Innate immunity recovers earlier than acquired immunity during severe postoperative immunosuppression

Evaluating perioperative stresses in children by noninvasive modalities using salivary cortisol and autonomic reactivity

PURPOSE

Salivary cortisol (SalC) and low to high pulse ratio (LHR) were used for evaluating perioperative stresses in children.

METHODS

Children aged 6 months-16 years having elective general (thoracic/abdominal) or minor (open/minimally invasive: MI) procedures underwent pulse monitoring during AM (08:00-12:00) and PM (17:00-21:00) saliva collections from the day before surgery (S-1) to 3 days after surgery (S + 3). SalC/LHR were correlated with age, sex, caregiver attendance, operative time, and surgical site/approach using mixed model analysis and face/numeric pain rating scales (FRS/NRS).

RESULTS

Mean ages (years): minor-open (n = 31) 4.7 ± 2.0, thoracic-open (n = 2) 8.7 ± 4.9, thoracic-MI (n = 6) 9.6 ± 6.1, abdominal-open (n = 14) 4.3 ± 4.1, and abdominal-MI (n = 32) 8.0 ± 5.0. Postoperative SalC increased rapidly and decreased to preoperative levels by S + 3 (p < 0.001). LHR increased slightly without decreasing (p = 0.038). SalC correlated positively with operative time (p = 0.036) and open surgery (p = 0.0057), and negatively with age (p < 0.0001) and caregiver attendance (p < 0.001). SalC correlated positively with FRS (n = 51) at S + 2(PM) (p = 0.023), S + 3(AM) (p < 0.001), S + 3(PM) (p = 0.012) and NRS (n = 34) at S + 1(AM) (p = 0.031), S + 3(AM) (p < 0.044). LHR positively correlated with age (p = 0.0072), female sex (p = 0.0047), and caregiver attendance (p = 0.0026). Postoperative SalC after robotic-assisted MI was significantly lower than after open surgery at S + 2(AM) (p = 0.020).

CONCLUSIONS

SalC correlated with pain. Caregiver attendance effectively alleviated stress.

Can peri-surgical electroacupuncture relieve immunity suppression? A pilot study in dogs

General anesthesia and surgical stress can suppress the immunological response by acting both directly on the immune system and indirectly on the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system. Disturbance of the immune system during the perioperative period can lead to complications such as wound-healing disorders and infections up to sepsis. Effectiveness of acupuncture in regulating the immune function by increasing leukocyte numbers and inhibiting inflammatory response has been proven. This study aimed to explore the impact of electroacupuncture (EAP) on the dynamic balance of the immune system and immune cell populations in dogs undergoing surgery. Twelve healthy bitches scheduled for elective ovariectomy were divided into two groups according to whether (EAP, n=6) or not (CTR, n=6) a peri-operative electroacupuncture treatment was performed. Levels of leukocytes (neutrophils, monocytes, T- and B-cells) and immunoglobulins M (IgM) and A (IgA) were measured in blood samples collected before (T0), 1 h (T1) and 2.5 h (T2) after anesthesia induction. Leukocytes count decreased from T0 to T1 in both groups and restored within 1.5 h in EAP group whereas remained significantly lower in CTR group (P<0.02). In particular, neutrophils and monocytes increased in dogs receiving EAP (P<0.01) while T-cells decreased in CTR group (P<0.04) at T2. B-cells and cytotoxic T-cells decreased in EAP dogs (P<0.04) at T2. No differences in helper T-cells, IgM and IgA levels were recorded between groups and over time. Our results suggest a modulatory effect of EAP on the immune system which is early expressed on neutrophils, monocytes and T-cells.

Postoperative Changes in Systemic Immune Tolerance Following Major Oncologic versus Minor Maxillofacial Surgery

BACKGROUND

There is increasing evidence of the benefits of adjuvant and neoadjuvant immunotherapy in the treatment of solid malignancies like oral squamous cell carcinoma (OSCC). To optimize (neo-)adjuvant treatment, the systemic immunomodulatory effects of tumor surgery itself need to be considered. Currently, there is little evidence on the immunological effects of major surgery, such as free microvascular flap reconstruction. The current study aims to analyze how and to what extent maxillofacial surgery affects systemic parameters of immune tolerance.

METHODS

A total of 50 peripheral whole blood samples from patients (Group 1 (G1) = extensive OSCC surgery; Group 2 (G2) = free flap reconstruction without persistent malignant disease; Group 3 (G3) = minor maxillofacial surgery) undergoing surgery were included for real-time quantitative polymerase chain reaction (RT-qPCR) to examine changes in mRNA expression of the biomarkers IL-6, IL-10, FOXP3, and PD-L1. Blood samples were taken immediately before and after surgery as well as on the second, fourth, and tenth postoperative days. Differences in mRNA expression between groups and time points were calculated using statistical tests, including Mann-Whitney U-test and Pearson correlation analysis.

RESULTS

Comparing postoperative expression of G1 and G3, there was a significantly higher PD-L1 expression (p = 0.015) in G1 compared to G3 and a significantly lower IL-6 (p = 0.001) and FOXP3 (p = 0.016) expression. Interestingly, IL-10 expression was higher pre- (0.05) and postoperative (p < 0.001) in G1 compared to G3. Additionally, in G1, there was a significant overexpression of IL-10 post-surgery compared to the preoperative value (p = 0.03) and a downregulated expression of FOXP3 between pre- and 2 d post-surgery (p = 0.04). Furthermore, there was a significant correlation between the duration of surgery and the perioperative expression changes of the analyzed biomarkers. As the duration of surgery increased, the expression of IL-10 and PD-L1 increased, and the expression of IL-6 and FOXP3 decreased.

CONCLUSION

Extensive surgery in OSCC patients is associated with a transient shift toward postoperative systemic immune tolerance compared with patients undergoing minor surgery. However, even extensive surgery causes no signs of long-lasting systemic immunosuppression. The degree of immune tolerance that occurred was associated with the duration of surgery. This supports efforts to minimize the duration of surgery.

Impact of Immunonutrition on T Cell Activation: A Randomized Control Study in Cardiac Surgery Patients

Background.

Cardiac surgery provokes an intense inflammatory response that can cause an immunosuppressive state and adverse postoperative outcomes. We recently showed that postoperative immunonutrition with glutamine in “fragile” low-risk cardiac surgery patients was associated with a significantly increased level of CD3+ and CD4+ T cells. In order to clarify the biological relevance and clinical importance of these findings, we investigated whether an increase in the CD4+ T cell level was caused by changes in the systemic inflammatory response (caused by surgery or infection) and if it was associated with their activation status.

Methods.

A randomized control study of low operative risk but “fragile” cardiac surgery patients was performed. Patients were randomized into immunonutrition (IN) and control groups (C). The IN group received normal daily meals plus special immune nutrients for 5 days postoperatively, while the C group received only normal daily meals. Laboratory parameters were investigated before surgery and on the sixth postoperative day and the groups were compared accordingly. The expression of the CD69+ marker was investigated to determine T cell activation status. Serum concentrations of cytokines (interleukin-10 (IL-10), tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6)) and C-reactive protein (CRP) were determined to assess the systemic inflammatory response, while procalcitonin (PCT) levels were evaluated to confirm or deny possible bacterial infection.

Results.

Fifty-five patients were enrolled in the study. Twenty-seven (49.1%) were randomized in the IN group. Results show that on the sixth postoperative day, the CD4+CD69+ and CD8+CD69+ counts did not differ between the IN and C groups, accordingly 0.25 [0.16–0.50] vs 0.22 [0.13-0.41], p=0.578 and 0.13 [0.06–0.3] vs 0.09 [0.05–0.14], p=0.178. Also, statistically significant differences were not observed in the cytokine levels (IN and C groups: TNF-α 8.13 [7.32–10.31] vs 8.78 [7.65–11.2], p=0.300; IL-6 14.65 [9.28–18.95] vs 12.25 [8.55–22.50], p=0.786; IL-10 5.0 [5.0–5.0] vs 5.0 [5.0–5.0], p=0.343 respectively), which imply that an elevated T cell count is not associated with the systemic inflammatory response. Also, PCT (IN and C groups: 0.03 [0.01–0.09] vs 0.05 [0.03–0.08], p=0.352) and CRP (IN and C groups 62.7 [34.2–106.0] vs 63.7 [32.9–91.0], p=0.840) levels did not differ between the two groups. Moreover, low levels of PCT indicated that the increase in T cell count was not determined by bacterial infection.

Conclusions.

Our findings showed that CD4+ T cell levels were associated with neither the systemic inflammatory response nor bacterial infection. Secondly, increases in T cells are not accompanied by their activation status. These results suggest a hypothesis that a higher postoperative T cell concentration may be associated with postoperative immunonutrition in low-risk cardiac surgery patients with intact cellular vitality, i.e. “fragile”. However, immunonutrition alone did not affect T cell activation status.

Immunomonitoring of Monocyte and Neutrophil Function in Critically Ill Patients: From Sepsis and/or Trauma to COVID-19

Immune cells and mediators play a crucial role in the critical care setting but are understudied. This review explores the concept of sepsis and/or injury-induced immunosuppression and immuno-inflammatory response in COVID-19 and reiterates the need for more accurate functional immunomonitoring of monocyte and neutrophil function in these critically ill patients. in addition, the feasibility of circulating and cell-surface immune biomarkers as predictors of infection and/or outcome in critically ill patients is explored. It is clear that, for critically ill, one size does not fit all and that immune phenotyping of critically ill patients may allow the development of a more personalized approach with tailored immunotherapy for the specific patient. In addition, at this point in time, caution is advised regarding the quality of evidence of some COVID-19 studies in the literature.

Trained Immunity as a Preventive Measure for Surgical Site Infections

Even with strict implementation of preventive measures, surgical site infections (SSIs) remain among the most prevalent health care-associated infections. New strategies to prevent SSIs would thus have a huge impact, also in light of increasing global rates of antimicrobial drug resistance. Considering the indispensable role of innate immune cells in host defense in surgical wounds, enhancing their function may represent a potential strategy for prevention of SSIs. Trained immunity is characterized by metabolic, epigenetic, and functional reprogramming of innate immune cells. These functional changes take place at multiple levels, namely, at the level of bone marrow precursors, circulating innate immune cells, and resident tissue macrophages. Experimental studies have shown that induction of trained immunity can protect against various infections. Increasing evidence suggests that it may also lower the risk and severity of SSIs. This may occur through several different mechanisms. First, trained immunity enhances local host defense against soft tissue infections, including those caused by Staphylococcus aureus, the most common cause of SSIs. Second, training effects on nonimmune cells such as fibroblasts have been shown to improve wound repair. Third, trained immunity may prevent or reverse the postoperative immunoparalysis that contributes to risk of infections following surgery. There are multiple approaches to inducing trained immunity, such as vaccination with the bacillus Calmette-Guérin (BCG) tuberculosis vaccine, topical administration of β-glucan, or treatment with the Toll-like receptor 7 agonist imiquimod. Clinical-experimental studies should establish if and how induction of trained immunity can best help prevent SSIs and what patient groups would most benefit.

Rapid Arc-SBRT: Non-invasive immune adjuvant for advanced stage Non-Small Cell Lung Carcinoma

In conjunction with Radio-chemotherapy, pulmonary resection is recommended for early-stage Non-small-cell lung carcinoma but not for advanced-stage NSCLC patients with having high-grade metastatic lesions. In these cases, Rapid Arc-Stereotactic body radiotherapy (Ra-SBRT) technique offers a therapeutic advantage by delivering focal irradiation to metastatic lung lesions and reduces the bystander toxicity to normal tissues. We have previously demonstrated that Ra-SBRT ablates metastatic lesions and induces tumor immune rejection of metastatic tumors by promoting in situ programming of M2 TAM towards M1-TAM and infiltration of Siglec-8+ Eosinophils. Most interestingly, Ra SBRT has very low abscopal impact and spares normal tissues, which are the significant limitations with conventional radiotherapy. In view of this and Immune adjuvant potential of Ra SBRT, it promotes normalization of aberrant vasculature and inhibits the metastatic potential of NSCLC lesions. In view of this we here propose that Ra-SBRT indeed represents an immunogenic approach for the effective management of advanced-stage NSCLC.

Potential Targets to Mitigate Trauma- or Sepsis-Induced Immune Suppression

In sepsis and trauma, pathogens and injured tissue provoke a systemic inflammatory reaction which can lead to overwhelming inflammation. Concurrent with the innate hyperinflammatory response is adaptive immune suppression that can become chronic. A current key issue today is that patients who undergo intensive medical care after sepsis or trauma have a high mortality rate after being discharged. This high mortality is thought to be associated with persistent immunosuppression. Knowledge about the pathophysiology leading to this state remains fragmented. Immunosuppressive cytokines play an essential role in mediating and upholding immunosuppression in these patients. Specifically, the cytokines Interleukin-10 (IL-10), Transforming Growth Factor-β (TGF-β) and Thymic stromal lymphopoietin (TSLP) are reported to have potent immunosuppressive capacities. Here, we review their ability to suppress inflammation, their dynamics in sepsis and trauma and what drives the pathologic release of these cytokines. They do exert paradoxical effects under certain conditions, which makes it necessary to evaluate their functions in the context of dynamic changes post-sepsis and trauma. Several drugs modulating their functions are currently in clinical trials in the treatment of other pathologies. We provide an overview of the current literature on the effects of IL-10, TGF-β and TSLP in sepsis and trauma and suggest therapeutic approaches for their modulation.

Correlation study between blood cytokines and lymphocytes in early postoperative critical patients with compromised immune function

Major surgery due to traumatic injury can activate early systemic postoperative pro-inflammatory responses and postoperative immunosuppression. However, the interaction between them is complex and not entirely clear. This study was performed in postoperative patients admitted to the intensive care unit (ICU) to elucidate the correlation between the systemic cellular immunity function and circulating cytokines levels in the early postoperative period.Twenty-four cases of postoperative patients admitted to the ICU were enrolled in this study. Twelve hours after admission, blood routine examination and measurement of circulating cytokines (interleukin-2 [IL-2], IL-4, IL-6, IL-10, IL-17A, interferon-γ, tumor necrosis factor-alpha [TNF-α], TNF-β, granulocyte-colony stimulating factor [G-CSF], and granulocyte-macrophage colony-stimulating factor [GM-CSF]) were performed. The correlation analysis between cytokines levels and absolute peripheral blood lymphocyte count or lymphocytes/neutrophils ratio was analyzed.The cytokines (IL-2, IL-4, IL-6, IL-10, IL-17A, TNF-α, G-CSF, and GM-CSF) levels were increased above the normal upper limit at 12 hours after surgery. The number of leukocytes and neutrophils were markedly increased. In contrast, the absolute count and relative ratio of lymphocytes decreased below the lower normal limit. Spearman correlation analysis showed a moderate negative correlation between absolute peripheral blood lymphocyte count and IL-2 or IL-4 level. A low-negative correlation between absolute peripheral blood lymphocyte count and GM-CSF levels was detected. We also found that lymphocytes/neutrophils ratio was also negatively correlated with plasma IL-2, IL-4, or GM-CSF level.In ICU patients with compromised immune function in the early postoperative period, the elevated levels of IL-2, IL-4, and GM-CSF may be the compensatory responses to systemic immunosuppression.

Impact of using a perioperative artificial endocrine pancreas in pancreatic resection

AIM

Pancreatectomy causes both hyperglycemia, secondary to surgical stress, and pancreatic diabetes, which leads to difficult-to-control postoperative blood glucose levels. We investigated whether using an artificial pancreas perioperatively to provide appropriate blood glucose control could reduce postoperative complications following pancreatectomy.

METHODS

We retrospectively enrolled 52 patients who underwent pancreatectomy at Tokushima University Hospital from 2015 to 2019. The most recent 26/52 patients received perioperative blood glucose control using an artificial pancreas. Postoperative blood glucose control with manual insulin injections based on a sliding scale was performed in the earlier 26 patients (controls). We compared surgical outcomes between the artificial pancreas group and the control group.

RESULTS

There was no significant difference in patients' white blood cell or neutrophil counts, prognostic nutritional index, neutrophil-lymphocyte ratio, and C-reactive protein-to-albumin ratio on postoperative day 1; however, lymphocyte counts were higher in the artificial pancreas group. The number of serious complications of Clavien-Dindo grade >IIIa was significantly lower in the artificial pancreas group (P < .05).

CONCLUSIONS

Using an artificial pancreas for perioperative blood glucose control in patients undergoing pancreatectomy decreased the number of serious complications through proper management of blood glucose levels without hypoglycemia, and may influence peripheral lymphocytes.

Dynamic changes in routine blood parameters of a severe COVID-19 case

BACKGROUND

Novel coronavirus infectious disease (COVID-19) has been spreading worldwide, and tracking laboratory indexes during the diagnosis and treatment of patients with severe COVID-19 can provide a reference for patients in other countries and regions.

METHODS

We closely tracked the epidemiological history, diagnosis and treatment process, as well as dynamic changes in routine blood indicators, of a severe COVID-19 patient who was hospitalized for 26 days.

RESULTS

Our study found that the patient's condition worsened in the first week after admission, white blood cells (WBCs), neutrophils, lymphocytes, monocytes, eosinophils, red blood cells (RBCs), hemoglobin, neutrophil lymphocyte ratio (NLR), platelets (PLT) and platelet lymphocyte ratio (PLR) decreased. On the 7th day of admission, the levels of these cells decreased to their lowest values, though the red blood cell distribution width (RDW) and C-reactive protein (CRP) level remained at high values. From 8 to 14 days of admission, the patient's condition improved, hypoxemia was corrected, and mechanical ventilation was discontinued. The number of WBCs, neutrophils, monocytes, eosinophils and lymphocytes increased gradually, and the erythrocyte parameters stopped declining and stabilized in a certain range; CRP decreased rapidly. On the 20th day of admission, the nucleic acid test was negative, WBC, neutrophil, CRP, NLR and PLR decreased gradually, and monocyte, lymphocyte, and eosinophil counts increased. Although RBCs and hemoglobin (Hb) levels continued to decrease, RDW gradually increased, indicating the recovery of hematopoiesis. In addition, it should be noted that monocytes and eosinophils were at extremely low levels within 10 days after admission; the recovery time of eosinophils was approximately 12 days after admission, which was earlier than other parameters, which might be of great value in judging the progress of the disease.

CONCLUSIONS

Dynamic changes in routine blood parameters might be helpful for the prognosis of COVID-19 patients and evaluation of the treatment effect.

Impact of comorbidities on the performance of interferon-gamma release assay in an elderly Greek population without overt immunodeficiency

Background The prevalence of latent tuberculosis infection (LTBI) increases with age. Interferon-gamma release assay (IGRA) is a T-cell based assay widely used for the detection of LTBI. Objectives To identify the prevalence of LTBI among an elderly Greek population using IGRA and to evaluate comorbidities associated with LTBI. Methods Individuals aged at least 65 years who were non-immunocompromised and had no history of active tuberculosis infection (TBI) underwent IGRA to identify LTBI. Participant characteristics were compared between the LTBI and non-LTBI groups. Interferon-gamma (INFγ) levels were analysed in each group. Results A total of 130 (38.7%) participants with LTBI and 206 (61.3%) participants without LTBI were included. Multivariate logistic regression analysis identified the following features that were independently associated with a positive IGRA result: female sex (odds ratio [OR]: 0.45; 95% confidence interval [CI]: 0.28-0.72; P=0.001), chronic heart failure (OR: 0.41; 95% CI: 0.22-0.77; P=0.005), history of major surgery (OR: 0.55; 95% CI: 0.33-0.92; P=0.022) and Charlson Comorbidity Index >3 (OR: 3.06; 95% CI: 1.46-6.40; P=0.003). Production of stimulated INFγ was significantly lower in the non-LTBI group. Conclusions Female sex, history of chronic heart failure and history of any surgical intervention were independently associated with a negative IGRA result, and CCI >3 was associated with a positive IGRA result. These results indicate careful interpretation of IGRA is required among elderly individuals with these characteristics.

The effects of tumor resection and adjuvant therapy on the peripheral blood immune cell profile in patients with colon carcinoma

OBJECTIVE

The subset distribution and immunophenotype of circulating immune cells ("peripheral blood immune cell profile") may reflect tumor development and response to cancer treatment. In order to use the peripheral blood immune cell profile as biomarker to monitor patients over time, it is crucial to know how immune cell subsets respond to therapeutic interventions. In this study, we investigated the effects of tumor resection and adjuvant therapy on the peripheral blood immune cell profile in patients with colon carcinoma (CC).

METHODS

The subset distribution and immunophenotype of T cells (CD3⁺CD56^-), CD56^dim NK cells (CD3^-CD56^dim), CD56^bright NK cells (CD3^-CD56^bright) and NKT-like cells (CD3⁺CD56⁺) were studied in preoperative and postoperative peripheral blood mononuclear cell (PBMC) samples of 24 patients with CC by multiparameter flow cytometry. Changes in immunophenotype of circulating immune cells after tumor resection were studied in patients treated with and without (capecitabine-based) adjuvant therapy.

RESULTS

The NKT-like cell (% of total PBMCs) and CD8⁺ T cell (% of total T cells) populations expanded in the peripheral blood of non-adjuvant-treated CC patients after surgery. NK- and NKT-like cells showed upregulation of activating receptors and downregulation of inhibitory receptors in non-adjuvant-treated CC patients after surgery. These changes were not observed in the peripheral blood of adjuvant-treated CC patients.

CONCLUSIONS

Our results suggest tumor-induced suppression of NK- and NKT-like cells in CC patients, an effect that could not be detected after tumor resection. In contrast, adjuvant therapy maintained tumor-induced immunosuppression of NK- and NKT-like cells in CC patients.

Premetastatic niches, exosomes and circulating tumor cells: Early mechanisms of tumor dissemination and the relation to surgery

The physiological stress response to surgery promotes wound healing and functional recovery and includes the activation of neural, inflammatory and proangiogenic signaling pathways. Paradoxically, the same pathways also promote metastatic spread and growth of residual cancer. Human and animal studies show that cancer surgery can increase survival, migration and proliferation of residual tumor cells. To secure the survival and growth of disseminated tumor cells, the formation of premetastatic niches in target organs involves a complex interplay between microenvironment, immune system, circulating tumor cells, as well as chemical mediators and exosomes secreted by the primary tumor. This review describes the current understanding of the early mechanisms of dissemination, as well as how surgery may facilitate disease progression.

Late immune consequences of combat trauma: a review of trauma-related immune dysfunction and potential therapies

With improvements in personnel and vehicular body armor, robust casualty evacuation capabilities, and damage control resuscitation strategies, more combat casualties are surviving to reach higher levels of care throughout the casualty evacuation system. As such, medical centers are becoming more accustomed to managing the deleterious late consequences of combat trauma related to the dysregulation of the immune system. In this review, we aim to highlight these late consequences and identify areas for future research and therapeutic strategies. Trauma leads to the dysregulation of both the innate and adaptive immune responses, which places the injured at risk for several late consequences, including delayed wound healing, late onset sepsis and infection, multi-organ dysfunction syndrome, and acute respiratory distress syndrome, which are significant for their association with the increased morbidity and mortality of wounded personnel. The mechanisms by which these consequences develop are complex but include an imbalance of the immune system leading to robust inflammatory responses, triggered by the presence of damage-associated molecules and other immune-modifying agents following trauma. Treatment strategies to improve outcomes have been difficult to develop as the immunophenotype of injured personnel following trauma is variable, fluid and difficult to determine. As more information regarding the triggers that lead to immune dysfunction following trauma is elucidated, it may be possible to identify the immunophenotype of injured personnel and provide targeted treatments to reduce the late consequences of trauma, which are known to lead to significant morbidity and mortality.

Two polysaccharides from Porphyra modulate immune homeostasis by NF-κB-dependent immunocyte differentiation

Porphyra polysaccharides possess multiple pharmacological activities, such as immunoregulatory, anti-tumor and anti-inflammatory effects, but the specific underlying mechanisms are not fully understood.

Baicalin Inhibits Haemophilus Parasuis-Induced High-Mobility Group Box 1 Release during Inflammation

Haemophilus parasuis (H. parasuis) can cause Glässer’s disease in pigs. However, the molecular mechanism of the inflammation response induced by H. parasuis remains unclear. The high-mobility group box 1 (HMGB1) protein is related to the pathogenesis of various infectious pathogens, but little is known about whether H. parasuis can induce the release of HMGB1 in piglet peripheral blood monocytes. Baicalin displays important anti-inflammatory and anti-microbial activities. In the present study, we investigated whether H. parasuis can trigger the secretion of HMGB1 in piglet peripheral blood monocytes and the anti-inflammatory effect of baicalin on the production of HMGB1 in peripheral blood monocytes induced by H. parasuis during the inflammation response. In addition, host cell responses stimulated by H. parasuis were determined with RNA-Seq. The RNA-Seq results showed that H. parasuis infection provokes the expression of cytokines and the activation of numerous pathways. In addition, baicalin significantly reduced the release of HMGB1 in peripheral blood monocytes induced by H. parasuis. Taken together, our study showed that H. parasuis can induce the release of HMGB1 and baicalin can inhibit HMGB1 secretion in an H. parasuis-induced peripheral blood monocytes model, which may provide a new strategy for preventing the inflammatory disorders induced by H. parasuis.