The Enzygnost anti-Epstein-Barr virus
enzyme-linked
immunosorbent assay (ELISA) system, which is based on a defined
antigen mixture and on detection of
antibodies of the
immunoglobulin G (
IgG),
IgM, and
IgA classes, was evaluated for its reliability in diagnosing
Epstein-Barr virus infections in childhood. With samples from 66 children, the Epstein-Barr virus status and the
infection phase were defined by indirect immunofluorescence and
anticomplement fluorescence assays: 11 children were seronegative, 8 had a primary
infection, 20 had a recent primary or past
infection, and in 27 a reactivated
Epstein-Barr virus infection was diagnosed. When applying the Enzygnost ELISAs, 15 serum samples (22.7%) were not interpretable due to indeterminate results in at least one of the assays used and were therefore excluded from further evaluation. The respective sensitivities and specificities for the diagnosis of seronegativity were 100 and 100%, those for the diagnosis of primary
infection were 100 and 97%, those for the diagnosis of recent primary or past
infection were 100 and 52%, and those for the diagnosis of
reactivated infection were 10 and 100%. This poor performance of the Enzygnost system with reactivated
infections is due to the prerequisite of an
IgG antibody value of >650 IU/ml for the diagnosis of viral activity, which was fulfilled in only two of the children. Despite the high rate of indeterminate results, the Enzygnost system is useful in diagnosing acute and past
Epstein-Barr virus infection in childhood. For serological diagnosis of viral activity in childhood, a supplementary assay is necessary.