Blockmans D, Stevens E, Mariën G, Bobbaers H
Department of Internal Medicine, University Hospital, Leuven, Belgium.
Ann Rheum Dis. 1998 Mar;57(3):141-5. doi: 10.1136/ard.57.3.141.
To calculate the positive predictive value (ppv) of cytoplasmic antineutrophil cytoplasmic antibodies (c-ANCAs) and anti-proteinase 3 (PR 3) antibodies for Wegener's granulomatosis (WG) and to evaluate their association with other diseases.
The clinical files of all 94 patients who had a positive c- or perinuclear (p)-ANCA test, or both, in the laboratory of the University Hospital, Leuven between April 1995 and March 1996 and who attended the Internal Medicine Department of the hospital were retrospectively studied.
Of the 94 patients with ANCAs (fluorescence titre > or = 1/40), 57 were c-ANCA positive and 45 p-ANCA positive (eight were simultaneously c- and p-ANCA positive). Of the 57 c-ANCA positive patients, 23 had WG. The ppv for WG thus was 40%. This value did not increase by defining a higher threshold for a positive ANCA. There was not a good relation between ANCA titres and disease activity in the WG patients, nor was there a relation between anti-PR 3 antibody levels and WG disease activity. The ppv of anti-PR 3 antibodies for WG however was very high (85%). There was a positive correlation between the level of (hyper) gammaglobulinaemia and c-ANCA titres in those patients with final diagnoses not known to be associated with c-ANCA. Forty five patients had positive p-ANCAs. The largest group were those with inflammatory bowel disease (n = 20, of whom the majority had colitis ulcerosa or primary sclerosing cholangitis, or both); the great majority of these patients had no anti-myeloperoxidase antibodies. Vasculitis was present in eight patients, of whom two had WG (both were also c-ANCA positive).
There is a low ppv of c-ANCAs for WG, caused by a high percentage of PR 3 negative, positive c-ANCA determinations, possibly related to hypergammaglobulinaemia. Anti-PR 3 antibodies have a high ppv for WG. However, neither c-ANCA titre, nor the level of anti-PR 3 antibodies correlated with the activity of the disease.
计算胞浆型抗中性粒细胞胞浆抗体（c-ANCA）及抗蛋白酶3（PR3）抗体对韦格纳肉芽肿（WG）的阳性预测值（PPV），并评估它们与其他疾病的关联。
回顾性研究1995年4月至1996年3月在鲁汶大学医院实验室c-ANCA或核周型（p）-ANCA检测呈阳性或两者均呈阳性且在该医院内科就诊的所有94例患者的临床资料。
在94例ANCA阳性（荧光滴度≥1/40）患者中，57例c-ANCA阳性，45例p-ANCA阳性（8例同时c-ANCA和p-ANCA阳性）。在57例c-ANCA阳性患者中，23例患有WG。因此，WG的PPV为40%。通过设定更高的ANCA阳性阈值，该值并未增加。WG患者中ANCA滴度与疾病活动度之间无良好关系，抗PR3抗体水平与WG疾病活动度之间也无关系。然而，抗PR3抗体对WG的PPV非常高（85%）。在最终诊断与c-ANCA无关的患者中，（高）丙种球蛋白血症水平与c-ANCA滴度之间存在正相关。45例患者p-ANCA呈阳性。最大的一组是患有炎症性肠病的患者（n = 20，其中大多数患有溃疡性结肠炎或原发性硬化性胆管炎或两者皆有）；这些患者绝大多数没有抗髓过氧化物酶抗体。8例患者存在血管炎，其中2例患有WG（两者也均为c-ANCA阳性）。
c-ANCA对WG的PPV较低，这是由于PR3阴性但c-ANCA检测呈阳性的比例较高，可能与高丙种球蛋白血症有关。抗PR3抗体对WG具有较高的PPV。然而，c-ANCA滴度和抗PR3抗体水平均与疾病活动度无关。
