Division of Clinical Virology, University of Zurich, Zurich, Switzerland.
PLoS One. 2011;6(11):e27483. doi: 10.1371/journal.pone.0027483. Epub 2011 Nov 11.
Infants with severe primary combined immunodeficiency (SCID) and children post-allogeneic hematopoietic stem cell transplantation (HSCT) are extremely susceptible to unusual infections. The lack of generic tools to detect disease-causing viruses among more than 200 potential human viral pathogens represents a major challenge to clinicians and virologists. We investigated retrospectively the causes of a fatal disseminated viral infection with meningoencephalitis in an infant with gamma C-SCID and of chronic gastroenteritis in 2 other infants admitted for HSCT during the same time period. Analysis was undertaken by combining cell culture, electron microscopy and sequence-independent single primer amplification (SISPA) techniques. Caco-2 cells inoculated with fecal samples developed a cytopathic effect and non-enveloped viral particles in infected cells were detected by electron microscopy. SISPA led to the identification of astrovirus as the pathogen. Both sequencing of the capsid gene and the pattern of infection suggested nosocomial transmission from a chronically excreting index case to 2 other patients leading to fatal infection in 1 and to transient disease in the others. Virus-specific, real-time reverse transcription polymerase chain reaction was then performed on different stored samples to assess the extent of infection. Infection was associated with viremia in 2 cases and contributed to death in 1. At autopsy, viral RNA was detected in the brain and different other organs, while immunochemistry confirmed infection of gastrointestinal tissues. This report illustrates the usefulness of the combined use of classical virology procedures and modern molecular tools for the diagnosis of unexpected infections. It illustrates that astrovirus has the potential to cause severe disseminated lethal infection in highly immunocompromised pediatric patients.
患有严重原发性联合免疫缺陷（SCID）的婴儿和异基因造血干细胞移植（HSCT）后的儿童极易受到不常见感染的影响。缺乏通用工具来检测 200 多种潜在人类病毒病原体中的致病病毒，这对临床医生和病毒学家构成了重大挑战。我们回顾性研究了一名患有γC-SCID 的婴儿发生致命性播散性病毒感染伴脑膜脑炎的原因，以及在同一时期接受 HSCT 的另外 2 名婴儿发生慢性胃肠炎的原因。通过结合细胞培养、电子显微镜和序列非依赖性单引物扩增（SISPA）技术进行分析。接种粪便样本的 Caco-2 细胞会产生细胞病变效应，并且可以通过电子显微镜检测到感染细胞中的非包膜病毒颗粒。SISPA 导致鉴定出星状病毒为病原体。衣壳基因的测序和感染模式均表明，该病毒从慢性排泄的指数病例传播给了另外 2 名患者，导致 1 名患者发生致命感染，另外 2 名患者发生短暂感染。随后，对不同储存样本进行了病毒特异性、实时逆转录聚合酶链反应（PCR）检测，以评估感染程度。在 2 例中，感染与病毒血症有关，并导致 1 例死亡。尸检时，大脑和其他不同器官中均检测到病毒 RNA，而免疫化学检测则证实了胃肠道组织的感染。本报告说明了经典病毒学程序和现代分子工具联合使用对意外感染的诊断价值。它表明，星状病毒有可能在高度免疫功能低下的儿科患者中引起严重的播散性致命感染。
