Serum samples from 76 patients with clinical and serological (anti-hepatitis A virus IgM positive) evidence of hepatitis A were tested for antibodies to Epstein-Barr-virus (EBV). Among these sera 26 were found positive for anti-EBV-VCA-IgM, and 21 of them were positive for EBNA-1-IgG. EBV-VCA-IgM may become positive during primary or reactivated EBV-infection, by interference with rheumatoid factor (RF), by crossreactive antibodies or by EBV-induced polyclonal B-cell activation. The aim of the study was to elucidate the reasons for EBV-VCA-IgM positivity in our serum samples by a combination of additional tests and a survey of the literature.
Comparison with other tests for EBV-IgM and for EBV-IgG was performed, but did not give more conclusive results. Assessment of total-IgG showed a weak coherence with the EBV-VCA-IgM-results, whereas testing for RF did not give any additional information. The most likely reasons for the reactivity of EBV-IgM were reactivation of latent virus or IgG/RF-interference.
Assessment of VCA-IgM, VCA-IgG and EBNA-1-IgG in the serum sample is important for differentiation between primary and reactivated EBV-infection. For a correct diagnosis, relevant assays have to be chosen, based on a good medical history and a thorough medical examination. It is also important to know something about the epidemiology of the disease in the population. Furthermore, the sensitivity and specificity of the tests have to be considered, and thereby the validity of the results.