The role of eosinophils in sepsis and acute respiratory distress syndrome: a scoping review

Biologics for asthma and risk of pneumonia

OBJECTIVE

Modification of the immune system with biologics raises theoretical concerns about the risk of infections but it is still unclear whether currently routinely used biologics in severe asthma may facilitate the development of pneumonia. Therefore, we aimed to determine whether omalizumab, mepolizumab, benralizumab, and dupilumab are associated with pneumonia in a real-world setting.

METHODS

A retrospective disproportionality analysis was performed using adverse event (AE) reports submitted to FAERS from January 2020 to September 30, 2023. MedDRA was used to identify infections and infestations and then pneumonia cases. ROR and PRR were used to measure disproportionality.

RESULTS

The percentage of reported cases of pneumonia compared to infections and infestations was highest for mepolizumab (36.8%), followed by omalizumab (32.6%), benralizumab (19.2%) and dupilumab (5.7%). We found a moderate or strong signal for increased risk of pneumonia with mepolizumab (ROR = 3.74, 95%CI 3.50-4.00), omalizumab (ROR = 3.26, 95%CI 3.06-3.49) and benralizumab (ROR = 2.65, 95%CI 2.49-2.83).

CONCLUSIONS

Mepolizumab, omalizumab and benralizumab, but not dupilumab, were associated with high odds of reporting pneumonia. Our results represent only potential associations between these biologics and pneumonia but not causality. The nature of the FAERS database is such that the cause of the reported events is uncertain. Therefore, we can only roughly estimate the incidence of AEs by the signal strength (ROR value). Nevertheless, although causality could not be assessed, the signal from our study is interesting. We believe it deserves to be further substantiated by real-world studies with robust designs.

Exploring the Relationship between Plasma Adiponectin, Gender, and Underlying Diseases in Severe Illness

Adiponectin is low in obesity, plays a crucial role in metabolic health, and, moreover, possesses immunoregulatory properties. However, studies examining its levels in patients with systemic inflammatory response syndrome (SIRS) or sepsis have yielded conflicting results. While females typically have higher systemic adiponectin levels than males, research on sex-specific associations in this context is limited. In this study of 156 SIRS/sepsis patients, including those with liver cirrhosis, we aimed to explore the relationship between plasma adiponectin, body mass index (BMI), gender, disease severity, and underlying etiological conditions. Our findings revealed that patients with liver cirrhosis, who are susceptible to infections, exhibited elevated circulating adiponectin levels, irrespective of sex. When excluding cirrhosis patients, plasma adiponectin levels were similar between male SIRS/sepsis patients and controls but lower in female patients compared to female controls. Plasma adiponectin was inversely related to BMI in female but not male patients. Further analysis within the non-cirrhosis subgroup demonstrated no significant differences in adiponectin levels between sexes among SIRS, sepsis, and septic shock patients. Ventilation, dialysis, and vasopressor therapy had no discernible impact on adiponectin levels in either sex. A negative correlation between adiponectin and C-reactive protein (CRP) existed in males only. Notably, patients with pancreatitis showed the lowest plasma adiponectin concentrations, although sex-specific differences were not significant. Infection with Gram-negative or Gram-positive bacteria had minimal effects on plasma adiponectin levels in both sexes. However, infection with the severe acute respiratory syndrome coronavirus type 2 led to decreased adiponectin levels in females exclusively. Multivariate analysis considering all factors affecting plasma adiponectin levels in males or females identified BMI in females and CRP levels in males to predict plasma adiponectin levels in SIRS/sepsis patients. Additionally, our study observed a trend where the 25 patients who did not survive had higher plasma adiponectin levels, particularly among males. In summary, our investigation highlights the influence of underlying diseases and sex on plasma adiponectin levels in SIRS/sepsis patients, shedding light on potential implications for disease management and prognosis.

Admission blood eosinophil count, inpatient death and death at 1 year in exacerbating patients with COPD

BACKGROUND

Blood eosinophil counts have been studied in patients with stable chronic obstructive pulmonary disease (COPD) and are a useful biomarker to guide inhaled corticosteroid use. Less is known about eosinophil counts during severe exacerbation.

METHODS

In this retrospective study, 2645 patients admitted consecutively with COPD exacerbation across six UK hospitals were included in the study, and the clinical diagnosis was confirmed by a respiratory specialist. The relationship between admission eosinophil count, inpatient death and 1-year death was assessed. In a backward elimination, Poisson regression analysis using the log-link function with robust estimates, patients' markers of acute illness and stable-state characteristics were assessed in terms of their association with eosinopenia.

RESULTS

1369 of 2645 (52%) patients had eosinopenia at admission. Those with eosinopenia had a 2.5-fold increased risk of inpatient death compared with those without eosinopenia (12.1% vs 4.9%, RR=2.50, 95% CI 1.88 to 3.31, p<0.001). The same mortality risk with eosinopenia was seen among the subgroup with pneumonic exacerbation (n=788, 21.3% vs 8.5%, RR=2.5, 95% CI 1.67 to 2.24, p<0.001). In a regression analysis, eosinopenia was significantly associated with: older age and male sex; a higher pulse rate, temperature, neutrophil count, urea and C reactive protein level; a higher proportion of patients with chest X-ray consolidation and a reduced Glasgow Coma Score; and lower systolic and diastolic blood pressure measurements and lower oxygen saturation, albumin, platelet and previous admission counts.

DISCUSSION

During severe COPD exacerbation, eosinopenia is common and associated with inpatient death and several markers of acute illness. Clinicians should be cautious about using eosinophil results obtained during severe exacerbation to guide treatment decisions regarding inhaled corticosteroid use.

Interesting effects of interleukins and immune cells on acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a medical condition characterized by widespread inflammation in the lungs with consequent proportional loss of gas exchange function. ARDS is linked with severe pulmonary or systemic infection. Several factors, including secretory cytokines, immune cells, and lung epithelial and endothelial cells, play a role in the development and progression of this disease. The present study is based on Pubmed database information (1987-2022) using the words "Acute respiratory distress syndrome", "Interleukin", "Cytokines" and "Immune cells". Cytokines and immune cells play an important role in this disease, with particular emphasis on the balance between pro-inflammatory and anti-inflammatory factors. Neutrophils are one of several important mediators of Inflammation, lung tissue destruction, and malfunction during ARDS. Some immune cells, such as macrophages and eosinophils, play a dual role in releasing inflammatory mediators, recruitment inflammatory cells and the progression of ARDS, or releasing anti-inflammatory mediators, clearing the lung of inflammatory cells, and helping to improve the disease. Different interleukins play a role in the development or inhibition of ARDS by helping to activate various signaling pathways, helping to secrete other inflammatory or anti-inflammatory interleukins, and playing a role in the production and balance between immune cells involved in ARDS. As a result, immune cells and, inflammatory cytokines, especially interleukins play an important role in the pathogenesis of this disease Therefore, understanding the relevant mechanisms will help in the proper diagnosis and treatment of this disease.

Eosinophil recovery in hospitalized COVID-19 patients is associated with lower rates of ICU admission and in-hospital mortality: An observational cohort analysis

BACKGROUND

Admission eosinopenia (<100 cells/μL) is associated with poor clinical outcomes in hospitalized COVID-19 patients. However, the effects of eosinophil recovery (defined as reaching ≥50 eosinophils/μL) during hospitalization on COVID-19 outcomes have been inconsistent.

METHODS

The study included 1,831 patients admitted to UCLA hospitals between February 2020 and February 2021 with PCR-confirmed COVID-19. Using competing risk regression and modeling eosinophil recovery as a time-dependent covariate, we evaluated the longitudinal relationship between eosinophil recovery and in-hospital outcomes including ICU admission, need for mechanical ventilation, and in-hospital mortality. All analyses were adjusted for covariates including age, BMI, tobacco smoke exposure, comorbidities known to be risk factors for COVID-19 mortality, and treatments including dexamethasone and remdesivir.

RESULTS

Eosinophil recovery was evaluated in patients with <50 eosinophils/μL on admission (n = 1282). These patients cumulatively amassed 11,633 hospital patient-days; 3,985 of those days qualified as eosinophil recovery events, which were represented by 781 patients achieving at least one instance of eosinophil recovery during hospitalization. Despite no significant difference in the rate of mechanical ventilation, eosinophil recoverers had significantly lower rates of in-hospital mortality (aHR: 0.44 [0.29, 0.65], P = 0.001) and ICU admission (aHR: 0.25 [0.11, 0.61], P = 0.002).

CONCLUSION

Trending eosinophil counts during hospitalization is simple and can be performed in resource-limited healthcare settings to track the inflammatory status of a patient. Lack of eosinophil recovery events can identify those at risk for future progression to severe COVID.

Identification and experimental validation of mitochondria-related genes biomarkers associated with immune infiltration for sepsis

Background

Sepsis remains a complex condition with incomplete understanding of its pathogenesis. Further research is needed to identify prognostic factors, risk stratification tools, and effective diagnostic and therapeutic targets.

Methods

Three GEO datasets (GSE54514, GSE65682, and GSE95233) were used to explore the potential role of mitochondria-related genes (MiRGs) in sepsis. WGCNA and two machine learning algorithms (RF and LASSO) were used to identify the feature of MiRGs. Consensus clustering was subsequently carried out to determine the molecular subtypes for sepsis. CIBERSORT algorithm was conducted to assess the immune cell infiltration of samples. A nomogram was also established to evaluate the diagnostic ability of feature biomarkers via "rms" package.

Results

Three different expressed MiRGs (DE-MiRGs) were identified as sepsis biomarkers. A significant difference in the immune microenvironment landscape was observed between healthy controls and sepsis patients. Among the DE-MiRGs, NDUFB3 was selected to be a potential therapeutic target and its significant elevated expression level was confirmed in sepsis using in vitro experiments and confocal microscopy, indicating its significant contribution to the mitochondrial quality imbalance in the LPS-simulated sepsis model.

Conclusion

By digging the role of these pivotal genes in immune cell infiltration, we gained a better understanding of the molecular immune mechanism in sepsis and identified potential intervention and treatment strategies.

IFN- Is Protective in Cytokine Release Syndrome-associated Extrapulmonary Acute Lung Injury

The mechanisms by which excessive systemic activation of adaptive T lymphocytes, as in cytokine release syndrome (CRS), leads to innate immune cell-mediated acute lung injury (ALI) or acute respiratory distress syndrome, often in the absence of any infection, remains unknown. Here, we investigated the roles of IFN-γ and IL-17A, key T-cell cytokines significantly elevated in patients with CRS, in the immunopathogenesis of CRS-induced extrapulmonary ALI. CRS was induced in wild-type (WT), IL-17A- and IFN-γ knockout (KO) human leukocyte antigen-DR3 transgenic mice with 10 μg of the superantigen, staphylococcal enterotoxin B, given intraperitoneally. Several ALI parameters, including gene expression profiling in the lungs, were studied 4, 24, or 48 hours later. Systemic T-cell activation with staphylococcal enterotoxin B resulted in robust upregulation of several chemokines, S100A8/A9, matrix metalloproteases, and other molecules implicated in tissue damage, granulocyte as well as agranulocyte adhesion, and diapedesis in the lungs as early as 4 hours, which was accompanied by subsequent neutrophil/eosinophil lung infiltration and severe ALI in IFN-γ KO mice. These pathways were significantly underexpressed in IL-17A KO mice, which manifested mildest ALI and intermediate in WT mice. Neutralization of IFN-γ worsened ALI in WT and IL-17A KO mice, whereas neutralizing IL-17A did not mitigate lung injury in IFN-γ KO mice, suggesting a dominant protective role for IFN-γ in ALI and that IL-17A is dispensable. Ruxolitinib, a Janus kinase inhibitor, increased ALI severity in WT mice. Thus, our study identified novel mechanisms of ALI in CRS and its differential modulation by IFN-γ and IL-17A.

Blood Eosinophils and Clinical Outcomes in Inpatients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Prospective Cohort Study

Purpose

The prognostic value of blood eosinophils in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) remains controversial. This study aimed to evaluate whether blood eosinophils could predict in-hospital mortality and other adverse outcomes in inpatients with AECOPD.

Methods

The patients hospitalized for AECOPD were prospectively enrolled from ten medical centers in China. Peripheral blood eosinophils were detected on admission, and the patients were divided into eosinophilic and non-eosinophilic groups with 2% as the cutoff value. The primary outcome was all-cause in-hospital mortality.

Results

A total of 12,831 AECOPD inpatients were included. The non-eosinophilic group was associated with higher in-hospital mortality than the eosinophilic group in the overall cohort (1.8% vs 0.7%, P < 0.001), the subgroup with pneumonia (2.3% vs 0.9%, P = 0.016) or with respiratory failure (2.2% vs 1.1%, P = 0.009), but not in the subgroup with ICU admission (8.4% vs 4.5%, P = 0.080). The lack of association still remained even after adjusting for confounding factors in subgroup with ICU admission. Being consistent across the overall cohort and all subgroups, non-eosinophilic AECOPD was also related to greater rates of invasive mechanical ventilation (4.3% vs 1.3%, P < 0.001), ICU admission (8.9% vs 4.2%, P < 0.001), and, unexpectedly, systemic corticosteroid usage (45.3% vs 31.7%, P < 0.001). Non-eosinophilic AECOPD was associated with longer hospital stay in the overall cohort and subgroup with respiratory failure (both P < 0.001) but not in those with pneumonia (P = 0.341) or ICU admission (P = 0.934).

Conclusion

Peripheral blood eosinophils on admission may be used as an effective biomarker to predict in-hospital mortality in most AECOPD inpatients, but not in patients admitted into ICU. Eosinophil-guided corticosteroid therapy should be further studied to better guide the administration of corticosteroids in clinical practice.

The protective mechanism of salidroside modulating miR-199a-5p/TNFAIP8L2 on lipopolysaccharide-induced MLE-12 cells

OBJECTIVES

Salidroside is used for treating inflammation-based diseases; however, its molecular mechanism is unclear. In this study, we determined the protective role of salidroside on the endotoxin-induced damage caused to the mouse alveolar epithelial type II (MLE-12) cells and its underlying mechanism.

METHODS

An in vitro model for acute lung injury was constructed by inducing the MLE-12 cells using lipopolysaccharide (lipopolysaccharides, 1 mg/L). Then, The MTT assay was conducted to assess the survival rate of the MLE-12 cells in the different groups. After the treatment, apoptosis of MLE-12 cells was determined, and the mRNA and protein expression of miR-199a-5p, HMGB1, NF-kB65, TNFAIP8L2, p-IkB-α, and TLR4 was estimated by Western Blotting and RT-PCR. ELISA was also used to measure the concentration of inflammatory cytokine molecules IL-1β, IL-6, TNF-α, and IL-18 in the cell-free supernatant. Lastly, cell morphology was examined using the AO/EB technique.

RESULTS

We showed that salidroside reduced the protein and gene expression of HMGB1, NF-kB65, miR-199a-5p, p-IkB-α, and TLR4, whereas it increased the gene and protein expression of TNFAIP8L2. Furthermore, it decreased the concentrations of cytokine molecules like IL-1β, IL-6, TNF-α, and IL-18 in the cell-free supernatant. MLE-12 also showed a lower apoptosis rate, higher survival rate, and better cell morphology.

CONCLUSION

Salidroside significantly inhibited the LPS-induced MLE-12 cell damage. Our results suggest that this could be by reducing miR-199a-5p and enhancing TNFAIP8L2 expression.

Predictive role of blood eosinophils in adult varicella patients

The study aimed to explore the relationship between eosinophils and the prognosis of varicella in adults. We retrospectively reviewed the medical records of patients who were hospitalised in The Fifth People's Hospital of Suzhou with a diagnosis of adult varicella during the period between 1 January 2012 and 31 December 2020. Of the 359 patients, 228 (63.51%) had eosinopenia. The proportion of patients with mild type disease was significantly lower in the eosinopenia group than that in the non-eosinopenia group (50.44% vs. 65.65%, P = 0.006). The proportion of the patients with common type disease was significantly higher in the eosinopenia group than that in the non-eosinopenia group (39.47% vs. 28.24%, P = 0.039). The proportion of the patients with severe type disease was higher in the eosinopenia group, although the difference did not reach statistical significance (10.09% vs. 6.11%, P = 0.243). The rates of high fever (47.81% vs. 32.82%, P = 0.008; relative risk (RR) 1.296, 95% confidence interval (CI) 1.091–1.540), headache (43.42% vs. 22.14%, P < 0.001; RR 1.415, 95% CI 1.233–1.623), anorexia (53.51% vs. 35.88%, P = 0.001; RR 1.367, 95% CI 1.129–1.655) and complications (82.89% vs. 64.12%, P < 0.001; RR 2.106, 95% CI 1.460–3.038) were also significantly higher in the eosinopenia group. Among the complications, the liver injury and skin infection were more serious in the eosinopenia group. The disease course was significantly longer in the eosinopenia group than that in the non-eosinopenia group (9.43 ± 1.89 days vs. 8.73 ± 1.25 days, P < 0.001). The improvement rate of liver injury in the recovery period was lower in the eosinopenia group than that in the non-eosinopenia group (35.38% vs. 50%, P = 0.012). The study found that adult varicella patients with eosinopenia had a more serious condition, a higher morbidity of complications and a slower recovery. Blood eosinophils can be used as a new predictor of the severity of adult varicella.

Eosinopenia Predicting Long-term Mortality in Hospitalized Acute Exacerbation of COPD Patients with Community-acquired Pneumonia-A Retrospective Analysis

Background

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) could be triggered by community-acquired pneumonia (CAP). Peripheral blood eosinopenia are strongly associated with increased mortality. In hospitalized AECOPD patients with CAP, eosinopenia may be used to identify patients with high risk of death on admission.

Methods

We conducted a retrospective cohort study in 82 hospitalized AECOPD patients with CAP. Patients who had received systemic corticosteroids preadmission were excluded. The patients were identified by individual case file review. According to blood eosinophil count, patients were grouped as eosinopenia (<50/μL) and non-eosinopenia (≥50/μL). Association of eosinopenia with infection and 18-month survival were analyzed using appropriate statistical methods.

Results

Baseline demographic, comorbidity, CURB65 and Pneumonia Severity Index scores were similar between two groups. The eosinopenia group had significantly higher pro-brain natriuretic peptide, D-dimer, neutrophil percentage, and lower lymphocyte count and lymphocyte percentage. The eosinopenia group had significantly higher C-reactive protein (median 77.30 vs 16.55, p=0.008) and procalcitonin (median 0.32 vs 0.12, p=0.001). Survival at 18 months after hospital discharge was significantly lower in the eosinopenia group vs non-eosinopenia group (log rank, p=0.002).

Conclusion

Eosinopenia (<50/μL) was a strong predictor of 18-month mortality and associated with more severe infection in hospitalized AECOPD patients with CAP. Eosinophil count at admission can be used as a prognosis marker of mortality in those population.

Eosinophils and Chronic Respiratory Diseases in Hospitalized COVID-19 Patients

BACKGROUND

Studies on the role of eosinophils in coronavirus disease 2019 (COVID-19) are scarce, though available findings suggest a possible association with disease severity. Our study analyzes the relationship between eosinophils and COVID-19, with a focus on disease severity and patients with underlying chronic respiratory diseases.

METHODS

We performed a retrospective analysis of 3018 subjects attended at two public hospitals in Madrid (Spain) with PCR-confirmed SARS-CoV-2 infection from January 31 to April 17, 2020. Patients with eosinophil counts less than 0.02×109/L were considered to have eosinopenia. Individuals with chronic respiratory diseases (n=384) were classified according to their particular underlying condition, i.e., asthma, chronic pulmonary obstructive disease, or obstructive sleep apnea.

RESULTS

Of the 3018 patients enrolled, 479 were excluded because of lack of information at the time of admission. Of 2539 subjects assessed, 1396 patients presented an eosinophil count performed on admission, revealing eosinopenia in 376 cases (26.93%). Eosinopenia on admission was associated with a higher risk of intensive care unit (ICU) or respiratory intensive care unit (RICU) admission (OR:2.21; 95%CI:1.42-3.45; p<0.001) but no increased risk of mortality (p>0.05).

CONCLUSIONS

Eosinopenia on admission conferred a higher risk of severe disease (requiring ICU/RICU care), but was not associated with increased mortality. In patients with chronic respiratory diseases who develop COVID-19, age seems to be the main risk factor for progression to severe disease or death.