VZV IgG

The VZV IgG test is an immunological chemiluminescent (CLIA) test for the quantity determination of the specific IgG class antibodies against the Varicella-Zoster Virus (VZV) in serum or plasma (K3-EDTA, heparin sodium or sodium citrate) samples, using IDS automated analyzers.

This dosage is used as a diagnostic aid in the assessment of the immune status of the patient.

The Varicella-Zoster Virus (VZV) is an aetiological agent of varicella (chicken pox). VZV is usually introduced into the organism through the inhalation of respiratory droplets from an infected host; transmission can also occur through skin contact. The disease mainly occurs in childhood with an incubation period of 14-16 days. The VZV virus becomes latent after infection and is kept under control by the cell-mediated immunity of the immune system.

The commonest clinical symptoms of varicella in adults and adolescents are high temperature, unease, headache and abdominal pain which occur 24-48 hours before the skin eruption of erythematous macules which evolve rapidly to irregular blisters of 1-4 mm in diameter which can also be seen on the walls of mucous membranes such as the conjunctival, oropharyngeal, rectal or vaginal ones.

The commonest complications include bacterial super-infections, otitis media, endocarditis, pneumonia and complications of the central nervous system leading to long-term sequelae and an increase in the length of hospital stays. ⁽³⁾

Serological methods are usually used to determine the immune status of people at risk (mainly immunodepressed patients) and pre- and post-natal diagnosis of infected persons. The primary VZV infection causes the production of IgM, IgG and IgA antibodies which recognise different viral proteins. The production of antibodies can usually be detected within 3 days of the onset of the symptoms. The IgM diminish within a few months but the IgG remain for several years. People who fall ill with herpes zoster have a considerable, rapid increase in the IgG antibody titre⁽⁵⁾. The reactivation of varicella induces an increase in the IgM titre so their existence does not differentiate between a primary and a recurring infection.

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2. Zhang Z et al, Genome-Wide Mutagenesis Reveals That ORF7 Is a Novel VZV Skin-Tropic Factor, 2010. PLoS Pathog. 6:e1000971. doi:10.1371/ journal.ppat.1000971.
3. Cohen JI, et al 2007 Fields Virology, 5th ed. Philadelphia: Lippincott Williams & Wilkins: 2773-818
4. Weinberg A, et al Varicella-Zoster Virus–Specific Immune Responses to Herpes Zoster in Elderly Participants in a Trial of a Clinically Effective Zoster Vaccine, 2009. J. Infect. Dis. 200:1068 –1077.
5. Jenke AC et al, Serologic Analysis of the IgG Antibody Response in Children With Varicella Zoster Virus Wild-type Infection and Vaccination, 2012 Pediatr InfectDis J;31: 1148-1152