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Issue: 2/1998
Author: J. Gerenova, Y. Vulkov, S. Boeva, K. Halacheva
Department of Internal Medicine, Medical Faculty Thracian University, StaraZagora- Bulgaria
Abstract:
It is the purpose of the study to assay the clinical relevance of antithyroid antibodies pres-ence, serum thyroglobulin (hTg) concentrations, and their changes in the course of methimazole (M) treatment in diagnozing and prognosticating Graves' disease (CD) patients from the region of Stara Zagora. Thyrotropin-receptor antibodies (TRAb), thyroid peroxidase antibodies (TPO Ab) and antibodies to thyroglobulin (TgAb) are mea-sured in 51 hyperthyroid patients with GB. Serum hTg concentrations are also evaluated in 39 pa-tients without TgAb.
Following M treatment over 12-24 months, the patients are retrospectively distributed in two groups depending on whether or not the remis¬sion after M treatment persists. Group A – 25 cases with remission after M treatment, and group В -26 cases presenting relapses within 15 months of its suspension. Patients are studied prior to treat¬ment (IA, IB), at 6 months after the beginning of therapy (HA, IIB), and 2 months after M therapy discontinuation (IIIA, IIIB).
During the active hyperthyroid stage of GD, 76,5% of the patients under study are positive for TRAb, 86,3% – for TPO Ab, and 43,1 % – for TgAb; 43,6% are with serum hTg values > 75 ng/ ml. There is no statistically significant difference between IA and IB groups in terms of the param¬eters being examined. In group IB the percentage ofantiTg-positive patients is statistically significantly higher. The patients in group IIIB show statistically significantly higher serum levels of the parameters under study relative to group IIIA. Two months af¬ter suspending the antithyroid drug, serum hTg> 75 ng/ml and TRAb > 30 U/I show sensitivity 60 % and 42,3% respectively, and 100% specificity for both parameters. TgAb and TPO Ab levels have good specificity, but low sensitivity.
In conclusion, the obtained data demonsrtate that the presence of TRAb or TPO Ab is sufficient to confirm the autoimmune character of GD hyperthyroidism. For financial (cost-effec¬tive) reasons measurement of TPO Ab only may be used in practice. In patients presenting relapses and in those with early remission the dynamic patterns of changes in antithyroid antibodies and serum hTg after 6-month-long M therapy are different. At ter¬mination of thyrostatic therapy and after its dis¬continuation, the serum levels of hTg > 75 ng/ml and TRAb > 30 U/I are accepted as markers pre-dicting GD recurrence.
Keywords: Graves' disease, antithyroid antibodies, serum thyroglobulin, remission, relapse.
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