Association of Dynamics of Anellovirus Loads with Hospital-Acquired Pneumonia in Patients with Brain Injury During the Intensive Care Unit Stay

Background Critical illness induces immune disorders associated with an increased risk of hospital-acquired pneumonia (HAP) and acute respiratory distress syndrome (ARDS). Torque teno virus (TTV), from the Anelloviridae family, is proposed as a biomarker to measure the level of immunosuppression. Our objective was to describe the kinetics of TTV DNA loads and their association with critical illness-related complications.Methods We performed a longitudinal study in 115 patients with brain injury from a prospective cohort, collected endotracheal and blood samples at 3 successive time points after admission in the intensive care unit (ICU) (T1, 0-4 days post ICU admission; T2, 5-10; T3, 11-18), and measured viral DNA loads using the TTV R-GENE kit (BioMerieux) and a pan-Anelloviridae in-house quantitative real-time polymerase chain reaction.Results TTV DNA was detected in the blood of 69%, 71%, and 64% of patients with brain injury at T1, T2, and T3, respectively. Time-associated variations of TTV and anellovirus DNA loads were observed. Using a linear mixed-effects model, we found that HAP and ARDS were associated with lower blood anellovirus DNA loads.Conclusions Our results show that HAP or ARDS in patients who are critically ill is associated with changes in anellovirus DNA loads and should be evaluated further as a biomarker of immune disorders leading to these complications. In a cohort of patients with brain injury, longitudinal analysis of anelloviruses showed a decrease in viral loads associated with hospital-acquired pneumonia and acute respiratory distress syndrome in blood and respiratory samples, suggesting changes in virome composition possibly linked to immune disturbances.