Utility of monocyte HLA-DR and rationale for therapeutic GM-CSF in sepsis immunoparalysis

Causal relationship between OHSS and immune cells: A Mendelian randomization study

OBJECTIVE

To confirm the causal relationship between immune cells and Ovarian Hyperstimulation Syndrome.

DESIGN

Obtaining data, collecting single nucleotide polymorphisms, detecting instrumental variables heterogeneity, assessing causality, and assessing bidirectional causality.

SUBJECTS

A two sample Mendelian study to confirm the causal relationship between immune cells and Ovarian Hyperstimulation Syndrome.

EXPOSURE

Immune cell phenotype (including 22 million SNPs from GWAS on 3757 European individuals).

MAIN OUTCOME MEASURES

Inverse variance weighting, one-sample analysis, MR-Egger, weighted median and weighted mode are used to assess the causal relationship between 731 immunophenotypes and Ovarian Hyperstimulation Syndrome. The weighted median and Mendelian Randomization multi-effect residuals and Mendelian Randomization multi-effect residuals and outlier tests are used to assess bidirectional causality between this two.

RESULTS

After False Discovery Rate correction, 9 immunophenotypes were found to be significantly associated with the risk of Ovarian Hyperstimulation Syndrome. B cell panel: IgD+ AC (OR, 0.90) 、CD19 on CD24+ CD27+ (OR, 0.86) 、BAFF-R on CD20- CD38 (OR, -1.22); Mature T cell group panel: EM DN (CD4 -CD8-) AC (OR, 1.46); Myeloid cell panel: Mo MDSC AC (OR, 1.13) 、CD45 on CD33br HLA-DR+ (OR, 0.87); Monocyte panel: HLA-DR on monocyte (OR, 0.86) 、CCR2 on CD14+ CD16+ monocyte (OR, 1.15) 、cDC panel: HLA-DR on myeloid DC (OR, 0.89).

CONCLUSION

This study shows the potential link between OHSS and immune cells by genetic means, providing new ideas for future clinical and basic research.

Models of sepsis-induced acute kidney injury

Sepsis-induced acute kidney injury (S-AKI) is one of the most serious life-threatening complications of sepsis. The pathogenesis of S-AKI is complex and there is no effective specific treatment. Therefore, it is crucial to choose suitable preclinical models that are highly similar to human S-AKI to study the pathogenesis and drug treatment. In this review, we summarized recent advances in the development models of S-AKI, providing reference for the reasonable selection of experimental models as basic research and drug development of S-AKI.

The role of trained immunity in sepsis

Sepsis is defined as a life-threatening organ dysfunction syndrome caused by dysregulated host response to infection, characterized by a systemic inflammatory response to infection. The use of antibiotics, fluid resuscitation, and organ support therapy has limited prognostic benefit in patients with sepsis, and its incidence is not diminishing, which is attracting increased attention in medicine. Sepsis remains one of the most debilitating and expensive illnesses. One of the main reasons of septic mortality is now understood to be disruption of immune homeostasis. Immunotherapy is revolutionizing the treatment of illnesses in which dysregulated immune responses play a significant role. This "trained immunity", which is a potent defense against infection regardless of the type of bacteria, fungus, or virus, is attributed to the discovery that the innate immune cells possess immune memory via metabolic and epigenetic reprogramming. Here we reviewed the immunotherapy of innate immune cells in sepsis, the features of trained immunity, and the relationship between trained immunity and sepsis.

Time-Dependent Variation in Immunoparalysis Biomarkers Among Patients with Sepsis and Critical Illness

Immunoparalysis is a significant concern in patients with sepsis and critical illness, potentially leading to increased risk of secondary infections. This study aimed to perform a longitudinal assessment of immune function over the initial two weeks following the onset of sepsis and critical illness. We compared ex vivo stimulated cytokine release to traditional markers of immunoparalysis, including monocyte Human Leukocyte Antigen (mHLA)-DR expression and absolute lymphocyte count (ALC). A total of 64 critically ill patients were recruited in a tertiary care academic medical setting, including 31 septic and 33 non-septic patients. Results showed that while mHLA-DR expression significantly increased over time, this was primarily driven by the non-septic subset of critically ill patients. ALC recovery was more prominent in septic patients. Ex vivo stimulation revealed significant increases in TNF and IL-6 production over time in septic patients. However, IFNγ production varied with the stimulant used and did not show significant recovery when normalized to cell count. No significant correlation was found between mHLA-DR expression and other immunoparalysis biomarkers. These findings suggest the need for more nuanced immune monitoring approaches beyond the traditional 'sepsis' versus 'non-sepsis' classifications in critically ill patients. It also provided further evidence of a potential window for targeted immunotherapeutic interventions in the first week of critical illness.

Single-cell landscape of immunological responses in elderly patients with sepsis

Sepsis is a dysregulated host response to severe infections, and immune dysfunction plays a crucial role in its pathogenesis. Elderly patients, a special population influenced by immunosenescence, are more susceptible to sepsis and have a worse prognosis. However, the immunopathogenic mechanisms underlying sepsis in elderly patients remain unclear. Here, we performed single-cell RNA sequencing of peripheral blood samples from young and old subjects and patients with sepsis. By exploring the transcriptional profiles of immune cells, we analyzed immune cell compositions, phenotype shifts, expression heterogeneities, and intercellular communication. In elderly patients with sepsis, innate immune cells (e.g., monocytes and DCs) exhibit decreased antigen presentation, presenting an overactive inflammatory and senescent phenotype. However, the immunophenotype of T cells shifted to characterize effector, memory, and exhaustion. Moreover, we identified strong interferon-γ responses of T cells in both aging and sepsis groups and a deranged inflammaging status in elderly sepsis patients. Tregs in elderly patients with sepsis showed increased abundance and enhanced immunosuppressive effects. In addition, metabolism-associated pathways were upregulated in T cells in elderly patients with sepsis, and the lysine metabolism pathway was enriched in Tregs. Cell-cell interaction analysis showed that the expression profile of ligand-receptor pairs was probably associated with aggravated immune dysfunction in elderly patients with sepsis. A novel HLA-KIR interaction was observed between Tregs and CD8 + T cells. These findings illustrate the immunological hallmarks of sepsis in elderly patients, and highlight that immunosuppressive and metabolic regulatory pathways may undergo important alterations in elderly patients with sepsis.

Association between intracellular adenosine triphosphate content of CD4+ T lymphocytes and mortality in sepsis patients: A prospective observational study

OBJECTIVE

This study aimed to link intracellular adenosine triphosphate content in CD4+ T lymphocytes (CD4+ iATP) with sepsis patient mortality, seeking a new predictive biomarker for outcomes and enhanced management.

METHODS

61 sepsis patients admitted to the Intensive Care Unit between October 2021 and November 2022 were enrolled. iATP levels were gauged using whole blood CD4+ T cells stimulated with mitogen PHA-L. Based on CD4+ iATP levels (<132.24 and ≥132.24 ng/mL), patients were categorized into two groups. The primary endpoint was all-cause mortality. To identify factors associated with mortality, both univariate and multivariate Cox proportional hazard analyses were conducted.

RESULTS

Of the patients, 40 had high CD4+ iATP levels (≥132.24 ng/mL) and 21 had low levels (<132.24 ng/mL). In a 28-day follow-up, 21 (34.4%) patients perished. Adjusting for confounders like SOFA score, APACHE II score, lactic acid, and albumin, those with low CD4+ iATP had three- to fivefold higher mortality risk compared to high CD4+ iATP patients (61.9% vs. 20.0%; hazard ratio [95% confidence interval], Model 1: 4.515 [1.276-15.974], p = .019, Model 2: 3.512 [1.197-10.306], p = .022). CD4+ iATP correlated positively with white blood cell and neutrophil counts but not with lymphocytes, CD3, and CD4 counts.

CONCLUSIONS

Low CD4+ iATP levels were associated with a higher risk of mortality in sepsis patients. Measurement of CD4+ iATP may serve as a useful tool for identifying patients at a higher risk of mortality and could potentially provide a basis for clinical treatment. Further research is warranted to fully elucidate the underlying mechanisms of this association.

Immunotherapy in the context of sepsis-induced immunological dysregulation

Sepsis is a clinical syndrome caused by uncontrollable immune dysregulation triggered by pathogen infection, characterized by high incidence, mortality rates, and disease burden. Current treatments primarily focus on symptomatic relief, lacking specific therapeutic interventions. The core mechanism of sepsis is believed to be an imbalance in the host's immune response, characterized by early excessive inflammation followed by late immune suppression, triggered by pathogen invasion. This suggests that we can develop immunotherapeutic treatment strategies by targeting and modulating the components and immunological functions of the host's innate and adaptive immune systems. Therefore, this paper reviews the mechanisms of immune dysregulation in sepsis and, based on this foundation, discusses the current state of immunotherapy applications in sepsis animal models and clinical trials.

Immune profile of patients‑a new approach in management of sepsis and septic shock?

The present study was a prospective observational single center study, enrolling 102 patients with sepsis, admitted in the Intensive Care Unit of the County Emergency Clinical Hospital in Târgu Mureș (Mureș, Romania). The main goal of the present study was to compare the changes of the following parameters on day 1 compared with day 5, in sepsis compared with septic shock, as well as in survivors compared with non-survivors: Cell blood count parameters, neutrophil-lymphocyte ratio, platelet-lymphocyte ratio and systemic inflammation index, C reactive protein (CRP), ferritin, procalcitonin (PCT), CD 3+ T cells, CD4+ T cells, CD8+ T cells, CD16+CD56+/CD3-NK cells and CD19+ B cells. The relationship between the subcategories of lymphocytes with the inflammatory markers was evaluated. The serum concentration of CRP and PCT was significantly lower on day 5 compared with day 1 and serum ferritin was significantly higher in patients with septic shock. The percentage of cytotoxic T lymphocytes was significantly decreased and the percentage of NK lymphocytes was significantly increased in patients who developed septic shock. The results indicated a negative significant correlation between the proportion of T lymphocytes and PCT concentration and a positive significant correlation between the proportion of B lymphocytes and PCT concentration.

Comprehensive analysis of human monocyte subsets using full-spectrum flow cytometry and hierarchical marker clustering

Introduction

Exploring monocytes' roles within the tumor microenvironment is crucial for crafting targeted cancer treatments.

Methods

This study unveils a novel methodology utilizing four 20-color flow cytometry panels for comprehensive peripheral immune system phenotyping, specifically targeting classical, intermediate, and non-classical monocyte subsets.

Results

By applying advanced dimensionality reduction techniques like t-distributed stochastic neighbor embedding (tSNE) and FlowSom analysis, we performed an extensive profiling of monocytes, assessing 50 unique cell surface markers related to a wide range of immunological functions, including activation, differentiation, and immune checkpoint regulation.

Discussion

This in-depth approach significantly refines the identification of monocyte subsets, directly supporting the development of personalized immunotherapies and enhancing diagnostic precision. Our pioneering panel for monocyte phenotyping marks a substantial leap in understanding monocyte biology, with profound implications for the accuracy of disease diagnostics and the success of checkpoint-inhibitor therapies. Key findings include revealing distinct marker expression patterns linked to tumor progression and providing new avenues for targeted therapeutic interventions.

Monocyte HLA-DR level on admission predicting in-hospital mortality rate in exertional heatstroke: A 12-year retrospective study

BACKGROUND

Exertional heatstroke (EHS), a fatal illness, pronounces multiple organ dysfunction syndrome (MODS) and high mortality rate. Currently, no ideal factor prognoses EHS. Decreased monocyte human leukocyte-DR antigen (mHLA-DR) has been observed in critically ill individuals, particularly in those with sepsis. While most research focus on the pro-inflammatory response exploration in EHS, there are few studies related to immunosuppression, and no report targeted on mHLA-DR in EHS. The present study tried to explore the prognostic value of mHLA-DR levels in EHS patients.

METHODS

This was a single-center retrospective study. Clinical data of EHS patients admitted to the intensive care unit of the General Hospital of Southern Theatre Command between January 1, 2008, and December 31, 2020, were recorded and analyzed.

RESULTS

Seventy patients with 54 survivors and 16 nonsurvivors were ultimately enrolled. Levels of mHLA-DR in the nonsurvivors (41.8% [38.1-68.1]%) were significantly lower than those in the survivors (83.1% [67.6-89.4]%, p < 0.001). Multivariate logistic regression indicated that mHLA-DR (odds ratio [OR] = 0.939; 95% confidence interval [CI]: 0.892-0.988; p = 0.016) and Glasgow coma scale (GCS) scores (OR = 0.726; 95% CI: 0.591-0.892; p = 0.002) were independent risk factors related with in-hospital mortality rate in EHS. A nomogram incorporated mHLA-DR with GCS demonstrated excellent discrimination and calibration abilities. Compared to the traditional scoring systems, the prediction model incorporated mHLA-DR with GCS had the highest area under the curve (0.947, 95% CI: [0.865-0.986]) and Youden index (0.8333), with sensitivity of 100% and specificity of 83.33%, and a greater clinical net benefit.

CONCLUSION

Patients with EHS were at a risk of early experiencing decreased mHLA-DR early. A nomogram based on mHLA-DR with GCS was developed to facilitate early identification and timely treatment of individuals with potentially poor prognosis.

Monocytes as Targets for Immunomodulation by Regional Citrate Anticoagulation

Immune alterations in end-stage renal patients receiving hemodialysis are complex and predispose patients to infections. Anticoagulation may also play an immunomodulatory role in addition to the accumulation of uremic toxins and the effects of the dialysis procedure. Accordingly, it has been recently shown that the infection rate increases in patients under regional citrate anticoagulation (RCA) compared with systemic heparin anticoagulation (SHA). We hypothesized that RCA affects the immune status of hemodialysis patients by targeting monocytes. In a cohort of 38 end-stage renal patients undergoing hemodialysis, we demonstrated that whole blood monocytes of patients receiving RCA-but not SHA-failed to upregulate surface activation markers, like human leukocyte antigen class II (HLA-DR), after stressful insults, indicating a state of deactivation during and immediately after dialysis. Additionally, RNA sequencing (RNA-seq) data and gene set enrichment analysis of pre-dialysis monocytes evidenced a great and complex difference between the groups given that, in the RCA group, monocytes displayed a dramatic transcriptional change with increased expression of genes related to the cell cycle regulation, cellular metabolism, and cytokine signaling, compatible with the reprogramming of the immune response. Transcriptomic changes in pre-dialysis monocytes signalize the lasting nature of the RCA-related effects, suggesting that monocytes are affected even beyond the dialysis session. Furthermore, these findings demonstrate that RCA-but not SHA-impairs the response of monocytes to activation stimuli and alters the immune status of these patients with potential clinical implications.

[The Immune System of the Critically Ill Patient]

Critically ill patients often experience a dysregulated immune response, leading to immune dysfunction. Sepsis, trauma, severe infections, and certain medical conditions can trigger a state of systemic inflammation, known as the cytokine storm. This hyperactive immune response can cause collateral damage to healthy tissues and organs, exacerbating the patient's condition. On the other hand, some critically ill patients may suffer from immune paralysis which can increase the risk of nosocomial infections.Fever is an evolutionary adaptation that evolved as an effective defense mechanism to fight invading pathogens. By raising body temperature, fever enhances the immune response, inhibits pathogen growth, promotes recovery, and aids in the formation of immune memory. Understanding the role of fever in the context of immune defense is crucial for optimizing medical interventions and supporting the body's natural ability to combat infections.Future Directions: Advancements in immunology research and technology hold promise for better understanding the immune system's complexities in critically ill patients. Personalized medicine approaches may be developed to tailor therapies to individual patients based on their immune profile, optimizing treatment outcomes. Based on recent studies prognostic parameters such as lymphocyte count, IL-10 concentration and mHLA-DR expression can be used to stratify the immunological response pattern in septic patients.Conclusion: The immune system's response in critically ill patients is a multifaceted process, involving intricate interactions between various immune cells, cytokines, and organs. Striking the delicate balance between immune activation and suppression remains a significant challenge in clinical practice. Continued research and therapeutic innovations are vital to improve patient outcomes and reduce the burden of critical illness on healthcare systems.

From genes to systems: The role of food supplementation in the regulation of sepsis-induced inflammation

Systemic inflammation includes a widespread immune response to a harmful stimulus that results in extensive systemic damage. One common example of systemic inflammation is sepsis, which is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Under the pro-inflammatory environment of sepsis, oxidative stress contributes to tissue damage due to dysfunctional microcirculation that progressively causes the failure of multiple organs that ultimately triggers death. To address the underlying inflammatory condition in critically ill patients, progress has been made to assess the beneficial effects of dietary supplements, which include polyphenols, amino acids, fatty acids, vitamins, and minerals that are recognized for their immuno-modulating, anticoagulating, and analgesic properties. Therefore, we aimed to review and discuss the contribution of food-derived supplementation in the regulation of inflammation from gene expression to physiological responses and summarize the precedented potential of current therapeutic approaches during systemic inflammation.

Combination of NK and Other Immune Markers at Early Phase Stratify the Risk of Sepsis Patients: A Retrospective Study

Purpose

Immune dysfunction plays a pivotal role in sepsis pathogenesis. Previous studies have revealed the crucial role of T cells and human leukocyte antigen-DR (HLA-DR) in sepsis. However, the function of natural killer (NK) cells remains unclear. This study aimed to investigate whether NK cells are associated with sepsis prognosis. In addition, we aimed to explore the interrelation and influence between NK and other immunological features in patients with sepsis.

Patients and Methods

This retrospective, observational study included patients with sepsis from two hospitals in mainland China. The clinical characteristics and immune results during the early phase were collected. Patients were classified according to the level of immune cells to analyze the relationship between immunological features and 28-day mortality.

Results

A total of 984 patients were included in this study. Non-survivors were older and had lower levels of lymphocytes, monocytes, NK cells, HLA-DR, and T cells. Patients were classified into eight groups according to their levels of NK cells, HLA-DR, and T cells. Only patients with decreased NK and T cell counts showed a significant increase in 28-day mortality. An increase in CD8+ T cells was correlated with the alleviation of 28-day mortality only among patients with high NK cell levels.

Conclusion

This study provides novel insights into the association between NK cells and 28-day mortality as well as the interrelation between NK cells and other immune cells in sepsis. The relationship between CD8+ T cells and 28-day mortality in sepsis is dependent on NK cell count.

Clinical treatment for persistent inflammation, immunosuppression and catabolism syndrome in patients with severe acute pancreatitis (Review)

Severe acute pancreatitis (SAP) is a severe disease with a high prevalence and a 3-15% mortality worldwide, and premature activation of zymogen for any reason is the initial factor for the onset of SAP. Gallstone disease and heavy alcohol consumption are the two most common etiologies of SAP. Persistent inflammation, immunosuppression and catabolism syndrome (PICS) is a life-threatening illness, and there are no effective treatments. The relapse state of PICS mainly leads to high mortality due to septic shock or severe trauma, both of which are dangerous and challenging conditions for clinicians. Thus, it is important for medical staff to identify patients at high risk of PICS and to master the prevention and treatment of PICS in patients with SAP. The present review aims to increase the understanding of the pathogenesis of PICS, produce evidence for PICS diagnosis and highlight clinical treatment for PICS in patients with SAP. With this information, clinical workers could implement standardized and integrated measures at an early stage of SAP to stop its progression to PICS.