No abstract

There is a significant prevalence (22-49%) of occult active herpes family viruses in chronic critically ill surgical patients. The clinical significance of these viral infections is unknown, although CMV+ patients have significantly higher morbidity rates than CMV- patients. Several factors suggest pathogenicity, but further study is needed to define causality.

We have previously shown that cytomegalovirus (CMV) can reactivate in lungs of nonimmunosuppressed patients during critical illness. Our recent work has shown that polymicrobial bacterial sepsis can trigger reactivation of latent murine CMV (MCMV). We hypothesize that MCMV reactivation following bacterial sepsis may be caused by inflammatory mediators. To test this hypothesis, BALB/c mice latently infected with Smith strain MCMV received sublethal intraperitoneal doses of lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF-␣), interleukin-1␤ (IL-1␤), or saline. Lung tissue homogenates were evaluated for viral reactivation 3 weeks after mediator injection. Because LPS is known to signal via Toll-like receptor 4 (TLR-4) in mice, further studies blocking this signaling mechanism were performed using monoclonal MTS510. Finally, mice were tested with intravenous TNF-␣ to determine whether this would cause reactivation. All mice receiving sublethal intraperitoneal doses of LPS, TNF-␣, or IL-1␤ had pulmonary reactivation of latent MCMV 3 weeks following injection, and LPS caused MCMV reactivation with kinetics similar to those for sepsis. When TLR-4 signaling was blocked, exogenous LPS did not reactivate latent MCMV. Intravenous TNF-␣ administration at near-lethal doses did not reactivate MCMV. Exogenous intraperitoneal LPS, TNF-␣, and IL-1␤ are all capable of reactivating CMV from latency in lungs of previously healthy mice. LPS reactivation of MCMV appears dependent on TLR-4 signaling. Interestingly, intravenous TNF-␣ did not trigger reactivation, suggesting possible mechanistic differences that are discussed. We conclude that inflammatory disease states besides sepsis may be capable of reactivating CMV from latency.

CPS can be readily determined in the era of medication reconciliation. Trauma patients with CPS of 15 or greater are at greater risk of poor clinical outcomes. CPS constitutes a useful adjunct to currently available injury severity scoring tools as a predictor of morbidity, mortality, hospital resource utilization, and postdischarge disposition in older trauma patients.