobulin M / Q000235:genetics; D007797:Laminin / Q000378:metabolism; D013972:Thyrotropin / Q000235:genetics; D013974:Thyroxine / Q000235:genetics; D014312:Trisaccharides / Q000235:genetics*
D000939:Epitopes; D016326:Extracellular Matrix Proteins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007797:Laminin; D014312:Trisaccharides; C076569:alpha-galactosyl epitope; D013972:Thyrotropin; D013974:Thyroxine