Characteristics of anti-TSH receptor antibodies in two patients who developed spontaneous hypothyroidism after antithyroid drug therapy for hyperthyroid Graves' disease.
Spontaneous hypothyroidism was developed in two patients with Graves' hyperthyroidism 1.8 or 1 years after antithyroid drug therapy. In these patients anti-thyrotropin (TSH) receptor antibodies were detected. Thyrotropin receptor antibody (TRAb) index measured with TSH radioreceptor assay was 61.0% in case 1 and 68.0% in case 2 (normal value: -10 to 10%), and human thyroid adenylate cyclase stimulating activities (HTACS) were 154% in case 1 and 190% in case 2 (normal value: 70 to 130%). IgG from case 1 suppressed the stimulating activity of bovine TSH (bTSH) on thyroid adenylate cyclase in low concentrations in vitro. These results indicate that a blocking type of anti-TSH receptor antibodies as well as concomitant chronic thyroiditis might be a causative factor in patients who developed spontaneous hypothyroidism shortly after the cessation of antithyroid drugs.
Kaise
K
K
Second Department of Internal Medicine, Tohoku University School of Medicine, Sendai.
Kaise
N
N
Yoshida
K
K
Itagaki
Y
Y
Yamamoto
M
M
Sakurada
T
T
Saito
S
S
Yoshinaga
K
K
D000262:Adenylyl Cyclases / Q000378:metabolism; D001323:Autoantibodies / Q000276:immunology*; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006111:Graves Disease / Q000188:drug therapy* / Q000276:immunology; D006801:Humans; D007037:Hypothyroidism / Q000276:immunology*; D007074:Immunoglobulin G / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011989:Receptors, Thyrotropin / Q000276:immunology*; D013961:Thyroid Gland / Q000201:enzymology; D013972:Thyrotropin / Q000494:pharmacology
D001323:Autoantibodies; D007074:Immunoglobulin G; D011989:Receptors, Thyrotropin; D013972:Thyrotropin; D000262:Adenylyl Cyclases