Predictive value of peripheral lymphocyte subsets for the disease progression in patients with sepsis

Establishment and assessment of mortality risk prediction model in patients with sepsis based on early-stage peripheral lymphocyte subsets

This study is aimed to explore the value of lymphocyte subsets in evaluating the severity and prognosis of sepsis. The counts of lymphocytes, CD3+ T cells, CD4+ T cells, CD8+ T cells, CD19+ B cells, and NK cells significantly decreased between day 1 and day 3 in both the survivor and the non-survivor groups. The peripheral lymphocyte subsets (PLS) at day 1 were not significantly different between the survivor and the non-survivor groups. However, at day 3, the counts of lymphocytes, CD3+ T cells, CD4+ T cells, and NK cells were remarkably lower in the non-survivor group. No significant differences in CD8+ T cells, or CD19+ B cells were observed. The PLS index was independently and significantly associated with the 28-day mortality risk in septic patients (OR: 3.08, 95% CI: 1.18-9.67). Based on these clinical parameters and the PLS index, we developed a nomograph for evaluating the individual mortality risk in sepsis. The area under the curve of prediction with the PLS index was significantly higher than that from the model with only clinical parameters (0.912 vs. 0.817). Our study suggests that the decline of PLS occurred in the early stage of sepsis. The new novel PLS index can be an independent predictor of 28-day mortality in septic patients. The prediction model based on clinical parameters and the PLS index has relatively high predicting ability.

[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.

Analysis of mitochondrial function in lymphocytes obtained from COVID-19 patients

OBJECTIVES

There is a significant decline in the lymphocyte subset counts in the peripheral blood of COVID-19 patients. However, the mitochondrial function of lymphocytes obtained from COVID-19 patients has rarely been studied.

METHODS

A case-control study was conducted in 115 COVID-19 patients and 50 healthy controls from December 2022 to February 2023. The extent of lymphocytic mitochondrial damage in these patients using mitochondrial fluorescence staining and flow cytometry. Clinical symptoms were evaluated using the SOFA and APACHE II scores.

RESULTS

The mitochondrial function of lymphocytes was severely impaired in the peripheral blood of COVID-19 patients, compared to healthy controls, and was characterized by an increased single-cell mitochondrial mass (SCMM) and increased percentage of low mitochondrial membrane potential. The increase in the SCMM of T cells was more notable in patients with severe COVID-19 and was positively correlated with the SOFA and APACHE II scores. When the SCMM-CD8 cutoff value was 38.775, the AUC for distinguishing between severe and mild COVID-19 was 0.740, and the sensitivity, specificity, and Youden index were 65.8%, 82.1%, and 0.478, respectively.

CONCLUSION

SCMM-CD8 could act as a diagnostic biomarker of COVID-19 progression. However, this needs to be verified in other multi-center studies with a larger sample size.