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An antibody that depletes B lymphocytes may induce prolonged remissions in patients with hyperthyroidism caused by Graves’ disease
The background of the study. The cause of hyperthyroidism in patients with Graves’ disease is thyrotropin (TSH) receptor-stimulating antibodies (TRAb). The production of these antibodies is initiated by activation of lymphocytes (a type of blood cell) and their conversion into antibody-producing cells. These lymphocytes have a surface marker, CD20, and administration of the anti-CD20 antibody rituximab causes depletion of these cells and improvement in patients with rheumatoid arthritis and related disorders. This study was done to evaluate the effect of rituximab in patients with Graves’ hyperthyroidism.
How the study was done. The study subjects were 20 patients with Graves’ hyperthyroidism, as defined by high serum free thyroxine (T4), low serum TSH concentrations, high serum TRAb concentrations, and goiter. Ten patients were treated and the other 10 served as a control group. The patients in the rituximab group were treated with methimazole and rituximab, and the 10 patients in the control group were treated with methimazole.
The primary outcome was recurrent hyperthyroidism after cessation of methimazole.
The results of the study. All the patients became euthyroid while taking methimazole. The mean serum TRAb concentrations in the two groups were similar at base line, when rituximab was added, and when methimazole and rituximab were stopped.
The duration of methimazole therapy and total dose of methimazole were similar in the rituximab-treated patients who remained euthyroid and those who had recurrent hyperthyroidism. One year after treatment was stopped, four patients (40 percent) in the rituximab group remained euthyroid, and they had normal thyroid function after 435, 666, 743, and 904 days, as compared with only one patient (10 percent) in the control group.
The conclusions of the study. Rituximab, an antibody that depletes lymphocytes, may induce more prolonged remissions of Graves’ hyperthyroidism when added to methimazole therapy than methimazole alone.
The original article. El Fassi D, Nielsen CH, Bonnema SJ, Hasselbalch HC, Hegedus L. B lymphocyte depletion with the monoclonal antibody rituximab in Graves’ disease: a controlled pilot study. J Clin Endocrinol Metab 2007;92:1769-72.
 Next Article: Surgical removal of bone surrounding the eyes has long-term benefits in patients with Graves’ eye disease |
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| Thyroid Digest Index | | | July 2007 Thyroid Digest |
