T cell cytokines in the diagnostic of early-onset sepsis

Diagnostic Utility of Interleukin-6 in Early-Onset Sepsis among Term Newborns: Impact of Maternal Risk Factors and CRP Evaluation

(1) Background: Interleukin-6 (IL-6) levels act as an early infection marker preceding C-reactive protein (CRP) elevation. This study seeks to analyze IL-6 behavior in suspected early-onset sepsis (EOS) cases among term newborns, comparing it to that of CRP and evaluating IL-6's diagnostic utility. We also aim to assess the impact of maternal risk factors on EOS in term newborns, quantifying their influence for informed decision making. (2) Methods: The retrospective data analysis included 533 term newborns who were admitted to our hospital because of suspected EOS. IL-6, CRP, and the impact of maternal risk factors were analyzed in the context of EOS using binomial test, Chi-squared test, logistic and linear regression. (3) Results: In the cases of EOS, both IL-6 and CRP were elevated. The increase in CRP can be predicted by the initial increase in IL-6 levels. Among the assessed risk factors, intrapartum maternal fever (adjusted odds ratio 18.1; 95% CI (1.7-4.1)) was identified as the only risk factor significantly associated with EOS. (4) Conclusions: Employing IL-6 as an early infection marker enhanced EOS diagnostic precision due to its detectable early rise. However, caution is required, as elevations in IL-6 and CRP levels do not exclusively indicate EOS. Increased CRP levels in healthy newborns with maternal risk factors may be attributed to dynamics of vaginal labor.

Gram-negative bacterial infection causes aggravated innate immune response in sepsis: Studies from clinical samples and cellular models

Bacterial infection is the most common cause for sepsis. The purpose of this study was to evaluate the impact of different bacterial infection on sepsis based on human samples and cellular experiments. Physiological indexes and prognostic information of 121 sepsis patients were analysed based on whether they had a gram-positive or gram-negative bacterial infection. Moreover, murine RAW264.7 macrophages were treated with lipopolysaccharide (LPS) or peptidoglycan (PG) to simulate infection with gram-negative or gram-positive bacteria in sepsis, respectively. Exosomes derived from the macrophages were extracted for transcriptome sequencing. In patients with sepsis, most gram-positive bacterial infections were Staphylococcus aureus, and gram-negative infections were Escherichia coli. Gram-negative bacterial infection was significantly associated with high neutrophil and interleukin (IL)-6 levels in blood and shorter prothrombin (PT) and activated partial thromboplastin time (APTT). Intriguingly, the survival prognosis of sepsis patients was not affected by the type of bacterial infection, but it was significantly related to fibrinogen. Protein transcriptome sequencing of the macrophage-derived exosomes showed that differentially expressed proteins were significantly enriched in megakaryocyte differentiation, leukocyte and lymphocyte-mediated immunity, and complement and coagulation cascade pathways. The complement and coagulation-related proteins were significantly upregulated after LPS induction, which explained the shortened PT and APTT in gram-negative bacterial sepsis. Bacterial infection did not affect mortality in sepsis but did alter the host response. The immune disorder induced by gram-negative infection was more severe than that produced by gram-positive infection. This study provides references for the rapid identification and molecular research of different bacterial infections in sepsis.

Group B Streptococcus Early-Onset Disease: New Preventive and Diagnostic Tools to Decrease the Burden of Antibiotic Use

The difficulty in recognizing early-onset neonatal sepsis (EONS) in a timely manner due to non-specific symptoms and the limitations of diagnostic tests, combined with the risk of serious consequences if EONS is not treated in a timely manner, has resulted in a low threshold for starting empirical antibiotic treatment. New guideline strategies, such as the neonatal sepsis calculator, have been proven to reduce the antibiotic burden related to EONS, but lack sensitivity for detecting EONS. In this review, the potential of novel, targeted preventive and diagnostic methods for EONS is discussed from three different perspectives: maternal, umbilical cord and newborn perspectives. Promising strategies from the maternal perspective include Group B Streptococcus (GBS) prevention, exploring the virulence factors of GBS, maternal immunization and antepartum biomarkers. The diagnostic methods obtained from the umbilical cord are preliminary but promising. Finally, promising fields from the newborn perspective include biomarkers, new microbiological techniques and clinical prediction and monitoring strategies. Consensus on the definition of EONS and the standardization of research on novel diagnostic biomarkers are crucial for future implementation and to reduce current antibiotic overexposure in newborns.

Cytokine expression profiles in white blood cells of patients with small fiber neuropathy

BACKGROUND

The role of cytokines in the pathophysiology, diagnosis, and prognosis of small fiber neuropathy (SFN) is incompletely understood. We studied expression profiles of selected pro- and anti-inflammatory cytokines in RNA from white blood cells (WBC) of patients with a medical history and a clinical phenotype suggestive for SFN and compared data with healthy controls.

METHODS

We prospectively recruited 52 patients and 21 age- and sex-matched healthy controls. Study participants were characterized in detail and underwent complete neurological examination. Venous blood was drawn for routine and extended laboratory tests, and for WBC isolation. Systemic RNA expression profiles of the pro-inflammatory cytokines interleukin (IL)-1ß, IL-2, IL-8, tumor necrosis factor-alpha (TNF) and the anti-inflammatory cytokines IL-4, IL-10, transforming growth factor beta-1 (TGF) were analyzed. Protein levels of IL-2, IL-8, and TNF were measured in serum of patients and controls. Receiver operating characteristic (ROC)-curve analysis was used to determine the accuracy of IL-2, IL-8, and TNF in differentiating patients and controls. To compare the potential discriminatory efficacy of single versus combined cytokines, equality of different AUCs was tested.

RESULTS

WBC gene expression of IL-2, IL-8, and TNF was higher in patients compared to healthy controls (IL-2: p = 0.02; IL-8: p = 0.009; TNF: p = 0.03) and discriminated between the groups (area under the curve (AUC) ≥ 0.68 for each cytokine) with highest diagnostic accuracy reached by combining the three cytokines (AUC = 0.81, sensitivity = 70%, specificity = 86%). Subgroup analysis revealed the following differences: IL-8 and TNF gene expression levels were higher in female patients compared to female controls (IL-8: p = 0.01; TNF: p = 0.03). The combination of TNF with IL-2 and TNF with IL-2 and IL-8 discriminated best between the study groups. IL-2 was higher expressed in patients with moderate pain compared to those with severe pain (p = 0.02). Patients with acral pain showed higher IL-10 gene expression compared to patients with generalized pain (p = 0.004). We further found a negative correlation between the relative gene expression of IL-2 and current pain intensity (p = 0.02). Serum protein levels of IL-2, IL-8, and TNF did not differ between patients and controls.

CONCLUSIONS

We identified higher systemic gene expression of IL-2, IL-8, and TNF in SFN patients than in controls, which may be of potential relevance for diagnostics and patient stratification.

Altered Signatures of Plasma Inflammatory Proteins and Phonotypic Markers of NK Cells in Kidney Transplant Patients upon CMV Reactivation

Cytomegalovirus (CMV) reactivation remains a common opportunistic infection with a prominent role in immune reconstitution in organ transplant recipients. CMVs as important drivers of natural killer (NK) cell differentiation has been indicated to prompt several phenotypic and functional alteration in these cells. We aimed to monitor the reconstitution of NK cells and change the signature of inflammatory proteins at the critical phase of CMV reactivation over six months after kidney transplantation. The present study indicated that CMV reactivation is associated with the development of IL-6, IL-10, and cytotoxic granules, including granzyme-B and granulysin, and the drop in the frequency of CD16 + NKG2A-CD57 + NK cell subset in kidney transplant recipients (KTRs) with reactivation versus non- reactivated ones. Our findings describe distinct immune signatures that emerged with CMV reactivation after kidney transplantation, which may be helpful in the timely management of CMV infection in KTRs.

Prognostic Value of Platelet to Lymphocyte Ratio in Sepsis: A Systematic Review and Meta-analysis

The goal of this study was to conduct a systematic review of the literature on the relationship between peripheral blood platelet to lymphocyte ratio (PLR) and mortality in sepsis and to integrate the findings in a meta-analysis. An electronic search of three main databases was performed: PubMed, Embase, and Scopus on 19 December 2021. Finally, 16 studies comprising 2403 septic patients, including 1249 survivors and 1154 nonsurvivors, were included in this meta-analysis. We found that PLR levels were significantly higher in nonsurvivors than in survivors (random effect model: SMD = 0.72, 95% CI; 0.35–1.10, p < 0.001). However, significant heterogeneity was observed across the studies (I² = 94.1%, p < 0.01). So, we used random effect model in our meta-analysis. In the subgroup analysis, according to mortality time, patients deceased during one month after sepsis had elevated levels of PLR compared to survivors (SMD = 1.03, 95% CI = 0.15-1.92, p = 0.22). However, in-hospital mortality was not associated with PLR level (SMD = 0.41, 95% CI = −0.18-0.99, p = 0.175). Our findings support PLR to be a promising biomarker that can be readily integrated into clinical settings to aid in the prediction and prevention of sepsis mortality.

Correlation between thrombopoietin and inflammatory factors, platelet indices, and thrombosis in patients with sepsis: A retrospective study

BACKGROUND

Thrombopoietin (TPO) is a primary regulator of thrombopoiesis in physiological conditions. TPO, in combination with its specific cytokine receptor c-Mpl, drives platelet production by inducing the proliferation and differentiation of megakaryocytes. However, the role of TPO in sepsis is not well determined. The elevated levels of TPO are often accompanied by a decrease of platelet count (PLT) in systemic infected conditions, which is contrary to the view that TPO promotes platelet production under physiological conditions. In addition, whether TPO mediates organ damage in sepsis remains controversial.

AIM

To explore the relationships between TPO and inflammatory factors, platelet indices, and thrombotic indicators in sepsis.

METHODS

A total of 90 patients with sepsis diagnosed and treated at the emergency medicine department of The First People’s Hospital of Foshan between January 2020 and March 2021 were enrolled in this study. In addition, 110 patients without sepsis who came to the emergency medicine department were included as controls. Clinical and laboratory parameters including age, gender, TPO, blood cell count in peripheral blood, platelet indices, inflammatory factors such as high-sensitivity C-reactive protein (hs-CRP), interleukin (IL)-21, and IL-6, organ damage indicators, and thrombotic indicators were collected and analyzed by using various statistical approaches.

RESULTS

The results showed that the TPO levels were higher in the sepsis group than in controls [86.45 (30.55, 193.1) vs 12.45 (0.64, 46.09) pg/mL, P < 0.001], but PLT was lower (P < 0.001). Multivariable analysis showed that white blood cell count (WBC) [odds ratio (OR) = 1.32; 95% confidence interval (CI): 1.01-1.722; P = 0.044], TPO (OR = 1.02; 95%CI: 1.01-1.04; P = 0.009), IL-21 (OR = 1.02; 95%CI: 1.00-1.03; P = 0.019), troponin I (OR = 55.20; 95%CI: 5.69-535.90; P = 0.001), and prothrombin time (PT) (OR = 2.24; 95%CI: 1.10-4.55; P = 0.027) were independent risk factors associated with sepsis. TPO levels were positively correlated with IL-21, IL-6, hs-CRP, creatinine, D-dimer, PT, activated prothrombin time, international normalized ratio, fibrinogen, WBC count, and neutrophil count, and negatively correlated with PLT, thrombin time, red blood cell count, and hemoglobin concentration (P < 0.05). Receiver operating characteristic analysis showed that TPO had fair predictive value in distinguishing septic patients and non-septic patients (the area under the curve: 0.788; 95%CI: 0.723-0.852; P < 0.001). With an optimized cutoff value (28.51 pg/mL), TPO had the highest sensitivity (79%) and specificity (65%).

CONCLUSION

TPO levels are independently associated with sepsis. High TPO levels and low PLT suggest that TPO might be an acute-phase response protein in patients with infection.