Natural killer (NK) lymphocytosis induced by Epstein-Barr virus (EBV) reactivation in monoclonal gammopathy of undertermined significance (MGUS)

Abstract

We investigated the relationship between NK lymphocytosis and EBV infection in MGUS. We found that two out of 10 patients showed an increase of NK cells compared with normal controls. In addition, these two patients had far higher levels of CD5(LOW+) NK cells (activated NK cells) than controls. EBV DNA was detected by polymerase chain reaction in peripheral blood mono nuclear cells from the two patients, although the other eight patients with MGUS and all 20 normal controls had no detectable EBV DNA. Furthermore, EBV DNA was detected in sorted CD5(LOW+) NK cells. These results suggest that reactivation of EBV might be related to the increase of N K cells, particularly CD5(LOW+) NK cells in some patients with MGUS.