Test Is Also Helpful in Clinically Unclear Cases of Varicella Zoster
Regarding the laboratory tests explained in the article, the importance of varicella zoster virus (VZV) IgA antibodies in the serological diagnosis of (VZV) infection should be emphasized (1). Whereas mostly IgM and often also IgA antibodies are detectable during the acute primary infection (chickenpox), the IgM antibody response is lacking in reactivated VZV infection (herpes zoster) in 50–65% of cases (2, 3). In this setting, however, in addition to the obligatory VZV-IgG antibodies, VZV IgA antibodies are found one to four weeks after disease onset (2, 3). These can persist for three to six months. In two studies, the sensitivity of the VZV-IgA antibodies in herpes zoster was 67–94% (3, 4), the specificity is as high as 94% (4).
For this reason, VZV serology is also helpful in atypical or clinically unclear cases of zoster, such as “herpes sine herpete,” where the typical blisters are lacking, or in zoster encephalitis.
However, VZV-IgA antibodies and VZV DNA in the serum have been repeatedly found in asymptomatic persons (subclinical reactivation). The test for varicella DNA (PCR) in cerebrospinal fluid or in blister fluid is highly sensitive, but its use in the outpatient setting is not covered by the statutory health insurers.
A test for VZV specific CD4-T-cells, which in one study showed 100% specificity and almost 100% sensitivity, is still in the experimental stages (4).
Dr. med. Bernd Maire
Labor Staber, Heilbronn
|1.||Heckmann JG, Urban PP, Pitz S, Guntinas-Lichius O, Gágyor I: The diagnosis and treatment of idiopathic facial paresis (Bell´s palsy). Dtsch Arztebl Int 2019; 116: 692–702 VOLLTEXT|
|2.||Preiser W, Rabenau HF, Doerr HW: Varizella-Zoster-Virus (VZV). In: Preiser W, Rabenau HF, Doerr HW: Viren – Viruserkrankungen: Synopsis der Epidemiologie, Klinik, Diagnostik und Therapie viraler Erkrankungen. Steinen: Zett-Verlag 2002; 196–8.|
|3.||Opstelten W, van Loon AM, Schuller M, et al.: Clinical diagnosis of herpes zoster in family practice. Ann Fam Med 2007; 5: 305–9 CrossRef MEDLINE PubMed Central|
|4.||Schub D, Janssen E, Leyking S, et al.: Altered phenotype and functionality of varicella zoster virus–speciӿc cellular immunity in individuals with active infection. J Infect Dis 2015; 211: 600–12 CrossRef MEDLINE|