title: Why no simple relationship between thyroid peroxidase activity-inhibiting immunoglobulins and thyroid function in autoimmune thyroid disease?
abstract: We have reported that some anti-thyroid peroxidase antibodies inhibit the activity of thyroid peroxidase in vitro. These thyroid peroxidase activity-inhibiting immunoglobulins seem to inhibit thyroid function in some patients, but the relationship between thyroid peroxidase activity-inhibiting immunoglobulins and thyroid function is not simple. We designed this study to explore this lack of a simple relationship. We stained immunoglobulin G deposits by immunofluorescence staining or the peroxidase-antiperoxidase method, and stained endogenous thyroid peroxidase activity by enzyme histochemistry in thyroid sections. When cryostat thyroid sections were incubated with thyroid peroxidase activity-inhibiting immunoglobulins, immunoglobulin G deposits were seen as lines of stain on the apical border and as intracellular staining, and endogenous thyroid peroxidase activity was inhibited. In paraffin-embedded thyroid sections from 5 Hashimoto's patients and 6 Graves' patients, immunoglobulin G deposits were not found on the apical border of the follicular epithelium. In frozen thyroid sections from 22 Graves' patients, no clear deposits of immunoglobulin G on this apical border were seen. In organ-cultured thyroid slices incubated with thyroid peroxidase activity-inhibiting immunoglobulins, endogenous thyroid peroxidase activity was not inhibited. In conclusion, thyroid peroxidase activity-inhibiting immunoglobulins may reach its antigen only with difficulty. This is one of the reasons why no simple relationship is observed between thyroid peroxidase activity-inhibiting immunoglobulins and thyroid function.
authors.affiliation: Second Department of Internal Medicine, Osaka City University Medical School, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Okamoto
authors.forename: N
authors.initials: N
authors.lastname: Hamada
authors.forename: T
authors.initials: T
authors.lastname: Fujisawa
authors.forename: J
authors.initials: J
authors.lastname: Noh
authors.forename: J
authors.initials: J
authors.lastname: Yamakawa
authors.forename: M
authors.initials: M
authors.lastname: Ohno
authors.forename: K
authors.initials: K
authors.lastname: Ito
authors.forename: H
authors.initials: H
authors.lastname: Morii
mesh_terms: D000941:Antigens / Q000276:immunology; D001323:Autoantibodies / Q000276:immunology / Q000502:physiology*; D001327:Autoimmune Diseases / Q000276:immunology / Q000503:physiopathology*; D046508:Culture Techniques; D004848:Epithelium / Q000276:immunology / Q000503:physiopathology; D005260:Female; D005455:Fluorescent Antibody Technique; D006111:Graves Disease / Q000276:immunology / Q000503:physiopathology; D006651:Histocytochemistry; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology / Q000378:metabolism; D007453:Iodide Peroxidase / Q000276:immunology / Q000378:metabolism*; D008297:Male; D013959:Thyroid Diseases / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology*; D013961:Thyroid Gland / Q000503:physiopathology*; D013967:Thyroiditis, Autoimmune / Q000276:immunology / Q000503:physiopathology
chemical_list: D000941:Antigens; D001323:Autoantibodies; D007074:Immunoglobulin G; C056626:thyroid microsomal antibodies; D007453:Iodide Peroxidase