Differentiation of Herpes simplex virus types 1 and 2 in sera of patients with HSV central nervous system infections by type-specific enzyme-linked immunosorbent assay

Relative quantity of cerebrospinal fluid herpes simplex virus DNA in adult cases of encephalitis and meningitis

Herpes simplex virus (HSV) remains an important cause of meningitis and encephalitis in adults, and polymerase chain reaction (PCR)-based tests are the "gold standard" for diagnosis. The objective of this study was to assess differences in semiquantitative PCR values, based on the crossing threshold (Ct) value for cases of HSV meningitis and encephalitis. A retrospective chart review was performed for 29 patients with a documented diagnosis of HSV meningitis or encephalitis during the course of 5 years from a large urban academic hospital. Demographic information, cerebrospinal fluid (CSF) laboratory findings, and PCR data were obtained for each patient. There was no statistically significant difference in the Ct values in patients with meningitis or encephalitis. In addition, no differences were found in CSF chemistry and hematology parameters. There is a broad range in relative concentrations of HSV DNA in the CSF in cases of meningitis and encephalitis.

Reconsideration of viral protein immunoblotting for differentiation of human herpes simplex viruses

Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are ubiquitous human pathogens that infect their hosts for life and reactivate to cause disease at or near the initial site of infection. As the incidence of genital HSV-1 infections increase, there is an increased demand for valid viral typing diagnostics. In this report, we reconsidered and developed a triple-phase immune-typing procedure that compares differences in electrophoretic mobilities of viral ICP4, ICP27, and VP22 proteins between HSV-1 and HSV-2 strains. We isolated and immunotyped 5 primary HSV-1 strains derived from orofacial, ocular, and genital areas along with 2 primary HSV-2 strains from the genital area. Advantages of this methodology include its general technical simplicity, sensitivity, and ability to definitively type HSV. It is anticipated that this methodology will be useful in distinguishing viruses obtained in clinical cultures.

Discrimination of antibody to herpes B virus from antibody to herpes simplex virus types 1 and 2 in human and macaque sera

The antigenic cross-reactive characteristics of herpes B virus and herpes simplex virus (HSV) type 1 (HSV-1) and HSV-2 are responsible for false-positive diagnoses by serological assays in humans and macaques. In the present study, we developed a fluorometric indirect enzyme-linked immunosorbent assay (ELISA) with recombinant herpes B virus glycoprotein D (gD) and HSV-1 and HSV-2 gG (gG-1 and gG-2, respectively) to discriminate between the three primate herpesvirus infections. The secreted form of gD, gDdTM, was used to detect antibody to herpes B virus gD. Sera positive for herpes B virus, HSV-1, and HSV-2 showed specific reactions to gD, gG-1, and gG-2, respectively. Sera collected from humans and rhesus macaques were investigated for the presence of antibodies to the recombinant proteins of the three herpesviruses. The results suggested that the approach is able to discriminate between herpes B virus and HSV infections. The ELISA was also found to be able to detect infections with multiple primate herpesviruses and may have the potential to identify a subsequent infection in individuals that have already been infected with another herpesvirus. In addition, we found evidence of a greater cross-reactivity of herpes B virus with HSV-1 than with HSV-2. It is suggested that the ELISA with the recombinant antigens is useful not only for the serodiagnosis of primate herpesvirus infections but also for elucidation of the seroprevalence of herpesviruses in humans and primates.

Herpes simplex virus type 2 recurrent meningitis (Mollaret's meningitis): a consideration for the recurrent pathogenesis

We report a 44-year-old Japanese woman with herpes simplex virus (HSV) type 2 recurrent meningitis (Mollaret's meningitis). The diagnosis was confirmed by nested polymerase chain reaction in her cerebrospinal fluid, but the patient's conventional HSV antibodies by complement fixation, neutralizing test or enzyme immunoassay showed low titres with low lymphoproliferative response. Several similar cases are discussed. Although the reason for the recurrent pathogenesis is uncertain, our report suggests that the low immune response including immune evasion may be involved in the pathogenesis of HSV type 2 recurrent meningitis. For this patient, long-term suppressive and patient-initiated therapies were conducted to prevent the recurrence of meningitis.

Non-herpetic acute limbic encephalitis: cerebrospinal fluid cytokines and magnetic resonance imaging findings

OBJECTIVE

Non-herpetic acute limbic encephalitis (non-herpetic ALE) is regarded as a new subgroup of limbic encephalitis. In the present study, clinical findings and cerebrospinal fluid (CSF) cytokines in patients with non-herpetic ALE were investigated.

PATIENTS AND METHODS

For adult inpatients in our hospital and related hospitals from 1996 to 2001, non-herpetic ALE was examined according to the criteria described in this study. Six patients were diagnosed as having non-herpetic ALE, and their clinical data and magnetic resonance imaging (MRI) were analyzed. In the CSF samples of the 6 patients with non-herpetic ALE and 6 patients with herpes simplex encephalitis (HSE), the concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, and interferon (IFN)-gamma were determined using sandwich-type enzyme-linked immunosorbent assay (ELISA) kits.

RESULTS

The six patients with non-herpetic ALE showed all the acute encephalitis features, such as fever, altered consciousness, seizures, memory impairment, and mild CSF pleocytosis. MRI demonstrated selective abnormal signals in the limbic system, including the bilateral hippocampi and amygdalae. The levels of CSF IL-6 and IFN-gamma in patients with non-herpetic ALE were significantly lower than those in patients with HSE (p<0.05 and p<0.01, respectively). The levels of both TNF-alpha and IL-1beta were below the detection limits in both groups.

CONCLUSION

Six patients were newly diagnosed as having non-herpetic ALE in this study. These patients revealed both acute limbic encephalitis and MRI abnormalities in the bilateral hippocampi and amygdalae. The levels of IL-6 and IFN-gamma in the CSF of patients with non-herpetic ALE were significantly lower than those of patients with HSE, possibly reflecting an immunological process in this type of ALE rather than direct viral infection.