Disappearance of Humoral Thyroid Autoimmunity after Complete Removal of Thyroid Antigens

2 September 2003 | Volume 139 Issue 5 Part 1 | Pages 346-351

Background: The development of antibodies to thyroid peroxidase, thyroglobulin, and thyroid-stimulating hormone (TSH) receptor is a main feature of autoimmune thyroid diseases.

Objective: To investigate whether complete removal of thyroid antigens results in the abatement of humoral thyroid autoimmunity.

Design: Retrospective chart review study of patients treated and monitored with a standard prospective protocol.

Setting: University hospital in Pisa, Italy, between 1976 and 1994.

Patients: 182 patients with differentiated thyroid carcinoma and serum antibodies to thyroid peroxidase, thyroglobulin, or TSH receptor due to coexistent clinical Hashimoto thyroiditis, Graves disease, or focal autoimmune thyroiditis.

Intervention: Total thyroidectomy and radioiodine treatment to ablate residual or metastatic thyroid tissue. Regular follow-up with iodine-131 whole-body scanning and serum thyroglobulin measurement. Mean follow-up (±SD) was 10.1 ± 4.1 years (range, 4 to 20 years).

Measurements: Serum antibodies to thyroid peroxidase, thyroglobulin, and TSH receptor.

Results: Thyroid peroxidase, thyroglobulin, and TSH-receptor antibodies progressively disappeared after the initial treatment. The median disappearance time was 6.3 years for thyroid peroxidase antibodies and 3.0 years for thyroglobulin antibodies. There was a statistically significant correlation between the disappearance of thyroid tissue and that of thyroid antibodies. The coexistence of Hashimoto thyroiditis or Graves disease with thyroid cancer did not modify the pattern of disappearance of thyroid antibody compared with patients with focal autoimmune thyroiditis.

Conclusions: Complete ablation of thyroid tissue with its antigenic components results in the disappearance of antibodies to all major thyroid antigens, thus supporting the concept that continued antibody production depends on the persistence of autoantigen in the body.

Editors' Notes Context Theoretically, removal of thyroid tissue takes away inciting antigens and halts antibody production in patients with autoimmune thyroid disease. Contribution This retrospective study from a university thyroid disease center describes 4- to 20-year follow-up of 182 patients with differentiated thyroid carcinoma and thyroid antibodies due to coexistent autoimmune thyroid disease. After thyroidectomy and radioiodine treatment, thyroid peroxidase, thyroglubulin, and thyroid-stimulating hormone–receptor antibodies gradually disappeared in most patients. Implications Gradual disappearance of antibodies suggests that extrathyroidal tissues contribute to antibody production but that continued antibody production depends on persistence of thyroid antigens. –The Editors

 

Author and Article Information

From Università di Pisa, Pisa, Italy; and Boston University School of Medicine, Boston, Massachusetts.

Drs. Chiovato and Latrofa contributed equally to this paper.

Grant Support: By the University of Pisa (Fondi d'Ateneo) and from the Ministero d'struzione, d'niversità e della Ricerca (MIUR), Rome, Italy.

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Aldo Pinchera, MD, Dipartimento di Endocrinologia e Metabolismo, Ortopedia e Traumatologia, Medicina del Lavoro, Università di Pisa, Ospedale di Cisanello, Via Paradisa 2, 56124 Pisa, Italy; e-mail, a.pinchera{at}endoc.med.unipi.it.

Current Author Addresses: Dr. Chiovato: Cattedra di Endocrinologia, Università di Pavia, U.O. di Endocrinologia, Fondazione Salvatore Maugeri I.R.C.C.S., Istituto di Pavia, Via Ferrata 8, 27100 Pavia, Italy.

Dr. Latrofa: Autoimmune Disease Unit, Cedars-Sinai Research Institute and University of California, Los Angeles School of Medicine, 8700 Beverly Boulevard, D-3057, Los Angeles, CA 90048.

Dr. Braverman: Department of Medicine, Section of Endocrinology, Diabetes and Nutrition, Boston Medical Center, 88 East Newton Street, Boston University School of Medicine, Boston, MA 02118.

Drs. Pacini, Capezzone, Pinchera, and Grasso: Dipartimento di Endocrinologia e Metabolismo, Ortopedia e Traumatologia, Medicina del Lavoro, Università di Pisa, Ospedale di Cisanello, Via Paradisa 2, 56124 Pisa, Italy.

Dr. Masserini: Dipartimento di Statistica e Matematica Applicata all'Economia, Università di Pisa, Via Ridolfi 10, 56100 Pisa, Italy.

Author Contributions: Conception and design: L. Chiovato, F. Latrofa, A. Pinchera.

Analysis and interpretation of data: L. Chiovato, F. Latrofa, A. Pinchera.

Drafting of the article: L. Chiovato, F. Latrofa, L.E. Braverman, A. Pinchera.

Critical revision of the article for important intellectual content: L. Chiovato, F. Latrofa, L.E. Braverman, A. Pinchera.

Final approval of the article: L. Chiovato, F. Latrofa, L.E. Braverman, A. Pinchera.

Provision of study materials or patients: L. Chiovato, F. Latrofa, F. Pacini, M. Capezzone, L. Grasso, A. Pinchera.

Statistical expertise: F. Latrofa, M. Capezzone, L. Masserini.

Obtaining of funding: A. Pinchera.

Administrative, technical, or logistic support: M. Capezzone.

Collection and assembly of data: F. Latrofa, M. Capezzone.