Performance of the Euroline Western blot assay in the detection of herpes simplex virus type 2 antibody in Uganda, China and the USA

The Epidemiology of Herpes Simplex Virus Type 1 in Asia: Systematic Review, Meta-analyses, and Meta-regressions

Background

Herpes simplex virus type 1 (HSV-1) epidemiology in Asia was characterized by assessing seroprevalence levels and extent to which HSV-1 is isolated from clinically diagnosed genital ulcer disease (GUD) and genital herpes.

Methods

HSV-1 reports in Asia were systematically reviewed and synthesized, following PRISMA guidelines. Random-effects meta-analyses estimated pooled mean seroprevalence and proportion of HSV-1 detection in GUD and genital herpes. Random-effects meta-regressions identified predictors of seroprevalence and sources of between-study heterogeneity.

Results

Forty-nine relevant publications were identified. Fifty-four overall seroprevalence measures (182 stratified measures), and 8 and 24 proportions of HSV-1 detection in GUD and in genital herpes, respectively, were extracted. The pooled mean seroprevalence was 50.0% (n = 26; 95% confidence interval [CI], 41.3%–58.7%) for children and 76.5% (n = 151; 73.3%–79.6%) for adults. By age group, the pooled mean was lowest at 55.5% (n = 37; 95% CI, 47.5%–63.4%) in individuals aged <20 years, followed by 67.9% (n = 48; 62.4%–73.3%) in those aged 20–39 and 87.5% (n = 44; 83.4%–91.1%) in those aged ≥40 years. In meta-regression, age was the major predictor of seroprevalence. The mean proportion of HSV-1 detection was 5.6% (n = 8; 95% CI, 0.8%–13.6%) in GUD and 18.8% (n = 24; 12.0%–26.7%) in genital herpes.

Conclusions

HSV-1 epidemiology is transitioning in Asia. HSV-1 is probably playing a significant role as a sexually transmitted infection, explaining one-fifth of genital herpes cases. There is a need for expanded seroprevalence monitoring and GUD/genital herpes etiological surveillance.

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.

Herpes Simplex Virus Type 2 Seroprevalence Among Different National Populations of Middle East and North African Men

Herpes simplex virus type 2 seroprevalence among male blood donors from different Middle East and North Africa nationalities was in the range of few percentage points.

Supplemental digital content is available in the text.

Background

There are limited data on herpes simplex virus type 2 (HSV-2) seroprevalence in the Middle East and North Africa (MENA). We examined country- and age-specific HSV-2 seroprevalence among select MENA populations residing in Qatar.

Methods

Sera were collected from male blood donors attending Hamad Medical Corporation between June 2013 and June 2016. Specimens were screened for anti-HSV-2 IgG antibodies following a 2-test algorithm: HerpeSelect 2 ELISA was used to identify HSV-2–positive specimens, and Euroline-WB was used to confirm positive and equivocal specimens for final HSV-2 status. Trends and associations with HSV-2 seropositivity were assessed.

Results

Of the 2077 tested sera, 61 were found and confirmed positive. The proportion of those confirmed positive increased steadily with HerpeSelect 2 ELISA index value, ranging from 16.3% for index values of 1.101 to 1.999 to 92.9% for index values of 4 or greater. Nationality-specific seroprevalence was 6.0% (95% confidence interval [CI], 4.1%–8.8%) in Qataris, 5.3% (95% CI, 2.5%–11.1%) in Iranians, 4.2% (95% CI, 1.8%–9.5%) in Lebanese, 3.1% (95% CI, 1.2%–7.7%) in Sudanese, 3.0% (95% CI, 1.4%–6.4%) in Palestinians, 2.2% (95% CI, 1.1%–4.3%) in Egyptians, 2.0% (95% CI, 1.0%–5.0%) in Syrians, 1.0% (95% CI, 0.3%–3.6%) in Jordanians, 0.7% (95% CI, 0.1%–3.7%) in Yemenis, and 0.5% (95% CI, 0.1%–2.8%) in Pakistanis. There was evidence for higher seroprevalence in older age groups.

Conclusions

The seroprevalence of HSV-2 was in the range of few percentage points. There were no major differences in seroprevalence by nationality. These findings add to our understanding of HSV-2 epidemiology in MENA and indicate unmet needs for sexual health and control of sexually transmitted infections.

Performance of four diagnostic assays for detecting herpes simplex virus type 2 antibodies in the Middle East and North Africa

BACKGROUND

Assessments of commercial assays in detecting herpes simplex virus type 2 (HSV-2) antibodies have shown variable sensitivity and specificity, and variation in performance by global population.

OBJECTIVE

To evaluate performance of four assays in detecting HSV-2 antibodies in a composite Middle Eastern and North African (MENA) population. The assays are two ELISA kits: HerpeSelect^® 2 ELISA IgG and Euroimmun Anti-HSV-2 (gG2) ELISA (IgG), and two immunoblot (IB)/Western blot (WB) assays: HerpeSelect^® 1 and 2 Immunoblot IgG and Euroimmun Anti-HSV-1/HSV-2 gG2 Euroline-WB (IgG/IgM).

STUDY DESIGN

Blood specimens were drawn from blood donors between 2013-2016 in Doha, Qatar. Twenty specimens from ten nationalities (Egypt, Iran, Jordan, Lebanon, Pakistan, Palestine, Qatar, Sudan, Syria, and Yemen; total = 200) were randomly selected and tested for HSV-2 antibodies.

RESULTS

In the six possible assay comparisons, Cohen's kappa statistics indicated fair to good agreement, ranging between 0.57 (95% CI 0.28-0.86) and 0.69 (95% CI 0.44-0.95). Meanwhile, positive percent agreement ranged between 50.0 (95% CI 18.7-81.3%) and 63.6% (95% CI 30.8-89.1%); negative percent agreement ranged between 97.8% (95% CI 94.4-99.4%) and 99.5% (95% CI 97.0-100.0%); and overall percent agreement ranged between 95.8% (95% CI 91.9-97.9%) and 97.5% (95% CI 94.2-98.9%). The two ELISA kits demonstrated comparable sensitivities and specificities ≥50% and >98%, respectively, with respect to the IB/WB assays.

CONCLUSION

The study provided, for the first time, primary data on performance of these assays in diagnosing HSV-2 infection in MENA populations. Findings support comparable performance and utility of these assays, and demonstrate challenges in establishing seropositivity (versus seronegativity).

Performance of ELISA and Western blot to detect antibodies against HSV-2 using dried blood spots

BACKGROUND AND AIMS

Herpes simplex virus type 2 (HSV-2) is a sexually transmitted agent and is detected worldwide. HSV-2 is the main cause of genital ulcers and is diagnosed mainly with serological tests. The objective of current study was to evaluate the use of DBS samples to detect HSV-2 antibodies using commercial ELISA and Western blot tests.

MATERIALS AND METHODS

IgG-G2 ELISA (Human^® Diagnostics, Germany) and Western blot IgG/IgM (EUROLINE-WB, Euroimmun^® Germany) tests were modified to use DBS samples. Samples were processed by both methods to determine ELISA cutoff points using ROC curves. ELISA was performed with 100μl and the Western blot with 200μl of eluted DBS. A 1:5 dilution was used and the incubation times were increased for the Western blot.

RESULTS

908 DBS samples were processed and the following cutoff points were determined: negative (0-3.79), undetermined (3.8-4.6) and positive (≥4.61), with sensitivity and specificity close to 95%.

CONCLUSION

Modifications of the cutoff points of the ELISA test were obtained with technical adjustments done to detect HSV-2 antibodies by ELISA and Western blot using DBS samples.

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.

Protein purification and analysis: next generation Western blotting techniques

INTRODUCTION

Western blotting is one of the most commonly used techniques in molecular biology and proteomics. Since western blotting is a multistep protocol, variations and errors can occur at any step reducing the reliability and reproducibility of this technique. Recent reports suggest that a few key steps, such as the sample preparation method, the amount and source of primary antibody used, as well as the normalization method utilized, are critical for reproducible western blot results. Areas covered: In this review, improvements in different areas of western blotting, including protein transfer and antibody validation, are summarized. The review discusses the most advanced western blotting techniques available and highlights the relationship between next generation western blotting techniques and its clinical relevance. Expert commentary: Over the last decade significant improvements have been made in creating more sensitive, automated, and advanced techniques by optimizing various aspects of the western blot protocol. New methods such as single cell-resolution western blot, capillary electrophoresis, DigiWest, automated microfluid western blotting and microchip electrophoresis have all been developed to reduce potential problems associated with the western blotting technique. Innovative developments in instrumentation and increased sensitivity for western blots offer novel possibilities for increasing the clinical implications of western blot.

Current Concepts for Genital Herpes Simplex Virus Infection: Diagnostics and Pathogenesis of Genital Tract Shedding

Herpes simplex virus 2 (HSV-2) is a DNA virus that is efficiently transmitted through intimate genital tract contact and causes persistent infection that cannot be eliminated. HSV-2 may cause frequent, symptomatic self-limited genital ulcers, but in most persons infection is subclinical. However, recent studies have demonstrated that the virus is frequently shed from genital surfaces even in the absence of signs or symptoms of clinical disease and that the virus can be transmitted during these periods of shedding. Furthermore, HSV-2 shedding is detected throughout the genital tract and may be associated with genital tract inflammation, which likely contributes to increased risk of HIV acquisition. This review focuses on HSV diagnostics, as well as what we have learned about the importance of frequent genital HSV shedding for (i) HSV transmission and (ii) genital tract inflammation, as well as (iii) the impact of HSV-2 infection on HIV acquisition and transmission. We conclude with discussion of future areas of research to push the field forward.

Human papillomavirus incidence and clearance among HIV-positive and HIV-negative men in sub-Saharan Africa

OBJECTIVES

High-risk human papillomavirus (HR-HPV) infection is the most common sexually transmitted infection. Penile and cervical cancer rates are highest in sub-Saharan Africa. However, little is known about the impact of HIV infection on HR-HPV acquisition and clearance among heterosexual men.

DESIGN

HR-HPV incidence and clearance were evaluated in 999 men (776 HIV-negative and 223 HIV-positive) aged 15-49 years who participated in male circumcision trials in Rakai, Uganda.

METHODS

Penile swabs were tested for HR-HPV by Roche HPV Linear Array. A Poisson multivariable model was used to estimate adjusted incidence rate ratios (adjIRRs) and clearance risk ratios (adjRRs).

RESULTS

HR-HPV incidence was 66.5/100 person-years in HIV-positive men and 32.9/100 person-years among HIV-negative men [IRR=2.02, 95% confidence interval (CI) 1.67-2.44]. Incidence was higher in the unmarried men (adjIRR=1.73, 95% CI 1.19-2.52), and decreased with age (adjIRR for men >35 years=0.64, 95% CI 0.43-0.94) and male circumcision (adjIRR=0.70, 95% CI 0.55-0.89). HR-HPV clearance was 114.7/100 person-years for HIV-positive men and 170.2/100 person-years for HIV-negative men (risk ratio=0.67, 95% CI 0.59-0.77). HR-HPV clearance in HIV-negative men increased with circumcision (adjRR=1.48, 95% CI 1.26-1.74), HSV-2 infection (adjRR=1.20, 95% CI 1.01-1.44), and symptoms of urethral discharge (adjRR=1.35, 95% CI 1.06-1.73). Clearance of HR-HPV was significantly lower for unmarried men (adjRR 0.76, 95% CI 0.59-0.98).

CONCLUSION

HR-HPV is common among heterosexual Ugandan men, particularly the HIV-infected. HIV infection increases HR-HPV acquisition and reduces HR-HPV clearance. Promotion of male circumcision and additional prevention measures, such as HPV vaccination, is critical in sub-Saharan Africa.