Low HLA-DR expression on peripheral blood monocytes predicts bacterial sepsis after liver transplantation: relation with prednisolone intake

Dampened Inflammatory Signalling and Myeloid-Derived Suppressor-Like Cell Accumulation Reduces Circulating Monocytic HLA-DR Density and May Associate With Malignancy Risk in Long-Term Renal Transplant Recipients

Background

Malignancy is a major cause of morbidity and mortality in transplant recipients. Identification of those at highest risk could facilitate pre-emptive intervention such as reduction of immunosuppression. Reduced circulating monocytic HLA-DR density is a marker of immune depression in the general population and associates with poorer outcome in critical illness. It has recently been used as a safety marker in adoptive cell therapy trials in renal transplantation. Despite its potential as a marker of dampened immune responses, factors that impact upon monocytic HLA-DR density and the long-term clinical sequelae of this have not been assessed in transplant recipients.

Methods

A cohort study of stable long-term renal transplant recipients was undertaken. Serial circulating monocytic HLA-DR density and other leucocyte populations were quantified by flow cytometry. Gene expression of monocytes was performed using the Nanostring nCounter platform, and 13-plex cytokine bead array used to quantify serum concentrations. The primary outcome was malignancy development during one-year follow-up. Risk of malignancy was calculated by univariate and multivariate proportionate hazards modelling with and without adjustment for competing risks.

Results

Monocytic HLA-DR density was stable in long-term renal transplant recipients (n=135) and similar to non-immunosuppressed controls (n=29), though was suppressed in recipients receiving prednisolone. Decreased mHLA-DRd was associated with accumulation of CD14+CD11b+CD33+HLA-DRlo monocytic myeloid-derived suppressor-like cells. Pathway analysis revealed downregulation of pathways relating to cytokine and chemokine signalling in monocytes with low HLA-DR density; however serum concentrations of major cytokines did not differ between these groups. There was an independent increase in malignancy risk during follow-up with decreased HLA-DR density.

Conclusions

Dampened chemokine and cytokine signalling drives a stable reduction in monocytic HLA-DR density in long-term transplant recipients and associates with subsequent malignancy risk. This may function as a novel marker of excess immunosuppression. Further study is needed to understand the mechanism behind this association.

Biomarkers of Immunosuppression

It is now recognized that sepsis is not a uniformly proinflammatory state. There is a well-recognized counter anti-inflammatory response that occurs in many patients. The timing and magnitude of this response varies considerably and thus makes its identification and manipulation more difficult. Studies in animals and humans have now identified a small number of biologic responses that characterize this immunosuppressed state, such as lymphocyte death, HLA receptor downregulation, and monocyte exhaustion. Researchers are now trying to use these as markers of individual immunosuppression to predict outcomes and identify patients who would and would not benefit from new immune stimulatory therapies.

Differences in Expression of Human Leukocyte Antigen Class II Subtypes and T Cell Subsets in Behçet's Disease with Arthritis

It has been reported Human Leukocyte Antigen (HLA) gene polymorphism is a risk factor for the development of Behçet’s disease (BD). In this study, the association of HLA class II subtypes HLA-DP, DQ, DR, and T cell subsets in BD patients with arthritis was evaluated. Frequencies of HLA-DP, DQ, DR positive cells, and T cell subsets in peripheral blood leukocytes (PBL) were measured by flow cytometric analysis in BD, and compared to rheumatoid arthritis as disease controls and healthy controls. Frequencies of HLA-DQ were significantly decreased in whole PBL and granulocytes of BD active patients as compared to healthy controls. In monocytes populations, proportions of HLA-DR positive cells were significantly increased in BD active patients as compared to healthy controls. Proportions of CD4+CCR7+ and CD8+CCR7+ cells were significantly higher in BD active patients than in BD inactive in whole PBL. Frequencies of CD4+CD62L- and CD8+CD62L- cells in lymphocytes were significantly decreased in active BD than those in inactive BD. There were also correlations between disease activity markers and T cell subsets. Our results revealed HLA-DP, DQ, and DR expressing cell frequencies and several T cell subsets were significantly correlated with BD arthritis symptoms.

The CD14+HLA-DRlo/neg Monocyte: An Immunosuppressive Phenotype That Restrains Responses to Cancer Immunotherapy

Recent successes in cancer immunotherapy have been tempered by sub-optimal clinical responses in the majority of patients. The impaired anti-tumor immune responses observed in these patients are likely a consequence of immune system dysfunction contributed to by a variety of factors that include, but are not limited to, diminished antigen presentation/detection, leukopenia, a coordinated network of immunosuppressive cell surface proteins, cytokines and cellular mediators. Monocytes that have diminished or no HLA-DR expression, called CD14⁺HLA-DR^lo/neg monocytes, have emerged as important mediators of tumor-induced immunosuppression. These cells have been grouped into a larger class of suppressive cells called myeloid derived suppressor cells (MDSCs) and are commonly referred to as monocytic myeloid derived suppressor cells. CD14⁺HLA-DR^lo/neg monocytes were first characterized in patients with sepsis and were shown to regulate the transition from the inflammatory state to immune suppression, ultimately leading to immune paralysis. These immunosuppressive monocytes have also recently been shown to negatively affect responses to PD-1 and CTLA-4 checkpoint inhibition, CAR-T cell therapy, cancer vaccines, and hematopoietic stem cell transplantation. Ultimately, the goal is to understand the role of these cells in the context of immunosuppression not only to facilitate the development of targeted therapies to circumvent their effects, but also to potentially use them as a biomarker for understanding disparate responses to immunotherapeutic regimens. Practical aspects to be explored for development of CD14⁺HLA-DR^lo/neg monocyte detection in patients are the standardization of flow cytometric gating methods to assess HLA-DR expression, an appropriate quantitation method, test sample type, and processing guidances. Once detection methods are established that yield consistently reproducible results, then further progress can be made toward understanding the role of CD14⁺HLA-DR^lo/neg monocytes in the immunosuppressive state.

Monocyte HLA-DR Assessment by a Novel Point-of-Care Device Is Feasible for Early Identification of ICU Patients With Complicated Courses-A Proof-of-Principle Study

Background: Critically ill patients, especially following trauma or extensive surgery, experience a systemic immune response, consisting of a pro-inflammatory as well as a counterbalancing anti-inflammatory response. Pro-inflammation is necessary for the initiation of homeostatic control and wound healing of the organism. However, when the counterbalancing mechanisms dominate, a condition of secondary immunodeficiency occurs, which renders the patient susceptible for opportunistic or secondary infections. However, the incidence of this condition is yet illusive.

Methods: For a period of 3 months (May to July 2017), 110 consecutive patients admitted to the surgical ICU of the Heidelberg University Hospital, a tertiary university hospital, were enrolled in the study. Monocyte HLA-DR (mHLA-DR), a long-known surrogate of monocyte function, was assessed quantitatively once on admission utilizing a novel point-of-care flow cytometer with single-use cartridges (Accelix system). Patients were followed up for further 28 days and data on ICU stay, antibiotic therapy, microbiological findings, and mechanical ventilation were recorded. Statistical analysis was performed to evaluate the incidence of immunosuppression—defined by different thresholds—as well as its consequence in terms of outcome and clinical course.

Results: Depending on the HLA-DR threshold applied for stratification (≤8,000/≤5,000/≤2,000 molecules/cell), a large group of patients (85.5/68.2/40.0%) already presented with a robust decrease of HLA-DR on admission, independent of the cause for critical illness. Analyzed for survival, neither threshold was able to stratify patients with a higher mortality. However, both thresholds of 2,000 and 5,000 were able to discriminate patients with longer ICU stay, ventilation time and duration of antibiotic therapy, as well as higher count of microbiological findings. Moreover, a mHLA-DR value ≤2,000 molecules/cell was associated with higher incidence of overall antibiotic therapy.

Conclusion: Single assessment of mHLA-DR using a novel point-of-care flow cytometer is able to stratify patients according to their risk of a complicated course. Therefore, this device overcomes the technical boundaries for measuring cellular biomarkers and paves the way for future studies involving personalized immunotherapy to patients with a high immunological risk profile independent of their background.

Trial Registration: German Clinical Trials Register; ID: DRKS00012348.

Increased Circulating T Lymphocytes Expressing HLA-DR in Kidney Transplant Recipients with Microcirculation Inflammation

We consecutively enrolled 82 kidney transplant recipients (KTRs) with stable renal function and 24 KTRs who underwent indication biopsy to compare the histological grading of renal allografts with the activity of circulating T lymphocyte subsets and monocytes determined by flow cytometry, which were obtained at 2 weeks after kidney transplantation (KT) and at the time of indication biopsy, respectively. The sum of the scores of glomerulitis (g) + peritubular capillaritis (ptc), inflammation (i) + tubulitis (t), interstitial fibrosis (ci) + tubular atrophy (ct), and fibrointimal thickening (cv) + arteriolar hyaline thickening (ah) was used to assign a histological grade to the renal allograft samples. The frequencies of CD4⁺HLA-DR⁺/CD4⁺ T cells and CD8⁺HLA-DR⁺/CD8⁺ T cells were significantly increased in KTRs with a microcirculation inflammation (MI) sum score ≥ 1 when compared with KTRs with an MI sum score = 0 as well as stable KTRs. In these 2 subsets, only CD4⁺HLA-DR⁺/CD4⁺ T cells were positively correlated with MI sum scores. Analysis using the receiver operating characteristic (ROC) curve showed that antibody-mediated rejection (AMR) could be predicted with a sensitivity of 80.0% and a specificity of 94.7%, using a cutoff value of 29.6% frequency of CD4⁺HLA-DR⁺/CD4⁺ T cells. MI was significantly associated with an increased frequency of activated T lymphocytes expressing human leukocyte antigen-antigen D related (HLA-DR). Further studies should focus on validating the utility of circulating CD4⁺HLA-DR⁺/CD4⁺ T cells as a noninvasive, immunologic monitoring tool for the prediction of AMR.

Low-Dose Steroid Therapy Is Associated with Decreased IL-12 Production in PBMCs of Severe Septic Patients

Background. Sepsis-induced immunosuppression may result in higher mortality rates in patients. Methods. We examined the relationship of cytokine responses from stimulated peripheral blood mononuclear cells (PBMCs) and monocyte human leukocyte antigen-DR (HLA-DR) expression (days 1 and 7) with low-dose steroid therapy in 29 septic patients. Patients were treated according to the guidelines. Thirty healthy controls were enrolled for validation. Results. Eighteen patients were prescribed low-dose steroids and 11 were not. Interleukin- (IL-) 12 responses in patients without low-dose steroid therapy on days 1 and 7 were higher than those with low-dose steroid therapy. Compared to day 1, IL-12 responses significantly increased on day 7 in patients without low-dose steroid therapy. After regression analysis, the change in the IL-12 response from day 7 to day 1 was found to be independently associated with the low-dose steroid therapy. There was no difference in monocyte HLA-DR expression between patients treated with and without low-dose steroid on day 1 or 7. No change in monocyte HLA-DR expression from day 7 to day 1 was observed in patients with or without low-dose steroid therapy. Conclusion. Decreased IL-12 response was associated with the low-dose steroid therapy in PBMCs of septic patients.

Inflammation and innate immune function in critical illness

PURPOSE OF REVIEW

The purpose of review is to highlight the inflammatory response in critical illness and the importance of immune monitoring and modulation in the diagnosis and treatment of critical illness-induced innate immune suppression.

RECENT FINDINGS

The pro and anti-inflammatory responses are known to be concurrently activated in many patients requiring intensive care, with innate immune suppression emerging as an important, and potentially reversible, complication of critical illness.

SUMMARY

The initial inflammatory response to critical illness is typically driven by innate immune cells, including neutrophils, monocytes, and macrophages. The proinflammatory mediators made by these cells are responsible for many of the pathophysiologic features of critical illness. Concurrent with this, however, is a compensatory anti-inflammatory response, including the elaboration of anti-inflammatory mediators and impairment of innate immune cell function. This includes reduction of monocyte human leukocyte antigen-DR expression and impairment of the ability of innate immune cells to produce tumor necrosis factor alpha when stimulated ex vivo. In its most severe form this is referred to as immunoparalysis, and is associated with markedly increased risks for secondary infection and death in the ICU. Prospective testing can detect this phenomenon, and immunostimulatory strategies, including the use of granulocyte macrophage-colony stimulating factor, have the potential to restore innate immune function in this setting.

Immunologic Monitoring of T-Lymphocyte Subsets and Hla-Dr-Positive Monocytes in Kidney Transplant Recipients: A Prospective, Observational Cohort Study

The clinical significance of circulating T-lymphocyte subsets and human leukocyte antigen (HLA)-DR-positive monocytes in the peripheral blood of kidney transplant recipients (KTRs) remains unclear. We examined the efficacy of enumerating these cells for the immunologic monitoring of KTRs.Blood samples were obtained before transplantation, 2 weeks after transplantation and at diagnosis, and 2 weeks after treating biopsy-proven acute cellular rejection and cytomegalovirus (CMV) infection. Serial flow cytometric analysis was performed using peripheral blood obtained from 123 patients to identify the frequencies of HLA-DR, CD3, CD4, CD8, and CD25 T-lymphocytes and HLA-DR-positive monocytes.Frequencies of CD4CD25/CD4 T cells, CD8CD25/CD8 T cells, and HLA-DR-positive monocytes were significantly lower at 2 weeks after transplantation than before transplantation (all P < 0.001). This decrease was not correlated with clinical parameters. The frequency of CD4CD25/CD4 T cells was significantly higher in KTRs with acute rejection than in KTRs at 2 weeks after transplantation (9.10% [range 4.30-25.6%] vs 5.10% [range 0.10-33.3%]; P = 0.024). However, no significant differences were observed between stable KTRs and KTRs with CMV infection. Analysis of the receiver operating characteristic curve adjusted by covariates showed that acute rejection could be predicted with 75.0% sensitivity and 68.4% specificity by setting the cutoff value of CD4CD25/CD4 T cell frequency as 5.8%.Circulating T-lymphocyte and monocyte subsets showed significant and consistent changes in their frequencies after immunosuppression. Of the various immune cells examined, circulating levels of CD4CD25 T cells might be a useful noninvasive immunologic indicator for detecting acute rejection.

Effect of delayed CNI-based immunosuppression with Advagraf® on liver function after MELD-based liver transplantation [IMUTECT]

BACKGROUND

MELD-based allocation for liver transplantation follows the "sickest-patient-first" strategy. The latter patients present with both, decreased immune competence and poor kidney function which is further impaired by immunosuppressants.

METHODS/DESIGN

In this prospective observational study, 50 patients with de novo low-dose standard Advagraf®-based immunosuppression consisting of Advagraf®, Mycophenolat-mofetil and Corticosteroids after liver transplantation will be evaluated. Advagraf® trough levels of 7-10 μg/l will be reached at the end of the first postoperative week. Immunostatus, infectious complications, graft and kidney function are compared between patients with a pretransplant calculated MELD-score of ≤20 and >20. Each group comprises of 25 consecutive patients. Prior to liver transplantation and on the postoperative days 1, 3 and 7, the patients' graft function (LiMAx test) will be evaluated. On the postoperative days 3, 5 and 7 the patients' immune status will be evaluated by the measurement of their monocytic HLA-DR status.Infectious complications (CMV-reactivation, wound infection, urinary tract infection, and pneumonia), graft- and kidney function will be analysed on day 0, within the first week, and 1, 3, 6, 9 and 12 months after liver transplantation.

DISCUSSION

This study was designed to assess the effect of a standard low-dose Calcineurin inhibitor-based immunosuppression regime with Advagraf® on the rate of infectious complications, graft and renal function after liver transplantation.

TRIAL REGISTRATION

The trial is registered at "Clinical Trials" (http://www.clinicaltrials.gov), NCT01781195.

Duration and magnitude of hypotension and monocyte deactivation in patients with community-acquired pneumonia

The objective was to examine the relationship of duration and magnitude of arterial hypotension to subsequent cellular immune suppression and cytokinemia in patients hospitalized with community-acquired pneumonia (CAP). We studied an observational cohort of 525 subjects hospitalized after presenting to the emergency department with radiographic and clinical signs of CAP. We compared the duration and magnitude of hypotension, using the cardiovascular Sequential Organ Failure Assessment (CV SOFA) subscore, to day 3 monocyte expression of human leukocyte antigen-DR (mHLA-DR), a previously validated marker of cellular immune suppression. A significant association of CV SOFA with decreased mHLA-DR expression was present in univariate analysis (P < 0.001) and persisted after adjustment for illness severity and other covariates (P = 0.01). With CV SOFA separated into components of magnitude and duration, after covariate adjustment, only duration was associated with day 3 mHLA-DR expression (P = 0.03). Levels of key proinflammatory and anti-inflammatory cytokines (interleukin 6 [IL-6], IL-10, tumor necrosis factor) increased with hypotension exposure and were also associated with mHLA-DR expression. In patients admitted with CAP, arterial hypotension over the first 3 days is associated with markers of monocyte deactivation. The duration of exposure to hypotension may be more important than the magnitude, and monocyte deactivation correlates with IL-6 and IL-10 release. These results suggest that persistent hypotension might contribute to immunosuppression following septic shock.

Increased CD64 expression on polymorphonuclear neutrophils indicates infectious complications following solid organ transplantation

The aim of this study was to evaluate the diagnostic value of monitoring CD64 antigen upregulation on polymorphonuclear neutrophils (PMN) for the identification of infectious complications in the postoperative course of solid organ transplanted patients. Twenty-five kidney, 13 liver, and four pancreas-kidney transplanted patients were included. Beginning with preoperative values up to postoperative values after 3 months for each patient, the PMN CD64 Index, HLA-DR on monocytes, NKp44+ NK and NK/T cells, CXCR3+ NK cells, CXCR3+ T helper cells, CXCR3+ NK/T cells, and CD4/CD8 ratio were measured by flow cytometry. Subsequently they were correlated with confirmed postoperative complications. Measuring the PMN CD64 Index reached a sensitivity of 89% and a specificity of 65% in the detection of infectious complications. Concerning this matter, it was a significantly better marker than all other included parameters except CXCR3+ NK/T cells. In contrast, according to our results the PMN CD64 Index has no diagnostic relevance in detection of rejections. The combination of included parameters showed no improved diagnostic value. Due to its high sensitivity and specificity for infectious complications CD64 on PMN could be proven a very good indicator in evaluating suspected infectious complications in the postoperative course of transplanted patients.

Immune perturbations in patients along the perioperative period: alterations in cell surface markers and leukocyte subtypes before and after surgery

BACKGROUND

Surgery renders patients susceptible to life-threatening complications, including infections, multiple organ failure, and presumably cancer metastases. Surgery-induced immune perturbations were suggested to contribute to such deleterious effects, but also to facilitate post-injury healing. Preoperative psychological and physiological stress responses may contribute to these immune perturbations, and could thus jeopardize patients even before surgery. The current study assessed the effects of various operations on an array of immune indices during the perioperative period. To qualify immune changes before surgery, patients' immune status was also compared to that of healthy controls.

METHODS

A total of 81 subjects (operated patients and healthy controls) provided up to five daily blood samples during the perioperative period, for assessment of leukocyte subtypes (granulocytes, monocytes, Tc, Th, NK, NKT, CD4+CD25+, CD8(bright)CD4(dim), and B cells) and their surface markers (HLA-DR and LFA-1).

RESULTS

Even before surgery patients displayed immune perturbations, including reduced lymphocyte HLA-DR expression and increased monocyte LFA-1 expression. Following surgery, we recorded a reduction in lymphocyte numbers that was subtype specific, increased granulocyte numbers, and reduced expression of HLA-DR by lymphocytes and monocytes. Finally, no significant associations were found between alteration in leukocyte numbers and cell surface markers (although these indices showed high correlations with other variables), implying differential mediating mechanisms.

CONCLUSION

Several immune alterations are manifested prior to surgery, and contribute to the marked postoperative changes, which are commonly interpreted as immune suppression. We discuss the possible adaptive and maladaptive nature of these perturbations in the context of natural injury, stress, and surgery.

Perioperative gene expression analysis for prediction of postoperative sepsis

BACKGROUND

Postoperative sepsis is one of the main causes of death after major abdominal surgery; however, the immunologic factors contributing to the development of sepsis are not completely understood. In this study, we evaluated gene expression in patients who developed postoperative sepsis and in patients with an uncomplicated postoperative course.

METHODS

We enrolled 220 patients in a retrospective matched-pair, case-control pilot study to investigate the perioperative expression of 23 inflammation-related genes regarding their properties for predicting postoperative sepsis. Twenty patients exhibiting symptoms of sepsis in the first 14 days after surgery (case group) were matched with 20 control patients with an uncomplicated postoperative course. Matching criteria were sex, age, main diagnosis, type of surgery, and concomitant diseases. Blood samples were drawn before surgery and on the first and second postoperative days. Relative gene expression was analyzed with real-time reverse-transcription PCR.

RESULTS

Significant differences (P < 0.005) in gene expression between the 2 groups were observed for IL1B (interleukin 1, beta), TNF [tumor necrosis factor (TNF superfamily, member 2)], CD3D [CD3d molecule, delta (CD3-TCR complex)], and PRF1 [perforin 1 (pore forming protein)]. Logistic regression analysis and a subsequent ROC curve analysis revealed that the combination of TNF, IL1B, and CD3D expression had a specificity and specificity of 90% and 85%, respectively, and predicted exclusion of postoperative sepsis with an estimated negative predictive value of 98.1%.

CONCLUSIONS

These data suggest that gene expression analysis may be an effective tool for differentiating patients at high and low risk for sepsis after abdominal surgery.

The compensatory anti-inflammatory response syndrome (CARS) in critically ill patients

Like the systemic inflammatory response syndrome (SIRS), the compensatory anti-inflammatory response syndrome (CARS) is a complex pattern of immunologic responses to severe infection or injury. The difference is that while SIRS is a proinflammatory response tasked with killing infectious organisms through activation of the immune system, CARS is a global deactivation of the immune system tasked with restoring homeostasis. Much research now suggests that the timing and relative magnitude of this response have a profound impact on patient outcomes.

The importance of immune dysfunction in determining outcome in acute liver failure

Acute liver failure (ALF) shares striking similarities with septic shock with regard to the features of systemic inflammation, progression to multiple organ dysfunction and functional immunoparesis. While the existence of opposing systemic pro- and anti-inflammatory profiles resulting in organ failure and immune dysfunction are well recognised in septic shock, characterization of these processes in ALF has only recently been described. This review explores the evolution of the systemic inflammation in acute liver failure, its relation to disease progression, exacerbation of liver injury and development of innate immune dysfunction and extra-hepatic organ failure as sequelae. Defects in innate immunity are described in hepatic and extra-hepatic compartments. Clinical studies measuring levels of pro- and anti-inflammatory cytokines and expression of the antigen presentation molecule HLA-DR on monocytes, in combination with ex-vivo experiments, demonstrate that the persistence of a compensatory anti-inflammatory response syndrome, leading to functional monocyte deactivation, is a central event in the evolution of systemic immune dysfunction. Accurate immune profiling in ALF may permit the development of immunomodulatory strategies in order to improve outcome in this condition.

Monitoring immune dysfunctions in the septic patient: a new skin for the old ceremony

Septic syndromes represent a major although largely underrecognized healthcare problem worldwide, accounting for thousands of deaths every year. It is now agreed that sepsis deeply perturbs immune homeostasis by inducing an initial tremendous systemic inflammatory response which is accompanied by an antiinflammatory process, acting as negative feedback. This compensatory inhibitory response secondly becomes deleterious as nearly all immune functions are compromised. These alterations might be directly responsible for worsening outcome, as they may play a major role in the decreased resistance to nosocomial infections in patients who survived initial resuscitation. Consequently, immunostimulatory therapies may now be assessed for the treatment of sepsis. This review focuses on immune dysfunctions described in septic patients and on their potential use as markers on a routine standardized basis for prediction of adverse outcome or of occurrence of secondary nosocomial infections. This constitutes a prerequisite to a staging system for individualized treatment for these hitherto deadly syndromes.

Decreased monocyte human leukocyte antigen-DR expression after severe burn injury: Correlation with severity and secondary septic shock

OBJECTIVE

Severe thermal injury causes immune dysfunctions involving both pro- and anti-inflammatory mechanisms. It subsequently leads to a state of immune deficiency that shares some similarities with sepsis-induced immunosuppression. A hallmark of the latter is established by decreased monocyte human leukocyte antigen-DR (mHLA-DR) measurements. The main objective of the current study was to characterize the appearance and the duration of low mHLA-DR expression after severe burn as well as to determine its correlation with mortality and septic complications.

DESIGN

Observational study.

SETTING

Burn unit (intensive care unit) in a university hospital.

PATIENTS

Severe burn patients (total burn surface area >30%, n = 14) and healthy individuals (n = 29).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were immunologically monitored during 15 days. We quantified mHLA-DR expression with a standardized flow cytometry protocol. Every patient presented with decreased mHLA-DR expression at days 2-3 after burn. Then, from days 4-6, this expression increased in patients who would survive whereas it remained low in nonsurvivors. As early as days 7-10 after burn, patients who were going to develop secondary septic shock exhibited significantly lower mHLA-DR expression in comparison with patients recovering without severe septic complications. Using quantitative reverse transcriptase-polymerase chain reaction, at days 4-6, we found that the RNA level of the nonpolymorphic HLA-DRA chain and the transcription factor class II transactivator were also significantly decreased compared with healthy controls; however, plasma cytokines (interleukin-6, tumor necrosis factor-alpha, and interleukin-10) did not provide any significant prognostic information.

CONCLUSIONS

Severe burn injury induced a marked reduction in mHLA-DR expression at both protein and messenger RNA levels. Its persistent decrease was associated with mortality and the development of septic complications.

Endotoxemia contributes to the immune paralysis in patients with cirrhosis

BACKGROUND/AIMS

Immune paralysis, defined as decreased HLA-DR expression on monocytes and indicated immune dysfunctions, was found in sepsis, severe acute pancreatitis and acute liver failure. However, the relationship between HLA-DR expression and cirrhosis is unclear.

METHODS

We enrolled 64 patients with liver cirrhosis and 23 healthy volunteers. HLA-DR expressions, functions of monocyte, serum cytokines and endotoxin levels were measured.

RESULTS

Compared to healthy volunteers, HLA-DR expressions were significantly lower in Child-Pugh class C cirrhotic patients (89.28% vs 69.29%, p<0.001). These low-HLA-DR-expressed monocytes were with decreased ability of tumor necrosis factor (TNF)-alpha secretion, decreased expression of inducible nitric oxide synthetase (iNOS) and decreased allo-stimulatory ability but normal phagocytosis ability. The co-stimulatory molecules like CD40 and CD86 were down-regulated as well but not CD80. Furthermore, HLA-DR expression was linearly correlated with the presence of hepatic encephalopathy (r(2)=0.2642; p=0.008) and serum interleukin-10 (IL-10) (r(2)=0.2167; p=0.019) in patients with Child-Pugh class C. Serum endotoxin level was in linear relationship to serum IL-10 level (r(2)=0.1868; p=0.002) and HLA-DR expression (r(2)=0.0924; p=0.036). In addition, endotoxin, mediated by IL-10, could down-regulate the HLA-DR expression.

CONCLUSIONS

Child-Pugh class C cirrhotic patients suffer from down-regulation of HLA-DR expression. Endotoxemia, possibly mediated by IL-10, contributes to this HLA-DR down-regulation.

HLA-DR expression on monocytes and systemic inflammation in patients with ruptured abdominal aortic aneurysms

Introduction

Mortality from ruptured abdominal aortic aneurysms (RAAA) remains high. Severe systemic inflammation, leading to multi-organ failure, often occurs in these patients. In this study we describe the level of HLA-DR expression in a consecutive group of patients following surgery for RAAA and compare results between survivors and non-survivors. A similar comparison is made for IL-6 and IL-10 levels and Sequential Organ Failure Assessment (SOFA) scores.

Methods

This is a prospective observational study. Patients with RAAA were prospectively analysed. Blood samples were collected on days 1, 3, 5, 7, 10 and 14. The fraction of CD-14 positive monocytes expressing HLA-DR was measured by flow-cytometry. IL-6 and IL-10 levels were measured by ELISA.

Results

The study included 30 patients with a median age of 70 years, of which 27 (90%) were men. Six patients died from multiple organ failure, all other patients survived. The SOFA scores were significantly higher in non-survivors on days 1 through 14. HLA-DR expression on monocytes was significantly lower on days 3, 5, 7, 10 and 14 in non-survivors. IL-6 and IL-10 levels were significantly higher in non-survivors on day 1 and days 1 and 3, respectively.

Conclusion

HLA-DR expression on monocytes was decreased, especially in non-survivors. All patients with RAAA displayed a severe inflammatory and anti-inflammatory response with an increased production of IL-6 and IL-10. Poor outcome is associated with high levels of IL-6 and IL-10 and a high SOFA score in the first three days after surgery, while low levels of HLA-DR expression are observed from day three after RAAA repair.

Monitoring temporary immunodepression by flow cytometric measurement of monocytic HLA-DR expression: a multicenter standardized study

BACKGROUND

Single-center trials have shown that monocytic HLA-DR is a good marker for monitoring the severity of temporary immunodepression after trauma, major surgery, or sepsis. A new test for measuring monocytic HLA-DR is now available.

METHODS

We evaluated a new test reagent set for monocytic HLA-DR expression (BD Quantibritetrade mark HLA-DR/Monocyte reagent; Becton Dickinson) in single-laboratory and interlaboratory experiments, assessing preanalytical handling, lyse-no-wash (LNW) vs lyse-wash (LW) values, reference values, and the effect of use of different flow cytometers and different instrument settings on test variance.

RESULTS

For preanalytical handling, EDTA anticoagulation, storage on ice as soon as possible, and staining within 4 h after blood collection gave results comparable to values obtained for samples analyzed immediately after collection (mean increase of approximately 4% in monocytic HLA-DR). Comparison of LNW and LW revealed slightly higher results for LNW ( approximately 18% higher for LNW compared with LW; r = 0.982). Comparison of different flow cytometers and instrument settings gave CVs <4%, demonstrating the independence of the test from these variables and suggesting that this method qualifies as a standardized test. CV values from the interlaboratory comparison ranged from 15% (blood sample unprocessed before transport) to 25% (stained and fixed before transport).

CONCLUSIONS

For the BD Quantibrite HLA-DR/Monocyte test, preanalytical handling is standardized. Single-laboratory results demonstrated the independence of this test from flow cytometer and instrument settings. Interlaboratory results showed greater variance than single-laboratory values. This interlaboratory variance was partly attributable to the influence of transport and can be reduced by optimization of transport conditions.

Human leukocyte antigen-DR expression on peripheral blood monocytes and the risk of pneumonia in pediatric lung transplant recipients

BACKGROUND

Pneumonia is the leading cause of morbidity and mortality after living lobar lung transplantation (LT). Low levels of human leukocyte antigen-DR (HLA-DR) expression on peripheral blood monocytes, have been demonstrated to correlate with risk of infection in surgical, trauma, and adult transplant patients. In addition, interleukin (IL)-10 has been shown to be a negative regulator of HLA-DR expression. This study investigates whether HLA-DR expression and serum IL-10 levels correlate with the development of pneumonia after pediatric LT.

METHODS

Thirteen LT recipients were prospectively monitored with blood samples obtained pre-LT (baseline) and post-LT weeks 1-4. Mean fluorescence intensity (MFI) of HLA-DR on CD14+ monocytes was measured by flow cytometry. IL-10 levels were determined by ELISA from frozen serum collected at the same time points as monocyte HLA-DR expression. Correlates of pneumonia were abstracted from the medical record.

RESULTS

Monocyte HLA-DR expression declined in 11 of 13 patients in the first week post-LT. Two patients without an initial decline and four others whose HLA-DR expression recovered by week 2 post-LT, did not develop pneumonia or other infection or rejection. Pneumonia was observed in seven patients, six of whom failed to recover their monocyte HLA-DR expression by 2 weeks post-LT. Six of seven patients with pneumonia recovered, and one patient died of aspergillosis. During weeks 1-4, a statistically significant difference was seen in the profile of mean monocyte HLA-DR expression levels, analyzed as percent of baseline, between the patients with and without pneumonia (P=0.002). The greatest difference between groups over time was seen from post-LT weeks 1-2 (P=0.003). In addition, when comparing the values at each week, a significant difference was seen between the two groups at post-LT week 2 (P=0.006) and week 4 (P=0.05). Analysis of IL-10 concentrations revealed that the overall difference between the groups (patients with and without pneumonia) was statistically significant (P=0.014), with a paradoxical positive correlation between HLA-DR expression at post-LT week 4 and IL-10 concentrations.

CONCLUSIONS

Persistent low monocyte HLA-DR expression was associated with the risk of post-LT pneumonia in these patients. This measurement may be useful for monitoring risk of infection and stratifying patients into higher and lower risk groups. Increased IL-10 levels may be protective for infection in this group of patients. At present it is unknown whether the predictive power of HLA-DR expression is indicative of a global defect in monocytic function or a specific abnormality.

Monocyte Human Leukocyte Antigen–DR Transcriptional Downregulation by Cortisol during Septic Shock

Monocyte deactivation has been identified as a major factor of immunosuppression in sepsis and is associated with a loss of surface human leukocyte antigen-DR (HLA-DR) expression on circulating monocytes. Using flow cytometry, quantitative reverse transcription-polymerase chain reaction, we investigated this phenomenon in septic patients. We confirmed the early loss of monocyte HLA-DR expression in all infected patients and demonstrated that this persistent lowered expression at Day 6 correlated with severity scores, secondary infection, and death. This phenomenon occurred at a transcriptional level via a decrease in the class II transactivator A (CIITA) transcription. Furthermore, these abnormalities correlated with the high cortisol levels observed in sepsis and not with those of other putative factors such as catecholamines or interleukin-10. Finally, in vitro studies evidenced that glucocorticoids decrease HLA-DR expression at a transcriptional level via a decrease in CIITA mRNA levels, mainly by down modulating its isoforms I and III. We conclude that in human sepsis, the loss of HLA-DR expression on circulating monocytes is associated with a poor outcome. We suggest that the high endogenous cortisol level observed in septic shock may be a possible new factor involved in the loss of HLA-DR expression on monocytes via its effect on HLA-DR and CIITA transcription.