Cytomegalovirus reactivation occurs in burn patients and correlates with increased central memory and regulatory T cell populations. (39.32)

Cytomegalovirus reactivation (CMV-R) is an important cause of morbidity and mortality in immunocompromised patients. CMV-R has been recognized in critically ill patients. Severe burn injury leads to early and prolonged immune and adaptive immune dysfunction. We hypothesized that CMV-R would occur in burn patients correlating with specific changes in T cell phenotype. We prospectively evaluated incidence of CMV-R longitudinally among patients with >10% total body surface area (TBSA) injury using serum PCR. We determined changes in CMV specific CD8+ T cells by utilizing CMV-specific MHC Class I tetramers, functional responsiveness to CMV peptide and the generation of Tregs using qPCR for FoxP3. 24 burn patients enrolled, with CMV-R occurring in 36.8% of patients. We detected no difference in frequency of CMV-reactive CD8+ T cells nor in vitro anti-CMV CD8+ T cell response by IFN-γ staining between R and non-R patients. CMV-R patients had a significantly decreased proportion of CMV-specific CD8+ T cells that were central-memory (CD45RO+CD62L+CD28+) and increased effector-memory phenotype (CD28-) during the first week following injury. Elevated FoxP3 expression in the 10 days prior to R correlated with R in 4/6 patients tested. CMV-R occurred following burn injury and may be related to remodeling of the CD8+ T cell population after burn. Increased T cell regulatory activity after burn may also predict for CMV-R in a subset of patients.