Lymphocyte trajectories are associated with prognosis in critically ill patients: A convenient way to monitor immune status

Clinical impact of transient lymphopenia

Transient or persistent immunosuppression is a known risk factor for morbidity and mortality in critically ill patients. Aim of the present study is to evaluate the lymphopenia in patients admitted to the Emergency Unit of AOU Policlinico Umberto I, to investigate its prevalence at admission and the persistence during hospitalization until discharge. Possible correlations were evaluated between lymphopenia, diagnosis of admission, comorbidities and chronic treatments. In this study, 240 patients (142 men; 98 female; mean age 75.1 ± 15.1) were enrolled. Patients were divided into two groups according to the lymphocytes count at hospital admission, namely "Group A" with lymphopenia and "Group B" with values in the normal range. Moreover, the patients in group A were distinguished in relation to the regression or persistence of the lymphopenia assessed at the time of hospital discharge (Group A1: persistence; Group A2: normalization). Prevalence of lymphopenia at admission was 57%; Group A showed higher mean age and percentage of patients over 65 years of age; and none differences were observed regarding gender. Prevalence of lymphopenia at admission was 57%; Group A showed higher mean age and percentage of patients over 65 years of age; no differences were observed regarding gender. All subsets of the lymphocytes (CD4+, CD8+, NK) were equally reduced. Persistent lymphopenia was found in 19% of patients. Lymphopenia should be valued at the time of hospital admission as a factor influencing the prognosis, the management and the treatment of these patients.

Clinical practice of sepsis-induced immunosuppression: Current immunotherapy and future options

Sepsis is a potentially fatal condition characterized by the failure of one or more organs due to a disordered host response to infection. The development of sepsis is closely linked to immune dysfunction. As a result, immunotherapy has gained traction as a promising approach to sepsis treatment, as it holds the potential to reverse immunosuppression and restore immune balance, thereby improving the prognosis of septic patients. However, due to the highly heterogeneous nature of sepsis, it is crucial to carefully select the appropriate patient population for immunotherapy. This review summarizes the current and evolved treatments for sepsis-induced immunosuppression to enhance clinicians' understanding and practical application of immunotherapy in the management of sepsis.

[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.

Characteristics and Clinical Prognosis of Septic Patients With Persistent Lymphopenia

Background: Septic patients with persistent lymphopenia may be in an immunosuppressed state. Therefore, we evaluated and compared the clinical characteristics and outcomes of septic patients with persistent lymphopenia (≥2d) and those with nonpersistent lymphopenia. Methods: A retrospective cohort study was designed. A total of 1306 patients with sepsis who were attended to the First Affiliated Hospital of Dalian Medical University from March 2016 to August 2022 were included. The primary clinical outcome was 90d mortality. The secondary clinical outcomes were the length of stay, hospital mortality, 28d mortality, the incidence of secondary infection, and differences in clinical characteristics. Results: Among 1306 patients with sepsis, 913 (69.9%) patients developed persistent lymphopenia. Compared with patients with nonpersistent lymphopenia, patients with persistent lymphocytopenia were admitted to intensive care unit (75.7% vs 52.7%, P < .05), treated with mechanical ventilation (67.6% vs 39.2%, P < .05), positive rate of microbial culture pathogens (86.7% vs 71.2%, P < .05), SOFA [8.0 (6.0-10.0) vs 6.0 (4.0-8.0), P < .05], length of stay [17.0d (12.0-27.0) vs 13.0d (10.0-21.0), P < .05], hospital mortality (37.7% vs 24.2%, P < .05), 28d mortality (38.0% vs 22.9%, P < .05), and 90d mortality (51.2% vs 31.3%, P < .05) were higher. As the duration of lymphocytopenia increased, so did the mortality rate in hospital. In addition, the onset time of persistent lymphopenia was not associated with SOFA. But we found that the frequency of persistent lymphopenia during hospitalization was positively associated with SOFA. Conclusion: Septic patients with persistent lymphopenia have higher mortality, worse conditions, increased risk of secondary infection, and poor prognosis regardless of shock.

Dynamic increase in myoglobin level is associated with poor prognosis in critically ill patients: a retrospective cohort study

Background

Myoglobin is an important biomarker for monitoring critically ill patients. However, the relationship between its dynamic changes and prognosis remains unclear.

Methods

We retrospectively enrolled 11,218 critically ill patients from a general and surgical intensive care unit (ICU) of a tertiary hospital between June 2016 and May 2020. Patients with acute cardiovascular events, cardiac and major vascular surgeries, and rhabdomyolysis were excluded. To investigate the early myoglobin distribution, the critically ill patients were stratified according to the highest myoglobin level within 48 h after ICU admission. Based on this, the critically ill patients with more than three measurements within 1 week after ICU admission were included, and latent class trajectory modeling was used to classify the patients. The characteristics and outcomes were compared among groups. Sensitivity analysis was performed to exclude patients who had died within 72 h after ICU admission. Restricted mean survival time regression model based on pseudo values was used to determine the 28-day relative changes in survival time among latent classes. The primary outcome was evaluated with comparison of in-hospital mortality among each Trajectory group, and the secondary outcome was 28-day mortality.

Results

Of 6,872 critically ill patients, 3,886 (56.5%) had an elevated myoglobin level (≥150 ng/mL) at admission to ICU, and the in-hospital mortality significantly increased when myoglobin level exceeded 1,000 μg/mL. In LCTM, 2,448 patients were unsupervisedly divided into four groups, including the steady group (n = 1,606, 65.6%), the gradually decreasing group (n = 523, 21.4%), the slowly rising group (n = 272, 11.1%), and the rapidly rising group (n = 47, 1.9%). The rapidly rising group had the largest proportion of sepsis (59.6%), the highest median Sequential Organ Failure Assessment (SOFA) score (10), and the highest in-hospital mortality (74.5%). Sensitivity analysis confirmed that 98.2% of the patients were classified into the same group as in the original model. Compared with the steady group, the rapidly rising group and the slowly rising group were significantly related to the reduction in 28-day survival time (β = -12.08; 95% CI -15.30 to -8.86; β = -4.25, 95% CI -5.54 to -2.97, respectively).

Conclusion

Elevated myoglobin level is common in critically ill patients admitted to the ICU. Dynamic monitoring of myoglobin levels offers benefit for the prognosis assessment of critically ill patients.

Persistent lymphocyte reduction and interleukin-6 levels are independently associated with death in patients with COVID-19

To investigate the value of the peripheral blood lymphocyte count (LYM) combined with interleukin-6 (IL-6) in predicting disease severity and prognosis in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia. This was a prospective observational cohort study. A total of 109 patients with SARS-CoV-2 pneumonia who were admitted to Nanjing First Hospital from December 2022 to January 2023 were enrolled. The patients were divided into two groups based on disease severity: severe (46 patients) and critically ill (63 patients). The clinical data of all patients were collected. The clinical characteristics, sequential organ failure assessment (SOFA) score, peripheral blood lymphocyte count, IL-6 level and other laboratory test results were compared between the two groups. A receiver operating characteristic (ROC) curve was plotted to evaluate the predictive value of each index for SARS-CoV-2 pneumonia severity; patients were regrouped using the optimal cut-off value of the ROC curve, and the relationship between different LYM and IL-6 levels and the prognosis of patients was analysed. Kaplan‒Meier survival curve analysis was performed; in the different LYM and IL-6 groups, the patients were regrouped based on whether thymosin was used, and the effect of thymosin on patient prognosis was compared between the groups. Patients in the critically ill group were significantly older than patients in the severe group (age: 78 ± 8 vs. 71 ± 17, t = 2.982, P < 0.05), and the proportion of patients with hypertension, diabetes and cerebrovascular disease was significantly higher in the critically ill group than in the severe group (69.8% vs. 45.7%, 38.1% vs. 17.4%, 36.5% vs. 13.0%; χ2 values, 6.462, 5.495, 7.496, respectively, all P < 0.05). Compared with the severe group, the critically ill group had a higher SOFA score on admission (score: 5.4 ± 3.0 vs. 1.9 ± 1.5, t = 24.269, P < 0.05); IL-6 and procalcitonin (PCT) in the critically ill group were significantly higher than those in the severe group on the first day of admission [288.4 (191.4, 412.9) vs. 513.0 (288.2, 857.4), 0.4 (0.1, 3.2) vs. 0.1 (0.05, 0.2); Z values, 4.000, 4.456, both P < 0.05]. The lymphocyte count continued to decline, and the lymphocyte count on the 5th day (LYM-5d) was still low (0.6 ± 0.4 vs. 1.0 ± 0.4, t = 4.515, both P < 0.05), with statistically significant differences between the two groups. ROC curve analysis indicated that LYM-5d, IL-6 and LYM-5d + IL-6 all had value for predicting SARS-CoV-2 pneumonia severity; the areas under the curve (AUCs) were 0.766, 0.725, and 0.817, respectively, and the 95% confidence intervals (95% CI) were 0.676-0.856, 0.631-0.819, and 0.737-0.897, respectively. The optimal cut-off values for LYM-5d and IL-6 were 0.7 × 109/L and 416.4 pg/ml, respectively. LYM-5d + IL-6 had the greatest value in predicting disease severity, and LYM-5d had higher sensitivity and specificity in predicting SARS-CoV-2 pneumonia severity. Regrouping was performed based on the optimal cut-off values for LYM-5d and IL-6. Comparing the IL-6 ≥ 416.4 pg/ml and LYM-5d < 0.7 × 109/L group with the other group, i.e., patients in the non-low-LYM-5d and high-IL-6 group, patients in the low-LYM-5d and high-IL-6 group had a higher 28-day mortality rate (71.9% vs. 29.9%, χ2 value 16.352, P < 0.05) and a longer hospital stay, intensive care unit (ICU) stay and mechanical ventilation time (days: 13.7 ± 6.3 vs. 8.4 ± 4.3, 9.0 (7.0, 11.5) vs. 7.5 (4.0, 9.5), 8.0 (6.0, 10.0) vs. 6.0 (3.3, 8.5); t/Z values, 11.657, 2.113, 2.553, respectively, all P < 0.05), as well as a higher incidence of secondary bacterial infection during the disease course (75.0% vs. 41.6%, χ2 value 10.120, P < 0.05). Kaplan‒Meier survival analysis indicated that the median survival time of patients in the low LYM-5d and high-IL-6 group was significantly shorter than that of patients in the non-low LYM-5d and high-IL-6 group (14.5 ± 1.8 d vs. 22.2 ± 1.1 d, Z value 18.086, P < 0.05). There was no significant difference in the curative effect between the thymosin group and the nonthymosin group. LYM and IL-6 levels are closely related to SARS-CoV-2 pneumonia severity. The prognosis for patients with IL-6 ≥ 416.4 pg/ml at admission and a lymphocyte count < 0.7 × 10 9/L on the 5th day is poor.

Expert consensus on the monitoring and treatment of sepsis-induced immunosuppression

Emerged evidence has indicated that immunosuppression is involved in the occurrence and development of sepsis. To provide clinical practice recommendations on the immune function in sepsis, an expert consensus focusing on the monitoring and treatment of sepsis-induced immunosuppression was developed. Literature related to the immune monitoring and treatment of sepsis were retrieved from PubMed, Web of Science, and Chinese National Knowledge Infrastructure to design items and expert opinions were collected through an online questionnaire. Then, the Delphi method was used to form consensus opinions, and RAND appropriateness method was developed to provide consistency evaluation and recommendation levels for consensus opinions. This consensus achieved satisfactory results through two rounds of questionnaire survey, with 2 statements rated as perfect consistency, 13 as very good consistency, and 9 as good consistency. After summarizing the results, a total of 14 strong recommended opinions, 8 weak recommended opinions and 2 non-recommended opinions were produced. Finally, a face-to-face discussion of the consensus opinions was performed through an online meeting, and all judges unanimously agreed on the content of this consensus. In summary, this expert consensus provides a preliminary guidance for the monitoring and treatment of immunosuppression in patients with sepsis.