Treating HSV and CMV reactivations in critically ill patients who are not immunocompromised: pro

Herpes simplex virus 1 encodes a STING antagonist that can be therapeutically targeted

Herpes simplex virus 1 (HSV-1) is a ubiquitous human pathogen that causes serious symptoms and is known for its strong interactions with host immunity. Here, we revealed that the HSV-1-encoded UL38 is a stimulator of interferon genes (STING) antagonist that interacts with STING to abrogate the STING-TANK-binding kinase 1 (TBK1)-interferon regulatory factor 3 (IRF3) interaction, thereby suppressing cyclic GMP-AMP synthase (cGAS)-STING-dependent immune signaling. Losing UL38's STING antagonist activity made HSV-1 incapable of immune evasion and less replicable and pathogenic in vivo. Moreover, on the basis of the UL38-interacting sequence within STING, we rationally designed a series of peptides to target the STING-UL38 interface of UL38 specifically. Among them, a peptide effectively disrupts the STING-UL38 interaction, which unlocks the UL38-suppressed immune response and shows potent therapeutic efficacy against HSV-1 infection in vivo. Therefore, our findings demonstrate that HSV-1 UL38 is a STING antagonist, and targeting the activity of UL38 is a promising strategy for the development of antivirals against this notorious virus.

Characteristics and prognosis of Herpesviridae-related pneumonia in critically ill burn patients

BACKGROUND

The aim of this study was to describe the prevalence, characteristics and outcome of critically burn patients with pulmonary HSV reactivation.

METHODS

Retrospective, single-center cohort study in a burn critical care unit in a tertiary center, including all consecutive severely burn patients with bronchoalveolar lavage performed for pneumoniae suspicion and screened for HSV from January 2013 and April 2017. We used logistic regression to identify factors associated with HSV reactivation and outcomes.

RESULTS

94 patients were included, mean age was 51 (39-64) years; median total body surface area burned was 36 (25-54)% and ICU mortality 38%. Fifty-five patients (59%) had pulmonary HSV reactivation and 30 (55%) were treated with acyclovir. Patients with HSV reactivation were more severely ill with higher SOFA score at admission compared to patient without HSV reactivation (6 [3-8] vs. 2 [1-4], p < 0.0001 respectively). In multivariate analysis, sex, SOFA score at admission and smoke inhalation were significantly associated with HSV reactivation. Only septic shock was associated with 90-day mortality when HSV reactivation was not.

CONCLUSIONS

Pulmonary HSV reactivation is frequent among severely ill burn patients. Initial severity and smoke inhalation are risk factors. Antiviral treatment was not associated with outcome.

Herpesviruses in Critically Ill Patients With ARDS

Reactivation of herpsviruses, mainly HSV, CMV and EBV, are frequent among critically ill patients. Although they are not immunocompromised from a classical point of view, these patients often present an alteration of their immune system favoring viral reactivation. Seropositive patients with sepsis and under mechanical ventilation are particularly at risk. Herpesviruses have a pulmonary tropism and can be responsible for non-resolving forms of acute respiratory distress syndrome with high mortality. However, the direct causality between herpesviruses reactivation and impaired outcomes among severely ill patients remains under debate.

Surviving Sepsis Campaign: Research Opportunities for Infection and Blood Purification Therapies

Patients with infection can develop sepsis, and their mortality can be high. An important aspect in the treatment of sepsis is adequate management of the infection.

Impact of antiviral treatment on long-term prognosis in non-immunocompromised patients with CMV reactivation

Background

Reactivation of human cytomegalovirus (CMV) occurs in non-immunocompromised patients with or without specific organ involvement, but it is still unknown whether it has a clinical implication on long-term prognosis or not.

Methods

A retrospective cohort study evaluating non-immunocompromised adult patients with CMV reactivation was conducted during the period between January 2010 and February 2018. Patients were divided into ganciclovir-treated and non-treated groups. Patients who died within 30 days from CMV reactivation were excluded as they died from complex causes of conditions. Survivors were followed for 30-months to evaluate long-term prognosis.

Results

A total of 136 patients with CMV reactivation was included, consisting of 66 ganciclovir-treated (48.5%) and 70 non-treated (51.5%) patients. Overall, patients were old-aged (median 70 years old) and most were treated with pneumonia of any cause (91.2%). More patients in ganciclovir-treated group were treated at intensive care unit (43.9% vs 24.3%, respectively) and had higher viral load over 5000 copies/ml (48.5% vs 22.9%) than non-treated group (all P < 0.05). Primary and secondary endpoints including 30-months survival (28.0 vs 38.9%, respectively) and 12-months survival (40.3% vs 49.2%) were not statistically different between the ganciclovir-treated and non-treated groups. In the multivariate analyses, ganciclovir treatment was not associated with 30-months survival (HR 1.307, 95% CI 0.759–2.251) and 12-months survival (HR 1.533, 95% CI 0.895–2.624).

Conclusion

In a retrospective cohort study evaluating non-immunocompromised patients with CMV reactivation, ganciclovir treatment was not associated with long-term prognosis. Antiviral treatment in this condition would not be necessary unless organ involvement is suspected.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06098-4.

Update in Viral Infections in the Intensive Care Unit

The advent of highly sensitive molecular diagnostic techniques has improved our ability to detect viral pathogens leading to severe and often fatal infections that require admission to the Intensive Care Unit (ICU). Viral infections in the ICU have pleomorphic clinical presentations including pneumonia, acute respiratory distress syndrome, respiratory failure, central or peripheral nervous system manifestations, and viral-induced shock. Besides de novo infections, certain viruses fall into latency and can be reactivated in both immunosuppressed and immunocompetent critically ill patients. Depending on the viral strain, transmission occurs either directly through contact with infectious materials and large droplets, or indirectly through suspended air particles (airborne transmission of droplet nuclei). Many viruses can efficiently spread within hospital environment leading to in-hospital outbreaks, sometimes with high rates of mortality and morbidity, thus infection control measures are of paramount importance. Despite the advances in detecting viral pathogens, limited progress has been made in antiviral treatments, contributing to unexpectedly high rates of unfavorable outcomes. Herein, we review the most updated data on epidemiology, common clinical features, diagnosis, pathogenesis, treatment and prevention of severe community- and hospital-acquired viral infections in the ICU settings.

Effect of antiviral therapy on the outcomes of mechanically ventilated patients with herpes simplex virus detected in the respiratory tract: a systematic review and meta-analysis

Background

Herpes simplex virus (HSV) is frequently detected in the respiratory tract of mechanically ventilated patients. The aim of this study was to assess current evidence to determine whether antiviral therapy is associated with better outcomes in these patients.

Methods

MEDLINE, ISI Web of Science, Cochrane Database and ClinicalTrials.gov were searched from inception to 25 May 2020. All clinical studies investigating the effects of antiviral therapy on the outcome of mechanically ventilated ICU patients in whom HSV was detected in the respiratory tract were eligible for inclusion, regardless of study design, publication status or language. Titles and abstracts were reviewed independently by two authors. If the articles seemed eligible, full-text articles were reviewed and data extracted.

We performed a random-effects meta-analysis to estimate relative risks (RRs) with corresponding 95% confidence intervals (CIs). The primary endpoint was hospital all-cause mortality.

Results

Nine studies were included in the meta-analysis (one randomized controlled trial, eight cohort studies). Antiviral treatment was associated with lower hospital mortality (with antiviral treatment, 40.6% (189 out of 465 patients); without, 52.7% (193 out of 366 patients); RR 0.74 [0.64, 0.85]; eight studies, low quality of evidence). Furthermore, antiviral treatment was associated with lower 30-day mortality (RR 0.75 [0.59, 0.94]; three studies, very low quality of evidence). We did not observe evidence for differences in ICU mortality (RR 0.73 [0.51, 1.05]; three studies, very low quality of evidence).

Conclusions

This meta-analysis of the available data shows that antiviral therapy might result in lower hospital and 30-day all-cause mortality in mechanically ventilated ICU patients who are positive for HSV in the respiratory tract. However, this result must be interpreted with great caution due to the high risk of bias and limited number of patients. Large, well-designed randomized controlled clinical trials are urgently needed.

Trial registration

The study was registered in advance on International Prospective Register of Systematic Reviews (CRD42020180053).

Effect of Antiviral Therapy on the Outcome of Mechanically Ventilated Patients With Herpes Simplex Virus Type 1 in BAL Fluid: A Retrospective Cohort Study

BACKGROUND

Herpes simplex virus type 1 (HSV-1) is frequently detected in the BAL fluid of patients on mechanical ventilation.

RESEARCH QUESTION

The aim of the study was to investigate whether antiviral therapy is associated with improved overall survival within 30 days.

STUDY DESIGN AND METHODS

This was a retrospective cohort study in four ICUs between January 2011 and December 2017. All adult patients on mechanical ventilation with a respiratory tract infection with positive polymerase chain reaction testing for HSV-1 in the BAL were included. Patients already receiving antiviral agents on the day BAL was performed were excluded. We performed uni- and multivariable Cox and logistic regression modeling.

RESULTS

Overall, 306 patients were included in the analysis. Among them, 177 patients (57.8%) received antiviral therapy (90.9% acyclovir, 6.2% ganciclovir, 2.9% both). The overall 30-day mortality rate was 42.4% (n = 75) in the antiviral treatment group and 50.4% (n = 65) in the control group. The adjusted hazard ratio (HR) for the primary outcome was 0.62 (95% CI, 0.44-0.87; P = .005), indicating better overall survival within 30 days for the antiviral-treated group than for the untreated group. This benefit was also present in the subgroup of patients without immunosuppression (n = 246; adjusted HR, 0.53; 95% CI, 0.36-0.78; P = .001). Overall, the median lengths of hospital stay (31 vs 24 days, P = .002) and ICU stay (24 vs 17 days, P < .001), and the duration of mechanical ventilation (18 vs 11 days, P < .001), were longer for patients with therapy. No evidence for the treatment-related deterioration of renal function was observed.

INTERPRETATION

These data suggest that detection of HSV-1 in the BAL of patients on mechanical ventilation may be of clinical significance and that specific antiviral treatment may improve clinical outcomes. However, this needs to be proven in multicenter randomized controlled trials before implementation into the clinical routine.

Cytomegalovirus: A Troll in the ICU? Overview of the Literature and Perspectives for the Future

Cytomegalovirus (CMV) is one of the most pathogenic viruses in human. After a primary infection, CMV resides in the host for life as a latent infection. When immunity is reduced, CMV can escape the suppressive effects of the immune system and lead to viremia and antigenemia. This reactivation, first seen in transplant patients, has also been documented in non-immunocompromised CMV-seropositive critically ill patients and is associated with higher morbidity and mortality. In the latter, it is not clear whether CMV reactivation is an innocent bystander or the cause of this observed worse outcome. Two studies showed no difference in the outcome of CMV-seropositive and seronegative patients. In addition, proof-of-concept studies investigating prophylactic antiviral treatment to prevent CMV reactivation during critical illness, failed to show a beneficial effect on interleukin levels or clinical outcome. Further research is necessary to resolve the question whether CMV replication impairs the prognosis in non-immunocompromised critically ill patients. We here give a concise overview on the available data and propose strategies to further unravel this question. First, post-mortem investigation may be useful to evaluate the effect of viral replication on organ inflammation and function. Second, further research should focus on the question whether the level of viremia needs to exceed a threshold to be associated with worse outcome. Third, clinical and biochemical assessments may help to identify patients at high risk for reactivation. Fourth, preemptive treatment based upon early detection of the virus is currently under investigation. Finally, immune-stimulating biologicals may be beneficial in high-risk groups.

Respiratory viruses in mechanically ventilated patients: a pilot study

BACKGROUND

Respiratory virome is an integral part of the human microbiome and its characterization may contribute to a better understanding of the changes that arise in the disease and, consequently, influence the approach and treatment of patients with acute lower respiratory infections. The aim of this study was to evaluate the presence of respiratory viruses in the lower airways of individuals undergoing invasive mechanical ventilation, with and without acute lower respiratory infection (respectively WRI and WORI groups).

METHODS

We studied 44 mini-bronchoalveolar lavage samples (collected with a double catheter, Combicath® kit) from patients with mean age in the seventh decade, 20 from WORI group and 24 from WRI group, who were hospitalized for acute respiratory failure in Intensive Care Units of two hospitals in the Lisbon area. Real-time PCR was applied to verify analyse the presence of 15 common respiratory viruses (adenovirus, human bocavirus, influenza virus A and B, repiratory syncytial virus, human parainfluenza virus types 1, 2, 3 and 4, human enterovirus, human rhinovirus, human metapneumovirus, human coronavirus group 1 (229E, NL63) and 2 (OC43, HKU1).

RESULTS

Respiratory viruses were detected in six of the 20 patients in the WORI group: influenza AH3 (n = 2), parainfluenza virus 1/3 (n = 2), human rhinovirus (n = 2), respiratory syncytial virus (n = 1) and human metapneumovirus (n = 1). In the WRI group, respiratory viruses were detected in 12 of the 24 patients: influenza AH3 (n = 3), human rhinovirus (n = 3), respiratory syncytial virus (n = 3), human metapneumovirus (n = 3), human bocavirus (n = 2) and human enterovirus (n = 1). Simultaneous detection of two viruses was recorded in two samples in both groups.

CONCLUSIONS

The results of this study suggest the presence of common respiratory viruses in the lower respiratory tract without causing symptomatic infection, even in carefully collected lower samples. This may have important implications on the interpretation of the results on the diagnostic setting.

Acyclovir for Mechanically Ventilated Patients With Herpes Simplex Virus Oropharyngeal Reactivation: A Randomized Clinical Trial

IMPORTANCE

The role of herpes simplex virus (HSV) reactivation on morbidity and mortality in patients in the intensive care unit requiring mechanical ventilation remains unknown.

OBJECTIVE

To determine whether preemptive treatment with intravenous acyclovir reduces the duration of mechanical ventilation in patients with HSV oropharyngeal reactivation.

DESIGN, SETTING, AND PARTICIPANTS

A double-blind, placebo-controlled randomized clinical trial was conducted in 16 intensive care units in France. Participants included 239 adults (age, >18 years) who received mechanical ventilation for at least 96 hours and continued to receive mechanical ventilation for 48 hours or more, with HSV oropharyngeal reactivation. Patients were enrolled between February 2, 2014, and February 22, 2018.

INTERVENTIONS

Participants were randomized to receive intravenous acyclovir, 5 mg/kg, 3 times daily for 14 days or a matching placebo.

MAIN OUTCOMES AND MEASURES

The primary end point was ventilator-free days from randomization to day 60. Prespecified secondary outcomes included mortality at 60 days. Main analyses were conducted on an intention-to-treat basis.

RESULTS

Of 239 patients enrolled and randomized, 1 patient withdrew consent, leaving 238 patients, with 119 patients in both the acyclovir and placebo (control) groups (median [IQR] age, 61 [50-70] years; 76 [32%] women) available for primary outcome measurement. On day 60, the median (IQR) numbers of ventilator-free days were 35 (0-53) for acyclovir recipients and 36 (0-50]) for controls (P = .17 for between-group comparison). Among secondary outcomes, 26 patients (22%) and 39 patients (33%) had died at day 60 (risk difference, 0.11, 95% CI, -0.004 to 0.22, P = .06). The adverse event frequency was similar for both groups (28% in the acyclovir group and 23% in the placebo group, P = .40), particularly acute renal failure post randomization affecting 3 acyclovir recipients (3%) and 2 controls (2%). Four patients (3%) in the acyclovir group vs none in the placebo group stopped the study drug for treatment-related adverse events.

CONCLUSIONS AND RELEVANCE

In patients receiving mechanical ventilation for 96 hours or more with HSV reactivation in the throat, use of acyclovir, 5 mg/kg, 3 times daily for 14 days, did not increase the number of ventilator-free days at day 60, compared with placebo. These findings do not appear to support routine preemptive use of acyclovir in this setting.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02152358.

Impact of acyclovir use on survival of patients with ventilator-associated pneumonia and high load herpes simplex virus replication

Background

Herpes simplex virus (HSV) replication can be detected in the respiratory secretions of a high proportion of ventilated intensive care unit (ICU) patients. However, the clinical significance remains poorly defined. We investigated whether patients with ventilator-associated pneumonia not responding to antibiotics and in whom high levels of HSV could be detected in respiratory secretions benefit from acyclovir treatment.

Methods

Respiratory secretions (bronchoalveolar lavage fluid or tracheal aspirates) were tested for HSV replication by quantitative real-time PCR. ICU survival times, clinical parameters, and radiographic findings were retrospectively compared between untreated and acyclovir treated patients with high (> 10⁵ HSV copies/mL) and low (10³–10⁵ HSV copies/mL) viral load.

Results

Fifty-seven low and 69 high viral load patients were identified. Fewer patients with high viral load responded to antibiotic treatment (12% compared to 40% of low load patients, p = 0.001). Acyclovir improved median ICU survival (8 vs 22 days, p = 0.014) and was associated with a significantly reduced hazard ratio for ICU death (HR = 0.31, 95% CI 0.11–0.92, p = 0.035) in high load patients only. Moreover, circulatory and pulmonary oxygenation function of high load patients improved significantly over the course of acyclovir treatment: mean norepinephrine doses decreased from 0.05 to 0.02 μg/kg body weight/min between days 0 and 6 of treatment (p = 0.049), and median PaO₂/FiO₂ ratio increased from 187 to 241 between day 3 and day 7 of treatment (p = 0.02). Chest radiographic findings also improved significantly (p < 0.001).

Conclusions

In patients with ventilator-associated pneumonia, antibiotic treatment failure, and high levels of HSV replication, acyclovir treatment was associated with a significantly longer time to death in the ICU and improved circulatory and pulmonary function. This suggests a causative role for HSV in this highly selected group of patients.

Influenza Infections and Emergent Viral Infections in Intensive Care Unit

Critically ill patients are admitted to an intensive care unit (ICU) for multiple reasons. In this study, we aim to analyze the current evidence and findings associated with influenza and other emergent viral infections, namely, herpes simplex virus type 1 (HSV-1), Epstein-Barr virus (EBV), and cytomegalovirus (CMV).

Among medical conditions, community-acquired respiratory infections are the most frequent reason for ventilatory support in ICUs. Community-acquired pneumonia in a severe form including the need of invasive mechanical ventilation and/or vasopressors is associated with high mortality rates. However, after the pandemic that occurred in 2009 by H1N1 influenza, the number of cases being admitted to ICUs with viral infections is on the rise. Patients in whom an etiology would not have been identified in the past are currently being tested with more sensitive viral molecular diagnostic tools, and patients being admitted to ICUs have more preexisting medical conditions that can predispose to viral infections. Viral infections can trigger the dysregulation of the immune system by inducing a massive cytokine response. This cytokine storm can cause endothelial damage and dysfunction, deregulation of coagulation, and, consequently, alteration of microvascular permeability, tissue edema, and shock. In severe influenza, this vascular hyperpermeability can lead to acute lung injury, multiorgan failure, and encephalopathy. In immunocompetent patients, the most common viral infections are respiratory, and influenza should be considered in patients with severe respiratory failure being admitted to ICU. Seasonality and coinfection are two important features when considering influenza as a pathogen in critically ill patients.

Herpesviridae (HSV, CMV, and EBV) may reactivate in ICU patients, and their reactivation is associated with morbidity/mortality. However, whether a specific treatment may impact on outcome remains to be determined.

Réactivations à herpès virus (HSV, CMV) en réanimation : qui et quand traiter ?

Les réactivations à herpès simplex virus (HSV) et à cytomégalovirus (CMV) sont fréquentes chez le patient non immunodéprimé de réanimation. La réactivation HSV est localisée aux voies aériennes ; elle débute au niveau oropharyngé, progresse de façon descendante avec la contamination des voies aériennes distales et peut aboutir, chez certains malades, à une véritable bronchopneumonie herpétique. Elle est en outre associée à un pronostic défavorable. Le traitement prophylactique et préemptif des réactivations HSV ne peut pas être préconisé à l’heure actuelle. Le traitement curatif repose sur un avis d’experts, chez des malades présentant soit une charge virale élevée dans les voies aériennes distales, soit des signes cytologiques d’atteinte parenchymateuse pulmonaire sur les cellules recueillies lors du lavage bronchoalvéolaire. La réactivation CMV sanguine est fréquente et peut être isolée ou associée à une réactivation/atteinte pulmonaire et est aussi associée à un pronostic défavorable. Le traitement prophylactique de la réactivation CMV ne peut pas être préconisé, et le traitement préemptif est en cours d’évaluation. À l’heure actuelle, le traitement curatif des maladies pulmonaires à CMV repose soit sur des signes histologiques d’atteinte pulmonaire, soit sur un faisceau d’arguments clinicobiologiques évoquant une possible maladie à CMV.

Cytomegalovirus infection in immunocompetent critically ill adults: literature review

Cytomegalovirus (CMV) infection is increasingly recognized in critically ill immunocompetent patients. Some studies have demonstrated an association between CMV disease and increased mortality rates, prolonged intensive care unit and hospital length of stay, prolonged mechanical ventilation, and nosocomial infections. However, there is a considerable controversy whether such association represents a causal relationship between CMV disease and unfavorable outcomes or just a marker of the severity of the critical illness. Detection of CMV using polymerase chain reaction and CMV antigenemia is the standard diagnostic approach. CMV may have variety of clinical manifestations reflecting the involvement of different organ systems. Treatment of CMV in critical care is challenging due to diagnostic challenge and drug toxicity, and building predictive model for CMV disease in critical care setting would be promising to identify patients at risk and starting prophylactic therapy. Our objective was to broadly review the current literature on the prevalence and incidence, clinical manifestations, potential limitations of different diagnostic modalities, prognosis, and therapeutic options of CMV disease in critically ill patients.

Cytomegalovirus reactivation and mortality in patients with acute respiratory distress syndrome

PURPOSE

Cytomegalovirus (CMV) reactivation occurs frequently in patients with the acute respiratory distress syndrome (ARDS) and has been associated with increased mortality. However, it remains unknown whether this association represents an independent risk for poor outcome. We aimed to estimate the attributable effect of CMV reactivation on mortality in immunocompetent ARDS patients.

METHODS

We prospectively studied immunocompetent ARDS patients who tested seropositive for CMV and remained mechanically ventilated beyond day 4 in two tertiary intensive care units in the Netherlands from 2011 to 2013. CMV loads were determined in plasma weekly. Competing risks Cox regression was used with CMV reactivation status as a time-dependent exposure variable. Subsequently, in sensitivity analyses we adjusted for the evolution of disease severity until onset of reactivation using marginal structural modeling.

RESULTS

Of 399 ARDS patients, 271 (68%) were CMV seropositive and reactivation occurred in 74 (27%) of them. After adjustment for confounding and competing risks, CMV reactivation was associated with overall increased ICU mortality (adjusted subdistribution hazard ratio (SHR) 2.74, 95% CI 1.51-4.97), which resulted from the joint action of trends toward an increased mortality rate (direct effect; cause specific hazard ratio (HR) 1.58, 95% CI 0.86-2.90) and a reduced successful weaning rate (indirect effect; cause specific HR 0.83, 95% CI 0.58-1.18). These associations remained in sensitivity analyses. The population-attributable fraction of ICU mortality was 23% (95% CI 6-41) by day 30 (risk difference 4.4, 95% CI 1.1-7.9).

CONCLUSION

CMV reactivation is independently associated with increased case fatality in immunocompetent ARDS patients who are CMV seropositive.

Interferon-γ production by CMV-specific CD8+ T lymphocytes provides protection against cytomegalovirus reactivation in critically ill patients

PURPOSE

To evaluate the usefulness of the secretion of interferon-γ (IFNγ) by cytomegalovirus (CMV)-specific CD8+ T cells to determine the risk of CMV reactivation in critically ill non-immunosuppressed patients.

METHODS

Two-center prospective cohort study including critically ill non-immunosuppressed CMV-seropositive patients admitted between December 2012 and March 2013. The incidence of CMV reactivation by polymerase chain reaction (real-time PCR) in plasma was investigated. IFNγ secretion by CMV-specific CD8+ T lymphocytes was determined at the time of admission to the intensive care unit (ICU) by means of the QuantiFERON(®)-CMV (QF-CMV) test. Cox regression analyses were performed to investigate CMV reactivation risk factors.

RESULTS

Fifty-three patients were included, of whom 13 (24.5%) presented CMV reactivation. Twenty-six patients (49.1%) were QF-CMV "reactive" (QF-CMV(R)). Of the 26 QF-CMV(R) patients, 11.5% (3/26) had CMV reactivation, whereas 37% (10/27) of QF-CMV "non reactive" patients (QF-CMV(NR)) presented reactivation (p = 0.03). By Cox regression, the presence of QF-CMV(R) at ICU admission (HR 0.09, 95% CI 0.02-0.44; p = 0.003) was associated with a decreased risk of CMV reactivation. The sensitivity, specificity, positive predictive value, and negative predictive value of QF-CMV were 77, 57, 37, and 88%, respectively. Eleven of the 53 patients (20.7%) died during the follow-up period. Mortality was more frequent in patients with CMV reactivation (6/13, 46.1 vs. 5/40, 12.5%; p = 0.015).

CONCLUSIONS

In critically ill non-immunosuppressed patients, the presence of functional CMV-specific CD8+ T lymphocyte response at intensive care unit admission provides protection against CMV reactivation.

Cytomegalovirus reactivation in ICU patients

Introduction

Approximately 20 years have passed since we reported our results of histologically proven cytomegalovirus (CMV) pneumonia in non-immunocompromised ICU patients. Even if there are more recent reports suggesting that CMV may worsen the outcomes for ICU patients, there is no definite answer to this question: is CMV a potential pathogen for ICU patients or is it simply a bystander?

Methods

We will describe the pathophysiology of active CMV infection and the most recent insights concerning the epidemiological aspects of these reactivations.

Major findings

Cytomegalovirus can be pathogenic by a direct organ insult (such as for the lung), by decreasing host defences against other microorganisms and/or by enhancing the body’s inflammatory response (as in acute respiratory distress syndrome). The incidence of active CMV infection is dependent on the diagnostic method used. Using the most sophisticated available biological tools, the incidence can reach 15–20 % of ICU patients (20–40 % in ICU patients with positive CMV serology). In adequately powered cohorts of patients, active CMV infection appears to be associated with worse outcomes for mechanically ventilated ICU patients.

Discussion

There is no absolute direct proof of a negative impact of active CMV infection on the health outcomes of mechanically ventilated patients. Prospective randomized trials are lacking. Future trials should examine the potential benefits for health outcomes of using antiviral treatments. Such treatments could be prophylactic, pre-emptive or used only when there is an end-organ disease.

Conclusion

Cytomegalovirus infection may affect health outcomes for ICU patients. Additional prospective trials are necessary to confirm this hypothesis.