Chronological changes in Epstein-Barr virus genome and subsets of peripheral mononuclear cells in a case of HLH

Hemophagocytic lymphohistiocytosis (HLH) is a rare disorder characterized by high grade fever, heaptosplenomegaly, lymphadenopathy and cytopenia in association with hypercytokinemia and macrophage activation. Epstein-Barr virus (EBV) is a common cause of HLH particularly in Asian countries. Although EBV usually infects B cells and causes infectious mononucleosis, it is detected predominantly in CD8 T cells in EBV-associated HLH. In the present study we found the EBV genome in various lineages of the lymphoid cells including T, B, and natural killer cells in a 14-months-old boy with mild EBV-associated HLH. Furthermore, chronological changes in the copy number of EBV-DNA in each lineage are reported. Profound decrease in the number of peripheral natural killer cells at the early stage could be involved in the development of HLH.