Comparison of a multiplexed herpes simplex virus type-specific immunoglobulin G serology assay to immunoblot, Western blot, and enzyme-linked immunosorbent assays

Diagnosis of Herpes Simplex Virus: Laboratory and Point-of-Care Techniques

Herpes is a widespread viral infection caused by the herpes simplex virus (HSV) that has no permanent cure to date. There are two subtypes, HSV-1 and HSV-2, that are known to cause a variety of symptoms, ranging from acute to chronic. HSV is highly contagious and can be transmitted via any type of physical contact. Additionally, viral shedding can also happen from asymptomatic infections. Thus, early and accurate detection of HSV is needed to prevent the transmission of this infection. Herpes can be diagnosed in two ways, by either detecting the presence of the virus in lesions or the antibodies in the blood. Different detection techniques are available based on both laboratory and point of care (POC) devices. Laboratory techniques include different biochemical assays, microscopy, and nucleic acid amplification. In contrast, POC techniques include microfluidics-based tests that enable on-spot testing. Here, we aim to review the different diagnostic techniques, both laboratory-based and POC, their limits of detection, sensitivity, and specificity, as well as their advantages and disadvantages.

Characterization of polyclonal antibodies to Herpes Simplex Virus types 1 and 2

Infections with herpes simplex virus (HSV) types 1 and 2 have been linked to oral, facial, genital lesions, as well as some visceral organ changes in patients under immunosuppressed conditions. Immunohistochemistry (IHC) with HSV antibodies is used for identification of the viruses in tissue samples. In this study, two polyclonal antibodies, prepared separately with HSV-1 and HSV-2 immunogens, were characterized in comparison to a monoclonal antibody to HSV-1 (10A3). The polyclonal anti-HSV-1 and monoclonal antibody 10A3 were shown to be reactive to viral proteins of both HSV-1 and HSV-2 on Western blots, while the polyclonal anti-HSV-2 was reactive to HSV-2 proteins, but not to those of HSV-1. Cross-reactivity was not observed to proteins of six other frequently encountered herpes viruses. IHC characterization was performed on 29 cases of HSV-infected tissue samples, 61 samples infected with other herpes viruses and 35 samples without known infection. By IHC, the polyclonal anti-HSV-1 and a monoclonal antibody 10A3 exhibited a signal, mainly in a nuclear pattern, in all of the HSV-infected samples and not in other tissue types. A positive signal, mainly in the cytoplasm, was identified with the polyclonal anti-HSV-2 in 21 of the 29 HSV-infected samples. Genotyping analysis was successful in 14 of the HSV-infected samples, with IHC HSV-2 positivity correlative to the HSV-2 genotype. The results demonstrate that these antibodies are useful tools for identification of HSV-1 and HSV-2, and their combinatorial application may help to distinguish between these two types of infection.

Herpes simplex virus type 1 epidemiology in Africa: Systematic review, meta-analyses, and meta-regressions

OBJECTIVE

To assess herpes simplex virus type 1 (HSV-1) epidemiology in Africa.

METHODS

This systematic review was conducted per the Cochrane Collaboration guidelines. Findings were reported following the PRISMA guidelines. Research questions were addressed using random-effects meta-analyses and meta-regressions.

RESULTS

Forty-three overall (and 69 stratified) HSV-1 seroprevalence measures, and 18 and eight proportions of HSV-1 viral detection in genital ulcer disease (GUD) and in genital herpes, respectively, were extracted from 37 reports. Pooled mean seroprevalence was 67.1% (95% confidence interval (CI): 54.7-78.5%) in children, and 96.2% (95% CI: 95.0-97.3%) in adults. Across age groups, pooled mean was 44.4% (95% CI: 29.9-59.3%) in ≤5 years-old, 85.6% (95% CI: 81.0-89.6%) in 6-15 years-old, 93.3% (95% CI: 89.2-96.6%) in 16-25 years-old, and 93.8% (95% CI: 84.6-99.4%) in >25 years-old. Age explained 78.8% of seroprevalence variation. Pooled mean proportion of HSV-1 detection was 0.4% (95% CI: 0.0-1.5%) in GUD, and 1.2% (95% CI: 0.0-4.0%) in genital herpes.

CONCLUSIONS

HSV-1 is universally prevalent in Africa, at higher levels than other regions, with no evidence for declines in seroprevalence in recent decades. Nearly every person acquires the infection in childhood through oral-to-oral transmission, before sexual debut. Sexual oral-to-genital and genital-to-genital transmission appear very limited.

Performance evaluation of four type-specific commercial assays for detection of herpes simplex virus type 1 antibodies in a Middle East and North Africa population

BACKGROUND

The number of diagnostic assays for the detection of herpes simplex virus type 1 (HSV-1) antibodies has increased over the years. However, their performance characteristics could vary among global populations.

OBJECTIVE

To investigate performance of two commercial ELISA kits, HerpeSelect^® 1 ELISA and Euroimmun Anti-HSV-1 (gC1) ELISA (IgG); and two commercial immunoblot (IB)/Western blot (WB) assays, HerpeSelect^® 1 and 2 Immunoblot IgG, and Euroimmun Anti-HSV-1/HSV-2 gG2 Euroline-WB (IgG/IgM); in detecting HSV-1 antibodies in a Middle East and North Africa (MENA) population.

STUDY DESIGN

Blood specimens were collected from blood donors in Doha, Qatar, June 2013-2016. Twenty specimens were randomly selected from 10 MENA nationalities (Egypt, Iran, Jordan, Lebanon, Pakistan, Palestine, Qatar, Sudan, Syria, and Yemen; total = 200), and tested for HSV-1 antibodies.

RESULTS

Across all six comparisons between assays, positive percent agreement ranged between 95.7% (95% CI: 91.4-98.3%) and 100.0% (95% CI: 97.8-100.0%). Negative percent agreement ranged between 86.2% (95% CI: 68.3-96.1%) and 96.2% (95% CI: 80.4-99.9%). Overall percent agreement ranged between 95.7% (95% CI: 91.7-97.8%) and 99.4% (95% CI: 96.7-99.9%). Cohen's kappa statistic ranged between 0.84 (95% CI: 0.73-0.95) and 0.98 (95% CI: 0.93-1.00). Compared against IB/WB, HerpeSelect^® and Euroimmun had sensitivities and specificities >96% and >86%, respectively. Positive and negative predictive values were >97% and >83%, respectively.

CONCLUSION

The assays showed excellent concordance with one another, and with a high kappa statistic. The ELISA kits demonstrated robust diagnostic performance compared to the IB/WB assays. These findings support the assays' utility in clinical diagnosis and research in MENA populations.

Herpes Simplex Virus and Varicella-Zoster Virus

The most common specimens from immunocompromised patients that are analyzed for detection of herpes simplex virus (HSV) or varicella-zoster virus (VZV) are from skin lesions. Many types of assays are applicable to these samples, but some, such as virus isolation and direct fluorescent antibody testing, are useful only in the early phases of the lesions. In contrast, nucleic acid (NA) detection methods, which generally have superior sensitivity and specificity, can be applied to skin lesions at any stage of progression. NA methods are also the best choice, and sometimes the only choice, for detecting HSV or VZV in blood, cerebrospinal fluid, aqueous or vitreous humor, and from mucosal surfaces. NA methods provide the best performance when reliability and speed (within 24 hours) are considered together. They readily distinguish the type of HSV detected or the source of VZV detected (wild type or vaccine strain). Nucleic acid detection methods are constantly being improved with respect to speed and ease of performance. Broader applications are under study, such as the use of quantitative results of viral load for prognosis and to assess the efficacy of antiviral therapy.

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.

Multicenter evaluation of the Luminex® ARIES® HSV 1&2 Assay for the detection of herpes simplex virus types 1 and 2 in cutaneous and mucocutaneous lesion specimens

INTRODUCTION

The ARIES® HSV 1&2 Assay is a new FDA cleared real-time PCR test for detection and differentiation of HSV-1 and HSV-2 DNA from cutaneous and mucocutaneous lesions. The test is performed on the ARIES® System, an automated sample to answer real-time PCR instrument that provides a closed system and simple workflow for performing molecular testing. Areas covered: This article reports the clinical performance of the ARIES® HSV 1&2 Assay assessed on 1963 prospectively collected specimens. Assay sensitivities were 91.1-95% (cutaneous) and 97-98.5% (mucocutaneous), and specificities were 88.8-94.2% (cutaneous) and 93.2-95.4% (mucocutaneous), as compared to the ELVIS® HSV test system. Expert commentary: Detection of HSV DNA by PCR is rapid and more sensitive than traditional culture and immunoassay methods and is being widely adopted in many laboratory settings. Sample to answer molecular platforms like ARIES® will enable routine and non-molecular labs to perform sensitive and rapid molecular testing with ease.

Cardiac Myosin Epitopes Recognized by Autoantibody in Acute and Convalescent Rheumatic Fever

BACKGROUND

Acute rheumatic fever (ARF) is an autoimmune disorder associated with Streptococcus pyogenes infection. A prevailing hypothesis to account for this disease is that epitopes of self-antigens, such as cardiac myosin react to antibodies against S. pyogenes. The goal of our study was to confirm disease epitopes of cardiac myosin, identify immunodominant epitopes and to monitor the epitope response pattern in acute and convalescent rheumatic fever.

METHODS

Enzyme-linked immunosorbant assays were used to determine epitopes immunodominant in acute disease and to track the immune response longitudinally to document any changes in the epitope pattern in convalescent sera. Multiplex fluorescence immunoassay was used to correlate anti-streptolysin O (ASO) and anti-human cardiac myosin antibodies.

RESULTS

Disease-specific epitopes in rheumatic fever were identified as S2-1, 4 and 8. Epitopes S2-1, 4, 8 and 9 were found to be immunodominant in acute sera and S2-1, 8, 9, 29 and 30 in the convalescent sera. Frequency analysis showed that 50% of the ARF subjects responded to S2-8. S2-8 responders tended to maintain their epitope pattern throughout the convalescent period, whereas the S2-8 nonresponders tended to spread their responses to other epitopes later in the immune response. There was a significant correlation between anti-cardiac myosin and ASO titers. In addition, S2-8 responders showed elevated ASO titers compared with S2-8 non responders.

CONCLUSION

Our studies confirm the existence of S2-1, 4 and 8 as disease-specific epitopes. We provide evidence that cardiac myosin S2-8 responders remain epitope stable in convalescence, whereas S2-8 nonresponders shift to neoepitopes. Multiplex data indicated a correlation between elevated ASO and anti-human cardiac myosin antibody titers. Mapping of cardiac myosin epitopes recognized in rheumatic fever sera may identify immunophenotypes of rheumatic fever.

Light microscopy, culture, molecular, and serologic methods for detection of herpes simplex virus

Herpes simplex virus 1 (HSV-1) and 2 (HSV-2) cause a variety of human diseases, ranging from acute to chronic and mild to severe. The absence of curative therapy results in lifelong carriage marked by recurrent outbreaks and allows transmission of the virus to uninfected individuals. Nonspecific lesions, variable presentation, and chronic carriage necessitate the use of different laboratory testing methods appropriate for each presentation. A thorough understanding of the performance characteristics and limitations of available tests is critical for selection of the appropriate test and interpretation of results. Clinical sensitivity, specificity, and selection of the appropriate methodology is paramount to avoid misdiagnosis and guide therapy. In this article we review the different methods for detection and typing of HSV, including light microscopy, culture, serology, and nucleic acid-based tests. We discuss the strengths and weaknesses of each method for diagnosing HSV infection, cite performance characteristics, and review appropriate clinical uses.

Serologic prevalence of amoeba-associated microorganisms in intensive care unit pneumonia patients

BACKGROUND

Patients admitted to intensive care units are frequently exposed to pathogenic microorganisms present in their environment. Exposure to these microbes may lead to the development of hospital-acquired infections that complicate the illness and may be fatal. Amoeba-associated microorganisms (AAMs) are frequently isolated from hospital water networks and are reported to be associated to cases of community and hospital-acquired pneumonia.

METHODOLOGY/PRINCIPAL FINDINGS

We used a multiplexed immunofluorescence assay to test for the presence of antibodies against AAMs in sera of intensive care unit (ICU) pneumonia patients and compared to patients at the admission to the ICU (controls). Our results show that some AAMs may be more frequently detected in patients who had hospital-acquired pneumonia than in controls, whereas other AAMs are ubiquitously detected. However, ICU patients seem to exhibit increasing immune response to AAMs when the ICU stay is prolonged. Moreover, concomitant antibodies responses against seven different microorganisms (5 Rhizobiales, Balneatrix alpica, and Mimivirus) were observed in the serum of patients that had a prolonged ICU stay.

CONCLUSIONS/SIGNIFICANCE

Our work partially confirms the results of previous studies, which show that ICU patients would be exposed to water amoeba-associated microorganisms, and provides information about the magnitude of AAM infection in ICU patients, especially patients that have a prolonged ICU stay. However, the incidence of this exposure on the development of pneumonia remains to assess.

Evaluation of three multiplex flow immunoassays compared to an enzyme immunoassay for the detection and differentiation of IgG class antibodies to herpes simplex virus types 1 and 2

The diagnosis of herpes simplex virus (HSV) infections is routinely made based on clinical findings and supported by laboratory testing using PCR or viral culture. However, in instances of subclinical or unrecognized HSV infection, serologic testing for IgG class antibodies to type-specific HSV glycoprotein G (gG) may be useful. This study evaluated and compared the performances of three multiplex flow immunoassays (AtheNA Multi-Lyte [Zeus Scientific], BioPlex 2200 [Bio-Rad Laboratories], and Plexus HerpeSelect [Focus Diagnostics]) for the simultaneous detection of gG type-specific IgG antibodies to HSV types 1 and 2 (HSV-1 and HSV-2). Serum specimens (n = 505) submitted for routine gG type-specific HSV IgG testing by enzyme immunoassay (EIA) (HerpeSelect; Focus Diagnostics) were also tested by the three multiplex flow immunoassays. Specimens showing discordant results were tested by HSV type-specific Western blotting (WB). For HSV-1 IgG, the AtheNA, BioPlex, and Plexus assays demonstrated agreements of 94.9% (479/505 specimens), 97.8% (494/505 specimens), and 97.4% (492/505 specimens), respectively, with the results of EIA. For HSV-2 IgG, the AtheNA, BioPlex, and Plexus assays showed agreements of 87.9% (444/505 specimens), 97.2% (491/505 specimens), and 96.8% (489/505 specimens), respectively, with EIA results. Timing studies showed that the AtheNA, BioPlex, and Plexus assays could provide complete analysis of 90 serum specimens in 3.1, 1.5, and 2.9 h, respectively, versus 3.1 h by EIA. These findings suggest that the gG type-specific HSV IgG multiplex immunoassays may be beneficial to high-volume clinical laboratories experiencing significant increases in the number of specimens submitted for HSV serologic testing. The evaluated systems provide comparable results to those of EIA, while reducing hands-on time and eliminating the necessity to aliquot specimens prior to testing.