Edgar J D, McMillan S A, Bruce I N, Conlan S K
Department of Immunology, Queen's Medical Centre, Nottingham, UK.
Postgrad Med J. 1995 Oct;71(840):605-12. doi: 10.1136/pgmj.71.840.605.
We have reviewed the medical records of 301/327 consecutive patients in whom anti-neutrophil cytoplasmic antibodies (ANCA) were detected by the Regional Immunology Laboratory in Northern Ireland between January 1988 and October 1991 (45 months). We have collected data for each patient regarding age, sex, smoking habit, area of residence, and details of any other autoantibody activity. Clinical diagnosis was established, with the number of organ systems involved and the evidence for that involvement (symptomatic, biochemical, radiological, and histological). Diagnoses were divided into four groups according to their recognised vasculitic features and these were related to the pattern of immunofluorescence and maximum ANCA titre detected. The most frequent diagnosis was rheumatoid arthritis (18.2% of patients) and the connective tissue disorders as a whole accounted for 27.9% of patients. ANCA were also detected in a wide range of clinical conditions which are not associated with vasculitis and these patients were an important source of 'false-positives'. The positive predictive value (PPV) of ANCA of all patterns and titres for vasculitic conditions was 27%, however, the detection of a classical ANCA pattern at high titre (> or = 1:640) was associated with an increased PPV of 75%. The coexistence of an antinuclear antibody (ANA) reduces the PPV of both classical and perinuclear ANCA, although perinuclear ANCA with antimyeloperoxidase specificity had an improved PPV. We conclude that ANCA testing should not be used as the only screening investigation for vasculitis but should be included in a rational investigative scheme. The interpretation of a positive ANCA result must take into account the presence of other autoantibodies and the full range of non-vasculitic conditions when the clinical situation is not typical of vasculitis.
我们回顾了1988年1月至1991年10月（45个月）期间，北爱尔兰地区免疫实验室检测出抗中性粒细胞胞浆抗体（ANCA）的327例连续患者中的301例的病历。我们收集了每位患者的年龄、性别、吸烟习惯、居住地区以及任何其他自身抗体活性的详细信息。确立了临床诊断，包括受累器官系统的数量以及受累证据（症状、生化、放射学和组织学）。根据公认的血管炎特征将诊断分为四组，并将这些与检测到的免疫荧光模式和最大ANCA滴度相关联。最常见的诊断是类风湿关节炎（占患者的18.2%），结缔组织疾病总体占患者的27.9%。在一系列与血管炎无关的临床病症中也检测到了ANCA，这些患者是“假阳性”的重要来源。所有模式和滴度的ANCA对血管炎病症的阳性预测值（PPV）为27%，然而，检测到高滴度（≥1:640）的经典ANCA模式与PPV增加至75%相关。抗核抗体（ANA）的共存会降低经典和核周ANCA的PPV，尽管具有抗髓过氧化物酶特异性的核周ANCA的PPV有所改善。我们得出结论，ANCA检测不应作为血管炎的唯一筛查检查，而应纳入合理的检查方案中。当临床情况不典型为血管炎时，对阳性ANCA结果的解释必须考虑其他自身抗体的存在以及所有非血管炎病症。
