The Nature and Clinical Significance of Atypical Mononuclear Cells in Infectious Mononucleosis Caused by the Epstein-Barr Virus in Children

Atypical mononuclear cells (AM) appear in significant numbers in peripheral blood of patients with Epstein-Barr virus (EBV)-associated infectious mononucleosis (IM). We investigated the number and lineage-specific clusters of differentiation (CD) expression of atypical mononuclear cells in 110 children with IM using the anti-CD antibody microarray for panning leukocytes by their surface markers prior to morphology examination. The AM population consisted primarily of CD8(+) T cells with a small fraction (0%-2% of all lymphocytes) of CD19(+) B lymphocytes. AM amount in children with mononucleosis caused by primary EBV infection was significantly higher than for IM caused by EBV reactivation or other viruses and constituted 1%-53% of all peripheral blood mononuclear cells compared to 0%-11% and 0%-8%, respectively. Children failing to recover from classic IM associated with primary EBV infection within 6 months had significantly lower percentage of CD8(+) AM compared to patients with normal recovery rate.

Automated summary

Atypical mononuclear cells (AM) appear in significant numbers in peripheral blood of patients with Epstein-Barr virus (EBV)-associated infectious mononucleosis (IM), primarily consisting of CD8(+) T cells and a small fraction of CD19(+) B lymphocytes. The AM population amount is significantly higher in children with mononucleosis caused by primary EBV infection compared to other viral infections, and the recovery from classic IM associated with primary EBV infection is correlated with the percentage of CD8(+) AM.