Detection of Circulating VZV-Glycoprotein E-Specific Antibodies by Chemiluminescent Immunoassay (CLIA) for Varicella–Zoster Diagnosis

Abstract

Varicella and herpes zoster are mild symptoms-associated diseases caused by varicella–zoster virus (VZV). They often cause severe complications (disseminated zoster), leading to death when diagnoses and treatment are delayed. However, most commercial VZV diagnostic tests have low sensitivity, and the most sensitive tests are unevenly available worldwide. Here, we developed and validated a highly sensitive VZV diagnostic kit based on the chemiluminescent immunoassay (CLIA) approach. VZV-glycoprotein E (gE) was used to develop a CLIA diagnostic approach for detecting VZV-specific IgA, IgG, and IgM. The kit was tested with 62 blood samples from 29 VZV-patients classified by standard ELISA into true-positive and equivocal groups and 453 blood samples from VZV-negative individuals. The diagnostic accuracy of the CLIA kit was evaluated by receiver-operating characteristic (ROC) analysis. The relationships of immunoglobulin-isotype levels between the two groups and with patient age ranges were analyzed. Overall, the developed CLIA-based diagnostic kit demonstrated the detection of VZV-specific immunoglobulin titers depending on sample dilution. From the ELISA-based true-positive patient samples, the diagnostic approach showed sensitivities of 95.2%, 95.2%, and 97.6% and specificities of 98.0%, 100%, and 98.9% for the detection of VZV-gE-specific IgA, IgG, and IgM, respectively. Combining IgM to IgG and IgA detection improved diagnostic accuracy. Comparative analyses on diagnosing patients with equivocal results displaying very low immunoglobulin titers revealed that the CLIA-based diagnostic approach is overall more sensitive than ELISA. In the presence of typical VZV symptoms, CLIA-based detection of high titer of IgM and low titer of IgA/IgG suggested the equivocal patients experienced primary VZV infection. Furthermore, while no difference in IgA/IgG level was found regarding patient age, IgM level was significantly higher in young adults. The CLIA approach-based detection kit for diagnosing VZV-gE-specific IgA, IgG, and IgM is simple, suitable for high-throughput routine analysis situations, and provides enhanced specificity compared to ELISA.

Current Methods for the Detection of Antibodies of Varicella-Zoster Virus: A Review

“…After incubation with diluted serum samples, secondary anti-human IgA/IgM/IgG antibodies conjugated with isoluminol or acridinium are used to detect the captured VZV-specific antibodies. Next, chemiluminescent detection reagents are added to produce a signal, and the relative light units (RLU) are measured using a full-automatic chemical luminescence immune analyzer and converted to the antibody concentration according to the standard curve [ 77 , 78 ]. The reported CLIA used cutoff values of 150 mIU/mL [ 79 ] and 100 mIU/mL [ 80 ].…”

“…However, the sensitivity of CLIA still needs to be improved. Recently, a VZV gE-CLIA has shown better sensitivity and specificity than the gp-ELISA (Abcam, Cambridge, MA, USA) [ 78 ], but further application and validation of this method are still required.…”

Scrub Typhus Diagnostics: The Present and the Future

“…The primary advantage of CLIA is its wide dynamic range, which may aid in setting appropriate test cut-offs [111]. Currently, CLIA has been found to be very useful for laboratory diagnosis of HIV, hepatitis B [112], adenovirus [113], HCV, syphilis [114], T. gondii [115], Varicella Zoster [116], and West Nile virus [117].…”

Scrub typhus diagnostics: An overview

“…The biggest advantage of CLIA is wider dynamic range which may allow setting more appropriate cut-off for the test (84) . Currently, CLIA has been evaluated and found to be very useful for laboratory diagnosis of HIV, Hepatitis B (85), adenovirus (86), HCV, syphilis (87), T. gondii (88), Varicella Zoster (89) and West Nile virus (90) .…”