Occasionally a patient with Epstein-Barr Virus (EBV) infection will develop secondary hemophagocytic lymphohistiocytosis (HLH). This is considered a severe form of infectious mononucleosis and can be fatal.


Most cases occur during an initial infection with EBV. It may develop in patients with the X-linked lymphoproliferative disease (XLP).



(1) systemic symptoms which may be severe

(2) generalized lymphadenopathy

(3) hepatosplenomegaly

(4) elevated blood levels of cytokines (interferon-gamma, macrophage-colony stimulating factor, interleuken-12, other), which cause a proliferation of T cells and monocytes

(5) presence of hemophagocytic histiocytes in lymph nodes, spleen, liver and bone marrow

(6) evidence of EBV within T cells

(7) exclusion of other explanations for HLH


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