EPSTEIN-BARR-VIRUS (EBV) INFECTS T-LYMPHOCYTES IN CHILDHOOD EBV-ASSOCIATED HEMOPHAGOCYTIC SYNDROME IN TAIWAN

We have reported the prevalence of a fulminant hemophagocytic syndrome (HS) in previously healthy young children In Taiwan, most of which pr obably represent a lethal form of primary or active Epstein-Barr virus (EBV) infection. To further confirm their EBV association, in situ EB V hybridization (ISH) was performed on tissue biopsies from 15 pediatr ic HS patients (median age, 3 years and 4 months) using digoxigenin-la beled RNA probes EBER1. Double labeling immunostaining and ISH was the n performed to define the immunophenotype of the lymphoid cells contai ning the EBV transcripts. Among the 13 patients who had serological ev idence of acute or active EBV infection, 3 had demonstrable EBER1 tran scripts in bone marrow, liver, and/or skin biopsies. EBER1-specific si gnal was not detectable in the two specimens from EBV-seronegative pat ients. The distribution of EBV-containing cells could be extensive or scattered To our surprise, the EBER1 transcripts existed exclusively i n T lymphoid cells in all nine cases examined rather than in B cells a s previously believed in infectious mononucleosis. Considering the you ng affected age of the HS patients and the serological response to EBV , we suggest that EBV can infect T cells in primary EBV infection and the proliferation of these EBV-infected T cells may be responsible for the ominous outcome in childhood HS patients in Taiwan.