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
Abbas Vafai, Ph.D. inventor of shingles vaccine, SHINGRIX, develops ZosterGent® VZV Identification Reagent, a more sensitive test in detecting the shingles virus.
SNELLVILLE, Ga., June 9, 2020 (Newswire.com) –
Viro Research, developer of high quality biologics and reagents, announced today the launch of ZosterGent® for lesion testing of at-risk patients suspected of having chickenpox or shingles, such as immunosuppressed populations like pregnant women or those with HIV, cancer, or organ transplants. Viro Research was co-founded by father and son team, Dr. Abbas Vafai, microbiologist, and his son, Dr. Nicholas Vafai, cellular biologist.
“The marketing success of the recently released shingles vaccine, SHINGRIX, has increased interest in detecting and preventing Varicella-Zoster Virus (VZV) infections,” states David R. Kilpatrick, Ph.D., microbiologist formerly of the Centers for Disease Control and Prevention. “A simple, highly specific and rapid assay such as ZosterGent® is desirable and fills the clinical need to detect VZV antigens in skin lesions and cell cultures.”
Herpes zoster, commonly referred to as shingles, is caused by the reactivation of the VZV, the same virus that causes varicella (chickenpox) typically in childhood. After chickenpox resolves, the VZV still remains in the body but lies dormant, often reactivating in the elderly and immunocompromised individuals as shingles, causing a painful rash with open sores.
Having HIV or cancer can increase a person’s risk, as the immune system is compromised and more receptive to disease. Radiation or chemotherapy can also lower one’s resistance and could be a catalyst for shingles. Certain medications such as prednisone (steroids) or those that prevent rejection of transplanted organs can also increase the risk of contracting shingles.
“Other tests – including PCR and ELISA – exist today for detection of VZV. Many are time-consuming and need to be sent to testing facilities but can be processed in larger batches which can be attractive for high-volume reference labs,” remarks Nicholas Vafai, PhD, MBA, CEO and co-founder of Viro Research. “However, pathologists may be required to directly detect and observe the infected cells in skin lesions and in the patient’s tissue under the microscope, which is why they would prefer ZosterGent®, an immunofluorescent assay (IFA) approach.”
About ZosterGent®
The ZosterGent® Reagent is a fast (20-30 minutes), simple (one-step, one-solution) fluorescent antibody test for the detection and confirmation of chickenpox (varicella) and shingles (zoster) in clinical specimens and inoculated cell cultures. Under a fluorescent microscope samples will appear with bright green intensity making the specimen easy to see and recognize.
About Viro Research
Viro Research provides high quality biological products and reagents for research and in vitro diagnosis of human viruses, enabling an early, accurate patient diagnosis and effective treatment pathway for the physician. For more information visit www.viroresearch.com.
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Source: Viro Research
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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
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