Immune disorders in sepsis and their treatment as a significant problem of modern intensive care

Plasma fibronectin can affect the cytokine profile and monocytes/macrophages function in addition to predicting the prognosis of advanced sepsis

The value of plasma fibronectin (pFN) in the diagnosis and prognosis of sepsis has not been fully established. Previous studies finding that pFN is significantly reduced in sepsis, however, whether reduced pFn affects the prognosis of sepsis has not been clarified. Here, we detected and analyzed pFN and other conventional inflammatory markers in advanced sepsis patients and performed correlation analysis with SOFA score. We also used Fn gene conditional knockout mice which were performed by cecum ligation and puncture (CLP) to investigate the effect of FN deficiency on sepsis prognosis. We found, compared with procalcitonin, c-reactive protein, and interleukin-6, pFN was more correlated with SOFA score in advanced sepsis patients (r -.720, p < .001). In animal experiments, Fn gene knockout mice showed significantly greater mortality after CLP compared with the control group because of inhibited phagocytosis and bacterial clearance ability of macrophages, with double cytokine storm. Furthermore, FN can regulate macrophages through the integrin α5β1/Fak/Src signaling pathway. Overall, we found pFN can more accurately reflect the severity and prognosis of advanced sepsis. The absence of FN altered the cytokine storm and phagocytic function of macrophages, suggesting that FN could be a potential therapeutic target in sepsis.

Benefits of Chimeric Antigen Receptor T-Cell Therapy for B-Cell Lymphoma

Objective: The aim was to study the benefits and risks of anti-CD19 chimeric antigen receptor (CAR) T-cells in adults with B-cell lymphoma.

Methods: From October 2015 to October 2021, we treated five patients with B-cell lymphoma, comprising two with mantle cell lymphoma, one case of Burkitt lymphoma, one case of diffuse large B-cell lymphoma, and one case of chronic lymphocytic leukemia/small lymphocytic lymphoma. The patients were given the FC regimen 5 days before the infusion of anti-CD19 CAR T-cells. The median total number of CAR T-cells infusions was 350*10^6 (88*10^6–585*10^6).

Results: 1) Patients who received CAR T-cell induction therapy achieved complete remission (CR) in Case 1 and Case 3 and partial remission (PR) in Case 2. Case 3’s ATM and D13S25 gene deletions were negative 42 days after CAR T-cell therapy, and molecular biology CR (mCR) and minimal residual disease (MRD) were negative for 5 years and 6 months. The patient in Case 3 was cured. 2) Case 4 patient’s TP53 gene mutation became negative 1 month after CAR T-cell therapy. MRD was negative after CAR T-cell therapy at 41 and 42 months in Cases 4 and 5, respectively. 3) Case 1∼Case 3 patients developed cytokine release syndrome (CRS) without encephalopathy syndrome, accompanied with serious adverse events. CRS can be effectively managed with tocilizumab, etanercept, glucocorticoids, and plasmapheresis.

Conclusion: Anti-CD19 CAR T-cell therapy is effective in treating relapsed/refractory B-cell lymphoma, and the side effects of CAR T-cell therapy can be properly managed. CAR T-cell therapy has high efficacy and presented no side effects in the treatment of MRD in B-cell lymphoma (NCT03685786, NCT02456350).

Tetramethylpyrazine Ameliorates Lipopolysaccharide-Induced Sepsis in Rats via Protecting Blood-Brain Barrier, Impairing Inflammation and Nitrous Oxide Systems

The aim of this study was to assess the underlying impact of Tetramethylpyrazine (TMP), which is the main activity compound of Ligusticum chuanxiong Hort, on the blood–brain barrier, inflammatory and nitrous oxide systems in a rat model of lipopolysaccharide (LPS)-induced sepsis. The SD rats were divided into control group, LPS treatment group, and LPS + TMP treatment group. TMP administered by tail vein injection. The mortality of experimental rats was recorded during the experiment. Rats were sacrificed after 14 days. Peripheral blood was collected and the expression levels of inflammatory factors TNF-α, IL-1β, and IL-6 were detected by ELISA. The integrity of blood-brain barrier was detected by sodium fluorescein staining. Lung and brain tissues were taken to detect the infiltration of immune cells. Immunohistochemistry was performed to detect the expression of tight junctions related proteins and oxidative stress-related proteins. The results showed that TMP treatment for 14 days significantly decreased the weight loss and increased the survival rate of the septic rats significantly. TMP decreased the infiltration of inflammatory cells and alleviated the sepsis-induced damage in both the lung and brain tissues. The inflammatory cytokines TNF-α, IL-1β, and IL-6, were significantly decreased post-TMP treatment. Histopathological analysis with sodium fluorescein staining density showed that TMP had a protective effect on the basal lamina and cerebral cortex. Also, TMP significantly increased expression of the tight junction-related proteins claudin-5 and occludin in the brain tissue and increased the expression of the ZO-1, Occludin, and Claudin-5 genes, indicating alleviated the degree of blood–brain barrier destruction. Furthermore, immunohistochemistry (IHC) and immunoblotting confirmed that TMP could inhibit the indicators of the nitrous oxide system, iNOS and eNOS; in addition, TMP significantly decreased the levels of MDA and NO. The findings showed that TMP treatment during sepsis was associated with the protection of the blood–brain barrier and the suppression of inflammatory reactions and the nitrous oxide system. This study reveals a promising protective role of TMP in septic encephalopathy and may suggest a therapeutic approach for fighting the deadly disease of sepsis in the clinic.

The increased marginal zone B cells attenuates early inflammatory responses during sepsis in Gpr174 deficient mice

GPR174 plays a crucial role in immune responses, but the role of GPR174 in the pathological progress of sepsis remains incompletely understood. In this study, we generated a sepsis model by cecal ligation and puncture (CLP) to investigate the role of GPR174 in regulating functions and underlying mechanism of marginal zone B (MZ B) cells in sepsis. We found that in Gpr174 deficient mice, the number of splenic MZ B cells was increased. Moreover, Gpr174^-/- MZ B cells exhibited an enhanced response to LPS stimulation in vitro. By using the CLP-induced sepsis model, we demonstrated that the increased MZ B cells attenuated early inflammatory responses during sepsis. RNA sequencing results revealed that the expression of c-fos in splenic B lymphocytes was upregulated in Gpr174 deficient mice. However, the protective role of increased MZ B cells in Gpr174 deficient mice was weakened by a c-fos-specific inhibitor. Collectively, these findings suggested that GPR174 plays an immunomodulatory role in early immune responses during sepsis through the regulation of MZ B cells.

Notch signaling pathway regulates T cell dysfunction in septic patients

Sepsis disrupts innate and adaptive immune response, and immune disorders may also impact clinical course of sepsis. Notch signaling pathway plays a vital role in T cell modulation and differentiation. The aim of current study was to investigate the immunoregulatory function of Notch signaling pathway to T cells in patients with sepsis and septic shock. Twenty-seven sepsis patients, twenty-five septic shock patients, and twenty-one normal controls (NCs) were enrolled. Notch receptors mRNA levels were semi-quantified by real-time PCR. The absolute numbers of CD3⁺, CD4⁺, and CD8⁺ T cells were measured by flow cytometry. Key transcriptional factors of CD4⁺ T cells, cytotoxic molecules in CD8⁺ T cells, and cytotoxicity of CD8⁺ T cells were investigated. The regulatory activities of Notch signaling inhibition by γ-secretase inhibitor (GSI) on purified CD4⁺ and CD8⁺ T cells from sepsis and septic shock patients were also assessed. Notch1 mRNA relative level was significantly elevated in sepsis and septic shock patients when compared with NCs. CD4⁺ and CD8⁺ T cells were dysfunctional in sepsis and septic shock, which presented as decreased cell accounts, down-regulation of Th1/Th17 transcriptional factors and cytotoxic molecules (perforin, granzyme B, and FasL), and reduced cytotoxicity of CD8⁺ T cells. Notch signaling inhibition by GSI increased Th1 and Th17 differentiation of CD4⁺ T cells. Moreover, GSI stimulation not only promoted perforin, granzyme B, and FasL mRNA expression in CD8⁺ T cells, but also elevated CD8⁺ T cell-induced target cell death and IFN-γ/TNF-α production in sepsis and septic shock. The current data suggest that Notch signaling pathway contributes to T cell dysfunction and limited immune response in sepsis.

Plasma Exchange Can Be an Alternative Therapeutic Modality for Severe Cytokine Release Syndrome after Chimeric Antigen Receptor-T Cell Infusion: A Case Report

BACKGROUND

Tumor immunotherapy with chimeric antigen receptor-T cells (CAR-T) is a promising new treatment for B-cell malignancies and has produced exciting results. However, cytokine release syndrome (CRS) is the most significant toxicity associated with this treatment and can be life-threatening.

CASE PRESENTATION

A 23-year-old male patient had been diagnosed with relapsed and refractory B-cell acute lymphocytic leukemia. The patient was recruited into our CAR-T clinical trial, and 1 × 10⁶/kg of engineered anti-CD19 CAR-T cells was administered. After infusion of CAR-T cells (day 0), the patient underwent a typical CRS reaction, with increases in fever, muscle soreness, and inflammatory cytokines. He was treated with antiallergic and antipyretic drugs, glucocorticoids, and tocilizumab (4 mg/kg, days 3 and 5). However, CRS was not under control, and his condition rapidly deteriorated. He was transferred to the intensive care unit, where dexamethasone 10 mg q6h was administered, and plasma exchange was performed, with 3,000 mL of plasma replaced by fresh frozen plasma per day for 3 consecutive days. His symptoms gradually improved, and the CRS-related symptoms were relieved. Additionally, a bone marrow smear showed no lymphoblast cells, and minimal residual disease was negative on day 28. The patient was eventually discharged in a normal condition.

CONCLUSIONS

CRS is caused by an exaggerated systemic immune response, potentially resulting in organ damage that can be fatal. Although therapeutic plasma exchange is not included in CRS management guidelines, this case shows that plasma exchange is feasible in at least some patients with severe CRS.