Previously, Epstein-Barr virus (EBV) infection was diagnosed by serological examination; currently, many EBV antigen detection methods have been developed and applied clinically for diagnosing EBV infection. To delineate the clinical characteristics of EBV infection, clinical and laboratory findings were evaluated for patients who tested positive in EBV polymerase chain reaction (PCR).

EBV PCR was conducted in 352 patients admitted to the pediatric ward from January 2004 to December 2006, with more than 2 clinical signs such as fever (≥37.5℃), exudative throat infection, lymphadenopathy, hepatitis of unknown etiology, and splenomegaly. The EBV viral gene was detected by PCR in 115 patients (32%), and the clinical characteristics of these patients were evaluated. Laboratory findings such as leukocytosis, thrombocytopenia, atypical lymphocyte, and alteration in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in peripheral blood were examined. The EBV-specific immunoglobulin M antibody (EBV-IgM Ab) was also tested.

Most of the children were younger than 8 years (89%), and the male to female ratio was 1.3:1. Exudative throat infection and fever (≥37.5℃) were observed in all patients. Cervical lymph node enlargement was seen in 36 patients (31%); leukocytosis (WBC≥10,000/mm³), in 54 patients (47%); and atypical lymphocyte (≥20%), in 28 patients (24%). EBV-IgM Ab was positive in 33 patients (29%). The younger patients had higher ALT levels and higher incidence of positive EBV-IgM Ab than the older patients.

The cumulative number of patients diagnosed to have EBV infection by PCR increased markedly for those under 8 years. ALT was higher and EBV-IgM Ab was detected more in younger patients with EBV infection.