Slabá K, Skultéty L, Toman R
Laboratory for Diagnosis and Prevention of Rickettsial and Chlamydial Infections, Institute of Virology, Slovak Academy of Sciences, Dúbravská cesta 9, 845 05 Bratislava, Slovak Republic.
Acta Virol. 2005;49(2):123-7.
An indirect immunofluorescence assay (IFA) using a recently developed commercial kit for detecting antibodies against Coxiella burnetii (C.b.), the etiological agent of Q fever, has been evaluated using human field serum samples. The IFA was compared with an ELISA and a complement fixation test (CFT). The IFA was based on the corpuscular C.b. phase I and phase II antigens specific to anti-C.b. phase I and II antibodies, respectively. Fifty sera from persons with symptoms of Q fever were examined in this study. The IFA compared with the ELISA showed the sensitivities of 97.7% and 87.2% for IgG and 66.7% and 60.0% for IgM phase II and I antibodies, respectively and the specificities of 100% and 90.0% for IgG and 75.9% and 64.7% for IgM phase II and phase I antibodies, respectively. Due to a limited number of sera positive in the IgA antibody testing, the data presented should be considered with caution. It appears that the IFA strikes a very good balance between high specificity and sensitivity with phase II and phase I IgG antibodies and a less satisfactory one with IgM antibodies. The CFT failed in one of the above aspects showing a good specificity but a poor sensitivity, especially for phase I antibodies. The study demonstrated that the IFA is suitable for diagnosing Q fever and its therapeutic follow-up and is a good candidate for screening sera in large numbers. A certain limitation, especially in testing early stages of the chronic disease, could be a low fluorescence intensity of the IgA positive control in comparison with the IgA negative one.
使用一种最近开发的用于检测针对Q热病原体伯氏考克斯体（C.b.）抗体的商业试剂盒，通过间接免疫荧光法（IFA）对人类现场血清样本进行了评估。将IFA与酶联免疫吸附测定（ELISA）和补体结合试验（CFT）进行了比较。IFA基于分别针对抗C.b. I相和II相抗体的I相和II相颗粒状C.b.抗原。本研究检测了50份有Q热症状者的血清。与ELISA相比，IFA检测IgG的灵敏度分别为97.7%和87.2%，检测II相和I相IgM抗体的灵敏度分别为66.7%和60.0%；检测IgG的特异性分别为100%和90.0%，检测II相和I相IgM抗体的特异性分别为75.9%和64.7%。由于IgA抗体检测中阳性血清数量有限，所呈现的数据应谨慎看待。IFA似乎在II相和I相IgG抗体的高特异性和高灵敏度之间达到了很好的平衡，而与IgM抗体的平衡不太理想。CFT在上述一个方面表现不佳，显示出良好的特异性但灵敏度较差，尤其是针对I相抗体。该研究表明，IFA适用于Q热的诊断及其治疗随访，是大量血清筛查的良好选择。一个特定的局限性，特别是在检测慢性病的早期阶段，可能是与IgA阴性对照相比，IgA阳性对照的荧光强度较低。
