Epidemiology of Multiple Herpes Viremia in Previously Immunocompetent Patients With Septic Shock

The immunology of sepsis

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to an infection. This recently implemented definition does not capture the heterogeneity or the underlying pathophysiology of the syndrome, which is characterized by concurrent unbalanced hyperinflammation and immune suppression. Here, we review current knowledge of aberrant immune responses during sepsis and recent initiatives to stratify patients with sepsis into subgroups that are more alike from a clinical and/or pathobiological perspective, which could be key for identification of patients who are more likely to benefit from specific immune interventions.

Association of HHV-6 With Outcomes in CMV-seronegative Liver Transplant Recipients With CMV-seropositive Donors Receiving Preemptive Antiviral Therapy

BACKGROUND

Risk factors, virological parameters, and outcomes associated with HHV-6 viremia in high-risk donor CMV-seropositive and recipient CMV-seronegative (D+R-) liver transplant recipients in the current era are incompletely defined.

METHODS

The study population consisted of patients in the preemptive therapy (PET) arm of a randomized, controlled trial of PET versus valganciclovir prophylaxis for CMV prevention in D+R- liver transplant recipients. Weekly blood samples through 100 d in the PET group were tested for HHV-6 viremia using a real-time quantitative polymerase chain reaction. Assessments included virological characteristics and relationship with CMV, risk factors, and impact of HHV-6 viremia with outcomes through 12 mo posttransplant.

RESULTS

HHV-6 viremia at any level developed in 42% (40 of 96). Older patient age (P = 0.03), longer hospitalization (P = 0.015), and ICU stay at transplantation (P = 0.029) were significantly associated with high-grade viremia. Concurrent HHV-6 and CMV viremia was associated with earlier onset of HHV-6 viremia (P = 0.004), higher HHV-6 area under the curve (P = 0.043), and higher peak HHV-6 viral load (P = 0.006) versus HHV-6 viremia alone. High-grade viremia was independently associated with biopsy-proven rejection within 12 mo (P = 0.045) posttransplant.

CONCLUSIONS

Among D+R- liver transplant recipients receiving valganciclovir as PET, high-grade HHV-6 viremia was associated with increased age and critical illness in ICU at time of transplant and was independently associated with allograft rejection.

Sepsis-Induced Immunosuppression

Sepsis is expected to have a substantial impact on public health and cost as its prevalence increases. Factors contributing to increased prevalence include a progressively aging population, advances in the use of immunomodulatory agents to treat a rising number of diseases, and immune-suppressing therapies in organ transplant recipients and cancer patients. It is now recognized that sepsis is associated with profound and sustained immunosuppression, which has been implicated as a predisposing factor in the increased susceptibility of patients to secondary infections and mortality. In this review, we discuss mechanisms of sepsis-induced immunosuppression and biomarkers that identify a state of impaired immunity. We also highlight immune-enhancing strategies that have been evaluated in patients with sepsis, as well as therapeutics under current investigation. Finally, we describe future challenges and the need for a new treatment paradigm, integrating predictive enrichment with patient factors that may guide the future selection of tailored immunotherapy. Expected final online publication date for the Annual Review of Physiology, Volume 84 is February 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Presence and clinical impact of human herpesvirus-6 infection in patients with moderate to critical coronavirus disease-19

Human herpesvirus-6 (HHV-6) may cause serious diseases in immunocompromised individuals. SARS-CoV-2/HHV-6 coinfection has been emphasized in previous works, mostly case reports, small series, or epidemiological studies, but few are known about its real clinical outcomes. Here we present a real-world pilot study aiming to understand the frequency and the clinical impact of HHV-6 coinfection in moderate to critically ill patients hospitalized due to COVID-19. SARS-CoV-2 and HHV-6 were evaluated in nasopharyngeal samples at the hospital admission of suspected COVID-19 patients. From 173 consecutive cases, 60 were SARS-CoV-2 positive and 13/60 (21.7%) were HHV-6 positive after identified as the HHV-6B species by a Sanger sequencing. The SARS-CoV-2+/HHV-6+ group was younger but not significant for cardiovascular diseases, diabetes, obesity, and cancer, but significant among therapeutic immunosuppressed patients (as systemic lupus erythematosus and kidney transplant patients). In the medical records, only sparse data on cutaneous or neurological manifestations were found. Biochemical and hematological data showed only a trend towards hyperferritinemic status and lymphopenia. In conclusion, despite the impressive high frequency of HHV-6 coinfection in SARS-CoV-2 positive cases, it did not impact general mortality. We suggest larger future prospective studies to better elucidate the influence of HHV-6 reactivation in cases of COVID-19, designed to specific assessment of clinical outcomes and viral reactivation mechanisms.

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.

Perceived Social Support and Latent Herpesvirus Reactivation: Testing Main and Stress-Buffering Effects in an Ethnically Diverse Sample of Adults

OBJECTIVE

Perceived social support is consistently associated with physical health outcomes, and one potential physiological mechanism underlying this association is immune function. In this study, we tested both the main and stress-buffering effects of perceived social support on cellular immunity measured via latent herpesvirus reactivation.

METHODS

Data were collected from a community-based sample of 1443 ethnically diverse adults between the ages of 25 and 90 years. Participants self-reported measures of perceived social support, stressful life events, daily hassles, and perceived stress, and provided a blood sample to assess antibody titers to the herpes simplex virus type 1 and Epstein-Barr virus (EBV).

RESULTS

In accordance with the main effect hypothesis, results indicated that perceived social support was directly associated with EBV viral capsid antigen antibody titers (β = -0.06, 95% confidence interval = -0.12 to -0.01, p = .029). Perceived social support, however, did not interact with stressful life events, daily hassles, or perceived stress to influence latent herpesvirus reactivation (p values > .05). Neither race/ethnicity nor age moderated any of the interactions between perceived social support and the stress measures on latent herpesvirus reactivation (p values > .10).

CONCLUSIONS

Overall, the current study supports the main effect hypothesis, according to which higher levels of perceived social support were associated with lower levels of herpesvirus antibody titers.

Septic shock complicated by disseminated herpes simplex virus-1 infection: a case report

Background

Herpes virus remains dormant in human cells and could reactivate under immunosuppressed conditions, such as prolonged critical illnesses. The phenomenon of viral replication during intensive care is well known, even in patients without a history of immunosuppression, but it usually does not have a clinical impact. Systemic reactivation leads to viral DNA in blood. It remains unclear whether this replication is a marker of morbimortality or a true pathogenic process. Therefore, it is unclear what medical treatment is most appropriate for simple replication. In organ damage suspected to be induced by herpes virus, there is no consensus on the most appropriate treatment duration. Here, we report a rarely described case of multiorgan failure implicating herpes simplex virus and discuss its treatment.

Case report

A 53-year-old Caucasian immunosuppressed woman was admitted to the intensive care unit for septic shock. She presented pneumonia due to Klebsiella pneumoniae. Two weeks after admission, she showed multiorgan failure with acute respiratory distress syndrome and circulation failure. She had digestive and cutaneous lesions typical of herpes simplex virus 1. Blood and respiratory polymerase chain reaction was strongly herpes simplex virus-1 positive. No other bacteria, fungi, or viruses were found. The evolution was rapidly favorable after the initiation of antiviral treatment. Treatment was stopped after 3 weeks of well-conducted antiviral therapy. Curative-dose treatment was interrupted despite continuous strongly positive blood polymerase chain reaction results. In this context, prophylactic treatment was continued.

Conclusion

We report an exceptional presentation of multiorgan failure in the intensive care unit due to herpes simplex virus-1. The diagnosis was made based on typical herpes simplex virus-1 visceral lesions and the absence of other responsible microorganisms. Intense viral replication is a key diagnostic element. There is no consensus regarding the most appropriate treatment duration, but such decisions should not be based on blood polymerase chain reaction.

Viral Micro-RNAs Are Detected in the Early Systemic Response to Injury and Are Associated With Outcomes in Polytrauma Patients

OBJECTIVES

To evaluate early activation of latent viruses in polytrauma patients and consider prognostic value of viral micro-RNAs in these patients.

DESIGN

This was a subset analysis from a prospectively collected multicenter trauma database. Blood samples were obtained upon admission to the trauma bay (T0), and trauma metrics and recovery data were collected.

SETTING

Two civilian Level 1 Trauma Centers and one Military Treatment Facility.

PATIENTS

Adult polytrauma patients with Injury Severity Scores greater than or equal to 16 and available T0 plasma samples were included in this study. Patients with ICU admission greater than 14 days, mechanical ventilation greater than 7 days, or mortality within 28 days were considered to have a complicated recovery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Polytrauma patients (n = 180) were identified, and complicated recovery was noted in 33%. Plasma samples from T0 underwent reverse transcriptase-quantitative polymerase chain reaction analysis for Kaposi's sarcoma-associated herpesvirus micro-RNAs (miR-K12_10b and miRK-12-12) and Epstein-Barr virus-associated micro-RNA (miR-BHRF-1), as well as Luminex multiplex array analysis for established mediators of inflammation. Ninety-eight percent of polytrauma patients were found to have detectable Kaposi's sarcoma-associated herpesvirus and Epstein-Barr virus micro-RNAs at T0, whereas healthy controls demonstrated 0% and 100% detection rate for Kaposi's sarcoma-associated herpesvirus and Epstein-Barr virus, respectively. Univariate analysis revealed associations between viral micro-RNAs and polytrauma patients' age, race, and postinjury complications. Multivariate least absolute shrinkage and selection operator analysis of clinical variables and systemic biomarkers at T0 revealed that interleukin-10 was the strongest predictor of all viral micro-RNAs. Multivariate least absolute shrinkage and selection operator analysis of systemic biomarkers as predictors of complicated recovery at T0 demonstrated that miR-BHRF-1, miR-K12-12, monocyte chemoattractant protein-1, and hepatocyte growth factor were independent predictors of complicated recovery with a model complicated recovery prediction area under the curve of 0.81.

CONCLUSIONS

Viral micro-RNAs were detected within hours of injury and correlated with poor outcomes in polytrauma patients. Our findings suggest that transcription of viral micro-RNAs occurs early in the response to trauma and may be associated with the biological processes involved in polytrauma-induced complicated recovery.

Positive Epstein-Barr virus detection in coronavirus disease 2019 (COVID-19) patients

The objective of this study was to detect the Epstein-Barr virus (EBV) coinfection in coronavirus disease 2019 (COVID-19). In this retrospective single-center study, we included 67 COVID-19 patients with onset time within 2 weeks in Renmin Hospital of Wuhan University from January 9 to February 29, 2020. Patients were divided into EBV/SARS-CoV-2 coinfection group and SARS-CoV-2 infection alone group according to the serological results of EBV, and the characteristics differences between the two groups were compared. The median age was 37 years, with 35 (52.2%) females. Among these COVID-19 patients, thirty-seven (55.2%) patients were seropositive for EBV viral capsid antigen (VCA) IgM antibody. EBV/SARS-CoV-2 coinfection patients had a 3.09-fold risk of having a fever symptom than SARS-CoV-2 infection alone patients (95% CI 1.11-8.56; P = 0.03). C-reactive protein (CRP) (P = 0.02) and the aspartate aminotransferase (AST) (P = 0.04) in EBV/SARS-CoV-2 coinfection patients were higher than that in SARS-CoV-2 infection alone patients. EBV/SARS-CoV-2 coinfection patients had a higher portion of corticosteroid use than the SARS-CoV-2 infection alone patients (P = 0.03). We find a high incidence of EBV coinfection in COVID-19 patients. EBV/SARS-CoV-2 coinfection was associated with fever and increased inflammation. EBV reactivation may associated with the severity of COVID-19.

Herpesvirus latency

Herpesviruses infect virtually all humans and establish lifelong latency and reactivate to infect other humans. Latency requires multiple functions: maintaining the herpesvirus genome in the nuclei of cells; partitioning the viral genome to daughter cells in dividing cells; avoiding recognition by the immune system by limiting protein expression; producing noncoding viral RNAs (including microRNAs) to suppress lytic gene expression or regulate cellular protein expression that could otherwise eliminate virus-infected cells; modulating the epigenetic state of the viral genome to regulate viral gene expression; and reactivating to infect other hosts. Licensed antivirals inhibit virus replication, but do not affect latency. Understanding of the mechanisms of latency is leading to novel approaches to destroy latently infected cells or inhibit reactivation from latency.

High incidence of Epstein-Barr virus, cytomegalovirus, and human-herpes virus-6 reactivations in critically ill patients with COVID-19

Background

Systemic reactivation of herpesviruses may occur in intensive care unit (ICU) patients and is associated with morbidity and mortality. Data on severe Coronavirus disease-19 (COVID-19) and concomitant reactivation of herpesviruses are lacking.

Methods

We selected patients admitted to ICU for confirmed COVID-19 who underwent systematic testing for Epstein–Barr virus (EBV), cytomegalovirus (CMV) and human-herpes virus-6 (HHV-6) DNAemia while in the ICU. We retrospectively analysed frequency, timing, duration and co-occurrence of viral DNAemia.

Results

Thirty-four patients were included. Viremia with EBV, CMV, and HHV-6 was detected in 28 (82%), 5 (15%), and 7 (22%) patients, respectively. EBV reactivation occurred early after ICU admission and was associated with longer ICU length-of-stay.

Conclusions

While in the ICU, critically ill patients with COVID-19 are prone to develop reactivations due to various types of herpesviruses.

Effects of viral infection and microbial diversity on patients with sepsis: A retrospective study based on metagenomic next-generation sequencing

BACKGROUND

The study aims to investigate the performance of a metagenomic next-generation sequencing (NGS)-based diagnostic technique for the identification of potential bacterial and viral infections and effects of concomitant viral infection on the survival rate of intensive care unit (ICU) sepsis patients.

METHODS

A total of 74 ICU patients with sepsis who were admitted to our institution from February 1, 2018 to June 30, 2019 were enrolled. Separate blood samples were collected from patients for blood cultures and metagenomic NGS when the patients' body temperature was higher than 38 °C. Patients' demographic data, including gender, age, ICU duration, ICU scores, and laboratory results, were recorded. The correlations between pathogen types and sepsis severity and survival rate were evaluated.

RESULTS

NGS produced higher positive results (105 of 118; 88.98%) than blood cultures (18 of 118; 15.25%) over the whole study period. Concomitant viral infection correlated closely with sepsis severity and had the negative effect on the survival of patients with sepsis. However, correlation analysis indicated that the bacterial variety did not correlate with the severity of sepsis.

CONCLUSIONS

Concurrent viral load correlates closely with the severity of sepsis and the survival rate of the ICU sepsis patients. This suggests that prophylactic administration of antiviral drugs combined with antibiotics may be beneficial to ICU sepsis patients.

EBV DNA increase in COVID-19 patients with impaired lymphocyte subpopulation count

Objectives

The immunologic profile and opportunistic viral DNA increase were monitored in Italian patients with COVID-19 in order to identify markers of disease severity.

Methods

A total of 104 patients infected with SARS-CoV-2 were evaluated in the study. Of them, 42/104 (40.4%) were hospitalized in an intensive care unit (ICU) and 62/104(59.6%) in a sub-intensive care unit (SICU). Human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV), Parvovirus B19 and Human Herpesvirus 6 virus reactivations were determined by real-time PCR, and lymphocyte subpopulation counts were determined by flow cytometry.

Results

Among opportunistic viruses, only EBV was consistently detected. EBV DNA was observed in 40/42 (95.2%) of the ICU patients and in 51/61 (83.6%) of the SICU patients. Comparing the two groups of patients, the EBV DNA median level among ICU patients was significantly higher than that observed in SICU patients. In parallel, a significant reduction of CD8 T cell and NK count in ICU patients as compared with SICU patients was observed (p < 0.05). In contrast, B cell count was significantly increased in ICU patients (p = 0.0172).

Conclusions

A correlation between reduced CD8⁺ T cells and NK counts, EBV DNA levels and COVID-19 severity was observed. Other opportunistic viral infections were not observed. The relationship between EBV load and COVID-19 severity should be further evaluated in longitudinal studies.

Pulmonary infections complicating ARDS

Pulmonary infection is one of the main complications occurring in patients suffering from acute respiratory distress syndrome (ARDS). Besides traditional risk factors, dysregulation of lung immune defenses and microbiota may play an important role in ARDS patients. Prone positioning does not seem to be associated with a higher risk of pulmonary infection. Although bacteria associated with ventilator-associated pneumonia (VAP) in ARDS patients are similar to those in patients without ARDS, atypical pathogens (Aspergillus, herpes simplex virus and cytomegalovirus) may also be responsible for infection in ARDS patients. Diagnosing pulmonary infection in ARDS patients is challenging, and requires a combination of clinical, biological and microbiological criteria. The role of modern tools (e.g., molecular methods, metagenomic sequencing, etc.) remains to be evaluated in this setting. One of the challenges of antimicrobial treatment is antibiotics diffusion into the lungs. Although targeted delivery of antibiotics using nebulization may be interesting, their place in ARDS patients remains to be explored. The use of extracorporeal membrane oxygenation in the most severe patients is associated with a high rate of infection and raises several challenges, diagnostic issues and pharmacokinetics/pharmacodynamics changes being at the top. Prevention of pulmonary infection is a key issue in ARDS patients, but there is no specific measure for these high-risk patients. Reinforcing preventive measures using bundles seems to be the best option.

Epstein-Barr virus reactivation in sepsis due to community-acquired pneumonia is associated with increased morbidity and an immunosuppressed host transcriptomic endotype

Epstein-Barr virus (EBV) reactivation is common in sepsis patients but the extent and nature of this remains unresolved. We sought to determine the incidence and correlates of EBV-positivity in a large sepsis cohort. We also hypothesised that EBV reactivation would be increased in patients in whom relative immunosuppression was the major feature of their sepsis response. To identify such patients we aimed to use knowledge of sepsis response subphenotypes based on transcriptomic studies of circulating leukocytes, specifically patients with a Sepsis Response Signature endotype (SRS1) that we have previously shown to be associated with increased mortality and features of immunosuppression. We assayed EBV from the plasma of intensive care unit (ICU) patients with sepsis due to community-acquired pneumonia. In total 730 patients were evaluated by targeted metagenomics (n = 573 patients), digital droplet PCR (n = 565), or both (n = 408). We had previously analysed gene expression in peripheral blood leukocytes for a subset of individuals (n = 390). We observed a 37% incidence of EBV-positivity. EBV reactivation was associated with longer ICU stay (12.9 vs 9.2 days; p = 0.004) and increased organ failure (day 1 SOFA score 6.9 vs 5.9; p = 0.00011). EBV reactivation was associated with the relatively immunosuppressed SRS1 endotype (p = 0.014) and differential expression of a small number of biologically relevant genes. These findings are consistent with the hypothesis that viral reactivation in sepsis is a consequence of immune compromise and is associated with increasing severity of illness although further mechanistic studies are required to definitively illustrate cause and effect.

Viral Infections in Burns

Background: Viral infections after burns are less common than bacterial infections but usually occur in the more severely burned patients and have been associated with poor outcomes. Methods: Retrospective reviews and case series were examined to provide an overview of the management of viral infections in the burn patient. Results: The most common viral pathogens in these patients are the herpesviruses, which include herpes simplex, varicella zoster, cytomegalovirus, and human herpesvirus 6. Established viral infections that may complicate patient management include human immunodeficiency virus, hepatitis B and C, and, more recently, the novel coronavirus SARS-CoV-2. Herpesvirus infections can occur as primary or nosocomial pathogens but clinical manifestations most commonly are re-activation of latent viral infection. Because of the paucity of data in the burn population, much of the evidence for specific treatments is extrapolated from patients with severe immunosuppression or critical illness. Antiviral therapy is employed for the burn patient with herpesvirus infections. This is an area of active study, and further research is needed to better understand the risks, clinical manifestations, and attributable morbidity and mortality of viral infections. Conclusions: Major burn injury results in immunosuppression and viral infection in a small number of patients. Recognition and antiviral therapy are employed, but additional studies are necessary to improve outcomes in these patients.

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.

Reactivation Viremia in Pediatric Sepsis

OBJECTIVES

Reactivation viremia is associated with adverse clinical outcomes and immune dysfunction in adults with sepsis. We determined the incidence of viremia and its association with clinical outcomes and immune paralysis phenotype in children with severe sepsis.

DESIGN

Prospective cohort study.

SETTING

Single academic PICU from September 2016 to March 2018.

PATIENTS

Fifty-nine patients 2-17 years old treated for severe sepsis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We performed real-time polymerase chain reaction assays on whole blood specimens to determine the incidence of cytomegalovirus. Cytomegalovirus was detected in three patients (5%). All patients with cytomegalovirus viremia were seropositive, with an incidence of 13% in this subset. We additionally performed Epstein-Barr virus and human herpesvirus-6 polymerase chain reaction assays on last available specimens and detected Epstein-Barr virus in 4% and human herpesvirus-6 in 30% of the study population. Overall, viremia was not associated with clinical outcomes or immune function in univariable analyses. However, viremia was associated with lower odds of complicated course (defined as death within 28 d or ≥ 2 organ dysfunctions at 7 d) after controlling for age, Pediatric Risk of Mortality III score, and blood transfusion (adjusted odds ratio, 0.08; 95% CI, 0.01-0.84; p = 0.04).

CONCLUSIONS

Children with severe sepsis had low rates of detectable viremia, which limited analyses of its association with clinical outcomes or immune paralysis phenotype. Given the rare occurrence of cytomegalovirus viremia, in particular, our study does not support a role for viremia as a biomarker of illness severity or as a modifiable risk factor of clinical outcomes for most patients. Future studies on the role of viremia in pediatric sepsis will need to consider the challenges posed by low rates of viremia in this population.

Ventilator-associated pneumonia in adults: a narrative review

Ventilator-associated pneumonia (VAP) is one of the most frequent ICU-acquired infections. Reported incidences vary widely from 5 to 40% depending on the setting and diagnostic criteria. VAP is associated with prolonged duration of mechanical ventilation and ICU stay. The estimated attributable mortality of VAP is around 10%, with higher mortality rates in surgical ICU patients and in patients with mid-range severity scores at admission. Microbiological confirmation of infection is strongly encouraged. Which sampling method to use is still a matter of controversy. Emerging microbiological tools will likely modify our routine approach to diagnosing and treating VAP in the next future. Prevention of VAP is based on minimizing the exposure to mechanical ventilation and encouraging early liberation. Bundles that combine multiple prevention strategies may improve outcomes, but large randomized trials are needed to confirm this. Treatment should be limited to 7 days in the vast majority of the cases. Patients should be reassessed daily to confirm ongoing suspicion of disease, antibiotics should be narrowed as soon as antibiotic susceptibility results are available, and clinicians should consider stopping antibiotics if cultures are negative.

Current Understanding of Cytomegalovirus Reactivation in Critical Illness

Cytomegalovirus (CMV) reactivation has been described in adults with critical illness caused by diverse etiologies, especially severe sepsis, and observational studies have linked CMV reactivation with worse clinical outcomes in this setting. In this study, we review observational clinical data linking development of CMV reactivation with worse outcomes in patients in the intensive care unit, discuss potential biologically plausible mechanisms for a causal association, and summarize results of initial interventional trials that examined the effects of CMV prevention. These data, taken together, highlight the need for a randomized, placebo-controlled efficacy trial (1) to definitively determine whether prevention of CMV reactivation improves clinical outcomes of patients with critical illness and (2) to define the underlying mechanism(s).

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.

Frequency and mortality of septic shock in Europe and North America: a systematic review and meta-analysis

Background

Septic shock is the most severe form of sepsis, in which profound underlying abnormalities in circulatory and cellular/metabolic parameters lead to substantially increased mortality. A clear understanding and up-to-date assessment of the burden and epidemiology of septic shock are needed to help guide resource allocation and thus ultimately improve patient care. The aim of this systematic review and meta-analysis was therefore to provide a recent evaluation of the frequency of septic shock in intensive care units (ICUs) and associated ICU and hospital mortality.

Methods

We searched MEDLINE, Embase, and the Cochrane Library from 1 January 2005 to 20 February 2018 for observational studies that reported on the frequency and mortality of septic shock. Four reviewers independently selected studies and extracted data. Disagreements were resolved via consensus. Random effects meta-analyses were performed to estimate pooled frequency of septic shock diagnosed at admission and during the ICU stay and to estimate septic shock mortality in the ICU, hospital, and at 28 or 30 days.

Results

The literature search identified 6291 records of which 71 articles met the inclusion criteria. The frequency of septic shock was estimated at 10.4% (95% CI 5.9 to 16.1%) in studies reporting values for patients diagnosed at ICU admission and at 8.3% (95% CI 6.1 to 10.7%) in studies reporting values for patients diagnosed at any time during the ICU stay. ICU mortality was 37.3% (95% CI 31.5 to 43.5%), hospital mortality 39.0% (95% CI 34.4 to 43.9%), and 28-/30-day mortality 36.7% (95% CI 32.8 to 40.8%). Significant between-study heterogeneity was observed.

Conclusions

Our literature review reaffirms the continued common occurrence of septic shock and estimates a high mortality of around 38%. The high level of heterogeneity observed in this review may be driven by variability in defining and applying the diagnostic criteria, as well as differences in treatment and care across settings and countries.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2478-6) contains supplementary material, which is available to authorized users.

Early herpes and TTV DNAemia in septic shock patients: a pilot study

BACKGROUND

Septic shock patients exhibit an increased incidence of viral reactivation. Precise timing of such reactivation-as an early marker of immune suppression, or as a consequence of the later-is not known precisely. Here, using a fully designed nucleic acid extraction automated procedure together with tailored commercial PCR kits, we focused on the description of early reactivation within the first week of ICU admission of several herpes viruses and Torque Teno virus (TTV) in 98 septic shock patients.

RESULTS

Most of septic shock patients had at least one viremia event during the first week (88%). TTV and herpesviruses were detected in 56% and 53% of septic shock patient, respectively. The two most frequent herpesviruses detected within the first week were EBV (35%) and HSV1 (26%). Different kinetic were observed among herpesviruses, faster for EBV and HSV1 than for CMV and HHV6. Although no association was found between herpes viremia and secondary infections, patients with herpesviridae-related viremia were more severe, e.g., higher SOFA scores and plasma lactate levels. While reactivating only 1 virus was not associated with mortality, patients with multiple viremia events had higher ICU mortality. Surprisingly, EBV + TTV early reactivation seemed associated with a lower D28 mortality. No clear association was observed between viremia and immune biomarkers.

CONCLUSION

Applying a semi-automated process of viral DNAemia determination to this cohort of 98 patients with septic shock, we observed that the number of patients with positive viremia increased during the first week in the ICU. Of note, there was no improvement in predicting the outcome when using viremia status. Nevertheless, this pilot study, introducing standardized procedures from extraction to detection, provides the basis for future standardized diagnostic criteria. A prospective longitudinal clinical study using these procedures will enable determination of whether such viremia is due to a lack of a latent virus control by the immune system or a true clinical viral infection.

Human herpesvirus 6, 7, and 8 in solid organ transplantation: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of HHV-6A, HHV-6B, HHV-7, and HHV-8 in the pre- and post-transplant period. The majority of HHV-6 (A and B) and HHV-7 infections in transplant recipients are asymptomatic; symptomatic disease is reported infrequently across organs. Routine screening for HHV-6 and 7 DNAemia is not recommended in asymptomatic patients, nor is prophylaxis or preemptive therapy. Detection of viral nucleic acid by quantitative PCR in blood or CSF is the preferred method for diagnosis of HHV-6 and HHV-7 infection. The possibility of chromosomally integrated HHV-6 DNA should be considered in individuals with persistently high viral loads. Antiviral therapy should be initiated for HHV-6 encephalitis and should be considered for other manifestations of disease. HHV-8 causes Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman disease and is also associated with hemophagocytic syndrome and bone marrow failure. HHV-8 screening and monitoring may be indicated to prevent disease. Treatment of HHV-8 related disease centers on reduction of immunosuppression and conversion to sirolimus, while chemotherapy may be needed for unresponsive disease. The role of antiviral therapy for HHV-8 infection has not yet been defined.

Diagnostic Usefulness of Varicella-Zoster Virus Real-Time Polymerase Chain Reaction Analysis of DNA in Saliva and Plasma Specimens From Patients With Herpes Zoster

Background

We evaluated the diagnostic usefulness of polymerase chain reaction (PCR) analysis for detecting varicella-zoster virus (VZV) infection and reactivation of VZV, using DNA extracted from saliva and plasma specimens obtained from subjects with suspected herpes zoster and from healthy volunteers during stressful and nonstressful conditions.

Methods

There were 52 patients with a diagnosis of herpes zoster (group 1), 30 with a diagnosis of zoster-mimicking disease (group 2), and 27 healthy volunteers (group 3). Saliva and plasma samples were evaluated for VZV DNA by real-time PCR analysis.

Results

Among patients with suspected herpes zoster (ie, patients in groups 1 and 2), the sensitivity of PCR analysis of salivary DNA for detecting VZV (88%; 95% confidence interval [CI], 74%-95%) was significantly higher than that of PCR analysis of plasma DNA (28%; 95% CI, 16%-44%; P < .001), whereas the specificity of PCR analysis of salivary DNA (100%; 95% CI, 88%-100%) was similar to that of PCR analysis of plasma DNA (100%; 95% CI, 78%-100%; P > .99). VZV DNA was not detected in saliva and plasma samples from group 3 (0%; 95% CI, 0%-14%).

Conclusions

Real-time PCR analysis of salivary DNA is more sensitive than that of plasma DNA for detecting VZV among patients with suspected herpes zoster. We found no subclinical reactivation of VZV in group 3 following exposure to common stressful conditions.

Evidence for Persistent Immune Suppression in Patients Who Develop Chronic Critical Illness After Sepsis

BACKGROUND

Many sepsis survivors develop chronic critical illness (CCI) and are assumed to be immunosuppressed, but there is limited clinical evidence to support this. We sought to determine whether the incidence of secondary infections and immunosuppressive biomarker profiles of patients with CCI differ from those with rapid recovery (RAP) after sepsis.

METHODS

This prospective observational study evaluated 88 critically ill patients with sepsis and 20 healthy controls. Cohorts were defined based on clinical trajectory (early death, RAP, or CCI), whereas immunosuppression was clinically determined by the presence of a postsepsis secondary infection. Serial blood samples were collected for absolute lymphocyte counts (ALCs), monocytic human leukocyte antigen-DR (mHLA-DR) expression, and plasma-soluble programmed death-ligand 1 (sPD-L1) concentrations.

RESULTS

Of the 88 patients with sepsis, 3 (3%) died within 14 days of sepsis onset, 50 (57%) experienced RAP, and 35 (40%) developed CCI. Compared with RAP patients, CCI patients exhibited a higher incidence and overall number of infections adjusted for hospital length of stay. ALC and mHLA-DR levels were dramatically reduced at the time of sepsis diagnosis when compared with healthy controls, whereas sPD-L1 concentrations were significantly elevated. There were no differences between RAP and CCI patients in ALC, sPD-L1, or mHLA-DR at the time of diagnosis or within 24 h after sepsis diagnosis. However, in contrast to the RAP group, CCI patients failed to exhibit any trend toward restoration of normal values of ALC, HLA-DR, and sPD-L1.

CONCLUSIONS

Septic patients demonstrate clinical and biological evidence to suggest they are immunosuppressed at the time of sepsis diagnosis. Those who develop CCI have a greater incidence of secondary infections and persistently aberrant markers of impaired host immunity, although measurements at the time of sepsis onset did not distinguish between subjects with RAP and CCI.

Sepsis erodes CD8+ memory T cell-protective immunity against an EBV homolog in a 2B4-dependent manner

Epstein-Barr virus (EBV) reactivation commonly occurs following sepsis, but the mechanisms underlying this are unknown. We utilized a murine EBV homolog (gHV) and the cecal ligation and puncture model of polymicrobial sepsis to study the impact of sepsis on gHV reactivation and CD8⁺ T cell immune surveillance following a septic insult. We observed a significant increase in the frequency of gHV-infected germinal center B cells on day 7 following sepsis. This increase in viral load was associated with a concomitant significant decrease in the frequencies of gHV-specific CD8⁺ T cells, as measured by class I MHC tetramers corresponding to the immunodominant viral epitopes. Phenotypic analysis revealed an increased frequency of gHV-specific CD8⁺ T cells expressing the 2B4 coinhibitory receptor in septic animals compared with sham controls. We sought to interrogate the role of 2B4 in modulating the gHV-specific CD8⁺ T cell response during sepsis. Results indicated that in the absence of 2B4, gHV-specific CD8⁺ T cell populations were maintained during sepsis, and gHV viral load was unchanged in 2B4^-/- septic animals relative to 2B4^-/- sham controls. WT CD8⁺ T cells upregulated PD-1 during sepsis, whereas 2B4^-/- CD8⁺ T cells did not. Finally, adoptive transfer studies revealed a T cell-intrinsic effect of 2B4 coinhibition on virus-specific CD8⁺ T cells and gHV viral load during sepsis. These data demonstrate that sepsis-induced immune dysregulation erodes antigen-specific CD8⁺ responses against a latent viral infection and suggest that blockade of 2B4 may better maintain protective immunity against EBV in the context of sepsis.

Endogenous Retroviruses Transcriptional Modulation After Severe Infection, Trauma and Burn

Although human endogenous retroviruses (HERVs) expression is a growing subject of interest, no study focused before on specific endogenous retroviruses loci activation in severely injured patients. Yet, HERV reactivation is observed in immunity compromised settings like some cancers and auto-immune diseases. Our objective was to assess the transcriptional modulation of HERVs in burn, trauma and septic shock patients. We analyzed HERV transcriptome with microarray data from whole blood samples of a burn cohort (n = 30), a trauma cohort (n = 105) and 2 septic shock cohorts (n = 28, n = 51), and healthy volunteers (HV, n = 60). We described expression of the 337 probesets targeting HERV from U133 plus 2.0 microarray in each dataset and then we compared HERVs transcriptional modulation of patients compared to healthy volunteers. Although all 4 cohorts contained critically ill patients, the majority of the 337 HERVs was not expressed (around 74% in mean). Each cohort had differentially expressed probesets in patients compared to HV (from 19 to 46). Strikingly, 5 HERVs were in common in all types of severely injured patients, with 4 being up-modulated in patients. We highlighted co-expressed profiles between HERV and nearby CD55 and CD300LF genes as well as autonomous HERV expression. We suggest an inflammatory-specific HERV transcriptional response, and importantly, we introduce that the HERVs close to immunity-related genes might have a role on its expression.

Cytomegalovirus, Epstein-Barr virus and human herpesvirus 8 salivary shedding in HIV positive men who have sex with men with controlled and uncontrolled plasma HIV viremia: a 24-month longitudinal study

Background

This longitudinal study described Cytomegalovirus (CMV) DNA, Epstein-Barr (EBV) DNA and human herpesvirus 8 (HHV-8) DNA asymptomatic salivary shedding in HIV-positive men who have sex with men (MSM). We aimed to 1-analyze frequency and persistence of herpesvirus shedding, 2-correlate herpesvirus positivity and HIV viroimmunological parameters and 3-assess the association between HIV-RNA suppression and herpesvirus replication.

Methods

Herpesvirus DNA was tested with an in-house real-time PCR in 2 salivary samples obtained at T0 and T1 (24 months after T0). HIV-RNA was evaluated in the 24 months prior to T0 and in the 24 months prior to T1; MSM were classified as successfully suppressed patients (SSPs), viremic patients (VPs) and partially suppressed patients (PSPs). EBV DNA load was classified as low viral load (EBV-LVL, value ≤10,000 copies/ml) and as high viral load (EBV-HVL,> 10,000 copies/ml). Mann-Whitney U test tested the difference of the median between groups of patients. Chi-squared test and Fisher’s exact test compared categorical variables according to the frequencies. Kruskal-Wallis test compared continuous data distributions between levels of categorical variables.

Results

Ninety-two patients (median CD4+ count 575 cells/mm3, median nadir 330 CD4+ cells/mm3) were included: 40 SSPs,33 VPs and 19 PSPs. The more frequently single virus detected was EBV, both at T0 and at T1 (in 67.5 and 70% of SSPs, in 84.8 and 81.8% of VPs and in 68.4 and 73.7% of SPSs) and the most frequently multiple positivity detected was EBV + HHV-8. At T1, the percentage of CMV positivity was higher in VPs than in SSPs (36.4% vs 5%, p < 0.001), the combined shedding of HHV-8, CMV and EBV was present only in VPs (15.1%, p = 0.01 respect to SSPs) and no VPs confirmed the absence of shedding found at T0 (vs 17.5% of SSPs, p = 0.01). EBV-HVL was more frequent in VPs than in SSPs: 78.6% at T0 (p = 0.03) and 88.9% at T1 (p = 0.01).

Conclusions

The relationship between uncontrolled plasma HIV viremia and CMV, EBV, and HHV-8 shedding is multifaceted, as demonstrated by the focused association with EBV DNA load and not with its frequency and by the persistent combined detection of two oncogenic viruses as EBV and HHV-8 regardless of HIV virological control.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3591-x) contains supplementary material, which is available to authorized users.

Effect of cytomegalovirus reactivation on the time course of systemic host response biomarkers in previously immunocompetent critically ill patients with sepsis: a matched cohort study

BACKGROUND

Cytomegalovirus (CMV) reactivation in previously immunocompetent critically ill patients is associated with increased mortality, which has been hypothesized to result from virus-induced immunomodulation. Therefore, we studied the effects of CMV reactivation on the temporal course of host response biomarkers in patients with sepsis.

METHODS

In this matched cohort study, each sepsis patient developing CMV reactivation between day 3 and 17 (CMV+) was compared with one CMV seropositive patient without reactivation (CMVs+) and one CMV seronegative patient (CMVs-). CMV serostatus and plasma loads were determined by enzyme-linked immunoassays and real-time polymerase chain reaction, respectively. Systemic interleukin-6 (IL-6), IL-8, IL-18, interferon-gamma-induced protein-10 (IP-10), neutrophilic elastase, IL-1 receptor antagonist (RA), and IL-10 were measured at five time points by multiplex immunoassay. The effects of CMV reactivation on sequential concentrations of these biomarkers were assessed in multivariable mixed models.

RESULTS

Among 64 CMV+ patients, 45 could be matched to CMVs+ or CMVs- controls or both. The two baseline characteristics and host response biomarker levels at viremia onset were similar between groups. CMV+ patients had increased IP-10 on day 7 after viremia onset (symmetric percentage difference +44% versus -15% when compared with CMVs+ and +37% versus +4% when compared with CMVs-) and decreased IL-1RA (-41% versus 0% and -49% versus +10%, respectively). However, multivariable analyses did not show an independent association between CMV reactivation and time trends of IL-6, IP-10, IL-10, or IL-1RA.

CONCLUSION

CMV reactivation was not independently associated with changes in the temporal trends of host response biomarkers in comparison with non-reactivating patients. Therefore, these markers should not be used as surrogate clinical endpoints for interventional studies evaluating anti-CMV therapy.

Epidemiology and Immune Pathogenesis of Viral Sepsis

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis can be caused by a broad range of pathogens; however, bacterial infections represent the majority of sepsis cases. Up to 42% of sepsis presentations are culture negative, suggesting a non-bacterial cause. Despite this, diagnosis of viral sepsis remains very rare. Almost any virus can cause sepsis in vulnerable patients (e.g., neonates, infants, and other immunosuppressed groups). The prevalence of viral sepsis is not known, nor is there enough information to make an accurate estimate. The initial standard of care for all cases of sepsis, even those that are subsequently proven to be culture negative, is the immediate use of broad-spectrum antibiotics. In the absence of definite diagnostic criteria for viral sepsis, or at least to exclude bacterial sepsis, this inevitably leads to unnecessary antimicrobial use, with associated consequences for antimicrobial resistance, effects on the host microbiome and excess healthcare costs. It is important to understand non-bacterial causes of sepsis so that inappropriate treatment can be minimised, and appropriate treatments can be developed to improve outcomes. In this review, we summarise what is known about viral sepsis, its most common causes, and how the immune responses to severe viral infections can contribute to sepsis. We also discuss strategies to improve our understanding of viral sepsis, and ways we can integrate this new information into effective treatment.

Simulation shows undesirable results for competing risks analysis with time-dependent covariates for clinical outcomes

Background

We evaluate three methods for competing risks analysis with time-dependent covariates in comparison with the corresponding methods with time-independent covariates.

Methods

We used cause-specific hazard analysis and two summary approaches for in-hospital death: logistic regression and regression of the subdistribution hazard. We analysed real hospital data (n=1864) and considered pneumonia on admission / hospital-acquired pneumonia as time-independent / time-dependent covariates for the competing events ’discharge alive’ and ’in-hospital death’. Several simulation studies with time-constant hazards were conducted.

Results

All approaches capture the effect of time-independent covariates, whereas the approaches perform differently with time-dependent covariates. The subdistribution approach for time-dependent covariates detected effects in a simulated no-effects setting and provided counter-intuitive effects in other settings.

Conclusions

The extension of the Fine and Gray model to time-dependent covariates is in general not a helpful synthesis of the cause-specific hazards. Cause-specific hazard analysis and, for uncensored data, the odds ratio are capable of handling competing risks data with time-dependent covariates but the use of the subdistribution approach should be neglected until the problems can be resolved. For general right-censored data, cause-specific hazard analysis is the method of choice.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0535-5) contains supplementary material, which is available to authorized users.

Human pegivirus persistence in human blood virome after allogeneic haematopoietic stem-cell transplantation

OBJECTIVES

Because commensal viruses are defined by the immunologic tolerance afforded to them, any immunomodulation, such as is received during haematopoietic stem-cell transplantation, may shift the demarcation between innocuous viral resident and disease-causing pathogen.

METHODS

We analysed by deep-sequencing the plasma virome of 40 allogeneic haematopoietic stem-cell transplantation patients 1 month after transplantation. Because human pegivirus (HPgV) was highly prevalent, we performed a 1-year screening of 122 plasma samples by specific real-time reverse transcription PCR assay. We used the log-rank test and the Gray test to assess association with outcomes, and the Mann-Whitney test and multivariable linear regression model to assess association with T-cell reconstitution.

RESULTS

Polyomaviruses (PyV) (20/40 patients), anelloviruses (16/40), pegiviruses (14/40) and herpesviruses (14/40) were most frequently identified, including ten cytomegalovirus; three Epstein-Barr virus; two herpes simplex virus type 1; one human herpesvirus 6b and one human herpesvirus 7; 18 Merkel cell-PyV; two BK-PyV; three PyV-6; and one JC-PyV. Papillomavirus and adenovirus were identified in 11 and two patients, respectively. The HPgV specific real-time reverse transcription PCR screening identified 51 of 122 positive samples, high virus loads and persistent infections up to 1 year after transplantation. Comparison between patients with or without HPgV infection at time of transplantation did not reveal a significant difference in infections, engraftment, survival, graft vs. host disease, relapse or immune reconstitution.

CONCLUSIONS

The blood virome after allogeneic haematopoietic stem-cell transplantation includes several DNA viruses, notably herpesviruses and PyV. Among RNA viruses, HPgV is highly prevalent and persists for several months, and it thus may deserve special attention in further research on immune reconstitution.

Advances in the understanding and treatment of sepsis-induced immunosuppression

Sepsis is defined as a life-threatening organ dysfunction that is caused by a dysregulated host response to infection. Sepsis can induce acute kidney injury and multiple organ failures and represents the most common cause of death in the intensive care unit. Sepsis initiates a complex immune response that varies over time, with the concomitant occurrence of both pro-inflammatory and anti-inflammatory mechanisms. As a result, most patients with sepsis rapidly display signs of profound immunosuppression, which is associated with deleterious consequences. Scientific advances have highlighted the role of metabolic failure, epigenetic reprogramming, myeloid-derived suppressor cells, immature suppressive neutrophils and immune alterations in primary lymphoid organs (the thymus and bone marrow) in sepsis. An improved understanding of the mechanisms underlying this immunosuppression as well as of the similarities between sepsis-induced immunosuppression and immune defects in cancer or immunosenescence has led to novel therapeutic strategies aimed at stimulating immune function in patients with sepsis. Trials assessing the therapeutic benefit of IL-7, granulocyte-macrophage colony-stimulating factor (GM-CSF) and antibodies against programmed cell death protein 1 (PD1) and programmed cell death 1 ligand 1 (PDL1) for the treatment of sepsis are in progress. The reappraisal of sepsis pathophysiology has also resulted in a novel approach to the design of clinical trials evaluating sepsis treatments, based on an evaluation of the immune status and biomarker-based stratification of patients.

Management of Sepsis-Induced Immunosuppression

It is now well established that profound immunosuppression develops within a few days after sepsis onset in patients. This should be considered additional organ failure because it is associated with increased rate of nosocomial infections, mortality, and long-term complications, thus constituting the rationale for immunomodulation in patients. Nevertheless, the demonstration of the efficacy of such therapeutic strategy in improving deleterious outcomes in sepsis remains to be made. Results from clinical trials based on interleukin 7 and granulocyte macrophage colony-stimulating factor immunoadjuvant therapies in septic shock patients are expected for 2018.