In contrast, CMV infection has been shown to lead to significant disease in immunocompromised hosts such as those with HIV infection or transplant recipients. End-stage HIVinfected patients with a CD4 lymphocyte count of less than 50 cells/mm 3 are at the highest risk of developing CMV retinitis [2] . In transplant recipients, CMV disease occurs in 11 to 72% of patients especially in the first three months after transplant while the patients are receiving maximum immunosuppression [3] . In addition to febrile syndrome and end-organ disease directly as a result of viral replication, immunomodulatory characteristics of CMV may contribute to opportunistic infections, allograft rejection, and higher mortality in transplant recipients. Clinical trials have shown that preventive approaches utilizing antiviral agents have lead to a reduction in the rates of CMV infection and disease, and indirect sequelae associated with CMV [3] [4] [5] . Currently, prophylaxis or periodic monitoring and antiviral therapy targeted towards patients with viral replication are routinely employed at many transplant centers. APACHE : Acute Physiology and Chronic Health Evaluation; ARDS: acute respiratory distress syndrome; BAL: bronchoalveolar lavage; CI: confidence interval; CMV: cytomegalovirus; HHV: human herpesvirus; HSV: herpes simplex virus; ICU: intensive care unit; IL: interleukin; MeSH: medical subject headings; NF-B: nuclear factor-B; OR: odds ratio; PCR: polymerase chain reaction; SAPS: simplified acute physiology score; SOFA: sepsis-related organ failure assessment, TNF: tumor necrosis factor; VAP: ventilator-associated pneumonia.