Analysis of autoantibodies in the mechanism of the occurrence of multiple autoimmune endocrinopathies

我们建立了以酶联免疫吸附试验(ELISA)为筛选试验的抗垂体抗体(APA)检测方法，并对其临床应用进行了评价。以大鼠脑垂体细胞的可溶性部分为抗原，进行了与间接酶自身抗体类似的检测。用比色反应和450 nm处的吸光度计算截止指数(C.I值)。自身免疫性甲状腺疾病(桥本甲状腺炎Graves病)患者的ELISA/APA阳性率约为20%。另一方面，桥本甲状腺炎患者和Graves病患者分别有34%和28%的患者有阳性条带，与22 kDa的蛋白完全一致。进一步对与胰岛素依赖型糖尿病匹配的22 kDa蛋白进行蛋白质印迹分析，获得了22 kDa的蛋白，对该蛋白的氨基酸序列进行分析，得到N端侧的P-A-M-L-S-S-L-F-N-A-V-L-R。通过同源性分析，发现该匹配抗原与生长激素分子量完全相同，其他阳性条带的性质有待进一步研究。根据先前的报道，一些患有垂体性侏儒症和全垂体功能减退症的患者APA呈阳性。在这些观察的基础上，本研究提示APA的测定是多种自身免疫性内分泌疾病的有用指标。

We have established an assay method of antipituitary antibodies (APA) as a screening test, using enzyme-linked immunosorbent assay (ELISA) and evaluated on its clinical usefulness. The soluble fractions of rat pituitary cells were used as antigens of ELISA/APA.The assay, similar to that utilized indirect enzyme autoantibodies, was performed. The results by this assay method were calculated as the cut off index (C.I value), using colorimetric reaction and absorvance at 450 nm.Pathiens with autoimmune thyroid diseases (Hashimoto's thyroiditis Graves, disease) showed approximately 20% positive for ELISA/APA.On the other hand, 34% in Hashimoto's thyroiditis and 28% in Graves disease had a positive band by Western blot analysis, which was identical with 22 kDa protein. Furthermore, 39% in patients with insulin-dependent diabetes mellitus (IDDM) was positive for ELISA/APA,in which 64% in such patients was positive by Western blot analysis.We next analyzed 22 kDa protein ontained by Western blot method, which was one of matched antigens to APA.The analysis of amino acid sequence in this protein resulted in P-A-M-L-S-S-L-F-N-A-V-L-R from the N terminal side. Employing homology analysis, this matched antigens was found to be identical with molecular weight of somatotropin.Further studies are needed to determine the nature of other positive bands by Western blot analysis. As reported previously, some patients with pituitary dwarfism and panhypopituitarism showed positive APA.On the basis of these observations, the present study suggests that measurements of APA are a useful indicator of multiple autoimmune endocrinopathies.