COMPARATIVE-EVALUATION OF 3 ELISA TECHNIQUES AND AN INDIRECT IMMUNOFLUORESCENCE ASSAY FOR THE SEROLOGICAL DIAGNOSIS OF EPSTEIN-BARR-VIRUS INFECTION

Background: The reference method for detecting specific Epstein-Barr v irus (EBV) antibodies is indirect immunofluorescence (IF) with EBV-inf ected cells. The availability of protein purified from infected cells and more recently of recombinant polypeptides designed to contain immu nodominant epitopes, has enabled the development of commercial enzyme- linked immunosorbent assays (ELISA) for the specific serodiagnosis of EBV infection. Objective: Evaluation of ELISA-based EBV serodiagnosis in comparison with indirect immunofluorescence. Study design: We have first compared three commercial ELISA test systems with our in house i ndirect immunofluorescence assay for classifying correctly a set of se rum samples into clinical categories (acute infection, past infection, interfering non-EBV infection, persistent infection). Additionally a prospective analysis with the best performing ELISA test (Enzygnost) w as then carried out by running the ELISA test in parallel with the ind irect immunofluorescence assay on 324 consecutive clinical samples sen t to our laboratory for EBV serodiagnosis. Results: For the serodiagno sis of past EBV infection and acute EBV infection all three commercial ELISAs performed well in comparison with indirect immunofluorescence. When testing samples positive for cytomegalovirus (CMV), Toxoplasma o r herpes simplex IgM, interference in the IgM tests was observed with the three ELISAs. In some instances we could demonstrate that the posi tive IgM results were due to EBV reactivation. The observed discrepanc ies between ELISA and IF for the serodiagnosis of chronic EBV infectio n or EBV reactivation, point to the difficulty for the serodiagnosis o f persistent EBV infection on single serum samples. According to our p rospective study the EBV IgG determination was accurate. A positive Ig M result was not always indicative of an acute infection. Positive IgM results due to EBV reactivation were observed. A positive EBV nuclear antigen (EBNA) IgG result in those samples precluded acute infection. Conclusions: 90-95% of samples could be classified correctly into cli nical categories by a two parameter ELISA system detecting IgG and IgM against a standardized mixture of EBV antigens, allowing standardizat ion and automation of EBV-specific serology. The absence of EBNA Ige w as useful as a second line confirmatory assay for acute EBV infection. (C) 1997 Elsevier Science B.V.