Analysis of Immunity to Febrile Malaria in Children That Distinguishes Immunity from Lack of Exposure
Analysis of Immunity to Febrile Malaria in Children That Distinguishes Immunity from Lack of Exposure
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DOI：
10.1128/iai.01358-08
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发表时间：
2009-05-01
影响因子：
3.1
通讯作者：
Marsh, Kevin
中科院分区：
文献类型：
--
作者：
Bejon, Philip;Warimwe, George;Marsh, Kevin
在对疟疾免疫的研究中，没有发热性疟疾通常被认为是“保护”的证据。然而，表面上的“保护”可能是由于没有接触到受感染的蚊子叮咬或由于免疫力。我们研究了在监测开始前给予治疗抗疟疾药物的队列，并记录了在3个月的监测期间新获得的无症状寄生虫血症和发热性疟疾发作。随着年龄的增长，从发热性疟疾转变为无症状寄生虫血症，总体感染率没有变化。受感染红细胞表面的抗体与获得无症状感染有关，而不是与发热性疟疾或保持未感染有关。蚊帐的使用与保持未感染有关，而不是获得无症状感染或发热性疟疾。这些观察表明，大多数未感染的儿童没有接触到病毒，而不是“免疫”。如果他们是免疫的，我们会预计未感染儿童的比例会随着年龄的增长而上升，并且通过保护性抗体反应将未感染儿童与患有发热性疟疾的儿童区分开来。我们表明，从常规分析中剔除接触较少的儿童可以澄清免疫力、传播强度、蚊帐和年龄的影响。如果观察性研究和疫苗试验区分未接触和免疫的儿童，它们将具有更大的威力。
In studies of immunity to malaria, the absence of febrile malaria is commonly considered evidence of "protection." However, apparent "protection" may be due to a lack of exposure to infective mosquito bites or due to immunity. We studied a cohort that was given curative antimalarials before monitoring began and documented newly acquired asymptomatic parasitemia and febrile malaria episodes during 3 months of surveillance. With increasing age, there was a shift away from febrile malaria to acquiring asymptomatic parasitemia, with no change in the overall incidence of infection. Antibodies to the infected red cell surface were associated with acquiring asymptomatic infection rather than febrile malaria or remaining uninfected. Bed net use was associated with remaining uninfected rather than acquiring asymptomatic infection or febrile malaria. These observations suggest that most uninfected children were unexposed rather than "immune." Had they been immune, we would have expected the proportion of uninfected children to rise with age and that the uninfected children would have been distinguished from children with febrile malaria by the protective antibody response. We show that removing the less exposed children from conventional analyses clarifies the effects of immunity, transmission intensity, bed nets, and age. Observational studies and vaccine trials will have increased power if they differentiate between unexposed and immune children.