Serological diagnosis of Epstein-Barr virus infection by novel ELISAs based on recombinant capsid antigens p23 and p18

A new pair of Epstein-Barr virus ELISAs (Biotest Anti-EBV VCA IgG and VCA I gM ELISA) was evaluated for usefulness for routine diagnosis of acute EBV i nfections. The ELISAs are based on two viral capsid antigens (VCA), p23 (BL RF2, full-length) and p18 (BFRF3, carboxy-half), that are combined by autol ogous gene fusion. In total, 179 sera were tested in direct comparison with classical VCA immunofluorescence assays (IFA). With the help of clinical d ata and additional reference serology, i.e., heterophile antibodies, anti-E A IgG (IFA) and anti-EBNA-1 IgG (ELISA), the patients were divided into the following categories: seronegatives (46), acute primary infections (67), p revious infections (39), suspected reactivations (20) and constellations wi th intermediate serological patterns (7). The VCA IgG and VCA IgM ELISAs sh owed overall agreement to IFA of 95.0% and 94.4%, respectively. The calcula ted analytical performance (sensitivity; specificity) of VCA IgG and VCA Ig M was 94.0%; 97.8% and 97.1%; 96.5%, respectively. A certain delay in seroc onversion of anti-p23-p18 IgG may account for a significant difference in s ensitivity of the VCA IgG ELISA between primary (88.4%) and previous infect ions(100%). In summary, the new recombinant VCA ELISAs yielded good correla tion to VCA IFA and in combination with EBNA-1 IgG allow rapid, sensitive, and specific diagnosis of infectious mononucleosis or EBV immune status in general. (C) 2001 Wiley-Liss, Inc.