High frequencies of asymptomatic Epstein-Barr virus viremia in affected and unaffected individuals with CTLA4 mutations

Patients with CTLA4 mutations present with autoimmune diseases, lymphoproliferation, and hypogammaglobulinemia, and a subset of patients developed Epstein-Barr virus (EBV)-associated malignancies, suggesting an impaired immune function against EBV. Here we investigated EBV infection in individuals with CTLA4 mutations. We measured EBV viral DNA in healthy individuals, individuals with autoimmune diseases, and individuals with CTLA4 mutations. In addition, we evaluated the numbers and function of EBV-specific T cells, invariant NKT cells, and NK cells. More than half of individuals with CTLA4 mutations including asymptomatic ones had detectable EBV DNA, which is a significantly higher frequency with higher viral loads compared with healthy and disease controls. However, individuals with CTLA4 mutations had almost normal immunity against EBV. Individuals with CTLA4 mutations have an increased susceptibility to Epstein-Barr virus infections. Asymptomatic viremia occurs at high frequencies, which can be persistent and can occur in unaffected individuals.