Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark.
Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark; Cystic Fibrosis Center Copenhagen, Rigshospitalet, Copenhagen, Denmark.
J Cyst Fibros. 2019 Jul;18(4):516-521. doi: 10.1016/j.jcf.2018.11.011. Epub 2018 Nov 29.
Early signs of Mycobacterium avium complex pulmonary disease can be missed in patients with cystic fibrosis due to subclinical infection or delays in mycobacterial culture. The aim of this study was to determine the diagnostic accuracy of a novel enzyme linked immunosorbent assay for immunoglobulin G against Mycobacterium avium complex, which could help stratify patients according to risk.
A retrospective cross sectional analysis of serum samples from the Copenhagen Cystic Fibrosis Center was performed. Corresponding clinical data were reviewed and patients with cystic fibrosis were assigned to one of four groups based on their mycobacterial culture results. In addition, anti-Mycobacterium avium complex immunoglobulin G levels were measured longitudinally before and after first positive culture in the period 1984-2015.
Three-hundred and five patients with cystic fibrosis were included with a median of five nontuberculous mycobacterial cultures. Four individuals had Mycobacterium avium complex pulmonary disease at the time of cross sectional testing and their median antibody level was 22-fold higher than patients with no history of infection (1820 vs. 80 IgG units; p < 0.001). Test sensitivity was 100% (95% CI 40-100) and specificity 77% (95% CI 72-81). Longitudinal kinetics showed rising antibodies prior to first positive culture suggesting diagnostic delay.
Antibody screening for Mycobacterium avium complex may be used as a supplement to culture. Although confirmation in a larger cohort is needed, our findings suggest that stratifying a cystic fibrosis population into high- and low-risk groups based on antibody levels may help clinicians identify patients in need of more frequent culture.
由于无症状感染或分枝杆菌培养延迟，囊性纤维化患者的鸟分枝杆菌复合体肺病的早期迹象可能会被漏诊。本研究旨在确定一种针对鸟分枝杆菌复合抗体 IgG 的新型酶联免疫吸附试验的诊断准确性，该试验可帮助根据风险对患者进行分层。
对哥本哈根囊性纤维化中心的血清样本进行回顾性横断面分析。回顾了相应的临床数据，并根据分枝杆菌培养结果将囊性纤维化患者分为四组之一。此外，在 1984 年至 2015 年期间，在首次分枝杆菌培养阳性前后对患者进行了纵向抗鸟分枝杆菌复合 IgG 水平测量。
共纳入 305 例囊性纤维化患者，平均有 5 次非结核分枝杆菌培养。在横断面检测时，有 4 例患者患有鸟分枝杆菌复合体肺病，其抗体水平中位数比无感染史的患者高 22 倍（1820 与 80 IgG 单位；p < 0.001）。试验敏感性为 100%（95%CI 40-100），特异性为 77%（95%CI 72-81）。纵向动力学研究显示，在首次分枝杆菌培养阳性之前抗体水平升高，提示存在诊断延迟。
鸟分枝杆菌复合抗体筛查可作为培养的补充。尽管需要在更大的队列中进行确认，但我们的研究结果表明，根据抗体水平将囊性纤维化人群分层为高风险和低风险组可能有助于临床医生识别需要更频繁培养的患者。
