Is It Possible to Predict the Onset of Graves' Disease?

EDITORIAL

www.nature.com/clinicalpractice/endmet Is it possible to predict the onset of Graves’ disease? Nobuyuki Amino

Ideally, medicine enables us to prevent disease; It might be microsomes. Of the 71 of these antibody- failing that, it should allow us to detect and possible to positive women examined after preg- diagnose diseases at an early stage, and to nancy, 5 developed Graves’ disease. Hidaka stop them from progressing to a severe state. predict the et al. confirmed that all the women with post- Endocrine diseases are no exception to postpartum partum Graves’ disease had TRAb in early preg- these ideals. Autoimmune thyroid disease is onset of nancy that were detectable by highly sensitive a frequently observed illness (predominantly Graves’ bioassay. It might be possible, therefore, to affecting females), and hyperthyroid or hypo- disease, if predict the postpartum onset of Graves’ disease, thyroid conditions markedly disturb the quality if a sensitive enough assay for TRAb is used in of life. It is well established that hyperthyroidism a sensitive early pregnancy; however, cost-effectiveness of in Graves’ disease is induced by antibodies enough assay this approach should be considered. against the TSH receptor (TRAb) that stimulate is used in early Predicted cases of postpartum Graves’ the thyroid gland. Sensitive assay techniques pregnancy disease could, moreover, be prevented by for the detection of TRAb have been developed, short-term corticosteroid therapy initiated and these show a positive reaction in 99% of immediately after delivery, similar to the patients with Graves’ disease. In other auto- prevention of postpartum development of hypo- immune diseases, detection of the appropriate thyroidism (Tada H et al. [2003] Int J Endocrinol autoantibodies often predicts the clinical onset Metab 2: 48–54). Postpartum Graves’ disease of disease. Detection of TRAb before disease is estimated to account for around 20% of onset might similarly enable us to predict which all cases of Graves’ disease (including those patients are likely to develop Graves’ disease affecting males). Postpartum prevention could, and, therefore, allow intervention to prevent therefore, eliminate a significant proportion of disease onset. Graves’ disease, and serve as a good model Maternal thyroid dysfunction is commonly of prevention of postpartum onset of other observed after delivery because of post- autoimmune diseases. partum aggravation of subclinical autoimmune This procedure to predict disease could also thyroiditis, which exists in about 10% of adult apply to the prevention of Graves’ disease females. During pregnancy, immune reactions not related to pregnancy. In the subjects with are suppressed to avoid rejection of the fetus family history of autoimmune thyroid disease, (which has paternal antigens). After delivery, or other autoimmune diseases and/or goiter, however, immune reactions are enhanced screening for autoantibodies against thyroid compared with before pregnancy because of microsomes or peroxidase might be useful for the immune rebound mechanism; as a result, detection of subclinical autoimmune thyroid 5–10% of women develop various types of abnormalities. If subjects show positive reac- thyroid dysfunction postpartum. Around 5% N Amino is a tion, a second screening for TRAb might consultant physician of these women develop postpartum Graves’ be useful to detect the preonset of Graves’ at Kuma Hospital, disease. In New York, it was reported that in Center for Excellence disease. We should pay particular atten- parous women with Graves’ disease, 45% were in Thyroid Care, tion to subjects who have allergic rhinitis or diagnosed in the postpartum period (Benhaim Kobe 650–0011, Japan. those who are planning to have therapy with Rochester D and Davies TF [2005] Thyroid a gonadotropin-releasing-hormone analog, 15: 1287–1290). Hidaka Y et al. ([1994] Clin Competing interests since these factors can induce the onset of The author declared he has Endocrinol 41: 15–20) examined 3,405 consecu- no competing interests. Graves’ disease (Hidaka Y et al. [1996] Thyroid tive women early in pregnancy and found that 6: 349–351; Amino N et al. [2003] Thyroid 13: www.nature.com/clinicalpractice 7.7% of them had antibodies against thyroid doi:10.1038/ncpendmet0326 815–818).

NOVEMBER 2006 VOL 2 NO 11 NATURE CLINICAL PRACTICE ENDOCRINOLOGY & METABOLISM 589