Atypical Epstein-Barr virus infection during and after intermittent FK506 therapy

Atypical Epstein-Barr virus (EBV) infection developed in a patient under intermittent administration of FK506 (one dose in 10 days) after living-related liver transplantation. The clinical course was similar to severe chronic active EBV infection syndrome (SCAEBV), which is characterized by extremely high titers of antibody to EBV antigens. The clinical symptoms improved without graft rejection even after the cessation of FK506; however, the titers of antibody to EBV antigens remained at high levels. It was considered that: (i) even intermittent use of FK506 could influence the immune response, which then induced atypical EBV infection similar to SCAEBV; and (ii) the impaired immune response, especially to EBV antigens, remained after complete cessation of FK506.