Diagnostic Value of IgG and IgM Antibodies to Capsid Antigen of Epstein-Barr Virus in Infectious Mononucleosis

Abstract

The frequency and the diagnostic value of IgG and IgM antibodies to capsid antigen of Epstein-Barr virus (EBV) were studied in 40 children in whom the diagnosis of infectious mononucleosis was established by clinical and hematologic criteria and by a positive test for heterophile antibodies. Samples of blood were obtained at the time of admission to the Second Pediatric Department at the University of Athens (three to 28 days after the onset of disease) and 20 days later. Antibodies to capsid antigen of EBV were detected by the indirect immunofluorescence technique. The diagnosis of infectious mononucleosis was not confirmed in two of the cases studied. IgM antibodies were detected in 34 (89.5%) of the 38 cases of infectious mononucleosis tested, whereas the diagnosis could be established by seroconversion or fourfold increase in titer of IgG in only 24 (63.2%). Apart from the considerable value of IgM antibodies in the identification of primary infections in cases of infectious mononucleosis that are negative for heterophile antibodies, detection of IgM antibodies may be of diagnostic value for patients in whom heterophile antibodypositive results are doubtful or not compatible with clinical and/or hematological findings.