Clinicopathologic findings of chronic active Epstein-Barr virus infection in adults: A single-center retrospective study in China.

Chronic active Epstein-Barr virus (CAEBV) infection is a rare disease with a high mortality rate. Our study aimed to summarize the clinicopathological characteristics of CAEBV infection in adults and improve knowledge of the disease. Data for 19 adult patients with CAEBV confirmed at our hospital from January 2010 to December 2019 were collected retrospectively. There were 14 males and 5 females, and the median age was 33 years (range 14-83). The main clinical manifestations included recurrent fever (84.2%, 16/19), splenomegaly (89.5%, 17/19), hepatomegaly (73.6%, 14/19), lymphadenopathy (42.1%, 8/19), abnormal liver function (78.9%, 15/19), hemopenia (94.7%, 18/19), and hemophagocytosis (52.6%, 10/19). A total of 22 specimens were collected from 19 patients for histopathology. Most of the biopsy specimens showed lymphocyte infiltration. Immunohistochemical staining and EBV-encoded small RNA (EBER) in situ hybridization were performed for 14 of the 22 samples. CD3 and CD20 staining were positive, with more CD3-positive cells than CD20-positive cells (100%, 14/14), and EBER in situ hybridization was positive in most cases (85.7%, 12/14). More than half of TCR gene rearrangement tests showed monoclonal rearrangement (66.6%, 4/6). Mortality was high, with most CAEBV patients dying during the period from diagnosis to the end of follow-up (12/19, 63%); the median survival time was only 20.75 months. Based on limited data, we consider that CAEBV is a disease with different ages of onset and is a complex and heterogeneous syndrome with features of both immunodeficiency and malignant neoplasms. Furthermore, the prognosis of adult-onset CAEBV appears to be very poor.