Background: Human cytomegalovirus (CMV) is an important opportunistic pathogen after transplantations. In the present study, monitoring of CMV in patients with septic shock was used to discover whether T helper cell type 1 (Th1) cell and natural killer (NK) cell functions interact with CMV reactivation in patients not undergoing immunosuppressive therapy.
Methods: Thirty-eight patients with septic shock were monitored, and the 23 CMV-seropositive patients were included in this prospective study.
Results: Seven patients (30.4%) developed an active CMV infection despite the detection of CMV-reactive Th1 cells. After active CMV infection, the frequency of CMV-reactive Th1 cells increased from a median of 0.52% to 5.04% (P=.009). Active CMV infections were terminated without antiviral therapy within 2 weeks. In parallel, the frequency of staphylococcal enterotoxin B (SEB; superantigen)-reactive Th1 cells increased from a median of 1.11% to 8.48% (P=.027). In patients without active CMV infection, the frequency of CMV-reactive (median, 0.39%) and SEB-reactive (median, 1.11%) Th1 cells did not increase. Cytotoxic NK cell activity was persistently suppressed despite the presence of CD56(+)CD16(+) NK cells. Moreover, interleukin-2 application in vitro did not restore NK cell activity.
Conclusions: A proinflammatory immune response may contribute to CMV reactivation in patients with septic shock. Adaptive T cell immunity, more likely than NK cell immunity, may contribute to termination of active CMV infection without antiviral therapy in these patients.