Vitti P, Chiovato L, Fiore E, Mammoli C, Rocchi R, Pinchera A
Institute of Endocrinology, University of Pisa, Italy.
Acta Med Austriaca. 1996;23(1-2):52-6.
A clone of Chinese hamster ovary cells (CHO) transfected with the cDNA of the human thyrotropin (TSH) receptor (CHO-R) was used to optimise assays for TSH receptor antibodies with either thyroid stimulating (TSAb) or TSH blocking (TSH-blocking Ab) activity. The study group included 89 patients with Graves' disease, 38 patients with goitrous Hashimoto's thyroiditis (HT) and 47 subjects with atrophic thyroiditis (AT). In the HT group, 8 patients had subclinical hypothyroidism (HT-SH) and 30 had overt hypothyroidism (HT-H). In the assay for TSAb, CHO-R cells were incubated with 1mg/ml of the immunoglobulin G (IgG) from patients with Grave's disease, while in the assay for TSH-blocking Ab cells were incubated with IgGs from patients with HT or AT alone (1mg/ml), or IgGs plus TSH (10 mU/L). After 2 h of incubation the extracellular cAMP was measured by a RIA. In these conditions a significant stimulation by Graves' IgG was obtained in patients with active hyperthyroidism (33/35, 94% untreated; 21/23, 91% relapsed after a course of medical treatment), in 12/20 (60%) patients euthyroid under methimazole and in 4/11 (36%) euthyroid after a course of antithyroid drugs. TSH-blocking Ab were detected in 1/8 (12.5%) patients with HT-SH, in 7/30 (23.3%) with HT-H and in 16/47 (34.0%) patients with AT. TSAb and TSH-blocking Ab coexisted in 4 IgGs that belonged to patients in whom spontaneous hypothyroidism developed after hyperthyroidism, or viceversa. TSAb and TSH-blocking Ab were also tested on FTRL-5 cells. TSAb were positive in both assays in 43/58 (74%) patients with active Graves' disease, negative in both assays in 3 (5%), negative in FRTL-5 and positive in CHO-R in 11 (19%), negative in CHO-R and positive in FRTL-5 in 1 (1.7%). In FTRL-5 cells TSH-blocking Ab were detected in 1/8 (12.5%) patients with HT-SH, in 5/30 (16.6%) with HT-H and in 15/47 (31.9%) with AT. The results of cAMP stimulation in FRTL-5 and CHO-R showed a fairly good correlation in TSAb (r = 0.60, p < 0.0001) and in TSH-blocking Ab (r = 0.74, p < 0.0001) assays. In conclusion, CHO cells transfected with the cloned human TSH receptor are suitable for the clinical assay of TSAb and TSH-blocking Ab. The sensitivity of this assay is higher than that obtained using FRTL-5 cells, having the additional advantages of expressing the human TSH receptor and requiring less cumbersome procedures for cell culture.
用转染了人促甲状腺激素（TSH）受体cDNA的中国仓鼠卵巢细胞（CHO）克隆（CHO-R）来优化针对具有甲状腺刺激（TSAb）或TSH阻断（TSH阻断抗体）活性的TSH受体抗体的检测方法。研究组包括89例格雷夫斯病患者、38例甲状腺肿性桥本甲状腺炎（HT）患者和47例萎缩性甲状腺炎（AT）患者。在HT组中，8例患者为亚临床甲状腺功能减退（HT-SH），30例为显性甲状腺功能减退（HT-H）。在TSAb检测中，将CHO-R细胞与来自格雷夫斯病患者的1mg/ml免疫球蛋白G（IgG）孵育，而在TSH阻断抗体检测中，细胞分别与单独来自HT或AT患者的IgG（1mg/ml）或IgG加TSH（10 mU/L）孵育。孵育2小时后，通过放射免疫分析（RIA）测量细胞外cAMP。在这些条件下，活动性甲状腺功能亢进患者（33/35，94%未治疗；21/23，91%经一个疗程药物治疗后复发）、12/20（60%）接受甲巯咪唑治疗的甲状腺功能正常患者以及4/11（36%）经一个疗程抗甲状腺药物治疗后的甲状腺功能正常患者的格雷夫斯病IgG均产生了显著刺激。在1/8（12.5%）HT-SH患者、7/30（23.3%）HT-H患者和16/47（34.0%）AT患者中检测到TSH阻断抗体。TSAb和TSH阻断抗体在4份IgG中共存，这些IgG属于甲状腺功能亢进后发生自发性甲状腺功能减退或反之的患者。TSAb和TSH阻断抗体也在FTRL-5细胞上进行了检测。43/58（74%）活动性格雷夫斯病患者在两种检测中TSAb均为阳性，3例（5%）在两种检测中均为阴性，11例（19%）在FRTL-5检测中为阴性而在CHO-R检测中为阳性，1例（1.7%）在CHO-R检测中为阴性而在FRTL-5检测中为阳性。在FTRL-5细胞中，1/8（12.5%）HT-SH患者、5/30（16.6%）HT-H患者和15/47（31.9%）AT患者检测到TSH阻断抗体。FRTL-5和CHO-R中cAMP刺激的结果在TSAb检测（r = 0.60，p < 0.0001）和TSH阻断抗体检测（r = 0.74，p < 0.0001）中显示出相当好的相关性。总之，转染了克隆人TSH受体的CHO细胞适用于TSAb和TSH阻断抗体的临床检测。该检测的灵敏度高于使用FTRL-5细胞获得的灵敏度，还具有表达人TSH受体以及细胞培养程序不那么繁琐的额外优势。
