Suarez F, Lortholary O, Buland S, Rubio M T, Ghez D, Mahé V, Quesne G, Poirée S, Buzyn A, Varet B, Berche P, Bougnoux M E
Université Paris Descartes. Service de Bactériologie, Virologie, Parasitologie, Mycologie et Hygiène, Hôpital Necker-Enfants Malades, 149, rue de Sèvres, 75473 Paris Cedex 15, France.
J Clin Microbiol. 2008 Nov;46(11):3772-7. doi: 10.1128/JCM.01086-08. Epub 2008 Sep 24.
Detection of galactomannan antigen (GMA) in serum is the standard assay for the diagnosis of invasive aspergillosis (IA) in high-risk patients with hematological disorders. Detection of Aspergillus DNA in serum has been proposed, but its sensitivity is lower than that of GMA when small serum volumes (SSV) are used. In this study, we investigated whether extraction of DNA from large serum volumes (LSV) improves diagnostic yield. In a 13-month prospective study, we compared the performances of twice-weekly screening of serum for GMA by an enzyme immunoassay and weekly screening for Aspergillus fumigatus DNA by a real-time PCR (RT-PCR) assay of 1.0 ml (LSV) or 100 mul (SSV) of serum. We included 124 patients (138 treatment episodes), with 17 episodes of EORTC (European Organization for Research and Treatment of Cancer)/MSG (Mycoses Study Group)-documented IA. In all, 1,870 samples were screened for GMA. The sensitivity (Se), specificity (Sp), and positive and negative predictive values (PPV and NPV, respectively) of GMA for IA were 88.2%, 95.8%, 75%, and 98.3%, respectively. We screened 938 samples for Aspergillus DNA by using LSV; 404 of these samples were also tested with SSV. The Se, Sp, PPV, and NPV of RT-PCR were 100%, 96.7%, 81%, and 100%, respectively, with LSV and 76.5%, 96.7%, 81.3%, and 95.6%, respectively, with SSV. DNA detection gave a positive result when performed on LSV in two cases of IA where the GMA assay result remained negative. Furthermore, in four IA cases, DNA was detected earlier than GMA. The use of LSV for extraction improved the performance of the RT-PCR, which appears highly sensitive and specific for the early diagnosis of IA in high-risk patients with hematological disorders.
检测血清中的半乳甘露聚糖抗原（GMA）是诊断血液系统疾病高危患者侵袭性曲霉病（IA）的标准检测方法。有人提出检测血清中的曲霉DNA，但当使用少量血清（SSV）时，其敏感性低于GMA。在本研究中，我们调查了从大量血清（LSV）中提取DNA是否能提高诊断率。在一项为期13个月的前瞻性研究中，我们比较了每周两次通过酶免疫测定法筛查血清中的GMA以及每周一次通过实时PCR（RT-PCR）测定法筛查1.0 ml（LSV）或100 μl（SSV）血清中的烟曲霉DNA的性能。我们纳入了124例患者（138个治疗疗程），其中有17个欧洲癌症研究与治疗组织（EORTC）/真菌病研究组（MSG）记录的IA疗程。总共对1870份样本进行了GMA筛查。GMA检测IA的敏感性（Se）、特异性（Sp）、阳性预测值和阴性预测值（分别为PPV和NPV）分别为88.2%、95.8%、75%和98.3%。我们使用LSV对938份样本进行了曲霉DNA筛查；其中404份样本也用SSV进行了检测。RT-PCR检测LSV时的Se、Sp、PPV和NPV分别为100%、96.7%、81%和100%，检测SSV时分别为76.5%、96.7%、81.3%和95.6%。在两例GMA检测结果仍为阴性的IA病例中，对LSV进行DNA检测时得出了阳性结果。此外，在4例IA病例中，DNA比GMA更早被检测到。使用LSV进行提取提高了RT-PCR的性能，RT-PCR对于血液系统疾病高危患者IA的早期诊断似乎具有高度敏感性和特异性。
