INTRODUCTION

Herpes zoster (HZ) is caused by reactivation of latent varicella-zoster virus (VZV) within the cranial nerve or dorsal root ganglia after primary infection. There is a lifetime risk, ~10% to 30%, of HZ in adults, but is rare in healthy children. Immunocompromised individuals have an increased risk of other diseases, including HZ. Risk of HZ increases by age and a weakened immune system, especially in poor T-cell immunity. In children with cancer, HZ can lead to severe complications, including severe postherpetic neuralgia, visceral dissemination, acute or progressive outer retinal necrosis, and even death. Limited information is available on HZ in children with cancer. Lin et al.1 performed a nationwide population-based cohort study in Taiwan to estimate the incidence of HZ in children with cancer. The study, conducted on the sizeable data-scale dataset available from the National Health Insurance (NHI) program in Taiwan, explored HZ and cancer’s association.

DISCUSSION

In a study by Lin et al.1 , they identified 4,432 newly diagnosed children with cancer between 2000 and 2007 from the outpatient database. As a non-cancer control group, 17,653 children without cancer were frequency matched by sex and age. The average ages at the entry of the cancer group and non-cancer groups were 8.90 and 8.91 years, respectively. The distributions of age at entry, sex, urbanization level, or residential areas, and the prevalence of atopic dermatitis were similar in the two groups. All children received follow-up until death, HZ event, withdrawal from NHI, or end of December 2008. Children with cancer had a significantly lower prevalence of allergic rhinitis and bronchial asthma. The study demonstrated a higher incidence of HZ in children with cancer. The incidence rate of HZ in the population of 4,432 children with cancer was 20.7 per 10,000 person-years, and the incidence rate in the population of 17,653 without cancer was 2.4 per 10,000 person-years. The cumulative incidence was significantly higher in the cancer group (p < 0.0001, or 8.6 times higher). HZ may occur more frequently in children with cancer. More than 80% of children with lymphoma or acute leukemia developed HZ within two years of a cancer diagnosis. A study by Feldman, Hughes, and Kim 2 reported that the overall incidence of HZ in 1,132 children with cancer was 8.9%, and the incidence was 22% higher in patients with Hodgkin disease. Menon and Wan Maziah 3 identified a diagnosis of HZ in 5% (10/188) of the children with cancer and noted the most common malignancy in their study was leukemia.

CONCLUSION

Lin et al.1  found the incidence rates of HZ was 8.6-fold higher in children with cancer than those without cancer. They found that children with cancer were associated with an increased risk of HZ, with those who had leukemia having the highest magnitude of strength association. Early antiviral therapy is mandatory for immunocompromised patients. They concluded that vaccination with either heat-treated zoster vaccine or adjuvanted subunit vaccine (ShingrixTM) could be an appropriate policy to decrease herpes zoster incidence in children with cancer.

REFERENCES

  1. Lin, H.-C., Chao, Y.-H., Wu, K.-H., Yen, T.-Y., Hsu, Y.-L., Hsieh, T.-H., Wei, H.-M., Wu, J.-L., Muo, C.-H., Hwang, K.-P., Peng, C.-T., Lin, C.-C., & Li, T.-C. (2016). Increased risk of herpes zoster in children with cancer: A nationwide population-based cohort study. Medicine, 95(30), e4037. https://doi.org/10.1097/md.0000000000004037
  2. Feldman, S., Hughes, W. T., & Kim, H. Y. (1973). Herpes zoster in children with cancer. American Journal of Diseases of Children, 126(2), 178-184. https://doi.org/10.1001/archpedi.1973.02110190156009
  3. Menon, B. S., Wan Maziah, W. M. (2001). Herpes zoster in children with cancer. The Malaysian Journal of Pathology, 23(1), 47-48. Retrieved from https://europepmc.org/article/med/16329548

By David Kilpatrick, PhD and Abbas Vafai, PhD

MKTG 1051 Rev A – 110220

INTRODUCTION:
In the first nine months of 2020, it is becoming increasingly clear that being infected with the severe acute respiratory syndrome Coronavirus 2 (SARSCoV-2), now commonly referred to as COVID-19, may lead to the reactivation of varicella-zoster virus (VZV), causing herpes zoster (HZ). Read more

INTRODUCTION:
Surprisingly, much of the general public do not know one of the human Herpesviruses, varicellazoster virus (VZV), causes chickenpox, and results in a life-long infection. VZV can re-activate after decades of being dormant in sensory nerve ganglia (usually in those over 60 years of age) to cause shingles infection. Read more

INTRODUCTION:
Herpes zoster (HZ) reactivation is characterized as a vascular rash of unilateral distribution that can also cause complications such as post-herpetic neuralgia, ophthalmic zoster, and other neurological diseases. Emerging epidemiological and clinical data recognizes an association between HZ and subsequent acute strokes and myocardial infarction (MI). Read more

INTRODUCTION:
Patients have a higher risk of HZ with diseases such as rheumatoid arthritis (RA), psoriasis (PsO), and inflammatory bowel-related diseases (IBD) such as ulcerative colitis (UC) and Crohn’s disease (CD). Using immunosuppressive therapy, which treats these diseases, increases the risk of HZ.

DISCUSSION:
The most common risk factor for HZ is increasing age, presumably due to a weakening immune system as we age. In approximately 15% of the general population, varicella-zoster virus (VZV) reactivates after a latency period to cause HZ (shingles). Patients with autoimmune diseases, such as RA, IBD, UC, PsO, and CD diseases, have an increased risk of HZ compared to the general population. The risk of HZ increases by the use of immunosuppressive therapy to treat autoimmune diseases. One such drug for treatment is Janus kinase (JAK) inhibition. Tofacitinib, an oral JAK inhibitor for the treatment of RA and psoriatic arthritis, is under investigation for the treatment of UC and previously for PsO. Although there is a dose-dependent risk for HZ when taking tofacitinib, the majority of HZ cases reported are non-complicated, mild to moderate in severity, and manageable with standard antiviral therapy (acyclovir). Vaccination (Shingrix) should be considered before treating patients to reduce the risk of HZ patients receiving JAK inhibitors1Colombel, J. F. (2018). Herpes zoster in patients receiving JAK inhibitors for ulcerative colitis: mechanism, epidemiology, management, and prevention. Inflammatory Bowel Diseases, 24(10), 2173-2182. https://doi.org/10.1093/ibd/izy150. Cullen, Baden, and Chiefetz2Cullen, G., Baden, R., P., & Cheifetz, A. S. (2012). Varicella zoster infection in inflammatory bowel disease. Inflammatory Bowel Diseases, 18(12), 2392-2403. https://doi.org/10.1002/ibd.22950 presented a review of publications describing VZV infections in inflammatory bowel disease (IBD) patients. They looked at 20 cases of primary VZV infection with IBD and 32 cases of HZ infections in patients with IBD. Fifteen of the 20 VZV cases had CD, which likely reflects the greater use of immunosuppression in this disease than UC. They identified various immunosuppressive drugs used in 20 patients, including anti-TNF (9 patients), corticosteroids (13), and either thiopurine or methotrexate (12). All 32 cases of HZ in IBD patients were on immunosuppression with corticosteroids, thiopurines, and anti-TNF. Combination therapy increased the risk of HZ even further. However, in a more comprehensive nationwide Veteran Administration study with 295 patients, Khan et al.3Khan, N., Trivedi, C., Shay, Y., Patel, D., Lewis, J., & Yang, Y. (2018). The severity of herpes zoster in inflammatory bowel disease patients treated with anti-TNF agents. Inflammatory Bowel Diseases, 24(6), 1274-1279. https://doi.org/10.1093/ibd/izx115 found that the incidence and severity of HZ in patients on anti-TNF medications were found not to be associated with an increased risk of developing severe HZ among these IBD patients. They believed TNF-α to play an important role in viral clearance, so it was logical to think anti-TNF medications could impair host immune function. Still, the data suggest that IBD patients who develop HZ during anti-TNF therapy are not at increased risk of developing complications from the HZ infection.

CONCLUSION:
Despite the risk of a reactivating HZ infection in persons with autoimmune diseases, such as those described, there are several immunosuppressive drugs available to treat these diseases, while not increasing the further risk of HZ infections. Both tofacitinib and anti-TNF therapies, as referenced above, are two such drugs. There is growing support for patients with IBD to receive vaccination against HZ using the newly released vaccine, Shingrix, before immunosuppressive therapy treatment. Shingrix vaccination is recommended even if patients have received the previous live virus vaccine.

By David Kilpatrick, PhD and Abbas Vafai, PhD

MKTG 1047 Rev A

INTRODUCTION:
Oral fluids have been used to detect Herpes virus antibodies, including secretory IgA, IgM, and IgG. Herpes virus particles have also been identified in saliva. Several Herpes viruses, such as Epstein–Barr virus (EBV), varicella-zoster virus (VZV), and herpes-simplex-1 (HSV-1), have even been detected in the saliva of Astronauts from shuttle-flights and ISS missions1Cohrs, R. J., Mehta, S. K., Schmid, D. S., Gilden, D. H., & Pierson, D. L. (2008). Asymptomatic reactivation and shed of infectious varicella zoster virus in astronauts. Journal of Medical Virology, 80(6), 1116–1122. https://doi.org/10.1002/jmv.21173 2Rooney, B. V., Crucian, B. E., Pierson, D. L., Laundenslager, M. L., & Mehta, S. K. (2019). Herpes virus reactivation in astronauts during spaceflight and its application on earth. Frontiers in Microbiology. 10, 16. https://doi.org/10.3389/fmicb.2019.00016. The ease of sample collection, along with the cost-effective use of lateral flow assays for detection, opens a wide range of opportunities for easily detecting Herpes viruses in point-of-care settings.

DISCUSSION:
A recent review by Miočević et al.3Miočević, O., Cole, C. R., Laughlin, M. J., Buck, R. L., Slowey, P. D., & Shirtcliff, E. A. (2017). Quantitative lateral flow assays for salivary biomarker assessment: A review. Frontiers in Public Health, 5, 133. https://doi.org/10.3389/fpubh.2017.00133 discusses the strengths and weaknesses of using lateral flow assays (LFAs) for detecting viruses in saliva. The collection of saliva allows for a repeated collection, if needed, without the stress of drawing blood. Even with the advent of LFAs for diagnostic assays in recent years, there are relatively few such assays for viral detection in saliva. LFAs can work either as an immunoassay (LFIA) to detect viral-specific antibodies in the collected sample or to directly detect the virus particle present in the sample. The assay works based on liquid movement (containing the analyte to be detected) across a strip of polymeric material containing dry reagents that activate by the lateral movement of a liquid sample up the strip membrane. The specific detection area on the strip can contain either (1) viral-specific recombinant proteins, to which the viral antibodies in the saliva will recognize by binding to the recombinant viral protein; or (2) viral-specific antibodies on the test strip, to which the virus particle in the saliva will be recognized and bound. Despite the simplicity of this assay description, extensive development of these assays is required by the manufacturer to overcome assay limitations, such as lower analyte concentrations in the sample. Developers are utilizing various approaches such as using colloidal gold or carbon, fluorescent or luminescent materials, or colored latex beads. As an example, colloidal nanoparticles generate direct signals, whereas the use of other materials may require additional steps to derive analytical results, such as upconverting phosphor technology (UPT). UPT is based on sub-micron sized ceramic particles coated with lanthanides that absorb infrared light (excitation) and emit visible light (response signal). The particles functionalize with antibodies and antigens for use as labels on a lateral flow strip. There can be many steps in the assay development to consider including, sample composition and how the sample will flow along the strip, as well as the concentration of the analyte to be detected in the sample. Manufacturers must ensure that only the molecules of interest bind to the antigens or antibodies coated on the test strip.

CONCLUSION:
The use of lateral flow assays for detecting virus particles or virus-specific antibodies is a promising approach when applied to saliva-based assays. There are many advantages to both of these sample collection and detection assays. Although there are several commercial assays to detect Herpes viral nucleic acid in saliva, at present, there are few if any such assays available for detecting Herpes virus analytes (antibodies or virions) in saliva using an LFA.

By David Kilpatrick, PhD and Abbas Vafai, PhD

 

MKTG 1046 Rev A

INTRODUCTION:
Numerous labs are developing antibody assays to detect COVID-19. There are presently (as of May 1, 2020) four FDA approved assays for detecting IgG/IgM and three for detecting IgG only. Four of these assays use a lateral flow assay (LFA) architecture. All of the assays use the viral S1 glycoprotein as the antibody target. This short note will describe a typical LFA for COVID-19.

DISCUSSION:
A rapid point-of-care assay that detects either/or both IgG/IgM is critical for detecting spread on the infection through the population. A recent infection (<7days) is usually seen with the production of IgM, while older infections (>8 days since infection) detect the generation of IgG. Li et al. (2020) developed an assay that detects both IgG and IgM, detecting antibodies to the SARS-CoV-2 S1 spike protein. They purified the recombinant S1 antigen (MK201027) by protein A affinity chromatography and size-exclusion chromatography. They based the design of the S1 antigen on the published SARS-CoV-2 sequence (MK201027). Antibodies obtained from Sigma include bovine serum albumin (BSA), goat anti-human IgG and IgM antibodies, rabbit IgG, and goat anti-rabbit IgG antibodies. Shanghai KinBio Inc. provided 40Nm gold nanoparticle (AuNP) colloids, NC membrane, and plastic pad, and Whatman provided the glass fiber conjugate (GFC). Sigma produced the PBS. Hunan CDC, China supplied inactivated COVID-19 serum and negative serum samples of patients.

To prepare the AuNP conjugate, they added SARS-CoV-2 recombinant protein dissolved in PBS (1mg/ml) to the mixture of 1ml AuNP colloid (40nm in diameter, OD=1) and 0.1ml of borate buffer (0.1M, pH 8.5). After incubation for 30 minutes at room temperature, the mixture was centrifuged at 10,000 rpm at 4oC for 20 minutes. Next, and 1ml of BSA in PBS was added to the AuNP conjugate to be re-suspended after discarding the supernatant. They repeated the centrifugation and suspension twice, and the final suspension was in PBS. The AuNP-rabbit IgG conjugates were prepared/purified by the same procedure. The main body of the test strip consists of five parts, including plastic backing, sample pad, conjugate pad, absorbent pad, and NC membrane. Each component of the strip is pretreated as follows: the NC membrane was attached to a plastic backing layer for cutting/handling. Researchers immobilized the anti-human-IgM, anti-human-IgG, and anti-rabbit-IgG at test M, G, and control line C. Then, they sprayed conjugate pad with a mixture of AuNP-COVID-19 recombinant antigen conjugate and AuNP-rabbit-IgG. Sample pad was pretreated with BSA (3%, w/v) and Tween-20 (0.5% w/v) before use. To run the assay (at room temperature), researchers pipetted 20 ul whole blood sample (or 10 ul of serum/plasma samples) into the sample port, followed by adding 2-3 drops (70-100ul) of dilution buffer (10mM PBS) to drive capillary action along the strip. The test takes approximately 15 minutes to complete. If only the C line shows red, the sample is negative. Either M or G line or both lines turning red indicates the presence of anti-SARS-CoV-2-IgM or IgG, or both if IgG and IgM are in the specimen.

CONCLUSION:
Of the 397 blood samples (vein blood) from SARS-CoV-2 infected patients, 352 tested positive, for a sensitivity of 88.66%. Twelve of the blood samples from the 128 non-infected patients were positive, for a specificity of 90.63%. Also, 256 out of 397 (64.48%) were positive for both IgG and IgM. Patient finger stick blood was tested and showed that all positive/negative results matched with 100% consistency between vein and finger stick blood, indicating the use of this assay as a point-of-care test using fingerstick blood.

By David Kilpatrick, PhD and Abbas Vafai, PhD

Li, Z., Yi, Y., Luo, X., Xiong, N., Liu, Y., Li, S., Sun, R., Wang, Y., Hu, B., Chen, W., Zhang, Y., Wang, J., Huang, B., Lin, Y., Yang, J., Cai, W., Wang, X., Cheng, J., Chen, Z., Sun, K., Pan, W., Zhan, Z., Chen, L., & Zhang, Y. (2020). Development and clinical application of a rapid IgM‐IgG combined antibody test for SARS-CoV-2 infection diagnosis.

Journal of Medical Virology. https://doi.org/10.1002/jmv.25727

INTRODUCTION:
Positive and negative Kaposi sarcoma-associated (KSA) individuals need an improved diagnostic assay for human herpesvirus-8 (HHV-8) detection. The selection of one or more viral epitopes that elicit strong immune responses is essential in developing this assay.
Read more

INTRODUCTION:
Human herpesvirus-8 (HHV-8) is a γ-herpesvirus which is related to the Epstein-Barr virus and is etiologically associated with Kaposi’s sarcoma (KS). The AIDS epidemic over the last 40 years has resulted in a high rate of KS due to immunosuppression. The seroprevalence for HHV-8 varies from 1-5% in the US to up to 80% in sub-Saharan Africa. A rapid, inexpensive diagnostic assay to detect HHV-8 would be very beneficial to screen those who may be potentially at risk for developing KS. Several immunological assays are available which require advanced instrumentation or technical staff to perform and analyze the results. At present, there is no lateral flow assay (LFA) available for HHV-8. The future development of an LFA for HHV-8 would be ideal in terms of patient confidentiality, analytical speed, and low cost. Read more

INTRODUCTION:
Human Herpes Simplex Type 2 (HSV-2) causes a life-long infection and occurs in over 10% of adult individuals. This report details the approach by Goux et al. (2019) to identify HSV-2  infections using a Smartphone to detect the nanophosphor signal of a lateral flow device.

DISCUSSION:
Lateral flow assays (LFAs) are needed to improve the detection of HSV-2 without the time, cost, and lack of privacy associated with a laboratory setting. As of December 2019, there are no commercially available gold nanoparticle LFAs for HSV-2. Laderman et al. (2008) described the development of a gold nanoparticle-based immunoblot test for HSV-2. This assay, called Sure-Vue HSV-2 Rapid test, had a sensitivity of 94% and a specificity of 98%. Goux et al. (2019) developed the assay to improve the clinical sensitivity and specificity.

To do this, Paterson et al. (2004) noted they used strontium aluminate persistent luminescent nanoparticles, which they had previously developed (PLNPs, nanophosphors) as the LFA reporters. These PLNPs have a long-lasting, bright glow excitation, which allows for a delay of emission measurement, reduced background autofluorescence, and eliminates the need for precision optical filters. The strontium aluminate doped with europium and dysprosium has a bright, long-lasting light emission, which is inexpensive and widely used in “glow-in-the-dark” signs and toys. Paterson et al. (2014) stated that strontium aluminate PLNP LFAs showed to have a higher analytical sensitivity than traditional LFAs. Goux et al. (2019) tested a panel of 21 human plasma and serum samples ranging from negative to strongly positive for HSV-1 and HSV-2 (PTH2020; SeraCare Life Science). Then, they mixed 20μl of human plasma or serum samples (10μl of sample + 25μl of buffer) with 15μl of anti-human IgG-PLNP conjugate. Finally, they dispensed the sample/nanophosphor mixture (35 μl) onto the LFA pad. Goat anti-human IgG nanophosphors bearing anti-HSV human IgG (if present in the sample) migrated up the membrane. A recombinant HSV-2 antigen immobilized at the test line captured the
nanophosphors. Unbound anti-human nanophosphors bearing human IgG migrated further up the strip until captured by the goat anti-human IgGs immobilized at the control line.

A custom LFA iPhone app on an iPhone 7 Plus Smartphone (Apple Inc.) in combination with a 3D-printed attachment imaged the LFA strips. The PLNPs were excited by turning on the iPhone light (4s, maximum intensity) and then cycling the camera’s flash. After a delay (~100ms after excitation), the phone camera acquired an image of phosphor emission. Researchers repeated the excitation/imaging cycle four times, and the four images were stacked together to reduce background noise and increase reproducibility. They were able to detect between 5.7 to 23.3 mg/ml of human IgG. They detected no crossreactivity to HSV-1 in 10 tested samples. For comparison, the LFA test strips were also imaged on a FluorChembased imaging platform with two 10W ultraviolet LED lights (395-400nm) and a CoolSNAP K4 CCD 2,048 x 2,048-pixel camera. PLNP were excited with the LEDs for 1 min and imaged with an exposure time of 1s and pixel binning of 4.

CONCLUSION:
The nanophosphor HSV-2 LFA had a sensitivity of 96.7%, with 100% specificity for detecting HSV-2 in the tested samples. This sensitivity was higher than that of commercially available rapid HSV-2 assays tested with the same panel. This smartphone-based nanophosphor LFA technology shows promise for private self-testing for sexually-transmitted infections.

By David Kilpatrick, PhD and Abbas Vafai, PhD

Goux, H. J., Raja, B., Kourentzi, K., Trabuco, J. R. C., Vu, B. V., Paterson, A. S., Blane, T., Lee, M., Truong, V. T. T., & Pedroza, C. (2019). Evaluation of a nanophosphor lateral-flow assay for self-testing for herpes simplex virus type 2 seropositivity. PloS One, 14(12).
https://doi.org/10.1371/journal.pone.0225365

Laderman, E. I., Whitworth, E., Dumaual, E., Jones, M., Hudak, A., Hogrefe, W., Carney, J., & Groen, J. (2008). Rapid, sensitive, and specific lateral-flow immunochromatographic point-of-care device for detection of herpes simplex virus type 2-specific immunoglobulin G antibodies in serum and whole blood. Clin. Vaccine Immunol., 15(1), 159-163.
https://doi.org/10.1128/cvi.00218-07

Paterson, A. S., Raja, B., Garvey, G., Kolhatkar, A., Hagström, A. E., Kourentzi, K., Lee, T. R., & Willson, R. C. (2014). Persistent luminescence strontium aluminate nanoparticles as reporters in lateral flow assays. Analytical Chemistry, 86(19), 9481-9488.
https://doi.org/10.1021/ac5012624