Case 217. EBV-associated hemophagocytic syndrome (20 y-o F)
    Bone marrow aspirate from the young, manifesting fever, cervical lymphadenopathy, pancytopenia and atypical lymphocytosis (5%).    
Key words : EB virus, virus-associated hemophagocytic syndrome (VAHS)
An activated macrophage phagocytizes red cells and nuclear debris probably originated from white blood cells and platelets (Giemsa). Virus-associated hemophagocytic syndrome (VAHS) is strongly suspected.   Leukophagocytosis by macrophages is evident (HE). Supression of normal hematopoetic cells is associated. Elevation of IgG-type antibody to EBV is compatible with EB-VAHS.
Reference case 217A
Lethal EB-VAHS in a 17 y-o male, manifesting fever, pancytopenia and liver dysfunction. Enlarged abdominal lymph node was obtained at autopsy (HE). In the lymph node, marked increase of leukophagocytic macrophages is observed. Normal nodal structure is lost. Nuclear atypia is absent in the lymphocytes. EB-VAHS may be lethal, in sharp contrast to infectious mononucleosis, in which self-limiting infection of EBV occurs in B-cells.
  Reference case 217A
Double staining for EBER-1 (brown-stained nuclei by in situ hybridization) and T-cell marker, CD45RO (blue on the plasma membrane by immunostaining) in the autopsied lymph node. In EB-VAHS, EBV infection occurs in NK/T cells, as shown here. The variegated clinical manifestations and hemophagocytosis are due to hypercytokinemia. This form of acute EBV infection is most commonly seen in children and young adults. Refer also to cases 34, 41 and 228.