| Ringold et al., Los Angeles, CA, USA, found 99 twin pairs indicating a history of Graves' disease from a population of 13.726 twin pairs that responded to a written questionnaire. The pairwise concordance for GD was estimated at 17% in monozygotic (MZ) twins and 1.9% in dizygotic (DZ) twins. These results were in close agreement with those of a recent Danish twin registry report. GD/chronic thyroiditis concordance, in twins not concordant for GD, was observed in 17.2% of MZ twins vs. 2.1% in DZ twins. Concordance rates for GD/non-thyroidal autoimmune, in twins not concordant for GD, were 13.8% and 4.3% respectively. The authors state that the here reported concordance rates for GD in twin pairs are lower than from some other reports and suggest that apart from genetic factors, environmental factors may play a more substantial role in the etiology of GD. Furthermore, the results imply that thyroidal and non-thyroidal autoimmune diseases may share a common genetic substrate. Wallaschofski et al., Leipzig and Erfurt, Germany, studied thyrotropin binding inhibiting immunoglobulins (TBII), thyroid stimulating antibodies (TSAB), and thyrotropin stimulating blocking antibodies (TSBAB) in 64 patients with GD, at the time antithyroid drug treatment (given for 2 years) was stopped and 1 year later. Twenty-eight patients stayed in remission, whereas 36 patients were in a relapse. In patients in remission, there was a significant decrease in TSAB whereas TBII and TSBAB were not changed one year after discontinuation of drug treatment. Combined measurement of TSAB and TSBAB (loss of TSAB and transition of TSAB to TSBAB and vice versa) showed a higher prognostic significance for remission prediction (P = 0.0001) than measurement of TSAB alone. In relapsed patients no significant changes were seen in activities of the three parameters. Pegoraro et al., Sao Paulo, Brasil, measured IL-1 beta, soluble (s) IL-2R, IL-6, IL-8, and TNF-alpha in 31 patients with GD before and after 16-20 weeks of treatment with methimazole with or without L-T3 addition. In untreated GD, IL-1 beta, sIL-2R, and IL-6 were elevated (p < 0.001) while IL-8 and TNF-alpha were not. After restoring euthyroidism sIL-2R and TNF-alpha decreased significantly (p < 0.001 and p < 0.01 respectively) but no alteration was present with regard to IL-1 beta and IL-8. sIL-2R and IL-6 levels were positively correlated with serum T3, while this was only the case for sIL-2R with regard to serum free T4. The decrease of TNF-alpha was explained by a direct effect of methimazole. (Comment: The authors suggest that sIL-2R and IL-6 could be of clinical use in prediction of GD recurrence, however this hypothesis was not actually tested in this report.) Miyake et al., Kurume, Japan, measured velocity (V), pulsative index (PI), resistance index (RI), and flow volume (FV) of the superior thyroid artery, using colour pulse Doppler ultrasonography (CPDU) in 22 patients with Hashimoto's disease (HT), 4 patients with subacute thyroiditis (SAT), 16 patients with untreated GD (uGD), 23 patients with treated GD (tGD), and 15 healthy controls (C). Sixteen uGD were followed during treatment. V was significantly greater in uGD than in HT, SAT, and C. Positive correlations were found between V and FT3, FT4, TBII, and TSAB in uGD. PI showed significant correlations with FT3, FT4, TBII, and TSAB levels the same patients group. The authors conclude that CPDU may be of aid in the diagnosis of Graves' disease. (Comment: The technique may rather be useful in differentiating uGD from other causes of thyrotoxicosis.) Three reports were presented on the effect of antithyroid drugs (ATD) treatment on the subsequent efficacy of radioiodine therapy in GD. Andrade et al., Porto Allegre, RS, Brasil, prospectively pretreated 24 patients with Graves'disease with methimazole until euthyroidism and subsequently with I-131 and 24 GD patients with I-131 without pretreatment. In this randomized trial no differences between the two groups were present regarding age, gender, thyroid volume, 24h I-131 uptake, TRAb or basal thyroid hormone levels. Methimazole was stopped 4 days before I-131 administration. After one year no statistical difference between the two treatment groups was present with respect to persistent hyperthyroidism, euthyroidism or hypothyroidism. The authors suggest that methimazole pretreatment does not affect the efficacy of I-131 treatment. Asamoah et al., Providence, RI, USA, analyzed results of I-131 treatment in 161 patients (140 females) with Graves'disease. 17/161 Patients (12/140 females; 8%, and 5/21 males; 24%) needed a second dose. Mean goiter size of retreated patients versus non-retreated patients was 57.6 vs. 44.8 (p = 0.009). There was no significant difference with regard to mean age at the time of initial treatment between the two groups. Also pretreatment with ATD did not influence the efficacy of therapy. (Comment: Unfortunately the type of ATD used was not mentioned.) Santos et al., Campinas, SP, Brazil, evaluated 67 patients with GD, 3 and 6 months after I-131 treatment who were randomly assigned to pretreatment with propylthiouracil, methimazole, or no ATD. No differences between the three subgroups were present with regard to sex, age, thyroid weight and 24h I-131 thyroid uptake. Cure (eu- or hypothyroidism) was similar in methimazole group and no-ATD group being 72 and 75% respectively, whereas only 35% (p < 0.05) were cured of the propylthiourcil group. (Comment: Both abstracts are in favour of using methimazole if pre-treatment with ATD is desired. Another advantage of methimazole over propylthyouracil is its longer half-life.) |
