Glycosylation of sera thyroglobulin antibody in patients with thyroid diseases.
OBJECTIVE
Thyroglobulin antibody (TgAb) is an important autoantibody in thyroid diseases, which is a glycoprotein, predominantly of IgG class. Glycosylation of the IgG-Fc contributes to many effector functions exhibited by antibodies. The aim of our study was to investigate the glycosylation of sera TgAb in patients with different thyroid diseases.


METHODS
Sera from 146 patients were collected and divided into four groups: Hashimoto's thyroiditis (HT, n=90), Graves' disease (GD, n=20), papillary thyroid carcinoma (PTC, n=17), and PTC with histological lymphocytic thyroiditis (PTC-T, n=19). HT patients were further divided into euthyroidism and subclinical and overt hypothyroidism groups. Lectin-ELISAs were performed to detect the relative amount of core fucose, terminal galactose, and sialic acid on each TgAb respectively.


RESULTS
Among HT, GD, and PTC groups, HT patients had significantly lower core fucose content on TgAb than the other two groups; an increasing trend of sialylation was found in PTC sera (P=0.076) compared with HT groups. PTC-T patients had significantly higher sialylated TgAb than HT and GD patients, and no significant difference was found between PTC and PTC-T. There was no significant difference in the three carbohydrate residue contents on sera TgAb among HT subgroups. In all the patients, negative correlation was found between sialic acid content and TgAb IgG levels (r=-0.736, P<0.001).


CONCLUSIONS
Our study showed that glycosylation of sera TgAb varied in different thyroid diseases and it might be involved in pathogenesis of thyroid disorders.
Department of Endocrinology, Peking University First Hospital, Beijing 100034, People's Republic of China.
Lanlan
L
Zhao
Mingming
M
Liu
Ying
Y
Gao
Youyuan
Y
Huang
Guizhi
G
Lu
Yanming
Y
Gao
Xiaohui
X
Guo
Bingyin
B
She
D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D005260:Female; D006031:Glycosylation; D006801:Humans; D008297:Male; D008875:Middle Aged; D013954:Thyroglobulin / Q000097:blood / Q000276:immunology*; D013959:Thyroid Diseases / Q000097:blood / Q000276:immunology*; D013997:Time Factors; D055815:Young Adult
D001323:Autoantibodies; D015415:Biomarkers; D013954:Thyroglobulin