Olsson M, Strålin K, Holmberg H
Department of Parasitology, Swedish Institute for Infectious Disease Control, Stockholm, Sweden.
Clin Microbiol Infect. 2001 Sep;7(9):492-7. doi: 10.1046/j.1469-0691.2001.00309.x.
To study the clinical significance of a nested polymerase chain reaction (PCR) method compared to immunofluorescence (IF) for detection of Pneumocystis carinii.
The medical records of 89 patients with 91 episodes of pneumonia were scrutinised retrospectively. The pneumonia episodes were divided into categories according to the likelihood that the patient had had clinical Pneumocystis carinii pneumonia (PCP). All respiratory tract samples from the 89 patients (34 broncho-alveolar lavage (BAL) and 57 sputa) were tested for Pneumocystis carinii by IF and nested PCR.
Fifteen episodes, as diagnosed by IF, were classified as true PCP (combination of the groups with definite and probable PCP; sensitivity 60%, specificity 97%). Among the P. carinii DNA-positive episodes, detected with nested PCR, 24 were classified as true PCP (combination of the groups with definite and probable PCP; sensitivity 96%, specificity 59%), since all IF-positive samples were nested PCR positive. Only one pneumonia episode classified as a probable PCP, was negative with both methods, as applied to a BAL sample.
IF applied to BAL or sputum seems to be the most specific method for diagnosis of clinical PCP. Additional clinical cases can be found by nested PCR, although this then gives a high risk of detecting subclinical colonisation of P. carinii.
研究巢式聚合酶链反应（PCR）法相较于免疫荧光法（IF）检测卡氏肺孢子虫的临床意义。
回顾性分析89例患者91次肺炎发作的病历。根据患者患临床卡氏肺孢子虫肺炎（PCP）的可能性，将肺炎发作进行分类。对89例患者的所有呼吸道样本（34份支气管肺泡灌洗（BAL）样本和57份痰液样本）采用IF和巢式PCR检测卡氏肺孢子虫。
IF诊断的15次发作被归类为确诊PCP（确诊和疑似PCP组的组合；敏感性60%，特异性97%）。在巢式PCR检测出卡氏肺孢子虫DNA阳性的发作中，24次被归类为确诊PCP（确诊和疑似PCP组的组合；敏感性96%，特异性59%），因为所有IF阳性样本巢式PCR均为阳性。应用于一份BAL样本时，只有1次被归类为疑似PCP的肺炎发作两种方法检测均为阴性。
应用于BAL或痰液的IF似乎是诊断临床PCP最具特异性的方法。巢式PCR可发现更多临床病例，尽管这样会有较高风险检测到卡氏肺孢子虫的亚临床定植。
