Hirose Wataru, Uchiyama Takashi, Nemoto Asuka, Harigai Masayoshi, Itoh Kenji, Ishizuka Toshiaki, Matsumoto Mitsuyo, Yamaoka Kazue, Nanki Toshihiro
Hirose Clinic of Rheumatology, 2-14-7, Midori-cho, Tokorozawa city, Saitama, 359-1111, Japan.
Division of Respiratory Medicine, Fukujuji Hospital, Japan Anti-Tuberculosis Society, 3-1-24, Matsuyama, Kiyose city, Tokyo, 204-8522, Japan.
Arthritis Res Ther. 2015 Sep 28;17:273. doi: 10.1186/s13075-015-0787-y.
The aim of this study was to investigate the diagnostic performance of measuring antibodies to the glycopeptidolipid (GPL) core antigen specific to Mycobacterium avium complex (MAC) in patients with rheumatoid arthritis (RA).
We cross-sectionally investigated anti-GPL antibodies and radiographs of 396 patients with RA. A diagnosis of MAC pulmonary disease (MAC-PD) was made according to the criteria by the American Thoracic Society and the Infectious Diseases Society of America. Serum immunoglobulin A antibodies to MAC-specific GPL core antigen were measured by an enzyme immunoassay. All patients with RA with abnormal shadows on chest x-rays underwent chest computed tomography (CT). Bronchoscopy was performed on patients with negative cultures for MAC by expectorated sputum and positive CT findings compatible with MAC-PD.
Ten patients were newly diagnosed with MAC-PD. Eight individuals who already had diagnoses of MAC-PD at the time of enrollment and nineteen who had negative expectorated sputum cultures for MAC and positive CT images compatible with MAC-PD and who refused bronchoscopy were excluded from the following analysis. Anti-GPL antibodies were detected in 12 of 369 patients. Eight of the ten patients with MAC-PD and 4 of 359 patients without MAC-PD tested positive for the anti-GPL antibodies. The specificity and sensitivity were 99 % and 80 %, respectively. Positive and negative predictive values were 67 %, and 97 %, respectively. When we analyzed diagnostic performance of the antibodies in 57 patients with RA who had abnormal shadows on chest x-rays, the positive and negative predictive values were 100 %, and 96 %, respectively. Twelve patients underwent bronchoscopy. Bronchoalveolar lavage fluid (BALF) samples from six patients were positive for MAC, and BALF samples from the remainder were negative. Anti-GPL antibodies were detected in the sera of all six patients with positive results for MAC by BALF sampling, whereas the antibodies were not detected in the sera from the remainder with negative results for MAC by BALF sampling.
The measurement of anti-GPL antibodies is useful as a supplementary diagnostic tool for MAC-PD in patients with RA and may provide a new strategy, in combination with chest x-ray and CT, for differentiating MAC-PD from other pulmonary comorbidities in patients with RA.
本研究旨在调查检测类风湿关节炎（RA）患者中针对鸟分枝杆菌复合群（MAC）特异性糖肽脂（GPL）核心抗原的抗体的诊断性能。
我们对396例RA患者进行了抗GPL抗体和X线片的横断面研究。根据美国胸科学会和美国传染病学会的标准诊断MAC肺部疾病（MAC-PD）。采用酶免疫测定法检测血清中针对MAC特异性GPL核心抗原的免疫球蛋白A抗体。所有胸部X线有异常阴影的RA患者均接受胸部计算机断层扫描（CT）。对痰培养MAC阴性且CT表现符合MAC-PD但拒绝支气管镜检查的患者进行支气管镜检查。
10例患者新诊断为MAC-PD。8例在入组时已诊断为MAC-PD的患者以及19例痰培养MAC阴性且CT图像符合MAC-PD但拒绝支气管镜检查的患者被排除在以下分析之外。369例患者中有12例检测到抗GPL抗体。10例MAC-PD患者中有8例以及359例无MAC-PD患者中有4例抗GPL抗体检测呈阳性。特异性和敏感性分别为99%和80%。阳性预测值和阴性预测值分别为67%和97%。当我们分析57例胸部X线有异常阴影的RA患者中抗体的诊断性能时，阳性预测值和阴性预测值分别为100%和96%。12例患者接受了支气管镜检查。6例患者的支气管肺泡灌洗液（BALF）样本MAC检测呈阳性，其余患者的BALF样本检测呈阴性。通过BALF采样MAC检测结果为阳性的所有6例患者的血清中均检测到抗GPL抗体，而通过BALF采样MAC检测结果为阴性的其余患者的血清中未检测到该抗体。
抗GPL抗体检测作为RA患者MAC-PD的辅助诊断工具具有实用价值，并且与胸部X线和CT相结合，可能为鉴别RA患者的MAC-PD与其他肺部合并症提供一种新策略。
