Romaldini J H, Biancalana M M, Figueiredo D I, Farah C S, Mathias P C
Department of Endocrinology, Hospital do Servidor Publico Estadual-IAMSPE, São Paulo, Brazil.
Thyroid. 1996 Jun;6(3):183-8. doi: 10.1089/thy.1996.6.183.
The changes in the serum thyroid autoantibodies, antithyroglobulin (TgAb) and antithyroid-peroxidase (TPOAb), lipid profile, and thyroid volume following L-thyroxine (L-T4) therapy is still a controversial matter. We studied 23 patients with goiter due to Hashimoto's thyroiditis; 10 had clinical hypothyroidism (CH) and 13 had subclinical hypothyroidism (SH). Both groups received L-T4 (2.0 to 2.5 micrograms/kg/day) for a median period of 6 months. Serum concentration of TgAb (normal value: < 200 mUI/mL) and TPOAb (normal value: < 150 mUI/mL) were measured by a sensitive IRMA using 125I protein-A. Thyroid volume was determined by ultrasound (normal value: 8-14 mL). At the end of the observation period the median serum TSH concentration decreased significantly in both groups (42.9 to 0.55 in CH and 2.4 to 0.74 mU/L in SH patients) and serum FT4I levels increased only in the CH group (0.87 to 2.1; p < 0.05). Serum TgAb concentration did not change in SH patients (72 to 218 mUI/mL) but declined in CH patients (364.5 to 75 mU/mL; p < 0.05). TPOAb levels also fell in the CH group (871 to 194 mUI/mL; p < 0.05) and no significant change was noted in SH patients (260 to 116 mUI/mL). Further, a significant correlation was obtained between TSH and either TPOAb concentration (rs = 0.569, p < 0.01) or thyroid volume (rs = 0.488, p < 0.05) in the CH group but not in SH patients (rs = 0.232, NS). LDL-cholesterol was higher in the CH (159.4 mg/dL) compared with the SH group (116 mg/dL). Moreover, only in the CH patients was there a significant fall in total cholesterol (224.5 to 165.5 mg/dL, p < 0.05) and in LDL-cholesterol (159.4 to 104.3 mg/dL, p < 0.05) values. The thyroid volume decreased in all patients with CH and in 77% (10/13) of SH patients and a significant median in the thyroid volume decrease was found (39.7% of initial volume in the CH group and 80.9% in SH patients; p < 0.01). The influence of L-T4 on both thyroid autoantibody levels and thyroid volume might be explained by reduction of antigenic substance through a decreased stimulation of thyroid tissue by circulating TSH as was seen in CH but not in SH patients. The benefits of the administration of L-T4 replacement therapy in SH patients due to Hashimoto's thyroiditis remain to be clarified.
左甲状腺素（L-T4）治疗后血清甲状腺自身抗体、抗甲状腺球蛋白（TgAb）和抗甲状腺过氧化物酶（TPOAb）、血脂谱以及甲状腺体积的变化仍是一个有争议的问题。我们研究了23例桥本甲状腺炎所致甲状腺肿患者；其中10例有临床甲状腺功能减退（CH），13例有亚临床甲状腺功能减退（SH）。两组均接受L-T4（2.0至2.5微克/千克/天）治疗，中位疗程为6个月。采用125I蛋白A的灵敏免疫放射分析（IRMA）法测定血清TgAb（正常值：<200 mUI/mL）和TPOAb（正常值：<150 mUI/mL）浓度。通过超声测定甲状腺体积（正常值：8 - 14 mL）。观察期末，两组患者血清促甲状腺激素（TSH）中位浓度均显著下降（CH组从42.9降至0.55，SH组从2.4降至0.74 mU/L），且仅CH组血清游离甲状腺素指数（FT4I）水平升高（从0.87升至2.1；p<0.05）。SH患者血清TgAb浓度无变化（从72升至218 mUI/mL），而CH患者血清TgAb浓度下降（从364.5降至75 mU/mL；p<0.05）。CH组TPOAb水平也下降（从871降至194 mUI/mL；p<0.05），SH患者无显著变化（从260降至116 mUI/mL）。此外，CH组TSH与TPOAb浓度（rs = 0.569，p<0.01）或甲状腺体积（rs = 0.488，p<0.05）之间存在显著相关性，而SH患者中无此相关性（rs = 0.232，无显著性差异）。CH组低密度脂蛋白胆固醇（159.4 mg/dL）高于SH组（116 mg/dL）。此外，仅CH患者的总胆固醇（从224.5降至165.5 mg/dL，p<0.05）和低密度脂蛋白胆固醇（从159.4降至104.3 mg/dL，p<0.05）值有显著下降。所有CH患者及77%（10/13）的SH患者甲状腺体积减小，且甲状腺体积减小中位数显著（CH组为初始体积的39.7%，SH患者为80.9%；p<0.01）。L-T4对甲状腺自身抗体水平和甲状腺体积的影响可能是由于循环TSH对甲状腺组织的刺激减少，从而使抗原物质减少，这在CH患者中可见，但在SH患者中未见。桥本甲状腺炎所致SH患者给予L-T4替代治疗的益处仍有待阐明。
