Serology in epstein-barr virus infection in children.

Abstract

Introduction: The Epstein-Barr virus was found in 1968 as the major cause of infectious mononucleosis. Since then the diagnosis of EBV has gone a way from the nonspecific tests, such as the heterophile antibody test, to specific EBV antibody tests performed through IFA, the “gold standard”, different immunoassay techniques, additional tests, used for confirmation such as avidity test and Western blot, to PCR, mainly used in patient with immunosuppression. The seroprevalence in adult population is wide, ranging from 85% in developed counties to 95-100% in developing counties. By age 5 seroprevalence in the UK and USA is 50%. In RM the incidence of mononucleosis has increased from 0.97 in 1992, to 2.97 in 2007. Although laboratory diagnosis in mononucleosis is straightforward and available, it still imposes some questions, due to high variability of EBV serology. The objective of this research is to study and discuss the challenges of laboratory diagnosis and staging of EBV infection based on serological profiles of the patients tested to EBV infection at the Hospital for Infectious Diseases in Children, in Chisinau, R. of Moldova during the year 2015. Materials and methods: the materials used are blood serum or plasma samples from 311 patients from 5 months old to 17 years old from the Hospital for Infectious Diseases in Children, who were consulted or admitted with suspected mononucleosis or hepatitis of unknown origin. Blood was tested to EBV-CA IgM and IgG, EA IgG, EBNA-1 IgG, anti CMV IgM and IgG, anti HAV IgM. The testing system used is the enzyme immunoassay. The interpretation of the results given by reagent manufacturers is: 1) Primary infection VCA IgM positive, VCA IgG pos/neg, EA IgG pos/neg, EBNA IgG negative, 2)Past infection VCA IgM negative, VCA IgG and EBNA IgG positive, 3)Reactivation VCA IgM, VCA IgG, EBNA IgG positive.Patients are categorized by their serology profile (VCA IgM and IgG, EBNA-1 IgG) in 3 main groups, patients with serology characteristic to acute infection, past infection, and patients with serology that can be interpreted either way. Discussion results: 209 blood samples were found positive to at least 1 marker of EBV infection. 114 had VCA IgM negative, VCA IgG and EBNA IgG positive. 34 were VCA IgM and IgG positive and EBNA IgG negative. 12 were VCA IgG positive VCA IgM and EBNA IgG negative, 25 were VCA IgG and IgM positive, EBNA IgG positive, 19 were VCA IgM positive, VCA IgG and EBNA IgG negative, and 4 were only EA IgG or EBNA IgG positive. Conclusion: 67.2% of samples were positive to EBV infection, which meant primary or past infection, 65.8% being children under age of 6 years. From them 54.5% had a serological pattern of pastinfection, 25.3% had indicators of primary infection, the rest (19.6%) had serological patterns that might have benefit from additional tests, such as avidity tests, western blot or PCR.