抗核抗体阴性并不意味着肌炎患者不存在自身抗体：抗细胞质抗体作为抗合成酶综合征筛查试验的作用。
A Negative Antinuclear Antibody Does Not Indicate Autoantibody Negativity in Myositis: Role of Anticytoplasmic Antibody as a Screening Test for Antisynthetase Syndrome.
作者信息
Aggarwal Rohit, Dhillon Namrata, Fertig Noreen, Koontz Diane, Qi Zengbiao, Oddis Chester V
机构信息
From the Division of Rheumatology and Clinical Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
R. Aggarwal, MD, MS, Division of Rheumatology and Clinical Immunology, University of Pittsburgh School of Medicine; N. Dhillon, MD, Division of Rheumatology and Clinical Immunology, University of Pittsburgh School of Medicine; N. Fertig, BS, Division of Rheumatology and Clinical Immunology, University of Pittsburgh School of Medicine; D. Koontz, BS, Division of Rheumatology and Clinical Immunology, University of Pittsburgh School of Medicine; Z. Qi, PhD, Division of Rheumatology and Clinical Immunology, University of Pittsburgh School of Medicine; C.V. Oddis, MD, Division of Rheumatology and Clinical Immunology, University of Pittsburgh School of Medicine.
出版信息
J Rheumatol. 2017 Feb;44(2):223-229. doi: 10.3899/jrheum.160618. Epub 2016 Dec 1.
OBJECTIVE
To evaluate the utility of anticytoplasmic autoantibody (anti-CytAb) in antisynthetase antibody-positive (anti-SynAb+) patients.
METHODS
Anti-SynAb+ patients were evaluated for antinuclear antibody (ANA) and anti-CytAb [cytoplasmic staining on indirect immunofluorescence (IIF)] positivity. Anti-SynAb+ patients included those possessing anti-Jo1 and other antisynthetase autoantibodies. Control groups included scleroderma, systemic lupus erythematosus, Sjögren syndrome, rheumatoid arthritis, and healthy subjects. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy of anti-CytAb, and ANA were assessed. Anti-CytAb and ANA testing was done by IIF on human epithelial cell line 2, both reported on each serum sample without knowledge of the clinical diagnosis or final anti-SynAb results.
RESULTS
Anti-SynAb+ patients (n = 202; Jo1, n = 122; non-Jo1, n = 80) between 1985-2013 with available serum samples were assessed. Anti-CytAb showed high sensitivity (72%), specificity (89%), NPV (95%), and accuracy (86%), but only modest PPV (54%) for anti-SynAb positivity. In contrast, ANA showed only modest sensitivity (50%) and poor specificity (6%), PPV (9%), NPV (41%), and accuracy (12%). Positive anti-CytAb was significantly greater in the anti-SynAb+ patients than ANA positivity (72% vs 50%, p < 0.001), and 81/99 (82%) ANA-negative patients in the anti-SynAb+ cohort had positive anti-CytAb. In contrast, the control groups showed high rates for ANA positivity (93.5%), but very low rates for anti-CytAb positivity (11.5%). Combining anti-CytAb or Jo1 positivity showed high sensitivity (92%) and specificity (89%) for identification of anti-SynAb+ patients.
CONCLUSION
Assessing patients for anti-CytAb serves as an excellent screen for anti-SynAb+ patients using simple IIF. Cytoplasmic staining should be assessed and reported for patients suspected of having antisynthetase syndrome and a negative ANA should not be used to exclude this diagnosis.
目的
评估抗细胞质自身抗体（抗CytAb）在抗合成酶抗体阳性（抗SynAb+）患者中的应用价值。
方法
对抗SynAb+患者进行抗核抗体（ANA）和抗CytAb[间接免疫荧光法（IIF）检测细胞质染色]阳性情况评估。抗SynAb+患者包括那些具有抗Jo1及其他抗合成酶自身抗体的患者。对照组包括硬皮病、系统性红斑狼疮、干燥综合征、类风湿关节炎患者及健康受试者。评估抗CytAb和ANA的敏感性、特异性、阳性预测值（PPV）、阴性预测值（NPV）及准确性。抗CytAb和ANA检测通过对人上皮细胞系2进行IIF法完成，两份报告均基于各血清样本，且不知晓临床诊断或最终抗SynAb结果。
结果
对1985年至2013年间有可用血清样本的抗SynAb+患者（n = 202；抗Jo1，n = 122；非抗Jo1，n = 80）进行评估。抗CytAb对抗SynAb阳性显示出高敏感性（72%）、特异性（89%）、NPV（9五%）及准确性（86%），但PPV仅为中等水平（54%）。相比之下，ANA仅显示出中等敏感性（50%）且特异性较差（6%）、PPV（9%）、NPV（41%）及准确性（12%）。抗SynAb+患者中抗CytAb阳性显著高于ANA阳性（72%对50%，p < 0.001），抗SynAb+队列中99例ANA阴性患者中有81例（82%）抗CytAb阳性。相比之下，对照组ANA阳性率较高（93.5%），但抗CytAb阳性率极低（11.5%）。联合抗CytAb或抗Jo1阳性对识别抗SynAb+患者显示出高敏感性（92%）和特异性（89%）。
结论
使用简单的IIF法评估患者的抗CytAb可作为抗SynAb+患者的优秀筛查方法。对于疑似抗合成酶综合征的患者，应评估并报告细胞质染色情况，且不应因ANA阴性而排除该诊断。
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