Monitoring of Torque Teno virus DNAemia in critically ill COVID-19 patients: May it help to predict clinical outcomes?

BACKGROUND: : Torque teno virus (TTV) DNA load in plasma directly associates with the net state of immunosuppression and inflammation in different clinical settings, including transplantation and chronic inflammatory diseases. OBJECTIVES: : We investigated whether plasma TTV DNA load may predict the occurrence of certain infectious events and overall mortality in critically ill COVID-19 patients. PATIENTS AND METHODS: : 50 patients (median age, 65.5 years) were recruited. TTV DNA load was quantitated in serial plasma specimens by real-time PCR. Serum levels of interleukin-6, C-reactive protein, ferritin, lactate dehydrogenase, Gamma-Glutamyl Transferase (GGT), alanine transaminase (ALT) and aspartate transaminase (AST) and absolute lymphocyte counts (ALC) in paired specimens were available. Nosocomial bloodstream infections and ventilator-associated pneumonia and overall mortality were the clinical outcomes. RESULTS: : TTV DNA was detected in 38 patients (76%). A weak inverse correlation (Rho=-0.28; P = 0.004) was observed between TTV DNA loads and ALC. No direct correlation was found between TTV DNA load and serum levels of any of the above biomarkers. Patients with detectable TTV DNA had an increased risk of subsequently developing infectious events (HR 9.28; 95% CI, 1.29–69.5; P = 0.03). A trend (P = 0.05) towards higher TTV DNA area under a curve between days 7 and 17 after ICU admission (AUC(7–17)) was observed in patients who died, as compared to survivors. CONCLUSION: : Our findings suggested that plasma TTV DNA load monitoring may be helpful for predicting the occurrence of severe nosocomial infections and mortality in critically ill COVID-19 patients.