Jpn. J. Infect. Dis., 61, 18-24, 2008
Original Article
Clinical Application of Reverse-Transcription Polymerase Chain Reaction and Intravenous Immunoglobulin for Enterovirus Encephalitis Ming-Fang Cheng1,4, Bao-Chen Chen2,4, Tsi-Shu Huang2,4, Kai-Sheng Hsieh1,4, Shu-Nuan Chen2,4 and Yung-Ching Liu2,3,4* 1
Department of Pediatrics, 2Department of Microbiology, and 3Section of Infectious Diseases, Department of Internal Medicine, Veterans General Hospital-Kaohsiung, Kaohsiung, and 4National Yang-Ming University, Taipei, Taiwan (Received June 5, 2007. Accepted October 19, 2007)
SUMMARY: Although polymerase chain reaction (PCR) is a highly sensitive procedure for the diagnosis of enteroviruses, it has never been systemically applied to the treatment of enteroviral encephalitis using intravenous immunoglobulin (IVIg). We conducted a 2-year randomized, controlled comparison of reverse transcription (RT)-PCR of cerebrospinal fluid (CSF) with traditional viral isolation to guide IVIg treatment. Seventy-five patients were enrolled and classified into three groups: one group with clinical manifestations of enteroviral infections and two without. The latter two groups were separated on the basis of whether IVIg treatment was guided by RT-PCR or virus culture assay. CSF specimens from the 18 confirmed cases of enteroviral encephalitis were RT-PCR positive for enterovirus in all but one case. Of the remaining 57 cases of nonenteroviral encephalitis, only 4 were positive for enterovirus RT-PCR. One patient in the group of IVIg treatment guided by viral isolation subsequently displayed a sequel of epilepsy. No patients in the IVIg treatment groups guided by RT-PCR had any neurological sequelae. In conclusion, the use of RT-PCR allowed rapid, sensitive, and specific detection of enteroviral RNA in CSF. When used to guide IVIg treatment, RT-PCR may shorten hospitalization and improve outcomes of patients with enteroviral encephalitis. with the host’s age and immune status. Virulence determinants of the circulating virus may also be involved (9,10); antibodies play a pivotal role in resolving infection. Indeed, the use of immune globulin has quelled the incidence of enteroviral infections in the nursery (11-13) and in individually ill newborns (14-16). However, the clinical efficacy of IVIg in enteroviral encephalitis remains controversial (9). Patients with encephalitis who present characteristic herpangina or HFMD are easily diagnosed as enteroviral infections. However, many patients with enteroviral encephalitis do not display these characteristic manifestations; instead, diagnosis relies on the direct detection of the virus from cerebrospinal fluid (CSF), throat swab, or stool. These detection methods suffer from a slow turnaround time (17) and relative insensitivity (17,18). Brain biopsy, perhaps the only existing “gold standard” in diagnosing viral encephalitis, is rarely justified because of its invasive nature. RT-PCR more rapidly and sensitively detects EV genomic RNA in specimens as varied as muscle biopsy, CSF, throat swabs, serum, and stool (18,19). We used a commercially available PCR assay (AMPLICOR EV Test; Roche Molecular Systems, Branchburg, N.J., USA) that combined sufficient sensitivity and maximum specificity (17,18,20) for the rapid detection of EV RNA in clinical specimens by taking advantage of the new real-time LightCycler PCR technology (6) using the TaqMan format (21). Presently, we conducted a detailed prospective study of the clinical application of RT-PCR and the effects of treatment with IVIg on symptomatic enteroviral encephalitis.
INTRODUCTION An enterovirus (EV) epidemic in Taiwan in 1998, predominantly caused by EV 71 in 42% of cases, coxsackievirus A16 in 18%, and other EVs in 40%, resulted in a total of 129,106 cases reported to have the primary clinical marker of enteroviral infection--herpangina and hand-foot-mouthdisease (HFMD), with 405 severe cases and 78 deaths (1-3). This epidemic prompted the use of intravenous immunoglobulin (IVIg) for the treatment of severe enteroviral infections, including EV-mediated encephalitis in Taiwan (4). This treatment policy has been hampered by the need to prove the presence of enteroviral infections for those patients without characteristic herpangina or HFMD, since current tissue culture-based methods are laborious, time-consuming, and frequently unsuccessful exercises (5). In contrast, detection of EVs by reverse transcription-polymerase chain reaction (RT-PCR) is more rapid and sensitive (6). The objective of the present study was to assess the impact of high-dose IVIg adjuvant therapy in patients with enteroviral encephalitis diagnosed by the RT-PCR assay. EVs are a leading cause of meningoencephalitis (7). They reside in a genus within the family of Picornaviridae, and are single-stranded RNA viruses that can be subdivided into five species including human enterovirus (HEV) A to D species and poliovirus type species (8). Specific antiviral treatment is not currently available. The clinical disease observed during central nervous system enteroviral infections varies *Corresponding author: Mailing address: Section of Infectious Diseases, Department of Internal Medicine, Veterans General Hospital-Kaohsiung, 386 Ta-Chung 1st RD, Kaohsiung, Taiwan 81346. Tel: +886-7-3422121 ext. 2029, Fax: +886-7-3468067, E-mail:
[email protected]
MATERIALS AND METHODS Study design: The subjects (n = 75; all
