Detection of herpesvirus genomes by polymerase chain reaction in cerebrospinal fluid and clinical findings.

BACKGROUND: The viruses of the Herpesviridae family, in particular herpes simplex virus types 1 (HSV-1) and 2 (HSV-2), cytomegalovirus (CMV), Epstein-Barr virus (EBV), varicella zoster virus (VZV), and human herpesvirus 6 (HHV-6), are responsible for numerous infections of the central nervous system (CNS). These infections manifest as diverse clinical signs, many of which are not specific. The diagnosis of these infections is necessary to make it possible to adapt treatment appropriately, as treatment is specific for the particular virus concerned. OBJECTIVES: To apply a polymerase chain reaction (PCR) technique for the diagnosis in a single reaction of the six herpesviruses most frequently detected in the cerebrospinal fluid (CSF) and to analyse clinical events in patients presenting positive results in PCR for herpesviruses. STUDY DESIGN: We studied 141 patients, from whom 180 CSF samples were collected. The clinical files of the patients were consulted retrospectively, and a list of clinical signs was recorded. After testing by targeted PCR, at the clinician's demand, we tested these samples by herpes consensus PCR, which detects six herpesviruses (HSV-1, HSV-2, CMV, EBV, VZV, HHV-6), in a single PCR. RESULTS: Targeted PCR tests identified 25 CSF samples (13.9%), corresponding to 18 patients (12%), as positive. The herpes consensus PCR test detected 49 samples (27.2%) as positive, resulting in the identification of 54 individual viruses (four samples displayed co-infection) from 39 patients (27%). 130 CSF samples, from 101 patients, tested negative by both techniques. 23 HIV-positive patients (30.6%), three HIV-negative immunocompromised patients (27%), and 14 immunocompetent patients (25%) were CSF PCR-positive. In HIV-positive patients, CMV was the virus most frequently identified (13%), followed by EBV (10.6%), VZV (5.3%) and finally HSV-1 and HSV-2 (both 1.3%). We did not detect HHV-6 in any of these samples. We detected only HSV-2, EBV and VZV in the 11 HIV-negative immunocompromised patients. CSF samples of immunocompetent patients contained mostly VZV (9%) and HSV-1 (7.3%). CONCLUSIONS: The herpes consensus PCR for a given virus was more sensitive than the standard, targeted PCR used in our laboratory. The clinical signs presented by patients infected with HSV-1, HSV-2 and CMV were similar to those reported in previous studies. For VZV, we report the possibility of mild, transient cerebral viral reactivation. Our data on the detection of EBV by PCR suggest that the PCR test is of predictive value for cerebral lymphoma in immunocompromised patients. The possible role of HHV-6 in a subacute neurological disorder merits further investigation.

Amplification of the six major human herpesviruses from cerebrospinal fluid by a single PCR.

We used a novel type of primer system, a system that uses stair primers, in which the primer sequences are based on consensus sequences in the DNA polymerase gene of herpesvirus to detect herpesviruses by PCR. A single PCR in a single tube detected the six major herpesviruses that infect the central nervous system: herpes simplex virus type 1 (HSV-1), and type 2 (HSV-2), cytomegalovirus (CMV), Epstein-Barr virus (EBV), varicella-zoster virus (VZV), and human herpesvirus 6 (HHV-6). We used the technique to analyze 142 cerebrospinal fluid (CSF) samples that had been stored at -80 degrees C and compared the results with those obtained previously for the same samples by standard, targeted PCR. Four hundred one targeted PCR tests had been run with the 142 samples to detect HSV-1, HSV-2, CMV, and VZV; screening for EBV and HHV-6 was not prescribed when the samples were initially taken. Eighteen CSF samples tested positive by classic targeted PCR. The herpesvirus consensus PCR detected herpesviruses in 37 samples, including 3 samples with coinfections and 17 viral isolates which were not targeted. Two samples identified as infected by the targeted PCR tested negative by the consensus PCR, and eight samples that tested positive by the consensus PCR were negative by the targeted PCR. One hundred three samples scored negative by both the targeted and the consensus PCRs. This preliminary study demonstrates the value of testing for six different herpesviruses simultaneously by a sensitive and straightforward technique rather than screening only for those viruses that are causing infections as suggested by clinical signs.