BACKGROUND: Epstein-Barr virus (EBV) is one of the most frequent triggers of hemophagocytic lymphohistiocytosis (HLH). EBV-associated HLH (EBV-HLH) and ectopic infection of T cells has been particularly described in patients from Far East Asia. PROCEDURE: In a cohort of 12 children with EBV-HLH treated in Germany, the EB viral load was detected by real-time polymerase chain reaction in plasma and peripheral blood mononuclear cells (PBMC). Virological and clinical data were analyzed retrospectively. RESULTS: Among the 12 mainly German patients, children with underlying immunodeficiencies as well as otherwise healthy individuals were affected. The clinical course ranged from a steroid-responding to a fatal disease despite intensive treatment. Increased EBV copy numbers in plasma and/or PBMC were found in all patients. Serial measurements reflected the course of the disease. Cell-type specific viral load was determined in seven patients and revealed EBV-infection of T cells in all of them. In contrast to the reported Asian patients a significant viral load was also found in B cells. CONCLUSIONS: T cell infection appears to be a typical feature of EBV-associated HLH irrespective of patients ethnic background and the clinical course. Evaluation of cell-type specific infection should be considered when targeted therapy is applied.
