Miyakawa H, Kikazawa E, Abe K, Kikuchi K, Fujikawa H, Matsushita M, Kawaguchi N, Morizane T, Ohya K, Kako M
Fourth Department of Internal Medicine, Teikyo University School of Medicine, Kawasaki-shi, Kanagawa, Japan.
Autoimmunity. 1999;30(2):107-14. doi: 10.3109/08916939908994768.
Anti-liver kidney microsome-1 (LKM-1) autoantibody, which is a serological marker for autoimmune hepatitis type II, recognizes Cytochrome P450 IID6 (CYP2D6). This autoantibody is also detected in a portion of patients with chronic hepatitis C. Anti-LKM-1 has been measured by indirect immunofluorescence (IF) using rat liver and kidney sections. However, this method has some problems in specificity and is so laborious to handle with many samples. In this study, in order to determine anti-LKM-1, we established an enzyme-linked immunosorbent assay (ELISA) for anti-CYP2D6 using a recombinant CYP2D6 fusion protein. We studied sera from 29 patients positive for anti-LKM-1 by the new ELISA. We further studied sera from a total of 301 patients with various liver diseases and 100 sera from normal controls negative for anti-LKM-1 by the new ELISA. The specificity of the ELISA was ascertained by absorption tests using sera positive for anti-LKM-1. In 29 sera from patients positive for anti-LKM-1 by IF, we found a good correlation between the logarithms of the antibody titers determined by IF and ELISA indexes obtained by our new method. Anti-CYP2D6 was positive in 12 of 12 (100%) patient with autoimmune hepatitis type II and 16 of 17(94.1%) with chronic hepatitis C positive for anti-LKM-1 by IF. In other 401 sera negative for anti-LKM-1 by IF, anti-CYP2D6 was all negative except a few sera. We established a new ELISA for anti-LKM-1 (anti-CYP2D6). This ELISA system is sensitive, antigen-specific and easy to be done. Therefore, this assay allows a routine test of many serum samples, especially for diagnosing autoimmune hepatitis type II.
抗肝肾微粒体-1（LKM-1）自身抗体是Ⅱ型自身免疫性肝炎的血清学标志物，可识别细胞色素P450 IID6（CYP2D6）。部分丙型肝炎患者也可检测到这种自身抗体。抗LKM-1已通过使用大鼠肝脏和肾脏切片的间接免疫荧光法（IF）进行检测。然而，该方法在特异性方面存在一些问题，处理大量样本时也很费力。在本研究中，为了检测抗LKM-1，我们使用重组CYP2D6融合蛋白建立了一种抗CYP2D6的酶联免疫吸附测定（ELISA）方法。我们用新的ELISA法研究了29例抗LKM-1阳性患者的血清。我们进一步研究了总共301例各种肝病患者的血清以及100例新ELISA法检测抗LKM-1阴性的正常对照血清。通过使用抗LKM-1阳性血清的吸收试验确定了ELISA的特异性。在29例IF法检测抗LKM-1阳性患者的血清中，我们发现IF法测定的抗体滴度对数与我们新方法获得的ELISA指数之间具有良好的相关性。在12例Ⅱ型自身免疫性肝炎患者中，12例（100%）抗CYP2D6呈阳性；在17例IF法检测抗LKM-1阳性的丙型肝炎患者中，16例（94.1%）抗CYP2D6呈阳性。在其他401例IF法检测抗LKM-1阴性的血清中，除少数血清外，抗CYP2D6均为阴性。我们建立了一种新的抗LKM-1（抗CYP2D6）ELISA方法。该ELISA系统灵敏、抗原特异性强且易于操作。因此，该检测方法可对许多血清样本进行常规检测，尤其适用于Ⅱ型自身免疫性肝炎的诊断。
