[Clinical features of adult-onset chronic active Epstein-Barr virus infection].

Chronic active Epstein-Barr virus infection (CAEBV) presents with mononucleosis-like symptoms such as chronic persistent or recurrent pyrexia, lymphadenopathy, and hepatosplenomegaly because of the reactivation of Epstein-Barr virus (EBV) as demonstrated by the recurrence of EBV-infected cells. The mechanism of CAEBV remains obscure, and CAEBV can lead to fatal conditions such as hemophagocytic syndrome and malignant lymphoma by clonal expansion of EBV-infected T- or NK-cells. Without hematopoietic stem cell transplantation, CAEBV has a poor prognosis. CAEBV is listed in the revised 2016 World Health Organization classification as a chronic active EBV infection of T- and NK-cell types, systemic form, among EBV-positive T- and NK-cell lymphoproliferative diseases of childhood. However, similar clinical conditions have been reported in adult patients. Therefore, we investigated the clinical features of adult patients with CAEBV-like features (adult-onset CAEBV) in a relatively small number of cases. Additionally, genetic alterations related to CAEBV development have also been reported. Along with these results, we reviewed the clinical characteristics of adult-onset CAEBV.