Matli Venkata Vinod Kumar, Dies David F, Pandit Sudha, Wellman Gregory, Morris James D
Department of Internal Medicine, Christus Highland Medical Center, Shreveport, LA, USA.
Department of Gastroenterology and Hepatology, Christus Highland Medical Center, Shreveport, LA, USA.
Case Rep Gastroenterol. 2023 Jan 6;17(1):14-20. doi: 10.1159/000528437. eCollection 2023 Jan-Dec.
Antimitochondrial antibody-positive primary biliary cholangitis (AMA-pos PBC) is an autoimmune disorder in which monoclonal antibodies are produced against epitopes in the mitochondrial membranes of biliary epithelial cells, resulting in progressive nonsuppurative biliary cholangitis. Up to 5% of patients lack these autoantibodies, termed antimitochondrial antibody-negative (AMA-neg) PBC. Although a somewhat new variant of AMA-pos PBC, it is not an overlapping syndrome. Few studies to date have described this phenomenon. An 87-year-old woman was referred to our clinic with elevated serum alkaline phosphatase (714 U/L). She reported fatigue but no other symptoms. A physical examination revealed a benign lesion and bilateral lower extremity swelling secondary to lymphedema. The serological profile was significant for a high antinuclear antibody titer (>1:2,560) with a centromere pattern and negative for antimitochondrial antibody (AMA). The hepatitis panel was negative for viruses A, B, and C. Her serum immunoglobulin G level was 871 mg/dL (normal, <1,600 mg/dL). The rest of the serological tests, including anti-smooth muscle antibodies (ASMA) and anti-liver/kidney microsomal antibodies, were negative. Computed tomography of the abdomen and pelvis without contrast showed normal liver parenchyma and no acute intra-abdominal pathology. Histopathology indicated florid duct lesions. The background parenchyma showed no significant steatosis, and inflammatory changes were limited to the portal areas. Periodic acid-Schiff staining revealed intact hepatic parenchyma and architecture. The patient was diagnosed with AMA-neg PBC and responded well to ursodeoxycholic acid therapy. This case highlights the importance of recognizing AMA-neg PBC as a variant of AMA-pos PBC and differentiating between them. Autoimmune cholangitis is a vague and imprecise condition. All patients with AMA-negative PBC should be tested for other PBC-specific autoantibodies. Although the prognosis and bile duct damage and loss are worse in AMA-neg PBC for unknown reasons, treatment remains the same for both.
抗线粒体抗体阳性原发性胆汁性胆管炎（AMA-pos PBC）是一种自身免疫性疾病，其中针对胆管上皮细胞线粒体膜上的表位产生单克隆抗体，导致进行性非化脓性胆管炎。高达5%的患者缺乏这些自身抗体，称为抗线粒体抗体阴性（AMA-neg）PBC。尽管AMA-neg PBC是AMA-pos PBC的一种较新变体，但它不是重叠综合征。迄今为止，很少有研究描述这种现象。一名87岁女性因血清碱性磷酸酶升高（714 U/L）转诊至我们诊所。她自述疲劳，但无其他症状。体格检查发现良性病变及双侧下肢因淋巴水肿而肿胀。血清学检查显示抗核抗体滴度高（>1:2560）且呈着丝点型，抗线粒体抗体（AMA）阴性。肝炎病毒检测显示甲、乙、丙型肝炎病毒均为阴性。她的血清免疫球蛋白G水平为871 mg/dL（正常范围，<1600 mg/dL）。其余血清学检查，包括抗平滑肌抗体（ASMA）和抗肝肾微粒体抗体，均为阴性。腹部和盆腔非增强计算机断层扫描显示肝实质正常，无急性腹部病变。组织病理学显示有明显的胆管病变。背景实质无明显脂肪变性，炎症改变局限于门管区。过碘酸希夫染色显示肝实质和结构完整。该患者被诊断为AMA-neg PBC，对熊去氧胆酸治疗反应良好。该病例凸显了将AMA-neg PBC视为AMA-pos PBC的一种变体并加以鉴别的重要性。自身免疫性胆管炎是一种模糊且不精确的病症。所有AMA阴性PBC患者均应检测其他PBC特异性自身抗体。尽管原因不明，但AMA-neg PBC的预后、胆管损伤和丧失情况更差，两者的治疗方法相同。
