Clinical manifestations and quantitative analysis of virus load in Taiwanese children with Epstein-Barr virus-associated infectious mononucleosis.

BACKGROUND AND PURPOSE To delineate the clinical manifestations in different age groups and to define the viral load in patients with Epstein-Barr virus-associated infectious mononucleosis (EBV-associated IM). METHODS We reviewed data on 69 children with EBV-associated IM from November 2001 to October 2005. Clinical features were evaluated among four age groups: <3 years, 3 to 5 years, 6 to 9 years and 10 to 18 years. EBV viral load was measured by quantitative real-time polymerase chain reaction (PCR) in 13 patients with 15 specimens. RESULTS Majority of the children were younger than 7 years of age (76.8%) and the male-to-female ratio was 1.6:1. The symptoms and signs included fever (91.3%), tonsillopharyngitis (88.4%), lymphadenopathy (78.3%) and hepatitis (75.4%). The younger age group had higher monocyte count, lower occurrence of hepatitis, and lower glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) levels than the older age group. The median (range) EBV viral load of peripheral blood mononuclear cells (PBMCs) and plasma in IM patients was 738 (0-7455) copies/mug DNA and 51 (0-957) copies/mL plasma, respectively. The PBMC detection rate was high in the early (within 10 days after onset) and late phase (>10 days after onset) [90-100%]. The plasma detection rate in the early phase (66.7%) was higher than that in the late phase (40%). CONCLUSIONS The younger age group of EBV-associated IM patients had higher monocyte count, lower occurrence of hepatitis, and lower GOT and GPT levels than the older age group. The PBMC detection rate was almost equally high in both the early and late phases, while the plasma detection rate was higher in the early phase. Quantitative real-time PCR of EBV DNA is useful for diagnosing and monitoring EBV-associated IM, especially in younger children.