Evaluation of cytomegalovirus (CMV)-specific T-cell immunity for the assessment of the risk of active CMV infection in non-immunosuppressed surgical and trauma intensive care unit patients.

The current study was designed to assess the predictive value of the evaluation of cytomegalovirus (CMV)-specific T-cell immunity early following admission to the intensive care unit for inferring the risk of active CMV infection in non-immunosuppressed surgical and trauma patients. A total of 31 CMV-seropositive patients were included. Patients were screened for the presence of CMV DNA in plasma and in tracheal aspirates by real-time PCR. Enumeration of CMV pp65 and IE-1-specific IFN-γ CD8(+) and CD4(+) T cells was performed by flow cytometry for intracellular cytokine staining. Virological and immunological monitoring was conducted once or twice a week. Active CMV infection occurred in 17 out of 31 patients. Undetectable levels of pp65 and IE-1-specific IFN-γ CD8(+) and CD4(+) T-cell subsets cells were observed in 10 patients who developed active CMV infection and in one who did not (at a median of 2 days following ICU admission). Peak CMV DNA loads in both tracheal aspirates and plasma were substantially higher (P = 0.018 and P = 0.091, respectively) in patients with undetectable IFN-γ T-cell responses than in patients with detectable responses. The expansion of both CMV-specific T-cell subsets following detection of active CMV infection was demonstrated in 9 out of 14 patients with active CMV infection. In conclusion, the evaluation of CMV pp65 and IE-1-specific IFN-γ-producing CD8(+) and CD4(+) T cells early following ICU admission may allow the identification of patients most at risk of either having or developing an episode of active CMV infection, particularly those associated with high-level virus replication.