Neutrophil CD64 index as a superior indicator for diagnosing, monitoring bacterial infection, and evaluating antibiotic therapy: a case control study

P75NTR+CD64+ neutrophils promote sepsis-induced acute lung injury

Patients suffering from sepsis-induced acute lung injury (ALI) exhibit a high mortality rate, and their prognosis is closely associated with infiltration of neutrophils into the lungs. In this study, we found a significant elevation of CD64+ neutrophils, which highly expressed p75 neurotrophin receptor (p75NTR) in peripheral blood of mice and patients with sepsis-induced ALI. p75NTR+CD64+ neutrophils were also abundantly expressed in the lung of ALI mice induced by lipopolysaccharide. Conditional knock-out of the myeloid lineage's p75NTR gene improved the survival rates, attenuated lung tissue inflammation, reduced neutrophil infiltration and enhanced the phagocytic functions of CD64+ neutrophils. In vitro, p75NTR+CD64+ neutrophils exhibited an upregulation and compromised phagocytic activity in blood samples of ALI patients. Blocking p75NTR activity by soluble p75NTR extracellular domain peptide (p75ECD-Fc) boosted CD64+ neutrophils phagocytic activity and reduced inflammatory cytokine production via regulation of the NF-κB activity. The findings strongly indicate that p75NTR+CD64+ neutrophils are a novel pathogenic neutrophil subpopulation promoting sepsis-induced ALI.

Neutrophil CD64 index as a new early predictive biomarker for infected pancreatic necrosis in acute pancreatitis

OBJECTIVE

Infectious pancreatic necrosis (IPN) is a serious complication of acute pancreatitis, and early recognition and timely intervention are the keys to improving clinical outcomes. The purpose of this study was to investigate the predictive capacity of the neutrophil CD64 index (nCD64 index) on IPN in patients with acute pancreatitis METHODS: This study comprises two independent cohorts: the training cohort consisted of 202 patients from Hunan Provincial People's Hospital, and the validation cohort consisted of 100 patients from Changsha Central Hospital. Peripheral blood samples were collected on the day of admission and on the 3rd, 5th, 7th, and 10th days of hospitalization, and the nCD64 index was detected by flow cytometry. Additionally, relevant clinical characteristics and laboratory biomarkers were collected and analyzed.

RESULTS

We observed that nCD64 index on admission was significantly higher in the IPN group than Non-IPN group (p < 0.001). In the training cohort, a higher occurrence rate of IPN was observed in the high nCD64 index group compared to the moderate and low nCD64 index group (p < 0.001). Further analysis showed that nCD64 index was significant positive correlated with the incidence rate of IPN (p < 0.001, correlation coefficient = 0.972). Furthermore, logistic regression analysis showed that high expression of the nCD64 index on admission was a risk factor for the occurrence of IPN (OR = 2.971, p = 0.038). We further found that the nCD64 index of IPN patients was significantly higher than the Non-IPN patients on the days 1, 3, and 5 after admission, and the nCD64 index of IPN patients before and after the onset (p < 0.05). At the same time, this study revealed that the nCD64 index on admission showed good predictive efficacy for IPN (AUC = 0.859, sensitivity = 80.8%, specificity = 87.5%), which was comparable to APACHE II score. And this finding was further validated in an independent cohort of 100 participants (AUC = 0.919, Sensitivity = 100.0%, Specificity = 76.6%).

CONCLUSION

This study demonstrated the clinical value of nCD64 index in patients with IPN patients for the first time through two independent cohort studies. The nCD64 index can be used as an early prediction and risk assessment tool for the occurrence of IPN, contributing to the improvement of patient outcomes and efficiency of medical resource allocation.

Effect of pre-infusion of hypertonic saline on postoperative delirium in geriatric patients undergoing shoulder arthroscopy: a randomized controlled trial

BACKGROUND

Neuroinflammation may be a potential mechanism of postoperative delirium (POD) in geriatric patients, and hypertonic saline (HS) has immunomodulatory properties. The purpose of this study was to investigate whether HS could reduce the incidence of POD in elderly patients and its effect on neutrophil activation and inflammatory cytokine expression.

METHODS

We studied the effect of pre-infusion of 4 mL/kg 3% hypertonic saline vs. 4 mL/kg 0.9% normal saline on POD in patients undergoing shoulder arthroscopy in a prospective, randomized, double-blind, controlled trial. Neutrophil surface molecules (CD11b, CD66b and CD64) were analyzed by flow cytometry. Circulating concentrations of inflammatory factors IL-1β, IL-6, TNF-α and neurological damage factor S100β were assessed by enzyme immunoassay. The Confusion Assessment Method-Chinese Revision (CAM-CR) was applied for the assessment of POD 1-3 days after surgery.

RESULTS

The incidence of POD in group H was significantly lower than that in group N (7.14% vs 26.83%, P = 0.036). The expression levels of inflammatory cytokines ( IL-6 and TNF-α) and neutrophil surface markers (CD11b and CD66b) were significantly lower in group H than in group N at 24 h after surgery (P = 0.018, P < 0.001, P < 0.001, P = 0.024). There were no significant differences in postoperative pain, nausea and vomiting, infection, phlebitis, and patients satisfaction between the two groups.

CONCLUSION

Pre-infusion of HS can reduce the incidence of POD and the immune-inflammatory response.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (14/4/2022, registration number: ChiCTR2200058681.

Future Biomarkers for Infection and Inflammation in Rheumatoid Arthritis

Rheumatoid arthritis (RA) increases the susceptibility to a variety of infections that are often difficult to diagnose and can be asymptomatic or symptoms are atypical. Usually, this is a great challenge for rheumatologists, because it is difficult to distinguish infection and aseptic inflammation at an early stage. Prompt diagnosis and treatment of bacterial infections in immunosuppressed individuals is critical for clinicians, and early exclusion of infection allows for specific treatment of inflammatory diseases and avoids the unnecessary use of antibiotics. However, for patients with clinically suspected infection, traditional laboratory markers are not specific for bacterial infection and cannot be used to distinguish outbreaks from infections. Therefore, new infection markers that can distinguish infection from underlying disease are urgently needed for clinical practice. Here, we review the novel biomarkers in RA patients with infection. These biomarkers include presepsin, serology and haematology, as well as neutrophils, T cells, and natural killer cells. Meanwhile, we discuss meaningful biomarkers that distinguish infection from inflammation and develop novel biomarkers for clinical applications, allowing clinicians to make better decisions when diagnosing and treating RA.