J Korean Soc Endocrinol.  1994 Sep;10(3):229-241.

Changes in Thyrotropin Receptor Blocking Antibody after Antithyroid drug Administration to Patients with Atrophic Autoimmune Thyroiditis (Primary Myxedema)

• Kim SY
• Cho BY
• Lee HK
• Chung JH
• Koh CS
• Shin CS
• Kim WB

Abstract

It is well Known that antithyroid drug treatment of Graves' disease suppresses excessive thyroid hormone synthesis and causes a parallel decrease in serum thyroid autoantibody levels including thyroid stimulating antibodies(TSAb) in most patients suggesting the immunosuppressive or immunomodulating effects of antithyroid drugs. In the context of view that thyrotropin receptor blocking antibody may play an important pathogenetic role at least in some patients with primary myxedema(chronic atrophic autoimmune thyroiditis), antithyroid drug treatment in these patients might be beneficial to disease course. To evaluate the effect of antithyroid drug on the thyrotropin receptor blocking antibody levels, we serially measured thyrotropin-binding inhibitor immunoglobulins(TBII) and thyroid stimulation blocking antibodies(TSBAb) using FRTL-5 cells, antimicrosomal- and antithyroglobulin antibody activities in 7 patients with primary myedema who have blocking TSH receptor antibodies during 6 months of methimazole(MMI, 40mg/day) administration. TBII and TSBAb activities did not change after MMI, but one of them showed stepwise decrease and disappearance of TBII and TSBAb activities. Antimicrosomal- and antithyroglobulin antibody activities decreased significantly after 3 months of MMI administration in those patients. These results suggest a minimal effect of antithyroid drug treatment on the level of thyrotropin receptor blocking antibodies. Persistence of thyrotropin receptor blocking antibodies despite of the decrease in antimicrosomal and antithyroglobulin antibodies might suggest that blocking TSH receptor antibodies of primary myxedema is produced mainly in extrathyroidal tissue in contrast to the thyroid stimulating antibodies of Graves' disease. One patient, whose blocking antibody have disappeared after MMI treatment, is under observation to see if she will remain in remission of hypothyroidism.

MeSH Terms

Antibodies
Antibodies, Blocking
Antithyroid Agents
Graves Disease
Humans
Hypothyroidism
Immunoglobulins, Thyroid-Stimulating
Myxedema
Receptors, Thyrotropin*
Thyroid Gland
Thyroiditis, Autoimmune*
Thyrotropin*
Antibodies
Antibodies, Blocking
Antithyroid Agents
Immunoglobulins, Thyroid-Stimulating
Receptors, Thyrotropin
Thyrotropin