Atypische Epstein-Barr-Virus(EBV)-Infektionen im Kindes- und Jugendalter

The clinical syndrome of acute infectious mononucleosis is predominantly a disease of older children and adolescents. Primary EBV infection in younger infants is often subclinical. Complications may affect any organ system and are usually mild. In the majority of cases acute infectious mononucleosis has an excellent prognosis. Severly immuncompromised children and adolescents (i. e. under immunosuppressive therapy, after stem cell transplantation) may develop EBV⁺ B-cell lymphoproliferative disorders and malignant B-cell lymphoma. In this review, mainly the following forms of atypical EBV infections are described in detail: Fulminant, mostly fatal acute infectious mononucleosis following primary EBV infection may occur 1) sporadically (approx. 1 per 3000 cases of acute infectious mononucleosis), 2) in aprox. 60% of boys with X-linked lymphoproliferative disease (XLP), and 3) in very rare cases of a fulminant EBV+ T-cell lymphoproliferative disorder. No efficient therapy exists so far. Early allogeneic stem cell transplantation in boys with XLP may prevent fatal acute infectious mononucleosis and other complications. Chronic active EBV (CAEBV) infection is characterized by recurrent clinical episodes of severe infectious mononucleosis over months or years and additional unusual clinical signs and complications such as coronary artery aneurisms, hypersensitivity to mosquito bites and hydroa vacciniforme, as well as an markedly increased risk for malignant lymphoma, mostly of a T-cell type. In general, prognosis of CAEBV infection is poor. Allogeneic stem cell transplantation may lead to clinical remission. EBV-associated hemophagocytic syndrome may occur as an independent disorder [EBV-related hemophagocytic lymphhistiocytosis (EBV-HLH)] or as a serious complication of fatal infectious mononucleosis or CAEBV infection. Early treatment with etoposide, cyclosporine A and corticosteroids may improve the otherwise poor prognosis. The pathogenesis of atypical EBV infections is not known in most cases. Further molecular and immunologic studies may help to characterize these severe disorders and to develop more specific and more efficient therapies.