Epatocentro Ticino, 6900 Lugano, Switzerland.
Paediatric Liver, GI and Nutrition Centre, MowatLabs, King's College Hospital, Denmark Hill, London SE5 9RS, UK.
Eur J Intern Med. 2018 Feb;48:35-43. doi: 10.1016/j.ejim.2017.10.006. Epub 2017 Oct 19.
Serology is key to the diagnosis of autoimmune hepatitis (AIH). Clinicians need to be aware of which tests to request, how to interpret the laboratory reports, and be familiar with the laboratory methodology. If correctly tested, >95% of AIH patients show some serological reactivity. Indirect immunofluorescence on triple rodent tissue is recommended as first screening step, since it allows the detection of all liver-relevant autoantibodies, except for anti-soluble liver antigen (SLA) antibody, which needs to be detected by molecular based assays. The threshold of immunofluorescence positivity is a titer equal or exceeding 1/40, but for patients younger than 18years even lower titers are clinically significant. Anti-nuclear antibody (ANA) and/or anti-smooth muscle (SMA) antibody characterize type 1 AIH. ANA in AIH typically shows a homogeneous staining pattern on HEp2 cells, without any specific target antigen. Anti-SMA displays different staining patterns on indirect immunofluorescence: the vascular/glomerular (VG) and the vascular/glomerular/tubular (VGT) patterns are considered specific for AIH, whilst the V pattern can be found in a variety of diseases. Type 2 AIH, which is rare and affects mostly children/adolescents, is characterized by anti-liver kidney microsomal 1 and/or anti-liver cytosol 1 antibodies. The presence of anti-neutrophil cytoplasmic antibody (ANCA), particularly atypical p-ANCA (pANNA), points to the diagnosis of AIH, especially in absence of other autoantibodies. Since it is associated with sclerosing cholangitis and inflammatory bowel disease, these conditions have to be ruled out. The only antibody specific for AIH is anti-SLA, which is associated with a more severe disease course.
自身免疫性肝炎（AIH）的诊断关键在于血清学检查。临床医生需要了解应选择哪些检查，如何解读实验室报告，并熟悉实验室方法。如果检查正确，>95%的 AIH 患者会出现某种血清学反应。推荐使用三鼠组织间接免疫荧光法作为初步筛选步骤，因为它可以检测除抗可溶性肝抗原（SLA）抗体以外的所有与肝脏相关的自身抗体，后者需要通过分子基础检测来发现。免疫荧光阳性的阈值为滴度等于或超过 1/40，但对于 18 岁以下的患者，即使滴度较低也具有临床意义。抗核抗体（ANA）和/或抗平滑肌（SMA）抗体是 1 型 AIH 的特征。AIH 中的 ANA 通常在 Hep2 细胞上显示均匀染色模式，没有任何特定的靶抗原。抗 SMA 在间接免疫荧光中显示不同的染色模式：血管/肾小球（VG）和血管/肾小球/肾小管（VGT）模式被认为是 AIH 的特异性表现，而 V 模式可在多种疾病中发现。罕见且主要影响儿童/青少年的 2 型 AIH 的特征是抗肝微粒体 1 和/或抗肝胞浆 1 抗体。抗中性粒细胞胞质抗体（ANCA），特别是非典型 p-ANCA（pANCA）的存在提示 AIH 的诊断，特别是在没有其他自身抗体的情况下。由于它与硬化性胆管炎和炎症性肠病有关，因此必须排除这些情况。唯一针对 AIH 的抗体是抗 SLA，它与更严重的疾病过程有关。
