Evaluation of commercial herpes simplex virus IgG and IgM enzyme immunoassays

Current methods for microbiological diagnosis of acute central nervous system infections

The incidence of infections affecting the central nervous system has increased in recent years, making neuroinfections a current global health problem. The central nervous system is quite well protected from the external and internal environments, although it is susceptible to infection by a wide variety of pathogens. The etiological diversity further complicates the management of such infections because it is important to identify correctly the specific cause in order to choose the most appropriate antimicrobial therapy. Diagnosis is made not only based on clinical and epidemiological data but also on the results of clinical laboratory and microbiological examination of cerebrospinal fluid. This article aims to review current microbiological methods in the diagnosis of acute central nervous system infections and help healthcare providers to recognize their advantages and limitations in order to manage their patients appropriately.

Investigation of the association between the antibody responses to neurotropic viruses and dementia outcomes in the UK Biobank

The causes that trigger the onset of dementia are still unknown. Recently there has been an increasing interest in the possible role of infectious agents in the brain in the pathogenesis of this condition. Amongst the viruses, members of the Herpesviridae family, namely herpes simplex virus-1 (HSV1), cytomegalovirus (CMV), human herpesvirus-6 (HHV6), human herpesvirus-7 (HHV7) and varicella zoster virus (VZV) have been suggested as potential causes of the disease. However, the relative importance of these and other viruses in contributing to dementia remains unclear. We evaluated the association between seropositivity status of all viruses available in a large, population-based dataset (the UK Biobank) and dementia risk in an unbiased way. Of the 15 viruses investigated, our results showed a statistically significant increase of dementia risk associated only with HSV1 seropositivity (OR 2.14, 95% C.I. 1.21-3.81). However, by combining the data we found that seropositivity for 4 viruses (HSV1, HHV6, HHV7 and VZV) also significantly increases the risk of dementia (OR = 2.37, 95% C.I. 1.43-3.92). These four viruses have been described previously as neurotropic viruses. Our results provide support for a role for neurotropic viruses in the pathology of dementia.

Eczema herpeticum: A clinical diagnosis not to be missed

Eczema herpeticum is an uncommon complication of atopic dermatitis, but often has a typical recognisable appearance. This report serves to highlight this feature in a patient who was misdiagnosed initially with a bacterial skin infection and then with a severe cutaneous drug reaction.

Corneal Sub-Basal Nerve Changes in Patients with Herpetic Keratitis During Acute Phase and after 6 Months

Background and objectives: The purpose of this study was to describe corneal sensitivity and the morphological changes of sub-basal corneal nerves using in vivo laser scanning confocal microscopy (LSCM) in herpes simplex virus (HSV) keratitis-affected eyes, and to compare with both contralateral eyes and with the eyes of patients with a previous history of herpes labialis but no history of herpetic eye disease, and with healthy patients with no history of any HSV diseases, during the acute phase of the disease and after six months. Materials and Methods: A prospective clinical study included 269 patients. All of them underwent a complete ophthalmological examination, Cochet-Bonnet aesthesiometry and LSCM within the central 5 mm of the cornea. After six months, all the patients with herpetic eye disease underwent the same examination. Serology tests of the serum to detect HSV 1/2 IgG and IgM were performed. Results: HSV-affected eyes compared with contralateral eyes, herpes labialis and healthy control group eyes demonstrated a significant decrease in corneal sensitivity, corneal nerve fibre density, corneal nerve branch density, corneal nerve fibre length and corneal nerve total branch density (p < 0.05). During follow up after six months, corneal sensitivity and sub-basal nerve parameters had increased but did not reach the parameters of contralateral eyes (p < 0.05). Previous herpes labialis did not influence corneal sensitivity and was not a risk factor for herpetic eye disease. Conclusions: Corneal sensitivity and sub-basal nerve changes in HSV-affected eyes revealed a significant decrease compared with contralateral eyes, and with the eyes of patients with a previous history of herpes labialis, and of healthy controls. Following six months, corneal sensitivity and sub-basal nerve parameters increased; however, they did not reach the parameters of contralateral eyes and the eyes of healthy controls. The best recovery of corneal sensitivity was seen in patients with epithelial keratitis. Herpes labialis was not a risk factor for herpetic eye disease.

Tools for the Diagnosis of Herpes Simplex Virus 1/2: Systematic Review of Studies Published Between 2012 and 2018

Background

Herpes simplex virus (HSV)-1 and HSV-2 are common infections affecting the global population, with HSV-1 estimated to affect 67% of the global population. HSV can have rare but severe manifestations, such as encephalitis and neonatal herpes, necessitating the use of reliable and accurate diagnostic tools for the detection of the viruses. Currently used HSV diagnostic tools require highly specialized skills and availability of a laboratory setting but may lack sensitivity. The numerous recently developed HSV diagnostic tools need to be identified and compared in a systematic way to make the best decision about which diagnostic tool to use. The diagnosis of HSV is essential for prompt treatment with antivirals. To select the best test for a patient, knowledge of the performance and limitations of each test is critical.

Objective

This systematic review has summarized recent studies evaluating HSV-1 and HSV-2 diagnostic tools.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, selection criteria, data extraction, and data analysis were determined before the commencement of the study. Studies assessing the specificity/sensitivity of HSV-1 or HSV-2 diagnostic tools published between 2012 and 2018 were included. Quality assessment of included studies was performed using the quality assessment of diagnostic accuracy studies (QUADAS-2) tool.

Results

Searches of the PubMed database yielded 264 studies; 11 studies included 11 molecular assays, and 8 studies included 19 different serological assays for the detection of HSV-1, HSV-2, or both. A greater proportion of molecular assay–based tools are being developed by commercial entities. Studies that tested molecular assays mostly focused on cutaneous and mucosal HSV infections (n=13); 2 studies focused on ocular disease, whereas only 1 study focused on the central nervous system manifestations. The Simplexa HSV 1 & 2 Direct is currently the only Food and Drug Administration–approved device for use on cerebrospinal fluid. No tools focused on prenatal screening. We also present performance metrics of tests for benchmarking of future technology. Most of the included studies had a high risk of bias rating in half of the QUADAS-2 tool risk of bias domains.

Conclusions

The use of serologic tests to diagnose genital lesions is inappropriate because positive results may be due to chronic infection, whereas negative results may overlook recent infection. The incidence of acute infections is rising. As these infections present the greatest risk to fetuses, work needs to be done to prevent vertical transfer. Prenatal screening for primary infection and subsequent medical intervention will assist in lowering the rate of neonatal herpes. In conclusion, HSV diagnosis is moving away from culture-based methods to serology-based or polymerase chain reaction–based methods. Sensitive, rapid, and efficient HSV diagnostic tools should be adopted for the prevention of acute infections and neonatal herpes.

Genital ulcers caused by herpes simplex virus

Genital herpes is a sexually transmitted disease caused by herpes simplex virus type1 (HSV-1) and type2 (HSV-2) belonging to the alphaherpesvirus family, that includes the varicella zoster virus. HSV infection continues to be the most common cause of vulvar ulcers among the sexually active population. Its incidence increases every year. This review summarises the microbiology of the virus, pathogenesis and infection in genitalia, clinical manifestations and correct identification, the different laboratory diagnostic methods, and choice of the correct treatment according to the first infection, recurrence or special cases. Finally, the cost of routine herpes simplex virus infection is analysed.

Detection of antibody-secreting cells specific for the cytomegalovirus and herpes simplex virus surface antigens

Infections with the herpes simplex virus (HSV) and the human cytomegalovirus (HCMV) can lead to life-threatening diseases, particularly in immunosuppressed patients. Furthermore, HSV infections at birth (herpes neonatorum) can result in a disseminated disease associated with a fatal multiorgan failure. Congenital HCMV infections can result in miscarriage, serious birth defects or developmental disabilities. Antibody-based interventions with hyperimmunoglobulins showed encouraging results in clinical studies, but clearly need to be improved. The isolation of highly neutralizing monoclonal antibodies is a promising strategy to establish potent therapy options against HSV and HCMV infections.

Monoclonal antibodies are commonly isolated from hybridomas or EBV-immortalized B-cell clones. The screening procedure to identify virus-specific cells from a cell mixture is a challenging step, since most of the highly neutralizing antibodies target complex conformational epitopes on the virus surface. Conventional assays such as ELISA are based on purified viral proteins and inappropriate to display complex epitopes.

To overcome this obstacle, we have established two full-virus based methods that allow screening for cells and antibodies targeting complex conformational epitopes on viral surface antigens. The methods are suitable to detect surface antigen-specific cells from a cell mixture and may facilitate the isolation of highly neutralizing antibodies against HSV and HCMV.

Interpretation and Relevance of Advanced Technique Results

Advanced techniques in the field of diagnostic microbiology have made amazing progress over the past 25 years due largely to a technological revolution in the molecular aspects of microbiology [1, 2]. In particular, rapid molecular methods for nucleic acid amplification and characterization combined with automation in the clinical microbiology laboratory as well as user-friendly software and robust laboratory informatics systems have significantly broadened the diagnostic capabilities of modern clinical microbiology laboratories. Molecular methods such as nucleic acid amplification tests (NAATs) rapidly are being developed and introduced in the clinical laboratory setting [3, 4]. Indeed, every section of the clinical microbiology laboratory, including bacteriology, mycology, mycobacteriology, parasitology, and virology, has benefited from these advanced techniques. Because of the rapid development and adaptation of these molecular techniques, the interpretation and relevance of the results produced by such molecular methods continues to lag behind. The purpose of this chapter is to review, update, and discuss the interpretation and relevance of results produced by these advanced molecular techniques.

[Genital herpes and pregnancy: Serological and molecular diagnostic tools. Guidelines for clinical practice from the French College of Gynecologists and Obstetricians (CNGOF)]

OBJECTIVES

To describe serological and molecular tools available for genital and neonatal herpes, and their use in different clinical situations.

METHODS

Bibliographic investigations from MedLine database and consultation of international clinical practice guidelines.

RESULTS

Virological confirmation of genital herpes during pregnancy or neonatal herpes must rely on PCR (Professional consensus). HSV type-specific serology (IgG) will allow determining the immune status of a patient (in the absence of clinical lesions). However, there is currently no evidence to justify universal HSV serological testing during pregnancy (Professional consensus). In case of genital lesions in a pregnant woman that do not report any genital herpes before, it is recommended to perform a virological confirmation by PCR and HSV type-specific IgG in order to distinguish a true primary infection, a non-primary infection associated with first genital manifestation, from a recurrence (Grade C). HSV IgM is useless for diagnosis of genital herpes (Grade C). If a pregnant woman has personal history of genital herpes but no lesions, whatever the gestational age, it is not recommended to perform genital sampling nor serology (Professional consensus). In case of recurrence, if the lesion is characteristic of herpes, virological confirmation is not necessary (Professional Agreement). However, if the lesion is not characteristic, virological confirmation by PCR should be performed (Professional consensus). At birth, HSV PCR samples should be collected as soon as neonatal herpes is suspected (symptomatic neonate) (best before beginning antiviral treatment but must not delay the treatment), or after 24hours of life in case of asymptomatic neonate born to a mother with herpes lesions at delivery (Professional consensus). Clinical samples for virological confirmation should include at least blood and a peripheral location. In case of clinical manifestations of herpes in the neonate, first samples PCR positive, preterm birth, or maternal primary infection or non-primary infection associated with first genital manifestation at delivery, CSF should also be collected as well as samples of lesions in the neonate if present (Professional consensus). Sampling should be repeated in case of PCR negative but strong evidence of neonatal herpes (Professional consensus). HSV serology is useless for diagnosis of neonatal herpes (Grade C).

CONCLUSIONS

Virological confirmation for diagnosis of genital herpes during pregnancy or neonatal herpes must rely on PCR. PCR assays available in France are very reliable. Specific IgG are dedicated to restricted indications.

Comparison of commercial methods of immunoblot, ELISA, and chemiluminescent immunoassay for detecting type-specific herpes simplex viruses-1 and -2 IgG

BACKGROUND

Serology for type-specific herpes simplex virus (HSV) is based on the use of the respective glycoprotein G (gG).

METHODS

Chemiluminescent immunoassay (CLIA; BIO-FLASH^® , Biokit, Spain), ELISA (HerpeSelect^® , Focus, USA), and immunoblot (IB; Virotech, Germany) for detecting HSV-1- and HSV-2-specific IgG were compared using 384 serum samples received for HSV serology. The samples were classified as positive or negative according to a consensus criterion.

RESULTS

For HSV-1, 262 samples were positive and 118 were negative (four samples were unclassifiable). IB showed agreement, sensitivity, and specificity values of 98.68%, 98.47% and 99.15%, respectively. The corresponding figures for CLIA and ELISA were 98.95%, 99.24% and 98.31%, and 98.16%, 99.62% and 94.92%, respectively. For HSV-2, 106 samples were positive and 278 were negative. Agreement, sensitivity, and specificity of IB were 99.48%, 98.11%, and 100%, respectively. The corresponding figures for CLIA and ELISA were 99.48%, 99.06% and 99.64%, and 98.18%, 99.06% and 97.84%, respectively.

CONCLUSION

The three methods showed excellent and equivalent performance characteristics for the detection of type-specific IgG to HSV-1 and HSV-2.

Maternal Antibodies to Herpes Virus Antigens and Risk of Gastroschisis in Offspring

Gastroschisis risk is highest in offspring of young women and is increasing in prevalence, suggesting that exposures that are increasingly common among younger females may be causal. Some infections by viruses in the herpes family are more common in the earlier childbearing years and have been increasing in prevalence over time. Data from the Finnish Maternity Cohort were linked to Finnish malformation and birth registers (1987-2012) for this study, a nested case-control study of mothers of offspring with gastroschisis and age-matched controls. Maternal antibody responses in early pregnancy (mean gestational age = 11.1 weeks) to Epstein Barr virus (EBV), herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), and cytomegalovirus were measured. Conditional logistic regression models were used to estimate odds ratios (and 95% confidence intervals) for high immunoglobulin reactivity. Odds ratios for high immunoglobulin M (IgM) reactivity to EBV-viral capsid antigen and HSV-1 or HSV-2 (as indicators of recent infection) were 2.16 (95% confidence interval (CI): 0.97, 4.79) and 1.94 (95% CI: 0.74, 5.12), respectively. For higher immunoglobulin G (IgG) reactivity to EBV-viral capsid antigen and HSV-2 IgG, odds ratios were 2.16 (95% CI: 0.82, 5.70) and 2.48 (95% CI: 1.50, 4.10), respectively. Reactivities to HSV-1 IgG, cytomegalovirus IgM, or cytomegalovirus IgG did not appear to increase gastroschisis risk. Primary EBV infection was not associated with gastroschisis, but observed associations with both IgM and IgG reactivities to EBV and HSV suggest that reactivations may be risk factors for it.

Herpes Genitalis: Diagnosis, Treatment and Prevention

Herpes genitalis is caused by the herpes simplex virus type 1 or type 2 and can manifest as primary or recurrent infection. It is one of the most common sexually transmitted infections and due to associated physical and psychological morbidity it constitutes a considerable, often underestimated medical problem. In addition to providing the reader with basic knowledge of the pathogen and clinical presentation of herpes genitalis, this review article discusses important aspects of the laboratory diagnostics, antiviral therapy and prophylaxis. The article is aimed at all health-care workers managing patients with herpes genitalis and attempts to improve the often suboptimal counselling, targeted use of laboratory diagnostics, treatment and preventive measures provided to patients.

Laboratory Diagnosis of Central Nervous System Infection

Central nervous system (CNS) infections are potentially life threatening if not diagnosed and treated early. The initial clinical presentations of many CNS infections are non-specific, making a definitive etiologic diagnosis challenging. Nucleic acid in vitro amplification-based molecular methods are increasingly being applied for routine microbial detection. These methods are a vast improvement over conventional techniques with the advantage of rapid turnaround and higher sensitivity and specificity. Additionally, molecular methods performed on cerebrospinal fluid samples are considered the new gold standard for diagnosis of CNS infection caused by pathogens, which are otherwise difficult to detect. Commercial diagnostic platforms offer various monoplex and multiplex PCR assays for convenient testing of targets that cause similar clinical illness. Pan-omic molecular platforms possess potential for use in this area. Although molecular methods are predicted to be widely used in diagnosing and monitoring CNS infections, results generated by these methods need to be carefully interpreted in combination with clinical findings. This review summarizes the currently available armamentarium of molecular assays for diagnosis of central nervous system infections, their application, and future approaches.

Optimal management of genital herpes: current perspectives

As one of the most common sexually transmitted diseases, genital herpes is a global medical problem with significant physical and psychological morbidity. Genital herpes is caused by herpes simplex virus type 1 or type 2 and can manifest as primary and/or recurrent infection. This manuscript provides an overview about the fundamental knowledge on the virus, its epidemiology, and infection. Furthermore, the current possibilities of antiviral therapeutic interventions and laboratory diagnosis of genital herpes as well as the present situation and perspectives for the treatment by novel antivirals and prevention of disease by vaccination are presented. Since the medical management of patients with genital herpes simplex virus infection is often unsatisfactory, this review aims at all physicians and health professionals who are involved in the care of patients with genital herpes. The information provided would help to improve the counseling of affected patients and to optimize the diagnosis, treatment, and prevention of this particular disease.

Antibody and Viral Nucleic Acid Testing of Serum and Cerebrospinal Fluid for Diagnosis of Eastern Equine Encephalitis

Eastern equine encephalitis diagnostic serum antibody can appear 6 days after the onset of symptoms, and its numbers can increase 4-fold in 4 days, arguing for early and frequent serum testing. In populations where cerebrospinal fluid viral nucleic acid testing sensitivity and specificity remain undetermined, cerebrospinal antibody testing should also be performed.

Development of a time-resolved fluorescence immunoassay for herpes simplex virus type 1 and type 2 IgG antibodies

Enzyme-linked immunosorbent assays (ELISA) specific for anti-HSV glycoprotein G (gG) are most commonly used in the clinical diagnosis of HSV infection. But most of them are qualitative and with narrow detection ranges. A novel time-resolved fluoroimmunoassay (TRFIA) methodology was developed for the quantitative determination of HSV IgG in human serum. The assay was based on an indirect immunoassay format, and performed in 96-well microtiter plates. HSV-1 and HSV-2 were used as the coating antigens. Eu(3+)-labeled goat anti-(human IgG) polyclonal antibodies were used as tracers. The fluorescence intensity of each well was measured and serum HSV IgG levels quantified against a calibration curve. The detection range of the novel TRFIA was between 5 and 500 AU/mL. Assay sensitivity was 0.568 AU/mL. The intra- and inter-assay coefficients of variation were 0.59-3.63% and 3.65-6.81%, respectively. Analytical recovery, dilution tests and serum panel tests were performed using TRFIA and the results proved satisfactory. There were no statistically significant differences in sensitivity and specificity between the TRFIA and commercial ELISAs. An effective, sensitive and accurate quantitative HSV type 1 and type 2 IgG TRFIA was successfully developed and provided diagnostic value in clinical use.