[Development of highly sensitive assays of antithyroid microsomal antibodies and their clinical application--solid type ELISA using the avidin-biotin system].
We have developed new type of ELISA using avidin-biotin (AB) system in measuring antithyroid microsomal antibody (AMA). In the first method, AMA was detected by biotinylated anti-IgG (Indirect AB-ELISA) and in the second AMA was detected by biotinylated microsome antigen (Sandwich AB-ELISA). In the both methods, avidin-peroxidase was then added and peroxidase activity remained on the wells of a microplate was measured. In the study of samples from patients with Graves' disease with negative MCHA test (n = 39) and normal controls (n = 19), Indirect AB-ELISA showed a higher OD492 in Graves' patients than normal controls (p less than 0.01), whereas Sandwich AB-ELISA did not. In the study of patients with chronic thyroiditis which was confirmed by fine needle aspiration biopsy, 7 out of 9 samples with negative MCHA test and all of 11 with weakly positive MCHA test were positive in the Indirect AB-ELISA. These studies demonstrated the superior sensitivity of Indirect AB-ELISA than the other methods. Then the samples from patients with various kinds of diseases and negative MCHA test were assessed using this method. Forty-eight in 60 cases (80.0%) of Graves' disease, 3 in 4 cases (75%) of chronic thyroiditis, 6 in 7 cases (85.7%) of simple goiter, 7 in 8 cases (87.5%) of thyroid cancer, 2 in 9 cases (22.2%) of thyroid adenoma and 1 in 6 cases (16.7%) of pituitary hypothyroidism showed AMA activity. Therefore, autoimmune phenomena are far more common in various thyroid diseases than it has been previously recognized.
Fourth Department of Internal Medicine, Saitama Medical School, Japan.
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Sakatsume
D001323:Autoantibodies / Q000032:analysis*; D001360:Avidin; D001710:Biotin; D004797:Enzyme-Linked Immunosorbent Assay; D006042:Goiter / Q000276:immunology; D006111:Graves Disease / Q000276:immunology; D006801:Humans; D008861:Microsomes / Q000276:immunology*; D013959:Thyroid Diseases / Q000276:immunology*; D013961:Thyroid Gland / Q000276:immunology*; D013964:Thyroid Neoplasms / Q000276:immunology; D013966:Thyroiditis / Q000276:immunology
D001323:Autoantibodies; D001360:Avidin; D001710:Biotin