The Comparison of Monocyte Human Leukocyte Antigen-D-Related (mHLA-DR) Expression Levels Between Corona Virus Disease 2019 (COVID-19) Patients and Healthy Subjects.

BACKGROUND: SARS-CoV-2 can trigger a dysfunctional immune response in COVID-19 patients and lead to immunosuppression. HLA-DR molecule expressed on the surface of monocytes, known as mHLA-DR, has been widely used as a reliable marker of immunosuppression. Downregulation of mHLA-DR reflects an immunosuppressed state. This study aimed to compare the expression level of mHLA-DR between COVID-19 patients and healthy subjects concerning immune system dysregulation that can be triggered by SARS-CoV-2 and lead to immunosuppression. METHODS: This was an analytic observational study with a cross-sectional design that measured the mHLA-DR expression in EDTA blood samples from 34 COVID-19 patients and 15 healthy subjects using the BD FACSLyricTM Flow Cytometry System. The mHLA-DR examination results were expressed in AB/C (antibodies bound per cell) that were quantified using a standard curve constructed with Quantibrite phycoerythrin beads (BD Biosciences). RESULTS: Expression of mHLA-DR in COVID-19 patients (n = 34) were 21,201 [2,646-92,384] AB/C, with 40,543.5 [9,797-92,384] AB/C mild cases (n = 22), 21,201 [9,831-31,930] AB/C moderate cases (n = 6), and 7,496 [2,646-13,674] AB/C severe to critical cases (n= 6). Expression of mHLA-DR in healthy subjects (n = 15) was 43,161 [25,147-89,846] AB/C. Based on the Mann-Whitney U test, the mHLA-DR expression in COVID-19 patients significantly differed from the mHLA-DR expression in healthy subjects (p = 0.010). CONCLUSION: The level of mHLA-DR expression in COVID-19 patients was lower and significantly different from healthy subjects. Moreover, immunosuppression could be indicated by the decrease of mHLA-DR expression, which was below the reference range found in severe to critically ill COVID-19 patients.

Dynamic LTR retrotransposon transcriptome landscape in septic shock patients.

BACKGROUND: Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. Numerous studies have explored the complex and dynamic transcriptome modulations observed in sepsis patients, but a large fraction of the transcriptome remains unexplored. This fraction could provide information to better understand sepsis pathophysiology. Multiple levels of interaction between human endogenous retroviruses (HERV) and the immune response have led us to hypothesize that sepsis is associated with HERV transcription and that HERVs may contribute to a signature among septic patients allowing stratification and personalized management. METHODS: We used a high-density microarray and RT-qPCR to evaluate the HERV and Mammalian Apparent Long Terminal Repeat retrotransposons (MaLR) transcriptome in a pilot study that included 20 selected septic shock patients, stratified on mHLA-DR expression, with samples collected on day 1 and day 3 after inclusion. We validated the results in an unselected, independent cohort that included 100 septic shock patients on day 3 after inclusion. We compared septic shock patients, according to their immune status, to describe the transcriptional HERV/MaLR and conventional gene expression. For differential expression analyses, moderated t tests were performed and Wilcoxon signed-rank tests were used to analyze RT-qPCR results. RESULTS: We showed that 6.9% of the HERV/MaLR repertoire was transcribed in the whole blood, and septic shock was associated with an early modulation of a few thousand of these loci, in comparison to healthy volunteers. We provided evidence that a subset of HERV/MaLR and conventional genes were differentially expressed in septic shock patients, according to their immune status, using monocyte HLA-DR (mHLA-DR) expression as a proxy. A group of 193 differentially expressed HERV/MaLR probesets, tested in an independent septic shock cohort, identified two groups of patients with different immune status and severity features. CONCLUSION: We demonstrated that a large, unexplored part of our genome, which codes for HERV/MaLR, may be linked to the host immune response. The identified set of HERV/MaLR probesets should be evaluated on a large scale to assess the relevance of these loci in the stratification of septic shock patients. This may help to address the heterogeneity of these patients.

Monocytic HLA-DR expression kinetics in septic shock patients with different pathogens, sites of infection and adverse outcomes.

BACKGROUND: Decreased monocytic (m)HLA-DR expression is the most studied biomarker of sepsis-induced immunosuppression. To date, little is known about the relationship between sepsis characteristics, such as the site of infection, causative pathogen, or severity of disease, and mHLA-DR expression kinetics. METHODS: We evaluated mHLA-DR expression kinetics in 241 septic shock patients with different primary sites of infection and pathogens. Furthermore, we used unsupervised clustering analysis to identify mHLA-DR trajectories and evaluated their association with outcome parameters. RESULTS: No differences in mHLA-DR expression kinetics were found between groups of patients with different sites of infection (abdominal vs. respiratory, p = 0.13; abdominal vs. urinary tract, p = 0.53) and between pathogen categories (Gram-positive vs. Gram-negative, p = 0.54; Gram-positive vs. negative cultures, p = 0.84). The mHLA-DR expression kinetics differed between survivors and non-survivors (p < 0.001), with an increase over time in survivors only. Furthermore, we identified three mHLA-DR trajectories ('early improvers', 'delayed or non-improvers' and 'decliners'). The probability for adverse outcome (secondary infection or death) was higher in the delayed or non-improvers and decliners vs. the early improvers (delayed or non-improvers log-rank p = 0.03, adjusted hazard ratio 2.0 [95% CI 1.0-4.0], p = 0.057 and decliners log-rank p = 0.01, adjusted hazard ratio 2.8 [95% CI 1.1-7.1], p = 0.03). CONCLUSION: Sites of primary infection or causative pathogens are not associated with mHLA-DR expression kinetics in septic shock patients. However, patients showing delayed or no improvement in or a declining mHLA-DR expression have a higher risk for adverse outcome compared with patients exhibiting a swift increase in mHLA-DR expression. Our study signifies that changes in mHLA-DR expression over time, and not absolute values or static measurements, are of clinical importance in septic shock patients.

Persistent NLRP3 inflammasome activation is associated with delayed immunosuppression in septic patients.

Sepsis triggers a complex response marked by the simultaneous presence of proinflammatory and immunosuppressive elements, disrupting the mechanisms intended to maintain homeostasis. While the NLRP3 inflammasome has been demonstrated to contribute to the inflammatory side, its connection with delayed sepsis-induced immunosuppression remains unexplored. The present objective was to concomitantly and prospectively assess NLRP3 activation (IL-1ß, IL-18, and soluble receptors) and features of immune failure (IL-10, mHLA-DR, myeloid-derived suppressor cells) in septic patients. To validate our findings, we conducted a transcriptomic analysis of mRNA of NLRP3-related genes (IL-18R1, IL-1R2) on an additional cohort of 107 patients. Two distinct endotypes were identified. One cluster displayed moderate inflammation rapidly returning to normal values, while the other exhibited a higher inflammatory response persisting until day 28, which was associated with persistent marked immunosuppression and higher 28-d mortality. Identifying endotypes with different pro/anti-inflammatory trajectories could hold important clinical implications for the management of sepsis.

Association of pronounced elevation of NET formation and nucleosome biomarkers with mortality in patients with septic shock.

BACKGROUND: Understanding the mechanisms underlying immune dysregulation in sepsis is a major challenge in developing more individualized therapy, as early and persistent inflammation, as well as immunosuppression, play a significant role in pathophysiology. As part of the antimicrobial response, neutrophils can release extracellular traps (NETs) which neutralize and kill microorganisms. However, excessive NETs formation may also contribute to pathogenesis, tissue damage and organ dysfunction. Recently, a novel automated assay has been proposed for the routine measurement of nucleosomes H3.1 (fundamental units of chromatin) that are released during NETs formation. The aim of the present study was to measure nucleosome levels in 151 septic shock patients (according to sepsis-3 definition) and to determine association with mortality. RESULTS: The nucleosome H3.1 levels (as determined by a chemiluminescence immunoassay performed on an automated immunoanalyzer system) were markedly and significantly elevated at all-time points in septic shock patients compared to the control group. Immunological parameters indicated tremendous early inflammation (IL-6 = 1335 pg/mL at day 1-2) along with marked immunosuppression (e.g., mHLA-DR = 3853 AB/C and CD4 = 338 cell /µL at day 3-4). We found significantly positive correlation between nucleosome levels and organ failure and severity scores, IL-6 concentrations and neutrophil count. Significantly higher values (day 1-2 and 3-4) were measured in non-survivor patients (28-day mortality). This association was still significant after multivariate analysis and was more pronounced with highest concentration. Early (day 1-2) increased nucleosome levels were also independently associated with 5-day mortality. At day 6-8, persistent elevated nucleosome levels were negatively correlated to mHLA-DR values. CONCLUSIONS: This study reports a significant elevation of nucleosome in patients during a one-week follow-up. The nucleosome levels showed correlation with neutrophil count, IL-6 and were found to be independently associated with mortality assessed at day 5 or 28. Therefore, nucleosome concentration seems to be a promising biomarker for detecting hyper-inflammatory phenotype upon a patient's admission. Additional investigations are required to evaluate the potential association between sustained elevation of nucleosome and sepsis-induced immunosuppression.

Quantitation of mHLA-DR and nCD64 by Flow Cytometry to Study Dysregulated Host Response: The Use of QuantiBRITE™ PE Beads and Its Stability.

Quantitation of mHLA-DR and nCD64 is useful in understanding the dysregulated host response. The down regulation of HLA-DR expression on the circulating monocytes (mHLA-DR) is associated with anti-inflammatory response, and an increased expression of CD64 on neutrophil surface (nCD64) is associated with pro-inflammatory response. Quantitation of these antigen expression using beads (QuantiBRITE™ PE) is a precision technique. These beads are reported to be stable for 24 h after reconstitution. We report the results of our investigation examining the stability of QuantiBRITE PE beads over a period of 4-week post-reconstitution. The data suggest that reconstituted QuantiBRITE PE beads, if stored in dark at 2-8 °C, can be effectively used for up to 2 weeks for determining nCD64 and mHLA-DR antibody bound per cell (ABC) values.

Standardization of neutrophil CD64 and monocyte HLA-DR measurement and its application in immune monitoring in kidney transplantation.

Background: Infections cause high mortality in kidney transplant recipients (KTRs). The expressions of neutrophil CD64 (nCD64) and monocyte HLA-DR (mHLA-DR) provide direct evidence of immune status and can be used to evaluate the severity of infection. However, the intensities of nCD64 and mHLA-DR detected by flow cytometry (FCM) are commonly measured by mean fluorescence intensities (MFIs), which are relative values, thus limiting their application. We aimed to standardize nCD64 and mHLA-DR expression using molecules of equivalent soluble fluorochrome (MESF) and to explore their role in immune monitoring for KTRs with infection. Methods: The study included 50 KTRs diagnosed with infection, 65 immunologically stable KTRs and 26 healthy controls. The blood samples were collected and measured simultaneously by four FCM protocols at different flow cytometers. The MFIs of nCD64 and mHLA-DR were converted into MESF by Phycoerythrin (PE) Fluorescence Quantitation Kit. The intraclass correlation coefficients (ICCs) and the Bland-Altman plots were used to evaluate the reliability between the four FCM protocols. MESFs of nCD64 and mHLA-DR, nCD64 index and sepsis index (SI) with the TBNK panel were used to evaluate the immune status. Comparisons among multiple groups were performed with ANOVA one-way analysis. Receiver operating characteristics (ROC) curve analysis was performed to diagnose infection or sepsis. Univariate and multivariate logistic analysis examined associations of the immune status with infection. Results: MESFs of nCD64 and mHLA-DR measured by four protocols had excellent reliability (ICCs 0.993 and 0.957, respectively). The nCD64, CD64 index and SI in infection group were significantly higher than those of stable KTRs group. Patients with sepsis had lower mHLA-DR but higher SI than non-sepsis patients. ROC analysis indicated that nCD64 had the highest area under the curve (AUC) for infection, and that mHLA-DR had the highest AUC for sepsis. Logistic analysis indicated that nCD64 > 3089 and B cells counts were independent risk factors for infection. Conclusion: The standardization of nCD64 and mHLA-DR made it available for widespread application. MESFs of nCD64 and mHLA-DR had good diagnostic performance on infection and sepsis, respectively, which could be promising indicators for immune status of KTRs and contributed to individualized treatment.

Utility of Monocyte Expression of HLA-DR versus T Lymphocyte Frequency in the Assessment of COVID-19 Outcome.

Background: Dysregulated immunity is a hallmark of SARS-CoV-2 infection. Immune suppression is indicated by low monocyte expression of human leukocyte antigen D-related (mHLA-DR). T cells are important antiviral cells. We aimed to assess the role of mHLA-DR and T lymphocyte frequency in predicting COVID-19 severity. Patients and Methods: This cross-sectional study enrolled 97 SARS-CoV-2 positive patients, including mild to moderate (n = 49) and severe cases admitted to intensive care unit (ICU) (n = 48). These ICU cases were further subdivided into survivors (n = 35) and non-survivors (n = 13). Results: Severe cases had a significant decrease in the mHLA-DR mean fluorescence intensity (MFI) and T lymphocyte percentage compared to mild to moderate cases (P<0.001). Non-survivors had a lower T lymphocyte percentage (P=0.004) than survivors. The mHLA-DR MFI and T lymphocyte percentage correlated with oxygen saturation (r=0.632, P<0.001) and (r=0.669, P<0.001), respectively. According to the ROC curves, mHLA-DR MFI, at a cutoff of 143 and an AUC of 0.9, is a reliable biomarker for distinguishing severe COVID-19 cases, with 89.6% sensitivity and 81.6% specificity, while T lymphocyte frequency had 81.3% sensitivity and 81.6% specificity at a cutoff of 54.4% and an AUC of 0.9. The T lymphocyte percentage as a predictor of ICU survival at a cutoff of 38.995% exhibited 100% sensitivity and 57.1% specificity. According to multivariate regression analysis, reduced mHLA-DR MFI and T lymphocyte percentage are independent predictors of COVID-19 severity (OR = 0.976, 95% CI: 0.955-0.997, P = 0.025) and (OR = 0.849, 95% CI: 0.741-0.972, P = 0.018), respectively. Conclusion: Reduced mHLA-DR expression and T-lymphocyte percentage are independent predictors of COVID-19 severity. Oxygen saturation percentage is correlated with mHLA-DR MFI and T lymphocyte frequency. The T lymphocyte frequency is a proposed predictor of COVID-19 survival in ICU admitted patients.

Monocyte human leukocyte antigen-DR but not ß-D-glucan may help early diagnosing invasive Candida infection in critically ill patients.

BACKGROUND: Precision medicine risk stratification is desperately needed to both avoid systemic antifungals treatment delay and over prescription in the critically ill with risk factors. The aim of the present study was to explore the combination of host immunoparalysis biomarker (monocyte human leukocyte antigen-DR expression (mHLA-DR)) and Candida sp wall biomarker ß-D-glucan in risk stratifying patients for secondary invasive Candida infection (IC). METHODS: Prospective observational study. Two intensive care units (ICU). All consecutive non-immunocompromised septic shock patients. Serial blood samples (n = 286) were collected at day 0, 2 and 7 and mHLA-DR and ß-D-glucan were then retrospectively assayed after discharge. Secondary invasive Candida sp infection occurrence was then followed at clinicians' discretion. RESULTS: Fifty patients were included, 42 (84%) had a Candida score equal or greater than 3 and 10 patients developed a secondary invasive Candida sp infection. ICU admission mHLA-DR expression and ß-D-glucan (BDG) failed to predict secondary invasive Candida sp infection. Time-dependent cause-specific hazard ratio of IC was 6.56 [1.24-34.61] for mHLA-DR < 5000 Ab/c and 5.25 [0.47-58.9] for BDG > 350 pg/mL. Predictive negative value of mHLA-DR > 5000 Ab/c and BDG > 350 pg/mL combination at day 7 was 81% [95% CI 70-92]. CONCLUSIONS: This study suggests that mHLA-DR may help predicting IC in high-risk patients with septic shock. The added value of BDG and other fungal tests should be regarded according to the host immune function markers.

Case Report: Interferon- γ Rescues Monocytic Human Leukocyte Antigen Receptor (mHLA-DR) Function in a COVID-19 Patient With ARDS and Superinfection With Multiple MDR 4MRGN Bacterial Strains.

Background: CD14+ monocytes present antigens to adaptive immune cells via monocytic human leukocyte antigen receptor (mHLA-DR), which is described as an immunological synapse. Reduced levels of mHLA-DR can display an acquired immune defect, which is often found in sepsis and predisposes for secondary infections and fatal outcomes. Monocytic HLA-DR expression is reliably induced by interferon- γ (IFNγ) therapy. Case Report: We report a case of multidrug-resistant superinfected COVID-19 acute respiratory distress syndrome (ARDS) on extracorporeal membrane oxygenation (ECMO) support. The resistance profiles of the detected Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii and Citrobacter freundii isolates were equipped with resistance to all four antibiotic classes including carbapenems (4MRGN) and Cefiderocol in the case of K. pneumoniae. A causal therapeutic antibiotic strategy was not available. Therefore, we measured the immune status of the patient aiming to identify a potential acquired immune deficiency. Monocyte HLA-DR expression identified by FACS analysis revealed an expression level of 34% positive monocytes and suggested severe immunosuppression. We indicated IFNγ therapy, which resulted in a rapid increase in mHLA-DR expression (96%), rapid resolution of invasive bloodstream infection, and discharge from the hospital on day 70. Discussion: Superinfection is a dangerous complication of COVID-19 pneumonia, and sepsis-induced immunosuppression is a risk factor for it. Immunosuppression is expressed by a disturbed antigen presentation of monocytes to cells of the adaptive immune system. The case presented here is remarkable as no validated antibiotic regimen existed against the detected bacterial pathogens causing bloodstream infection and severe pneumonia in a patient suffering from COVID-19 ARDS. Possible restoration of the patient's own immunity by IFNγ was a plausible option to boost the patient's immune system, eliminate the identified 4MRGNs, and allow for lung recovery. This led to the conclusion that immune status monitoring is useful in complicated COVID-19-ARDS and that concomitant IFNγ therapy may support antibiotic strategies. Conclusion: After a compromised immune system has been detected by suppressed mHLA-DR levels, the immune system can be safely reactivated by IFNγ.

Myeloid phenotypes in severe COVID-19 predict secondary infection and mortality: a pilot study.

BACKGROUND: De-regulated host response to severe coronavirus disease 2019 (COVID-19), directly referring to the concept of sepsis-associated immunological dysregulation, seems to be a strong signature of severe COVID-19. Myeloid cells phenotyping is well recognized to diagnose critical illness-induced immunodepression in sepsis and has not been well characterized in COVID-19. The aim of this study is to review phenotypic characteristics of myeloid cells and evaluate their relations with the occurrence of secondary infection and mortality in patients with COVID-19 admitted in an intensive care unit. METHODS: Retrospective analysis of the circulating myeloid cells phenotypes of adult COVID-19 critically ill patients. Phenotyping circulating immune cells was performed by flow cytometry daily for routine analysis and twice weekly for lymphocytes and monocytes subpopulations analysis, as well as monocyte human leukocyte antigen (mHLA)-DR expression. RESULTS: Out of the 29 critically ill adult patients with severe COVID-19 analyzed, 12 (41.4%) developed secondary infection and six patients died during their stay. Monocyte HLA-DR kinetics was significantly different between patients developing secondary infection and those without, respectively, at day 5-7 and 8-10 following admission. The monocytes myeloid-derived suppressor cells to total monocytes ratio was associated with 28- and 60-day mortality. Those myeloid characteristics suggest three phenotypes: hyperactivated monocyte/macrophage is significantly associated with mortality, whereas persistent immunodepression is associated with secondary infection occurrence compared to transient immunodepression. CONCLUSIONS: Myeloid phenotypes of critically ill COVID-19 patients may be associated with development of secondary infection, 28- and 60-day mortality.

Early Immunoparalysis Was Associated with Poor Prognosis in Elderly Patients with Sepsis: Secondary Analysis of the ETASS Study.

PURPOSE: Although immune dysfunction has been investigated in adult septic patients, early immune status remains unclear. In this study, our primary aim was to assess early immune status in adult patients with sepsis stratified by age and its relevance to hospital mortality. PATIENTS AND METHODS: A post hoc analysis of a multicenter, randomized controlled trial was conducted; 273 patients whose immune status was evaluated within 48 hours after onset of sepsis were enrolled. Early immune status was evaluated by the percentage of monocyte human leukocyte antigen-DR (mHLA-DR) in total monocytes within 48 hours after onset of sepsis and it was classified as immunoparalysis (mHLA-DR ≤30%) or non-immunoparalysis (>30%). Three logistic regression models were conducted to explore the associations between early immunoparalysis and hospital mortality. We also developed two sensitivity analyses to find out whether the definition of early immune status (24 hours vs 48 hours after onset of sepsis) and immunotherapy affect the primary outcome. RESULTS: Of the 181 elderly (≥60yrs) and 92 non-elderly (<60yrs) septic patients, 71 (39.2%) and 25 (27.2%) died in hospital, respectively. The percentage of early immunoparalysis in the elderly was twice of that in the non-elderly patients (32% vs 16%, p=0.006). For the elderly, hospital mortality was higher in the immunoparalysis ones than the non-immunoparalysis ones (53.4% vs 32.5%, p=0.009). But there was no significant difference in hospital mortality between immunoparalysis non-elderly patients and non-immunoparalysis non-elderly ones (33.5% vs 26.0%, p=0.541). By means of logistic regression models, we found that early immunoparalysis was independently associated with increased hospital mortality in elderly, but not in non-elderly patients. Sensitivity analysis further confirmed the definition of early immune status and immunotherapy did not affect the outcomes. CONCLUSION: The elderly were more susceptible to early immunoparalysis after onset of sepsis. Early immunoparalysis was independently associated with poor prognosis in elderly, but not in non-elderly patients.

The role of neutrophil chemotaxis activity as an immunologic biomarker to predict mortality in critically-ill patients with severe sepsis.

BACKGROUND: Innate immunity is an important host response to infection. However, the role of innate immunity as a prognostic biomarker in severe sepsis is still unknown. This study is to evaluate the discriminatory characteristics of these biomarkers on clinical outcome. MATERIALS AND METHODS: Retrospective study was conducted in critically ill patients with severe sepsis. Neutrophil function was assessed by neutrophil chemotaxis activity and CD-11b expression. Monocyte function was assessed by measurement of mHLA-DR expression and presepsin level. The primary end point was 28 day-mortality. RESULTS: A total of 136 participants were enrolled. Patients were classified into 2 groups as survivors (n = 63, 46.3%) and non-survivors (n = 73, 53.7%). Neutrophil chemotaxis activity was significantly higher in survivors (46.7% vs. 41.2%, p = .023). There was no difference in the remaining biomarker levels between survivors and non-survivors. Only decreased neutrophil chemotaxis activity was associated with 28-day mortality. Combining neutrophil chemotaxis activity with mHLA-DR, CD-11b expression, presepsin, and SOFA score provided the highest AUC of 0.90 (0.84-0.96) in predicting 28-day mortality. CONCLUSION: Neutrophil chemotaxis activity appears to be a promising novel immunologic biomarker in predicting clinical outcome in patients with severe sepsis.

Effects of perioperative transcutaneous electrical acupoint stimulation on monocytic HLA-DR expression in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass: study protocol for a double-blind randomized controlled trial.

BACKGROUND: Cardiac surgery involving cardiopulmonary bypass (CPB) is known to be associated with a transient postoperative immunosuppression. When severe and persistent, this immune dysfunction predisposes patients to infectious complications, which contributes to a prolonged stay in the intensive care unit (ICU), and even mortality. Effective prevention and treatment methods are still lacking. Recent studies revealed that acupuncture-related techniques, such as electroacupuncture and transcutaneous electrical acupoint stimulation (TEAS), are able to produce effective cardioprotection and immunomodulation in adult and pediatric patients undergoing cardiac surgery with CPB, which leads to enhanced recovery. However, whether perioperative application of TEAS, a non-invasive technique, is able to improve immunosuppression of the patients with post-cardiosurgical conditions is unknown. Thus, as a preliminary study, the main objective is to evaluate the effects of TEAS on the postoperative expression of monocytic human leukocyte antigen (-D related) (mHLA-DR), a standardized "global" biomarker of injury or sepsis-associated immunosuppression, in patients receiving on-pump coronary artery bypass grafting (CABG). METHODS: This study is a single-center clinical trial. The 88 patients scheduled to receive CABG under CPB will be randomized into two groups: the group receiving TEAS, and the group receiving transcutaneous acupoint pseudo-electric stimulation (Sham TEAS). Expression of mHLA-DR serves as a primary endpoint, and other laboratory parameters (e.g., interleukin [IL]-6, IL-10) and clinical outcomes (e.g., postoperative infectious complications, ICU stay time, and mortality) as the secondary endpoints. In addition, immune indicators, such as high mobility group box 1 protein and regulatory T cells will also be measured. DISCUSSION: The current study is a preliminary monocentric clinical trial with a non-clinical primary endpoint, expression of mHLA-DR, aiming at determining whether perioperative application of TEAS has a potential to reverse CABG-associated immunosuppression. Although the immediate clinical impact of this study is limited, its results would inform further large-sample clinical trials using relevant patient-centered clinical outcomes as primary endpoints. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02933996. Registered on 13 October 2016.

Automated bedside flow cytometer for mHLA-DR expression measurement: a comparison study with reference protocol.

BACKGROUND: In various ICU conditions, measurement of diminished expression of human leukocyte antigen-DR on circulating monocytes (mHLA-DR) by flow cytometry appears to be a reliable marker of acquired immunosuppression. Low mHLA-DR is associated with an increased risk of nosocomial infections and mortality. Nevertheless, its use remains somewhat limited and has not been adopted in common medical practice. The main drawback of mHLA-DR measurement is likely related to the use of flow cytometry that is not accessible everywhere on a 24/7 basis. Recently, the Accellix system, a fully automated table top cytometer, was developed for use at bedside or emergency labs. METHODS: The objective was to assess the performance of the Accellix (beta site evaluation including repeatability and method comparison with reference protocol) for the measurement of mHLA-DR expression. RESULTS: Accellix repeatability at low and high expression levels of mHLA-DR was < 10% (i.e., within the range of acceptability for clinical flow cytometry). In comparison study including 139 blood samples (67 septic shock patients and 17 healthy volunteers), Pearson's correlation parameters (r 2) ranged from 0.71 to 0.97 (p < 0.001). Intra-class correlation coefficient was 0.92. CONCLUSIONS: This fully automated table top cytometer appears to be a suitable tool for ICU patient monitoring and on-going clinical trials as there is no sample preparation and no need for specific skills in flow cytometry. Upon validation in a larger cohort study to reinforce reliability, Accellix could represent a major step to make flow cytometry accessible to clinicians by placing the instrument inside intensive care units or emergency laboratories.

Assessment of immune organ dysfunction in critical illness: utility of innate immune response markers.

In critically ill patients, organ dysfunctions are routinely assessed, monitored, and treated. Mounting data show that substantial critical illness-induced changes in the immune system can be observed in most ICU patients and that not only "hyper-inflammation" but also persistence of an anti-inflammatory phenotype (as in sepsis-associated immunosuppression) is associated with increased morbidity and mortality. Despite common perception, changes in functional immunity cannot be adequately assessed by routine inflammatory biomarkers such as C-reactive protein, procalcitonin, or numerical analysis of leukocyte (sub)-counts. Cytokines appear also not suited due to their short half-life and pleiotropy, their unexclusive origin from immune cells, and their potential to undergo antagonization by circulating inactivating molecules. Thus, beyond leukocyte quantification and use of routine biomarkers, direct assessment of immune cell function seems required to characterize the immune systems' status. This may include determination of, e.g., ex vivo cellular cytokine release, phagocytosis activity, and/or antigen-presenting capacity. In this regard, standardized flow-cytometric assessment of the major histocompatibility-II complex human leukocyte antigen (-D related) (HLA-DR) has gained particular interest. Monocytic HLA-DR (mHLA-DR) controls the interplay between innate and adaptive immunity and may serve as a "global" biomarker of injury-associated immunosuppression, and its decreased expression is associated with adverse clinical outcomes (e.g., secondary infection risk, mortality). Importantly, recent data demonstrate that injury-associated immunosuppression can be reversed-opening up new therapeutic avenues in affected patients. Here we discuss the potential scientific and clinical value of assessment of functional immunity with a focus on monocytes/macrophages and review the current state of knowledge and potential perspectives for affected critically ill patients.

Predicting the Outcomes of Subjects With Severe Community-Acquired Pneumonia Using Monocyte Human Leukocyte Antigen-DR.

BACKGROUND: The objective was to study the level of monocyte-human leukocyte antigen-DR (mHLA-DR), an immune function-related biomarker, at 24 h after admission, to predict the outcomes of subjects with severe pneumonia. METHODS: Subjects with severe community-acquired pneumonia (n = 102) were included in the study. Blood samples were collected from each subject 24 h after admission. Data regarding age, sex, PaO2 /FIO2, comorbidities, occurrence of altered mental status, bacteremia, septic shock, Acute Physiology and Chronic Health Evaluation (APACHE) II score, and Sequential Organ Failure Assessment (SOFA) score within the first 24 h; the highest temperature within 24 h after admission; mechanical ventilation usage; timing of antibiotic therapy; ICU stay; and 28-d survival were collected. Expression of mHLA-DR was measured by flow cytometry. RESULTS: APACHE II score and SOFA score were significantly higher (P < .001), whereas the mHLA-DR expression was significantly lower (P < .001) in the non-survivors than in the survivors. The outcomes at day 28 after admission were significantly associated with the APACHE II score (P = .002, odds ratio [OR] = 1.27, 95% CI 1.10-1.48), the SOFA score (P = .003, OR = 1.52, 95% CI 1.15-2.00), and mHLA-DR level (P = .01, OR = 0.91, 95% CI 0.85-0.98), as shown by logistic regression. The area under the receiver operating characteristic curve was 0.877 (95% CI 0.81-0.94, P < .001), 0.862 (95% CI 0.79-0.93, P < .001), and 0.781 (95% CI 0.69-0.87, P < .001) for APACHE II score, SOFA score, and the mHLA-DR expression, respectively. The optimal threshold for mHLA-DR level was 27.2%. Kaplan-Meier survival analysis showed that subjects with mHLA-DR ≥ 27.2% had significantly better outcomes compared with < 27.2% level (P < .001, log rank test, hazard ratio = 0.963, 95% CI 0.94-0.99). CONCLUSIONS: mHLA-DR may be a reliable biomarker that can predict the outcomes of patients with severe community-acquired pneumonia, and 27.2% may be the cut-off value to predict the outcomes.