Epstein-Barr virus-associated infectious mononucleosis in Chinese children

Background. According to seroprevalence studies the majority of children in Hong Kong are infected by Epstein-Barr virus (EBV) before 10 years of age, but the characteristics of EBV-associated infectious mononucleosis (IM) in Chinese children are largely unreported. This study aims at defining the clinical presentation and complications of Chinese childhood IM in relation to age of the children. Methods. A retrospective study was performed on 77 consecutive Chinese childhood IM patients who fulfilled the serologic criteria for the diagnosis of primary EBV infection (viral capsid antigen IgM(+) viral capsid antigen IgG(+) Epstein-Barr nuclear antigen(-)). The clinical, hematologic and biochemical findings were evaluated among four age groups of <2 years, 2 to 4 years, 5 to 9 years and 10 to 15 years. Results and conclusions. EBV-associated IM occurred at all age groups with a peak incidence at 2 to 4 years, corresponding to the rapid rise in the seroprevalence of EBV in early childhood in the Hong Kong Chinese. The majority of children presented with fever, tonsillopharyngitis, lymphadenopathy and hepatosplenomegaly, similar to the adult IM patients, and recovered without major complications. Marked lymphocytosis with the presence of atypical lymphocytes was a consistent hematologic finding in all age groups. The occurrence of hepatitis showed a clear association with advancing age (P = 0.003). The age-related increase in IM-associated hepatitis may reflect difference in the host immune response against EBV between the infants and older children.