Serodiagnosis of herpes encephalitis by indirect enzyme-linked immunosorbent assay, experience from a Swedish antiviral trial

[Experience with multiplex nested PCR and fluorescent antibody tests in the diagnosis of acute central nervous system infections with herpes simplex virus type 1 and 2]

The specific diagnosis of herpes simplex virus type 1 and 2 infections has an extreme importance in acute infections of central nervous system due to both availability of specific antiviral therapy and the possible serious consequences of the disease.

AIMS

Evaluation of the relevance and interpretation of the results of PCR and the specific antibody testing.

METHODS

Home made multiplex nested herpes simplex virus PCR and immunofluorescent IgM, IgA, IgG antibody tests were carried out in a total of 474 cerebrospinal fluid and 555 serum samples of 396 patients with acute infection of the central nervous system between 1. January, 2003 and 31. December, 2009.

RESULTS

The herpes simplex virus etiology was verified in 21% of 396 patients (82 patients, mean 12 cases per year): 26 were diagnosed by both methods (32%), 41 by PCR only (50%), 15 by the detection of intrathecal antibody production only (18%) (p<0.0001). HSV type1 or 2 DNA remained detectable in 35% of the samples drawn after the 30th day of the disease. These patients were all younger than two years of age.

CONCLUSIONS

1. PCR increased the ratio of verified herpes simplex virus etiology in acute central nervous infections. 2. Testing the specific antibody response cannot be ceased even in the availability of PCR. 3. Herpes simplex virus type 1 or 2 DNA might persist in central nervous system in spite of the specific antiviral therapy especially in the infants. 4. Herpes simplex virus PCR can be repeated if an early sample is negative or if it is suspected false positive. 5. There is a need for cooperation between clinicians and virologists in the appropriate interpretation of the results and in finding etiology.

Monitoring of herpes simplex virus DNA types 1 and 2 viral load in cerebrospinal fluid by real-time PCR in patients with herpes simplex encephalitis

A quantitative polymerase chain reaction (PCR) assay was evaluated retrospectively on 92 cerebrospinal fluid (CSF) samples from 29 patients with herpes simplex virus (HSV) encephalitis with the aim to study if the concentration of HSV genomes can be used as a prognostic marker and for monitoring of antiviral therapy. The results were compared to those obtained previously by nested PCR, and the numbers of HSV genomes/ml were evaluated in correlation to patient outcome and treatment. The aims were to compare the sensitivity of a conventional nested PCR to a quantitative PCR, to investigate the range of HSV genome concentration in initial samples and to evaluate possible relationships between the HSV DNA concentrations in CSF, neopterin levels, and outcome of disease. The 29 initial samples contained between 2 x 10(2) and 42 x 10(6) HSV genomes/ml. There was no apparent correlation between the amount of HSV DNA in the initial samples and income status, initial neopterin levels, or prognosis. The number of HSV genomes/ml declined after treatment in all patients, but HSV DNA was still detectable after day 20 in 3 out of 16 patients. A long duration of genome detectability was found to correlate with poor outcome. There was no difference in sensitivity between the nested PCR and the quantitative PCR. While the quantitative PCR is more rational than a nested PCR, the quantitation of HSV genomes does not seem very useful as a prognostic marker in HSV encephalitis.

Seropositivity to herpes simplex virus antibodies and risk of Alzheimer's disease: a population-based cohort study

Background

Herpes Simplex Virus (HSV) infection has been proposed as a possible risk factor of Alzheimer's Disease (AD) notably because it is neurotropic, ubiquitous in the general population and able to establish lifelong latency in the host. The fact that HSV was present in elderly subjects with AD suggests that the virus could be a co-factor of the disease. We investigated the risk of developing AD in anti-HSV immunoglobulin G (IgG) positive subjects (indicator of a lifelong infection to HSV) and IgM-positive subjects (indicator of primary infection or reactivation of the virus) in a longitudinal population-based cohort of elderly subjects living in the community.

Methods

Cox proportional hazard models were used to study the risk of developing AD according to the presence or not of anti-HSV IgG and IgM antibodies, assessed in the sera of 512 elderly initially free of dementia followed for 14 years.

Results

During the follow-up, 77 incident AD cases were diagnosed. Controlled for age, gender, educational level and Apolipoprotein E4 (APOE4) status, IgM-positive subjects showed a significant higher risk of developing AD (HR = 2.55; 95% CI [1.38–4.72]), although no significant increased risk was observed in IgG-positive subjects (HR = 1.67; 95%CI [0.75–3.73]). No modification effect with APOE4 status was found.

Conclusion

Reactivation of HSV seropositivity is highly correlated with incident AD. HSV chronic infection may therefore be contributive to the progressive brain damage characteristic of AD.

Tumor necrosis factor-alpha response and herpesvirus infection in Bell's palsy

OBJECTIVES

To attempt early diagnosis of patients with Bell's palsy by detection of herpesviral DNA in body fluids, and to investigate whether tumor necrosis factor-alpha (TNF-alpha), a cytokine associated with demyelination, is involved in the inflammatory response in this disease.

STUDY DESIGN

Eleven patients with acute facial palsy admitted within 1 week after onset of the disease were followed in a consecutive prospective study.

METHODS

Antibodies reactive to herpesviruses were determined by enzyme-linked immunosorbent assay in serum samples from acute and convalescent (> 2-week interval) cases. Intrathecal antibody response was investigated by immunoblotting. Polymerase chain reaction amplification of herpesviral DNA was attempted from samples of serum, cerebrospinal fluid, tear fluid, and saliva TNF-alpha and its soluble receptors (types I and II) were assessed in serum and cerebrospinal fluid samples.

RESULTS

Ten of the 11 patients demonstrated serologic evidence of herpesviral primary infection or reactivation, supporting the evidence that herpesviruses are the most prevalent etiologic agents in Bell's palsy. Despite this, DNA amplifications by polymerase chain reaction were negative for herpesviruses in the body fluids tested. TNF-alpha concentrations were significantly elevated in serum, as compared with controls. Only one patient had a remaining facial nerve dysfunction at follow-up after 3 months.

CONCLUSION

The absence of herpes DNA in body fluids in the acute stage of serologically confirmed Bell's palsy suggests that viral replication is transient in cases with an early restoration of the facial nerve function. The elevated serum levels of TNF-alpha indicate that this cytokine might be a pathogenetic factor related to the demyelination in this disease.

Specific diagnostic methods for herpesvirus infections of the central nervous system: a consensus review by the European Union Concerted Action on Virus Meningitis and Encephalitis

BACKGROUND

Herpesvirus infections of the central nervous system are often severe but are fortunately rare. The incidence of these infections has however, increased in recent years as a consequence of an increase in the number of immune-compromised individuals. New diagnostic procedures have improved our ability to diagnose these infections and herpesviruses may yet be implicated as the cause of further neurological diseases with no known aetiology. Methodological standards for selection and evaluation of patient materials are essential to the provision of reliable diagnosis, yet few studies have addressed this important issue.

OBJECTIVES

To describe and define methodological standards and reference methodology for diagnosis of herpesvirus infections of the CNS.

STUDY DESIGN

Information gathered by literature review.

RESULTS

Only for herpes simplex encephalitis is there sufficient data to allow the definition of reference methodology. Good methodological standards exist but few studies have adhered to these standards. As methods for the detection of specific intrathecal antibody synthesis are well established yet under-used in diagnostic virology, the principle of these measurements is reviewed in some detail.

CONCLUSIONS

Herpesvirus infections of the CNS are of increasing importance. High quality, multi-centre studies are needed to establish the value of the new diagnostic test procedures if further improvement in the diagnostic sensitivity and specificity of these procedures is to be achieved.

Intrathecal production of measles-specific IgA in subacute sclerosing panencephalitis

OBJECTIVE

We measured measles-specific IgA in matched pairs of cerebrospinal fluid (CSF) and sera of patients with subacute sclerosing panencephalitis (SSPE), multiple sclerosis (MS), other central nervous system (CNS) infectious diseases (INF) and other neurological diseases (OND) by using enzyme linked immunosorbent assay.

MATERIALS AND METHODS

CSF and sera from 23 patients with SSPE, 15 with MS, 14 with INF, and 15 with OND were included in the study.

RESULTS

The ratios of measles-specific IgA in CSF to serum were increased in SSPE patients compared to patients with MS, INF or OND.

CONCLUSION

The data indicate a local production of measles-specific IgA in the CNS of SSPE patients.

Intrathecal IgM, IgA and IgG antibody response in tick-borne encephalitis. Long-term follow-up related to clinical course and outcome

BACKGROUND

Tick-borne encephalitis (TBE) of western subtype causes long-term morbidity and is considered a health problem in Scandinavia, eastern and central parts of Europe and Russia. The pathophysiology is not fully elucidated. As TBE RNA is rarely demonstrable in cerebrospinal fluid (CSF) the kinetics of the CSF antibody response to the disease has attracted attention.

OBJECTIVES

To investigate the intrathecal TBE-specific antibody response and to correlate its intensity and persistence to the clinical course. To compare indirect, commercially-based ELISA methods indexed against albumin ratio or IgG ratio with the capture ELISA method for the establishment of CSF response.

STUDY DESIGN

The specific IgM, IgG and IgA antibody responses in serum and CSF were analysed in 69 Swedish patients included in a prospective study of TBE from the acute phase up to 11-13 months after onset.

RESULTS

Antibody response by all three classes was demonstrable in serum and CSF. All methods were useful, but capture technique was the most sensitive and results were easiest to interpret. Peak IgM activity was seen early during the disease and persisted after 6 weeks. Maximum IgG levels were encountered in late convalescent samples (median 6 weeks). Intrathecal antibody production was demonstrable in nearly all patients: in 41% days 0-6, in 97% days 7-19, in 98% days 21-61 and-at lower levels-in 84% of the patients after 1 year (50/52 of CSF-serum sampled in the interval 11-61 days). Day 9 after onset, patients with dominating encephalitic symptoms showed significantly lower intrathecal IgM activity. The persistence of serum and CSF antibodies did not correlate to severity of disease.

CONCLUSIONS

Capture IgM and IgG assays were superior to indirect ELISA. Low early CSF IgM response correlated to encephalitic symptoms, otherwise the intensity and duration of intrathecal antibody response were of limited value for the prediction of clinical course and long-term outcome.

Detection of both herpes simplex and varicella-zoster viruses in cerebrospinal fluid from patients with encephalitis

Cerebrospinal fluid (CSF) samples from 46 patients with encephalitis were studied for the presence of herpes simplex virus (HSV) types 1 and 2 and/or varicella zoster virus (VZV)-specific DNA sequences by the polymerase chain reaction (PCR) assay. Patients were studied because of detection of intrathecal production of IgG antibody to HSV alone (10 patients, Group A) or to both HSV and VZV (11 patients, Group B) or because of the presence of specific anti-HSV IgG in CSF without evidence of intrathecal antibody production (25 patients, Group C). CSF samples taken between days 1 and 10 from onset of encephalitis were available from all patients, and follow-up samples (taken after 10 days from onset) were obtained from some of them. Positive PCR results were obtained in a total of 13 patients. Four patients (three from Group A and one from Group B) gave amplification of HSV type 1 DNA alone, two patients (both from Group B) showed amplification of VZV DNA alone, and seven patients (all from Group B) gave dual amplification of both HSV type 1 and VZV DNA sequences in CSF. All CSF samples from patients in Group C were negative by PCR. Ten patients with CSF samples positive by PCR lacked a prior history of herpetic cutaneous lesions. In seven patients, serum antibody tests (specific IgM detection and specific IgG avidity assays) identified both primary and recurrent infections. The results suggest that the dual presence of IgG antibody to both HSV and VZV in CSF from patients with encephalitis may reflect in some cases a dual infection of the central nervous system caused by both agents.

No findings of enteroviruses in Swedish patients with chronic fatigue syndrome

Enteroviruses have been proposed to cause an immune complex disease in the chronic fatigue syndrome. Altogether 34 patients with the chronic fatigue syndrome, according to criteria of the Centers for Disease Control, USA, were studied evenly over the seasons for the possible presence of a chronic enterovirus infection. In 11 patients, 1-5 faecal samples were collected at about 6 month intervals for virus isolation before and after acid treatment, followed by ultracetrifugation at pH 3 to dissolve possible enterovirus-antibody complexes. Another 14 fecal samples were subjected to routine virus isolation alone. Seven pairs of serum-cerebrospinal fluid samples were analysed for cross-reactive IgG antibody activity to enteroviruses. In 29 patients a muscle biopsy was collected for enterovirus polymerase chain reaction (PCR). We were unable to identify enteroviruses in any of these samples by any of these techniques. Our study does not confirm evidence for persistent enterovirus infection in the chronic fatigue syndrome.

Determination of total and herpes simplex virus specific monomeric and dimeric IgA in serum and cerebrospinal fluid by ultracentrifugation

An improved method is described for differentiating between monomeric and dimeric total and herpes simplex virus (HSV) specific IgA by ultracentrifugation in sucrose gradient, using recovery and quantitative analysis of the fractions obtained. Calculation of monomeric and dimeric IgA was based on IgG as an internal standard. Intrathecally produced monomeric and dimeric IgA were judged by calculating IgA indices for each form. A new type of formula indicating relative over-production of dimeric compared with monomeric IgG (IgA dimeric-monomeric index) is suggested. The method was applied to serum and cerebrospinal fluid (CSF) from three patients with HSV encephalitis. The index for monomeric as well as dimeric IgA was high during the acute phase of the disease, indicating intrathecal synthesis of both molecular forms. One year after onset, there was no detectable HSV-specific IgA in CSF: both molecular forms, however, remained in serum. The amount of dimeric compared with monomeric IgA was high during the acute phase, and subsequently decreased after successful treatment. A new finding was the detection of HSV-specific IgA heavier than dimeric IgA in serum one year after onset of the disease. These components may be tetrameric IgA, or immune complexes containing IgA.

Intrathecal production of specific IgA antibodies in CNS infections

Cerebrospinal fluid (CSF) and serum from subjects with herpes simplex encephalitis, herpes zoster, mumps meningitis and neuroborreliosis were analysed for the presence of immunoglobulin A (IgA) and G (IgG) antibodies to the corresponding four antigens. Specific intrathecal IgA antibody synthesis as manifested by an elevated index was a frequent finding. Higher IgA index values than the corresponding IgG was seen in one third of the samples from subjects with herpes simplex encephalitis and herpes zoster. Correlation between specific IgG and IgA index was most pronounced for varicella-zoster virus (r = 0.66, P < 0.001). In subjects with mumps meningitis a strong intrathecal IgA and IgG antibody response to Borrelia burgdorferi was demonstrated. Specific herpes simplex and varicella-zoster virus IgA was not found to contain secretory component, thus contradicting an active secretion into the CNS compartment. In conclusion, our data indicate that specific IgA is intrathecally produced in herpes simplex encephalitis, herpes zoster and mumps meningitis but is a rare finding in neuroborreliosis.

Serological responses to human papillomavirus type 16 antigens in women before and after renal transplantation

Female renal transplant recipients have an increased incidence of human papillomavirus (HPV) associated lesions, such as cervical dysplasia and neoplasia [Schneider et al., 1983]. In this study we tested the serological responses by enzyme-linked immunoadsorbent assays (ELISA) to 3 different antigenic regions of HPV type 16. Sera from 35 female renal transplant patients collected before and at different times, up to 3 years, after transplantation were collected and tested. Before transplantation IgG antibodies against peptide 49, corresponding to the HPV L2 region, were found in 21/35 of the patients' sera. Of the L2 positive sera, 16 also demonstrated activity with the HPV L1 region derived peptide 31. All sera that were active against peptide 31 (L1) were also reactive with peptide 49 (L2). After renal transplantation, the antibody levels against these 2 peptides (peptides 49 and 31) dropped significantly (OD > or = 0.2) in all previously positive sera and remained so throughout the study, which lasted up to 3 years. The proportion of patients with IgA activity against the E2 region (peptide 245), which is common among patients with cervical neoplasia, increased from 9/35 before transplantation to 18/35 after transplantation. In parallel, we monitored 25 of these patients' sera before and after transplantation for antibody activity against measles, adenoviruses, and cytomegaloviruses (CMV). The majority of these sera--17/25 (68%) and 18/25 (72%), respectively--had no titer changes against measles and adenoviruses. Furthermore, the changes in antibody titers observed with CMV in these patients were not correlated with the fate of the antibodies against the HPV peptides.(ABSTRACT TRUNCATED AT 250 WORDS)

Encephalitis in immunocompetent patients due to herpes simplex virus type 1 or 2 as determined by type-specific polymerase chain reaction and antibody assays of cerebrospinal fluid

A herpes simplex virus type 2 (HSV 2) etiology was sought in 93 consecutive cases of herpes simplex encephalitis (HSE) in immunocompetent post neonate patients. Antibodies to HSV 2 glycoprotein G antigen were determined by an enzyme-linked immunosorbent assay (ELISA) and HSV 2 DNA in cerebrospinal fluid (CSF) by a nested polymerase chain reaction (PCR) assay with primer pairs in the glycoprotein G gene. Evidence of HSV 2 infection was found in 6 patients; HSV 2 DNA was demonstrated in CSF and the intrathecal HSV 2 antibody response confirmed the findings. Five of the 6 patients with HSV 2 encephalitis presented a clinical picture, CSF, EEG, and CT findings characteristic of severe HSE. An atypically mild clinical course was seen in one patient. HSV 2 should be considered as an etiological agent in the viral diagnosis of HSE. With a combination of nested PCR assays for HSV 1 (primer pairs in the glycoprotein D gene) and HSV 2 in 10 microliters of CSF with no other preparation than freeze-thawing, HSV 1 or HSV 2 DNA was detected in 88 out of 93 (95%) of the first CSF specimens collected after the onset of neurological HSV disease. These findings extend and confirm previous results with PCR as a rapid and sensitive tool for early diagnosis of HSE.

Detection of herpes simplex virus DNA in cerebrospinal fluid of Saudi pediatric patients with encephalitis by the polymerase chain reaction

Twelve samples of cerebrospinal fluid (CSF) from Saudi pediatric patients with suspected encephalitis were found negative for herpes simplex virus by cell culture and by nucleic acid hybridization using(32)P-labeled specific probes. After amplification of DNA extracted from 100 microl of each sample using primers for the glycoprotein D gene of HSV, seven specimens were found positive for HSV DNA. Subsequent hybridization with the labeled DNA probe ensured the positivity of the seven samples and further detected one more positive sample, for a total of eight HSV DNA positive cases. This technique improved the detection of HSV in CSF samples and may assist in an early diagnosis for HSV ecephalitis.

The diagnostic significance of the polymerase chain reaction and isoelectric focusing in herpes simplex virus encephalitis

In this study, serum and CSF samples of 55 neurological patients have been examined to confirm the diagnosis of herpes simplex virus encephalitis (HSVE). Different methods were applied, including serological titer evaluations, determination of intrathecally-produced HSV-specific antibodies by isoelectric focusing with affinity immunoblotting (IEF), as well as HSV-specific ELISA and HSV-specific polymerase chain reaction (PCR). The results of IEF and PCR have been compared and contrasted to develop general directions for virological diagnosis of HSVE. Of 14 patients suffering from clinically diagnosed HSVE, HSVE was confirmed in 12 cases by the demonstration of PCR or IEF positivity. A HSV-specific CNS infection could be excluded in 2 of these 14 patients. In 17 patients suffering from non-HSVE, PCR and IEF results were negative. Twenty-four patients, suffering from other neurological diseases, serving as a control group, were PCR- and HSV-IEF-negative. The study indicated that there are two possibilities for unequivocal demonstration of HSV-specific CNS involvement: first, performance of PCR especially in the acute phase of disease and in suspicious relapses, and second, performance of HSV-specific IEF for determination of intrathecally synthesized HSV-specific antibodies. It is suggested that these two methods should be introduced in routine diagnosis of viral encephalitis.

Intrathecal antibody production against viruses of the herpesvirus family in acute retinal necrosis syndrome

Viruses of the herpesvirus family cause acute retinal necrosis syndrome, a devastating necrotic retinitis in immunocompetent individuals. Direct proof of the viral origin of this disease may be obtained by demonstration of the virus, viral antigens, or viral DNA in biopsy specimens of retinas. In search of alternative diagnostic methods, we analyzed cerebrospinal fluid and serum with enzyme-linked immunosorbent assays for virus-specific antibody activity. Intrathecally produced viral antibodies were found in three consecutive patients with acute retinal necrosis syndrome: herpes simplex type 2 in a 30-year-old woman with a history of suspected neonatal herpes encephalitis, herpes simplex type 1 in a 35-year-old man, and varicella-zoster virus activity in a 62-year-old woman. None of the patients had clinical signs indicating an acute disorder in the central nervous system. This serologic approach seems to be of value for the diagnosis of an associated intracerebral viral infection in cases of acute retinal necrosis syndrome.

Acute confusion--an unusual form of cerebral herpes simplex virus infection?

Herpes simplex virus (HSV) infections are common and, if afflicting the central nervous system, may cause death or severe sequelae. Since specific therapy is now available there is an increasing demand for the recognition of the various ways in which cerebral HSV-infections may be manifested. This report describes a 15-year-old boy who presented acutely with mental symptoms of confusion, hallucinations and sleep disturbance. Simultaneously, but without any increase in cerebrospinal fluid cell or protein content, an intrathecal production of HSV-antibodies of transient nature was detected. These findings suggest that the patient may have suffered from an unusual form of herpes infection in the central nervous system. We suggest that similar cases should be thoroughly explored for possible herpes etiology as early as possible during the acute phase of the disease.

Rapid diagnosis of herpes simplex encephalitis by nested polymerase chain reaction assay of cerebrospinal fluid

With the aim of improving early diagnosis of herpes simplex encephalitis a polymerase chain reaction (PCR) assay with two "nested" primer pairs was developed for the amplification of herpes simplex virus DNA in cerebrospinal fluid (CSF). Southern blotting was used to confirm the specificity of the amplification. The assay was applied to 151 CSF samples from 43 consecutive patients with herpes simplex encephalitis verified by the finding of herpes simplex virus/viral antigen in a brain biopsy sample or at necropsy (13) and/or intrathecal production of IgG antibody to the virus (40). As controls, 87 CSF samples from 60 patients with acute febrile focal encephalopathy (initially suspected to be herpes simplex encephalitis but excluded by the absence of intrathecal antibody synthesis) were tested. PCR detected herpes simplex virus DNA in 42 of the 43 patients with proven herpes simplex encephalitis; all but 1 were positive in the first CSF sample taken. The 1 PCR-negative patient had been treated with acyclovir from 20 h after the onset of symptoms. All the control subjects were PCR negative, as were 270 internal contamination controls. The PCR result remained positive in samples drawn up to 27 days after the onset of neurological symptoms. This method is a rapid and non-invasive means to diagnose herpes simplex encephalitis; it is highly sensitive and specific.