Centurion-Lara A, Barrett L, Van Voorhis W C
Department of Medicine, University of Washington, Seattle 98195.
J Infect Dis. 1994 Nov;170(5):1334-9. doi: 10.1093/infdis/170.5.1334.
Methods for detecting parasitemia in chronic Trypanosoma cruzi infection are either insensitive or nonquantitative. The polymerase chain reaction (PCR), used to detect parasite kinetoplast (k) minicircle DNA, has been shown to be virtually 100% sensitive and specific in chronically infected persons. This technique has now been modified to be quantitative by using a competitor DNA. The competitive PCR yields equal amounts of kDNA and competitor PCR products when they are mixed in equimolar ratios. Thus, the amount of parasites can be estimated from the quantity of competitor DNA at the equivalency point. Blood from 5 chronically infected mice gave results consistent with 3-260 parasites/mL, and blood from 1 chronically infected person yielded 4 parasites/mL. These are the first quantitative estimates of parasitemia in chronic T. cruzi infection. This technique could be useful for studying the natural history of T. cruzi infection and the response to therapy.
检测慢性克氏锥虫感染中虫血症的方法要么不敏感，要么无法定量。用于检测寄生虫动质体（k）小环DNA的聚合酶链反应（PCR），在慢性感染者中已显示出几乎100%的敏感性和特异性。现在通过使用竞争DNA对该技术进行了改进，使其能够定量。当等量摩尔比混合时，竞争性PCR产生等量的动质体DNA（kDNA）和竞争PCR产物。因此，可以从等效点处竞争DNA的量来估计寄生虫的数量。5只慢性感染小鼠的血液检测结果显示每毫升含有3 - 260个寄生虫，1名慢性感染患者的血液每毫升含有4个寄生虫。这些是慢性克氏锥虫感染中虫血症的首次定量估计。该技术可能有助于研究克氏锥虫感染的自然史以及对治疗的反应。
