New non-invasive rapid diagnosis of herpes simplex virus encephalitis by quantitative detection of intrathecal antigen with a chemiluminescence assay

Serial changes of intrathecal viral loads evaluated by chemiluminescence assay and nested PCR with aciclovir treatment in herpes simplex virus encephalitis

OBJECTIVE

We assessed the potential for estimating the effects of antiviral therapy on the clearance of intrathecal herpes simplex virus (HSV) antigens as evaluated by the chemiluminescence assay (CL) and on that of intrathecal HSV-DNA as evaluated by the nested polymerase chain reaction (PCR) in serial patients with herpes simplex virus encephalitis (HSVE).

METHODS

The materials comprised serial cerebrospinal fluid (CSF) samples from 18 patients with HSVE. All patients were diagnosed as having HSVE retrospectively based on the detection of intrathecal HSV antigens by the CL, that of HSV-DNA by the nested PCR, and also serological confirmation of intrathecal antibody production. The relationships between the days of aciclovir therapy and serial HSV viral loads as evaluated by the CL and nested PCR in the serial CSFs were assessed.

RESULTS

The serial intrathecal viral loads evaluated by the CL and nested PCR declined after the commencement of aciclovir administration in all patients. The serial alterations of the intrathecal viral load evaluated by the CL in each patient were similar to those of the intrathecal viral load evaluated by the nested PCR. The initial and maximum viral loads evaluated by the CL and nested PCR showed a wide distribution in the CSF samples taken from the patients with poor and good outcomes. Differences in the means of the viral loads in the CSF samples taken from the patients between a poor outcome and a good outcome were not evident. A transient increase of viral load as evaluated by these two methods was noted in the same 4 patients. The viral loads in these 4 patients also declined in the subsequent CSF samples. The outcome of these 4 patients was good in one patient and poor in the others.

CONCLUSION

Evaluation of intrathecal viral antigens by the CL has a potential for estimating the effects of antiviral therapy, as does evaluation of the intrathecal HSV-DNA by the nested PCR. The intrathecal viral loads evaluated by CL and nested PCR were not a predictor of outcome in HSVE.

Comparative study between chemiluminescence assay and two different sensitive polymerase chain reactions on the diagnosis of serial herpes simplex virus encephalitis

OBJECTIVE

A prospective study was undertaken on the diagnosis of herpes simplex encephalitis (HSVE) by comparing chemiluminescence assay (CL) and two different sensitive polymerase chain reactions (PCRs).

METHODS

The materials comprised 53 serial CSF samples from 31 patients with acute encephalitis with suspected HSVE. Each CSF was distributed to three independent laboratories to perform quantitative measurements by CL, the low sensitive (single) PCR, and high sensitive (nested) PCR. The CL provided a method of detecting HSV itself and the small fragment with HSV antigenicity which was composed of viral component proteins. The serial CSFs were found retrospectively to comprise 24 samples from 11 patients with HSVE due to HSV1 and 29 samples from 20 patients with non-HSVE.

RESULTS

the CL showed 50 to 48 000 pfu/ml in all samples of HSVE (except one) taken from the 3rd to the 25th day. The low sensitive PCR demonstrated 50 to 47 000 pfu/ml in only six samples of HSVE. The high sensitive PCR disclosed less than 100 to 120 000 copies/ml in 11 samples of HSVE. At the acute stage from the 1st to 7th day, the sensitivities of CL and the high sensitive PCR were 100%, but that of the low sensitive PCR was 75%. The sensitivity of CL was significantly higher than those of both PCRs after the acute stage on the 15th to 32nd day. The specificities and positive predictive values of the three methods were 100%. However, the negative predictive value of CL was significantly higher than that of the low sensitive PCR.

CONCLUSIONS

The sensitivity of CL is equivalent to that of the high sensitive PCR during the acute stage and significantly higher than that of the high sensitive PCR after the acute stage. A clear difference in sensitivity exists between the different PCRs. A combination of the PCR, chemiluminescence assay, and serological antibody diagnosis is currently considered the most effective approach for the clinical diagnosis of HSVE.

Herpesviruses--a rationale for antiviral treatment in multiple sclerosis

In multiple sclerosis (MS), the extensive and long lasting search for viruses or other pathogens has hitherto failed to identify a common etiological agent. However, the beneficial effects by interferon-beta treatment in MS, although suggested to depend mainly on immunomodulation, might lend support to a viral involvement in the pathogenesis. The human herpesviruses have attracted interest since their recurrent modes of infection share some similarity with the relapsing-remitting course of MS, most members are readily detected within the brain, and several of these viruses may induce demyelination within the central nervous system in human hosts as well as in animal models. Accumulated diagnostic and epidemiological data are compatible with a role for the herpesviruses as possible cofactors rather than etiological agents, and recent studies showing early neuronal damage in MS patients focus attention on the neurotropic alpha-herpesviruses. Antiviral treatment trials with safe and effective drugs such as valaciclovir offer a possibility of testing the hypotheses concerning herpesviral involvement in MS.

Cerebrospinal fluid

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