Virological and immunological features of active cytomegalovirus infection in nonimmunosuppressed patients in a surgical and trauma intensive care unit

Clinical characteristics of pediatric patients hospitalized with community-acquired pneumonia and cytomegalovirus DNA detected in bronchoalveolar lavage fluid

Background

This study aimed to investigate the clinical characteristics of pediatric patients hospitalized with community-acquired pneumonia (CAP) and concomitant cytomegalovirus (CMV) infection.

Methods

This cross-sectional study enrolled consecutive pediatric patients admitted with CAP who tested positive for CMV DNA in bronchoalveolar lavage fluid (BALF). Flexible fiberoptic bronchoscopy was performed when routine treatment for CAP proved ineffective. The study participants were further stratified into two groups based on CMV serological test results: recent CMV infection group and CMV replication group. Clinical characteristics were compared between these two groups.

Results

Among 124 patients aged 1-11 months included in this study, 80 (64.5%) patients were categorized as having recent CMV infection, and 44 (35.5%) tested positive for CMV replication. Co-infection with other pathogens was detected more frequently in the CMV replication group (n = 29, 65.9%) than in the recent CMV infection group (n = 35, 43.7%; P = 0.018). Patients with recent CMV infection were younger and exhibited higher levels of alanine transaminase (ALT) and aspartate aminotransferase compared to those with CMV replication (all P < 0.05). Multivariable regression analysis showed age was independently associated with recent CMV infection (odds ratio [OR], 0.707; 95% confidence interval [CI], 0.586-0.853; P < 0.001). Notably, receiver operating characteristic curve analysis showed that a CMV PCR level of 3,840 copies/ml in blood samples had a sensitivity of 34.7% and specificity of 90.0% for diagnosis of recent CMV infection with an area under the curve (AUC) of 0.625 (95% CI: 0.513-0.736, P = 0.048). A CMV PCR level of 6,375 copies/ml in urine samples had a sensitivity of 77.1% and specificity of 61.5% for diagnosis of recent CMV infection with an AUC of 0.695 (95% CI: 0.531-0.858, P = 0.04). Furthermore, multivariate linear regression analysis revealed that the blood CMV DNA copy number was associated with ALT (B = 0.001; P < 0.001).

Conclusions

The CMV DNA copy numbers in blood and urine could serve as discriminatory markers between recent CMV infection and CMV replication. Measuring CMV DNA levels in blood may be an effective method for monitoring liver function impairment in pediatric patients presenting with CAP and concurrent CMV infection.

Cytomegalovirus infection in non-immunocompromised critically ill patients: A management perspective

Critically ill patients are a vulnerable group at high risk of developing secondary infections. High disease severity, prolonged intensive care unit (ICU) stay, sepsis, and multiple drugs with immunosuppressive activity make these patients prone to immuneparesis and increase the risk of various opportunistic infections, including cytomegalovirus (CMV). CMV seroconversion has been reported in up to 33% of ICU patients, but its impact on patient outcomes remains a matter of debate. Even though there are guidelines regarding the management of CMV infection in immunosuppressive patients with human immunodeficiency virus/ acquired immuno deficiency syndrome, the need for treatment and therapeutic approaches in immunocompetent critically ill patients is still ambiguous. Even the diagnosis of CMV infection may be challenging in such patients due to non-specific symptoms and multiorgan involvement. Hence, a better understanding of the symptomatology, diagnostics, and treatment options may aid intensive care physicians in ensuring accurate diagnoses and instituting therapeutic interventions.

Comparative clinical manifestations and immune effects of cytomegalovirus infections following distinct types of immunosuppression

BACKGROUND

Cytomegalovirus (CMV) infection is a well-recognized complication of solid organ and hematopoietic cell transplantation. However, CMV infection also occurs in patients with human immunodeficiency virus (HIV) infection, previously immunocompetent intensive care unit (ICU) patients, and individuals on immunosuppressive medications for various underlying diseases.

OBJECTIVES

This review describes the comparative effects of CMV infection in distinct types of acquired immunosuppression.

SOURCES

Selected peer-reviewed publications on CMV infections published until December 2021.

CONTENT

CMV infection affects various organ systems through direct cytolytic mechanisms, but may also exert indirect effects by promoting pro-inflammatory and immunosuppressive responses. This has been well studied in transplant recipients, for whom antiviral prophylaxis and pre-emptive therapy have now become standard practice. These strategies not only prevent direct CMV disease manifestations, but also mitigate various immunopathological processes to reduce graft-versus-host disease, graft rejection, and the occurrence of secondary bacterial and fungal infections. The efficacy of neither prophylactic nor pre-emptive treatment of CMV infection has been demonstrated for patients with critical illness- or medication-induced immunosuppression. Many observational studies have shown an independent association between CMV reactivation and a prolonged duration of mechanical ventilation or increased mortality in the ICU. Furthermore, data suggest that CMV reactivation may increase pulmonary inflammation and prolong the duration of mechanical ventilation.

IMPLICATIONS

A large number of observational and experimental studies suggest attributable morbidity and mortality related to CMV infection, not only in transplant recipients and patients with HIV infection but also in patients with critically illness- or medication-induced immunosuppression. Adequately powered randomized controlled trials investigating the efficacy of prophylaxis or pre-emptive treatment of CMV infection in these patients are lacking, with a notable exception for transplant recipients.

Invasive pulmonary aspergillosis is associated with cytomegalovirus viremia in critically ill patients - A retrospective cohort study

BACKGROUND/PURPOSE

Cytomegalovirus (CMV) viremia is associated with a higher mortality rate and prolonged intensive care unit (ICU) stay for critically ill patients. CMV infection causes transient but substantial immunosuppression for transplant recipients, increasing risk of fungal infection. The association between CMV viremia and invasive pulmonary aspergillosis (IPA) for critically ill patients is still unknown.

METHODS

We retrospectively analyzed patients received bronchoalveolar lavage (BAL), galactomannan test, influenza survey and blood CMV viral load test in ICUs of a university hospital between April 2017 and May 2020. Independent risks for IPA were analyzed by multivariable logistic regression.

RESULTS

A total of 136 patients were included. Twenty-one patients had IPA, 48 patients had CMV viremia and 22 patients had influenza. In a multivariable logistic regression model, patients with CMV viremia or influenza had higher IPA risk (adjusted odds ratio, 3.98 and 8.72; 95% CI, 1.26-12.60 and 2.64-28.82; p value = 0.019 and <0.001, respectively.). Patients with detectable CMV in BAL fluid did not have higher IPA risk (crude odds ratio, 0.95; 95% CI, 0.33-2.79; p value = 0.933). After stratifying patients by CMV viral load, the IPA risk is higher for patients with higher viral loads. There is an additive synergistic effect on IPA risk between CMV viremia and influenza infection.

CONCLUSION

For critically ill patients, CMV viremia is an independent risk factor of IPA. Patients with higher blood CMV viral loads have a higher risk of IPA. CMV viremia and influenza have an additive synergistic effect for IPA risk in critically ill 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.

Incidence of Cytomegalovirus Antigenemia in patients with autoimmune rheumatic diseases: a 3-year retrospective study

OBJECTIVE

To determine the incidence of positive CMV antigenemia (CMV-Ag) in patients with autoimmune rheumatic diseases (AIRD) and to describe the outcomes of these patients.

METHODS

From January 2011 to December 2014, a total of 443 patients with AIRD were enrolled in this retrospective analysis. Demographic, clinical and laboratory data, current clinical manifestations, organs affected by CMV infection, therapeutic management and outcomes were evaluated. The CMV-Ag was considered positive when one cell was detected at least.

RESULTS

CMV-Ag was requested in 70 (15.8%) patients with suspicious CMV infection and was positive in 24 (34.3%). The incidence rate of positive CMV-Ag was 4.97% (95% CI 3.1-7.4%). Systemic lupus erythematosus (SLE) (59%), followed by ANCA-related vasculitis (18.2%) and rheumatoid arthritis (9%) were the diseases more associated with positive CMV-Ag. At the time of CMV infection, SLE patients had moderate to severe disease activity, with high frequency of positive anti-dsDNA antibody (69.2%) and complement consumption (61.5%), as well as high doses of corticosteroids and use of immunosuppressants. The main CMV sites involved were lung (45.5%), bone marrow (40.9%) and gut (27.3%). Mortality rate was 45.5%, especially in those with higher doses of daily oral corticosteroids (107 ± 55.4 mg vs. 71.7 ± 46.3 mg; p = 0.07) and lower number of lymphocytes (309 ± 368.2/mm³ vs. 821 ± 692.9/mm³; p = 0.06).

CONCLUSIONS

Our data showed high incidence of CMV-Ag in AIRD patients, particularly those with SLE and greater disease severity. In addition, it was observed high mortality in these patients, highlighting the CMV infection should be included in differential diagnosis.

Reactivation of Latent Cytomegalovirus Infection after Major Surgery: Risk Factors and Outcomes

Background: Reactivation of latent cytomegalovirus (CMV) infection occurs in previously immunocompetent critically ill individuals and may be associated with increased morbidity and mortality. Our aim was to explore risk factors for and outcomes after CMV reactivation in patients undergoing major surgery. Patients and Methods: We performed a retrospective case control study of patients without underlying immunocompromise who developed post-operative CMV reactivation from 2004-2016. Cases included patients testing positive for CMV by viral load, culture, or histopathology. Controls were matched by age, gender, type, and year of surgery. Results: Sixteen CMV cases were matched to 32 controls. Median age was 65 and median time from surgery to CMV diagnosis was 32 days. Symptoms included fever (94%), hepatitis (75%), myelosuppression (56%), and diarrhea (38%). Despite similar baseline comorbidities, cases were more likely to return to surgery (odds ratio [OR] 6.31; 95% confidence interval [CI], 1.29-30.74), require renal replacement therapy (OR 18.54; 95% CI, 2.36-145.6), total parenteral nutrition (OR 33.0; 95% CI, 6.60-262.37) and corticosteroids (OR 18.78; 95% CI, 4.5-103.9). Length of stay was increased (median 51 vs. 8 days, p = 0.005), co-infections were more common (OR 15.10; 95% CI, 1.89-120.8), and mortality was higher (38% vs. 0%, p < 0.01). Conclusions: Cytomegalovirus reactivation occurs in previously immunocomptent patients post-operatively and is associated with poor outcomes including other infections and mortality. Potential risk factors include prolonged length of stay, surgical complications, and corticosteroid use. It is not clear from our study whether CMV reactivation is a surrogate marker of severe illness and post-operative complications or if CMV reactivation plays a causative role in the development of these adverse outcomes.

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.

Cytomegalovirus infection and outcome in immunocompetent patients in the intensive care unit: a systematic review and meta-analysis

BACKGROUND

Cytomegalovirus (CMV) infection is common in immunocompetent patients in intensive care units (ICUs). However, whether CMV infection or CMV reactivation contributes to mortality of immunocompetent patients remains unclear.

METHODS

A literature search was conducted for relevant studies published before May 30, 2016. Studies reporting on CMV infection in immunocompetent patients in ICUs and containing 2 × 2 tables on CMV results and all-cause mortality were included.

RESULTS

Eighteen studies involving 2398 immunocompetent patients admitted to ICUs were included in the meta-analysis. The overall rate of CMV infection was 27% (95%CI 22-34%, I² = 89%, n = 2398) and the CMV reactivation was 31% (95%CI 24-39%, I² = 74%, n = 666). The odds ratio (OR) for all-cause mortality among patients with CMV infection, compared with those without infection, was 2.16 (95%CI 1.70-2.74, I² = 10%, n = 2239). Moreover, upon exclusion of studies in which antiviral treatment was possibly or definitely provided to some patients, the association of mortality rate with CMV infection was also statistically significant (OR: 1.69, 95%CI 1.01-2.83, I² = 37%, n = 912,). For CMV seropositive patients, the OR for mortality in patients with CMV reactivation as compared with patients without CMV reactivation was 1.72 (95%CI 1.04-2.85, I² = 29%, n = 664). Patients with CMV infection required significantly longer mechanical ventilation (mean difference (MD): 9 days (95% CI 5-14, I² = 81%, n = 875)) and longer duration of ICU stay (MD: 12 days (95% CI 7-17, I² = 70%, n = 949)) than patients without CMV infection. When analysis was limited to detection in blood, CMV infection without antiviral drug treatment or reactivation was not significantly associated with higher mortality (OR: 1.69, 95%CI 0.81-3.54, I² = 52%, n = 722; OR: 1.49, I² = 63%, n = 469).

CONCLUSION

Critically ill patients without immunosuppression admitted to ICUs show a high rate of CMV infection. CMV infection during the natural unaltered course or reactivation in critically ill patients is associated with increased mortality, but have no effect on mortality when CMV in blood. More studies are needed to clarify the impact of CMV infection on clinical outcomes in those patients.

Impaired polyfunctionality of CD8+ T cells in severe sepsis patients with human cytomegalovirus reactivation

Human cytomegalovirus (HCMV) establishes a lifelong chronic latent infection and often reactivates in immunocompromised patients. In addition, HCMV reactivates in patients with sepsis or other critical illnesses, particularly in patients with poor prognoses. However, the immunological characteristics of sepsis patients with HCMV reactivation have not been elucidated. In the present study, we examined T-cell responses in severe sepsis patients with and without HCMV reactivation. First, HCMV pp65-specific T-cell functions were assessed by intracellular cytokine staining (ICS) for IFN-γ, TNF-α, and MIP-1β and by CD107a staining. We analyzed the ICS data for each function individually and found no difference between the patient groups. However, the relative frequency of polyfunctional CD8⁺ T cells was significantly decreased in sepsis patients with HCMV reactivation. Next, we examined programmed cell death protein 1 (PD-1) expression. It was significantly increased in the CD8⁺ T-cell population in severe sepsis patients with HCMV reactivation, indicating CD8⁺ T-cell exhaustion. Interestingly, the frequency of PD-1⁺ cells in the CD8⁺ T-cell population was inversely correlated with the relative frequency of polyfunctional CD8⁺ T cells. Herein, we demonstrate that HCMV reactivation in severe sepsis patients is associated with PD-1 expression and impaired polyfunctionality of CD8⁺ T cells.

Known unknowns: how might the persistent herpesvirome shape immunity and aging?

The microbial community that colonizes all living organisms is gaining appreciation for its contributions to both physiologic and pathogenic processes. The virome, a subset of the overall microbiome, large and diverse, including viruses that persistently inhabit host cells, endogenous viral elements genomically or epigenomically integrated into cells, and viruses that infect the other (bacterial, protozoan, fungal, and archaeal) microbiome phylla. These viruses live in the organism for its life, and therefore are to be considered part of the aging process experienced by the organism. This review considers the impact of the persistent latent virome on immune aging. Specific attention will be devoted to the role of herpesviruses, and within them, the cytomegalovirus, as the key modulators of immune aging.

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.

Broncholaveolar lavage to detect cytomegalovirus infection, latency, and reactivation in immune competent hosts

Roughly 1/3rd of immune competent patients will reactivate latent cytomegalovirus (CMV) during critical illness. There are no standard methods to detect reactivation, and some investigators have postulated that presence of DNA in BAL fluid is indicative of viral replication. To test this hypothesis, we used a murine model that allows inclusion of matched healthy controls which is not possible in human studies. BALB/c mice infected with Smith-murine CMV or PBS (mock) had BAL evaluated 7, 14, or 21 days after acute infections, during latency, or during bacterial sepsis. Plaque assay, PCR, and rtPCR were performed on BALs and concomitantly obtained lung tissue. BAL cellular compositions, including tetramer evaluation of CMV-specific T cells were evaluated by flow cytometry. CMV DNA were detected in BAL at all time-points during acute infection, becoming undetectable in all mice during latency, then were detected again during bacterial sepsis, peaking 3 weeks after onset. mCMV specific T-cells were most numerous in BAL after acute viral infections, decreasing to low levels during latency, then fluctuating during bacterial sepsis. Specifically, mCMV-specific T-cells contracted at sepsis onset, expanding 2-4 weeks post-sepsis, presumably in response to increased viral loads at that time point. Altogether, our results support the use of BAL PCR for the diagnosis of CMV replication in immune competent hosts. Additionally, we demonstrate dynamic changes in CMV-specific T cells that occur in BAL during CMV infection and during sepsis induced viral reactivation. J. Med. Virol. 88:1408-1416, 2016. © 2016 Wiley Periodicals, Inc.

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.

Coreactivation of Human Herpesvirus 6 and Cytomegalovirus Is Associated With Worse Clinical Outcome in Critically Ill Adults

OBJECTIVES

Human herpesvirus 6 is associated with a variety of complications in immunocompromised patients, but no studies have systematically and comprehensively assessed the impact of human herpesvirus 6 reactivation, and its interaction with cytomegalovirus, in ICU patients.

DESIGN

We prospectively assessed human herpesvirus 6 and cytomegalovirus viremia by twice-weekly plasma polymerase chain reaction in a longitudinal cohort study of 115 adult, immunocompetent ICU patients. The association of human herpesvirus 6 and cytomegalovirus reactivation with death or continued hospitalization by day 30 (primary endpoint) was assessed by multivariable logistic regression analyses.

SETTING

This study was performed in trauma, medical, surgical, and cardiac ICUs at two separate hospitals of a large tertiary care academic medical center.

PATIENTS

A total of 115 cytomegalovirus seropositive, immunocompetent adults with critical illness were enrolled in this study.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Human herpesvirus 6 viremia occurred in 23% of patients at a median of 10 days. Human herpesvirus 6B was the species detected in eight samples available for testing. Most patients with human herpesvirus 6 reactivation also reactivated cytomegalovirus (70%). Severity of illness was not associated with viral reactivation. Mechanical ventilation, burn ICU, major infection, human herpesvirus 6 reactivation, and cytomegalovirus reactivation were associated with the primary endpoint in unadjusted analyses. In a multivariable model adjusting for mechanical ventilation and ICU type, only coreactivation of human herpesvirus 6 and cytomegalovirus was significantly associated with the primary endpoint (adjusted odds ratio, 7.5; 95% CI, 1.9-29.9; p = 0.005) compared to patients with only human herpesvirus 6, only cytomegalovirus, or no viral reactivation.

CONCLUSIONS

Coreactivation of both human herpesvirus 6 and cytomegalovirus in ICU patients is associated with worse outcome than reactivation of either virus alone. Future studies should define the underlying mechanism(s) and determine whether prevention or treatment of viral reactivation improves clinical outcome.

Sepsis and cytomegalovirus: foes or conspirators?

Cytomegalovirus (CMV) reactivation in non-immune-suppressed critically ill patients is an area of increasing interest. CMV has long been appreciated as a pathogen in immunocompromised hosts. CMV reactivates in approximately one-third of latently infected non-immune-suppressed hosts during critical illness; however, its role as a pathogen in these patients remains unclear. CMV reactivation has been linked to bacterial sepsis and likely results from inflammation, transient immune compromise, and viral epigenetic changes. While CMV may improve immune response to some bacterial infections, other data suggest that CMV induces exaggerated responses to severe infections that may be harmful to latently infected hosts. These results also suggest that previous infection history may explain significant differences seen between human septic responses and murine models of sepsis. While critically ill human hosts clearly have worse outcomes associated with CMV reactivation, determining causality remains an area of investigation, with randomized control trials currently being performed. Here we review the current literature and highlight areas for future investigation.

Presence of human cytomegalovirus DNA in blood of patients with community-acquired pneumonia

After a primary infection, human cytomegalovirus (HCMV) remains latent in certain human cells. Different stimuli, including immune deficiency and severe infection, can trigger the reactivation of latent HCMV infection. In the last decade, the role of the reactivation in immunocompetent patients with serious illness has been intensely studied; however, the knowledge of the potential role of moderately severe infections on HCMV dynamics is limited. In the prospective study, 80 HCMV-seropositive, immunocompetent adult patients with community-acquired pneumonia (CAP), treated outside the intensive care unit (ICU), were monitored with real-time polymerase chain reaction (PCR) for the presence of HCMV DNA. Detection of HCMV DNA in whole blood and/or plasma was interpreted as reactivation of latent HCMV infection. HCMV DNA was detected in 6 of 80 (7.5%) patients. All HCMV DNA-positive patients were classified according to the pneumonia severity index (PSI) as high-risk classes IV or V; thus, HCMV DNAaemia rate within these two PSI classes was 16.7%. All of the patients had positive whole blood samples, whereas plasma samples were positive in a single patient. We did not detect any significant differences comparing six patients with proven HCMV DNAaemia and 74 patients in whom HCMV DNAaemia was not demonstrated regarding the levels of inflammatory parameters on admission, length of treatment with supplemental oxygen, and length of hospital stay. In conclusion, the finding of HCMV DNAaemia in patients with CAP treated outside the ICU is a rare event and occurs only in patients with PSI classes designating more severe pneumonia.

Resistant pathogens, fungi, and viruses

Although originally described in Staphylococcus aureus, resistance among bacteria has now become a race to determine which classes of bacteria will become more resistant. Availability of antibacterial agents has allowed the development of entirely new diseases caused by nonbacterial pathogens, related largely to fungi that are inherently resistant to antibacterials. This article presents the growing body of knowledge of the herpes family of viruses, and their occurrence and consequences in patients with concomitant surgical disease or critical illness. The focus is on previously immunocompetent patients, as the impact of herpes viruses in immunosuppressed patients has received thorough coverage elsewhere.

Asymptomatic carriage of Pneumocystis jirovecii and cytomegalovirus in lungs of immunocompetent patients

PURPOSE

Pneumocystis jirovecii (PCP) and cytomegalovirus (CMV) are opportunistic pathogens which cause lung infection in immunocompromised individuals. However, scarce data are available regarding the carriage of CMV or PCP in immunocompetent, non critically ill patients. The purpose of this study was to evaluate the prevalence of PCP and CMV in broncholaveolar lavage of adult immunocompetent, non critically ill patients.

METHODS

BAL fluids from immunocompetent patients who underwent bronchoscopy were analyzed by polymerase chain reaction (PCR) for CMV and PCP DNA. We tested CMV antibodies in serum. In patients with positive CMV DNA in lavage fluid, we further analyzed peripheral blood for the presence of CMV DNA.

RESULTS

Ninety three patients were included. We did not detect PCP DNA in BAL in any patient. CMV DNA was found in BAL of 5 of 86 CMV IgG positive patients (5.8 %). Patients who were positive for CMV did not differ from patients with negative PCR for CMV regarding demographic and clinical features.

CONCLUSION

We did not find PCP colonization in our cohort of patients. However, we found significant prevalence of CMV DNA in BAL from immunocompetent patients, with no evidence of acute CMV infection. This finding may represent colonization by CMV in immunocompetent, non-critically ill individuals.

Quantification of cytomegalovirus viral load

Cytomegalovirus (CMV), a member of the Herpesviridae family, is worldwide distributed. After the primary infection, CMV induces a latent infection with possible reactivation(s). It is responsible for severe to life-threatening diseases in immunocompromised patients and in foetuses and newborns of infected mothers. For monitoring CMV load, classical techniques based on rapid culture or pp65 antigenemia are progressively replaced by quantitative nuclear acid tests (QNAT), easier to implement and standardize. A large variety of QNAT are available from laboratory-developed assays to fully-automated commercial tests. The indications of CMV quantification include CMV infection during pregnancy and in newborns, and viral surveillance of grafted and non-grafted immunocompromised patients, patients with bowel inflammatory diseases and those hospitalised in intensive care unit. A close cooperation between virologists and clinicians is essential for optimizing the benefit of CMV DNA monitoring.

Regulation of human cytomegalovirus transcription in latency: beyond the major immediate-early promoter

Lytic infection of differentiated cell types with human cytomegalovirus (HCMV) results in the temporal expression of between 170–200 open reading frames (ORFs). A number of studies have demonstrated the temporal regulation of these ORFs and that this is orchestrated by both viral and cellular mechanisms associated with the co-ordinated recruitment of transcription complexes and, more recently, higher order chromatin structure. Importantly, HCMV, like all herpes viruses, establishes a lifelong latent infection of the host—one major site of latency being the undifferentiated haematopoietic progenitor cells resident in the bone marrow. Crucially, the establishment of latency is concomitant with the recruitment of cellular enzymes that promote extensive methylation of histones bound to the major immediate early promoter. As such, the repressive chromatin structure formed at the major immediate early promoter (MIEP) elicits inhibition of IE gene expression and is a major factor involved in maintenance of HCMV latency. However, it is becoming increasingly clear that a distinct subset of viral genes is also expressed during latency. In this review, we will discuss the mechanisms that control the expression of these latency-associated transcripts and illustrate that regulation of these latency-associated promoters is also subject to chromatin mediated regulation and that the instructive observations previously reported regarding the negative regulation of the MIEP during latency are paralleled in the regulation of latent gene expression.

Frequent detection of cytomegalovirus (CMV) DNA in the lower respiratory tract in CMV-seropositive pediatric patients with underlying chronic bronchopulmonary diseases lacking canonical immunosuppression

Cytomegalovirus (CMV) may be a relevant cause of morbidity in patients displaying various inflammatory diseases. In this study, it was investigated whether CMV DNA is detected in the lower respiratory tract and the systemic compartment in pediatric patients with chronic or recurrent bronchopulmonary diseases. A total of 42 lower respiratory tract specimens and 11 paired plasma samples from 42 patients were analyzed for the presence of CMV DNA by real‐time PCR. The respiratory specimens were also screened for the presence of respiratory viruses and human herpesvirus 6 (HHV‐6) and 7 (HHV‐7) by PCR methods. Quantitative bacterial and fungal cultures were performed. IL‐6 levels in the respiratory specimens were quantified using ELISA. CMV DNA was detected either in the lower respiratory airways, in plasma, or both in 54.5% of CMV‐seropositive patients. The levels of IL‐6 were significantly higher in these patients than in those with no detectable levels of CMV DNA. HHV‐6 and HHV‐7 DNA were detected in three and one patients, respectively. Respiratory viruses were detected in 13 of the 42 patients. Significant growth of one or more bacterial species was observed in 17 patients. No significant association was found between the presence of CMV DNA and the detection of other microorganisms. The data indicated that the presence of CMV DNA in the lower respiratory tract is a frequent finding in children with chronic or recurrent bronchopulmonary diseases. Further, prospective observational studies are needed to assess the impact of this phenomenon, if any, on the clinical course of these patients. J. Med. Virol. 85:888–892, 2013. © 2013 Wiley Periodicals, Inc.

Interferon-γ production by natural killer cells and cytomegalovirus in critically ill patients

OBJECTIVE

The mechanisms involved in cytomegalovirus reactivation in critically ill patients who were previously immunocompetent are still unknown. The current study was designed to evaluate the possible role of natural killer cells in the reactivation of cytomegalovirus in these patients.

DESIGN

Prospective observational.

SETTING

: A medical intensive care unit of a university hospital.

PATIENTS

Fifty-one subjects, including 15 patients who experienced cytomegalovirus reactivation (cases) during their intensive care unit stay and 15 patients who matched intensive care unit controls, selected from a cohort of consecutive nonimmunocompromised intensive care unit patients, as well as healthy controls.

INTERVENTIONS

Tests included weekly systematic immunomonitoring and routine screening for cytomegalovirus infection until discharge from the intensive care unit or death. The immunophenotype and functions of natural killer cells were performed by flow cytometry, and serum levels of pro- and anti-inflammatory cytokines were determined by enzyme-linked immunosorbent assay.

MEASUREMENTS AND MAIN RESULTS

The overall occurrence of cytomegalovirus reactivation in the cohort was 27%. No differences of natural killer cell effector functions were observed at admission between cases and controls. Instead, before cytomegalovirus reactivation, the ability of natural killer cells to secrete interferon-γ was significantly reduced in cases as compared with controls upon stimulation with antibody-coated target cells (p = .029) and with K562 cell stimulation (p = .029). No phenotypic or quantitative differences were observed between cases and controls. Cases exhibited higher levels of interleukin 10 (p = .031) and interleukin 15 (p = .021) than controls before cytomegalovirus reactivation.

CONCLUSIONS

Impaired natural killer cell function with reduced interferon-γ secretion precedes the occurrence of cytomegalovirus reactivation among previously immunocompetent critically ill patients.

Cytomegalovirus and herpes simplex virus effect on the prognosis of mechanically ventilated patients suspected to have ventilator-associated pneumonia

OBJECTIVE

Cytomegalovirus (CMV) and herpes simplex virus (HSV) are common viruses that can affect critically ill patients who are not immunocompromised. The aim of this study was to determine whether the identification of CMV and/or HSV in mechanically ventilated critically ill patients suspected of having pneumonia was associated with an increased mortality.

DESIGN

Prospective epidemiological study.

SETTING

Medical intensive care unit of a tertiary medical center.

PATIENTS

Ninety-three patients with suspected pneumonia.

INTERVENTIONS

Patients with suspected pneumonia had bronchoalveolar lavage and blood samples taken to confirm the diagnosis. Antigenemia was used to detect CMV in the blood. Bronchoalveolar lavage samples were submitted to testing using quantitative real-time Polymerase Chain Reaction.

MEASUREMENTS AND MAIN RESULTS

We identified 22 patients with a CMV infection, 26 patients with an HSV infection and 45 patients without CMV or HSV infection (control group). Mortality at day 60 was higher in patients with a CMV infection than in patients from the control group (55% vs. 20%, P<0.01). Mortality at day 60 was not significantly increased in the group with HSV infection. Duration of ICU stay and ICU mortality were significantly higher in patients with CMV infections when compared to patients from the control group, whereas ventilator free days were significantly lower in patients with CMV infections when compared to patients from the control group.

CONCLUSIONS

In critically ill patients, a CMV infection is associated with an increased mortality. Further interventional studies are needed to evaluate whether treatment could improve the prognosis.

Transient CD8-memory contraction: a potential contributor to latent cytomegalovirus reactivation

It is clear that latent CMV can reactivate in immunocompetent individuals, but the mechanism triggering such reactivations remains unclear. Recent clinical data suggest that reactivation can be subverted by CMV-specific T-memory. We therefore monitored CMV-specific T cells in immunocompetent mice with latent mCMV after a known reactivation trigger (LPS). LPS induced transient systemic contraction of mCMV-specific CD8 memory that was followed by transcriptional reactivation. Subsequent recovery of mCMV-specific T cells coincided with resumption of latency. These data suggest that bacterial antigen encounters can induce transient T-memory contraction, allowing viral recrudescence in hosts latently infected with herpes family viruses.

Immunological insights into the pathogenesis of active CMV infection in non-immunosuppressed critically ill patients

Dissociation of cytomegalovirus (CMV) DNA loads between the lower respiratory tract and blood, with high levels in the former compartment and low or undetectable levels in the latter, commonly occurs during active CMV infection in critically ill patients despite the presence of high frequencies of CMV-specific IFN-γ-producing CD8(+) and CD4(+) T cells in blood. Data presented in this case report suggest that inter-compartmental differences in interleukin-10 (IL-10) levels may, in part, explain the pathobiology of this phenomenon. In the absence of ganciclovir treatment, a significant correlation was observed between IL-10 levels and CMV DNA loads in lower respiratory tract specimens (P = 0.016), but not in plasma samples (P = 0.46). Comparable data were obtained during the course of active CMV infection episodes that developed in six CMV-seropositive critically ill patients with no canonical immunosuppression. The presence of higher levels of IL-10 in the lower respiratory tract than in plasma may result in increased impairment of CMV-specific T-cell effector responses in the lung compared to the systemic compartment, facilitating local CMV replication.

Cytomegalovirus infection causes morbidity and mortality in patients with autoimmune diseases, particularly systemic lupus: in a Chinese population in Taiwan

To investigate the clinical outcome of cytomegalovirus (CMV) infection in febrile hospitalized patients with autoimmune diseases, mostly systemic lupus erythematosus (SLE). Fifty-four febrile patients were analyzed retrospectively. Half were diagnosed as CMV infection, by positive CMV pp65 antigenemia assay. Clinical and laboratory data between two groups were compared. Correlation between laboratory data and SELENA-SLEDAI scores/mortality were analyzed in the CMV infection group. Receiver operating characteristic analysis was performed to determine the cutoff points of different parameters for predicting mortality or morbidity. The CMV infection group received a higher corticosteroid dosage (mean 26.3 mg/day) and a higher percentage of azathioprine use before admission than the non-CMV infection group. In the former, the deceased subgroup had a significantly higher number of infected leukocytes for CMV (shortened as CMV counts, P = 0.013), more cases of bacterial infection (P = 0.090), and a higher SLE disease activity index score (P = 0.072) than the alive subgroup. The CMV infection group had lower lymphocyte count and more positive bacterial infection than the non-CMV infection group did (P = 0.013 and P = 0.027, respectively). A level of 25 CMV particles/5 × 10(5) polymorphonuclear neutrophils (PMN) was the best cutoff point for predicting CMV-associated mortality, with a sensitivity of 75.0% and specificity of 72.2%. Moderate dose (30 mg/day) of prednisolone or azathioprine use predisposes patients with autoimmune diseases to CMV infection with concurrent bacterial infection. In particular, peak CMV counts at 25/5 × 10(5) PMN or low lymphocyte counts predict mortality or morbidity, respectively.

Cytomegalovirus reactivation in critically ill immunocompetent hosts: a decade of progress and remaining challenges

Human cytomegalovirus (HCMV) is an undisputed pathogen in humans with severe immune compromise, which has historically been thought to carry little consequence in immunocompetent hosts. During the past decade, however, accumulating data suggest that significant numbers of immunocompetent humans reactivate HCMV during critical illness, and that these reactivation episodes are associated with worsened outcomes. Because most people are infected with this ubiquitous virus by adulthood, confirming pathogenicity has now become a clinical priority. In this article, we will review the incidence and implications of reactivation, the relevant immune responses and reactivation triggers relevant to the immunocompetent host. We will summarize the progress made during the past ten years, outline the work ongoing in this field, and identify the major gaps remaining in our emerging understanding of this phenomenon.

The role of natural killer cells in sepsis

Severe sepsis and septic shock are still deadly conditions urging to develop novel therapies. A better understanding of the complex modifications of the immune system of septic patients is needed for the development of innovative immunointerventions. Natural killer (NK) cells are characterized as CD3⁻NKp46⁺CD56⁺ cells that can be cytotoxic and/or produce high amounts of cytokines such as IFN-γ. NK cells are also engaged in crosstalks with other immune cells, such as dendritic cells, macrophages, and neutrophils. During the early stage of septic shock, NK cells may play a key role in the promotion of the systemic inflammation, as suggested in mice models. Alternatively, at a later stage, NK cells-acquired dysfunction could favor nosocomial infections and mortality. Standardized biological tools defining patients' NK cell status during the different stages of sepsis are mandatory to guide potential immuno-interventions. Herein, we review the potential role of NK cells during severe sepsis and septic shock.

The role of viruses in nosocomial pneumonia

PURPOSE OF REVIEW

The frequency and impact of viruses among intensive care unit (ICU) nonimmunocompromised patients remains controversial. This review analyzes their place as causal pathogens in ventilator-associated pneumonia, as well as their effects on ICU patients' outcomes.

RECENT FINDINGS

Herpesviruses, namely herpes simplex virus (HSV) and cytomegalovirus (CMV), are the most frequent viruses detected among nonimmunosuppressed ICU patients, as confirmed by recent prospective studies. Patients infected with these viruses show increased morbidity and, especially for CMV, mortality. An increase of bacterial or fungal superinfections was observed in ICU patients with CMV reactivation. A therapeutic trial of acyclovir (HSV antiviral) in ICU patients was negative. Concerning CMV, pathogenicity was suggested by histologic assessment in ICU patients, and recent murine models with a positive effect of prophylaxis with ganciclovir that prevented postseptic CMV reactivation and secondary lung damage.

SUMMARY

Using efficient and rapid virologic diagnostic tests (antigenemia or PCR), the identification of viruses in ICU patients is frequent. Their role in the occurrence of ventilator-acquired pneumonia and their impact on patient outcome depend on the virus. There is sufficient evidence suggesting CMV pathogenicity to conduct an interventional randomized trial using anti-CMV drugs.

[Ventilator-associated viral pneumonia]

Viral infections (especially respiratory infections) are not rare in critically ill non-immunocompromised patients. Efficient and rapid virologic diagnosis tests such as polymerase chain reaction (PCR) are now widely available. Herpesviridae (herpes simplex virus and cytomegalovirus) are the most frequent viruses detected among non-immunocompromised patients admitted to the intensive care unit (ICU). However, causal relationships between detected viruses and outcomes are still debated, with a variable level of demonstration among the different viruses. The aim of this review was to assess the role of viruses in causing mechanical ventilation-acquired pneumonias in non-immunocompromised ICU adult patients. We also discuss the possible physiopathology of these viral infections, as well as the opportunity for therapeutic interventions.