Lindgren O, et al. - In this prospective observational study, researchers ascertained whether all patients treated with radioiodine respond with a release of TSH-receptor antibodies (TRAb), anti-thyroperoxidase (anti-TPO), and anti-thyroglobulin (anti-TG). For treatment with radioiodine, 131 Graves’ disease (GD) subjects were admitted. Before and 3 months after iodine-131 treatment, thyroid antibodies were measured. Between TRAb and anti-TPO, but not between TRAb and anti-TG, a significant positive association was observed. Findings revealed that radioiodine treatment causes an increase in thyroid antibodies, but not in all patients with GD. Responders varied in proportion and were affected by age, resulting in a stronger immune response at a younger age. There were, however, no additional smoking effects.