Automated measurement of neutrophil CD64 expression for diagnosing sepsis in critically ill patients

An integrative model with HLA-DR, CD64, and PD-1 for the diagnostic and prognostic evaluation of sepsis

BACKGROUND

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection and progressive immunosuppression with high mortality. HLA-DR, CD64, and PD-1 were assumed to be useful biomarkers for sepsis prediction. However, the ability of a combination of these biomarkers has not been clarified.

METHODS

An observational case-control study was conducted that included 30 sepsis patients, 30 critically ill patients without sepsis admitted to the intensive care unit (ICU), and 32 healthy individuals. The levels of HLA-DR, CD64, and PD-1 expression in peripheral blood immune cells and subsets was assayed on Days 1, 3, and 5, and the clinical information of patients was collected. We compared these biomarkers between groups and evaluated the predictive validity of single and combined biomarkers on sepsis mortality.

RESULTS

The results indicate that PD-1 expression on CD4- CD8- T (PD-1+ CD4- CD8- T) (19.19% ± 10.78% vs. 9.88% ± 1.79%, p = .004) cells and neutrophil CD64 index (nCD64 index) (9.15 ± 5.46 vs. 5.33 ± 2.34, p = .001) of sepsis patients were significantly increased, and HLA-DR expression on monocytes (mHLA-DR+ ) was significantly reduced (13.26% ± 8.06% vs. 30.17% ± 21.42%, p = 2.54 × 10-4 ) compared with nonsepsis critically ill patients on the first day. Importantly, the expression of PD-1+ CD4- CD8- T (OR = 0.622, 95% CI = 0.423-0.916, p = .016) and mHLA-DR+ (OR = 1.146, 95% CI = 1.014-1.295, p = .029) were significantly associated with sepsis mortality. For sepsis diagnosis, the mHLA-DR+ , PD-1+ CD4- CD8- T, and nCD64 index showed the moderate individual performance, and combinations of the three biomarkers achieved greater diagnostic value (AUC = 0.899, 95% CI = 0.792-0.962). When adding PCT into the combined model, the AUC increased to 0.936 (95% CI = 0.840-0.983). For sepsis mortality, combinations of PD-1+ CD4- CD8- T and mHLA-DR+ , have a good ability to predict the prognosis of sepsis patients, with an AUC = 0.921 (95% CI = 0.762-0.987).

CONCLUSION

These findings indicate that the combinations of HLA-DR, CD64, and PD-1 outperformed each of the single indicator in diagnosis and predicting prognosis of sepsis.

Point-of-care neutrophil CD64 as a rule in diagnostic test for bacterial infections in the emergency department

INTRODUCTION

Bacterial infections are frequently seen in the emergency department (ED), but can be difficult to distinguish from viral infections and some non-infectious diseases. Common biomarkers such as c-reactive protein (CRP) and white blood cell (WBC) counts fail to aid in the differential diagnosis. Neutrophil CD64 (nCD64), an IgG receptor, is suggested to be more specific for bacterial infections. This study investigated if nCD64 can distinguish bacterial infections from other infectious and non-infectious diseases in the ED.

METHODS

All COVID-19 suspected patients who visited the ED and for which a definitive diagnosis was made, were included. Blood was analyzed using an automated flow cytometer within 2 h after presentation. Patients were divided into a bacterial, viral, and non-infectious disease group. We determined the diagnostic value of nCD64 and compared this to those of CRP and WBC counts.

RESULTS

Of the 291 patients presented at the ED, 182 patients were included with a definitive diagnosis (bacterial infection n = 78; viral infection n = 64; non-infectious disease n = 40). ROC-curves were plotted, with AUCs of 0.71 [95%CI: 0.64-0.79], 0.77 [0.69-0.84] and 0.64 [0.55-0.73] for nCD64, WBC counts and CRP, respectively. In the bacterial group, nCD64 MFI was significantly higher compared to the other groups (p < 0.01). A cut-off of 9.4 AU MFI for nCD64 corresponded with a positive predictive value of 1.00 (sensitivity of 0.27, a specificity of 1.00, and an NPV of 0.64). Furthermore, a diagnostic algorithm was constructed which can serve as an example of what a future biomarker prediction model could look like.

CONCLUSION

For patients in the ED presenting with a suspected infection, nCD64 measured with automatic flow cytometry, has a high specificity and positive predictive value for diagnosing a bacterial infection. However, a low nCD64 cannot rule out a bacterial infection. For future purposes, nCD64 should be combined with additional tests to form an algorithm that adequately diagnoses infectious diseases.

Neutrophil CD64 index for diagnosis of infectious disease in the pediatric ICU: a single-center prospective study

BACKGROUND

Infection is a major cause of death in children, and it is particularly important to identify biological indicators of early infection. Previous studies showed that the neutrophil CD64 (nCD64) index may be a useful biomarker for infection. The purpose of this study was to investigate use of the nCD64 index to identify infection in children from a pediatric ICU (PICU) in China.

METHODS

This prospective observational study enrolled 201 children who were admitted to our PICU and were divided into an infection group and a non-infection group. In each patient, C-reactive protein (CRP), nCD64 index, procalcitonin (PCT), and white blood cell count were measured during the first 24 h after admission. Receiver operating characteristic (ROC) analyses were used to determine the sensitivity, specificity, and diagnostic value of the nCD64 index for infection.

RESULTS

Among all 201 children, the infection group had greater levels of CRP, nCD64 index, and PCT (all p < 0.05). ROC analysis indicated the nCD64 index had a sensitivity of 68.8%, specificity of 90.7%, accuracy of 80.5%, and an optimal cut-off value of 0.14, which had better diagnostic value than CRP or PCT. For children with postoperative fever, the nCD64 index also distinguished systemic inflammatory response syndrome (SIRS) from infection with accuracy of 79%.

CONCLUSIONS

The nCD64 index is a useful biomarker for the diagnosis of early infection in children admitted to the PICU.

Clinical Value of Neutrophil CD64 Index, PCT, and CRP in Acute Pancreatitis Complicated with Abdominal Infection

Objective: To study the clinical diagnostic value of neutrophil CD64 index, PCT, and CRP in patients with acute pancreatitis with abdominal infection. Methods: A number of patients with acute pancreatitis (n = 234) participated in the study. According to the infection and health conditions, they were further divided into the non-infection group (n = 122), infection group (n = 78), and sepsis group (n = 34), and 40 healthy subjects were selected in the control group (n = 40). Expression levels of infection indexes, such as CD64 index, PCT, and CRP, were detected and compared. ROC curves were drawn to compare the efficacy of each index in the diagnosis of acute pancreatitis with abdominal infection and sepsis. The study was retrospectively registered under the China Clinical Trial Registry as a trial number ChiCTR2100054308. Results: All indexes were significantly higher in three clinical groups than the healthy control group (p < 0.05). The CD64 index, CD64 positive rate, and PCT in the infected group were significantly higher than those in the uninfected group (ALL p < 0.05). The PCT of patients infected with Gram-negative bacteria was significantly higher than that of Gram-positive bacteria-infected patients (p < 0.05). CD64 index had the best diagnostic efficiency for acute pancreatitis infection, with 82.14% sensitivity, 88.51% specificity, and 0.707 Youden indexes. The CD64 Youden index (0.780) for sepsis diagnosis was the highest, while the AUC of PCT was the highest (0.897). Conclusion: CD64 index combined with PCT has good sensitivity and specificity in diagnosing acute pancreatitis infection and sepsis.

Longitudinal assessment of the inflammatory response: The next step in personalized medicine after severe trauma

Infections in trauma patients are an increasing and substantial cause of morbidity, contributing to a mortality rate of 5-8% after trauma. With increased early survival rates, up to 30-50% of multitrauma patients develop an infectious complication. Trauma leads to a complex inflammatory cascade, in which neutrophils play a key role. Understanding the functions and characteristics of these cells is important for the understanding of their involvement in the development of infectious complications. Recently, analysis of neutrophil phenotype and function as complex biomarkers, has become accessible for point-of-care decision making after trauma. There is an intriguing relation between the neutrophil functional phenotype on admission, and the clinical course (e.g., infectious complications) of trauma patients. Potential neutrophil based cellular diagnostics include subsets based on neutrophil receptor expression, responsiveness of neutrophils to formyl-peptides and FcγRI (CD64) expression representing the infectious state of a patient. It is now possible to recognize patients at risk for infectious complications when presented at the trauma bay. These patients display increased numbers of neutrophil subsets, decreased responsiveness to fMLF and/or increased CD64 expression. The next step is to measure these biomarkers over time in trauma patients at risk for infectious complications, to guide decision making regarding timing and extent of surgery and administration of (preventive) antibiotics.

Assessment of continuous neutrophil CD64 index measurement for diagnosing sepsis and predicting outcome in a Chinese pediatric intensive care unit: a prospective study

BACKGROUND

The high affinity immunoglobulin-Fc fragment receptor I CD64 on neutrophils is widely assumed to be a useful biomarker in the early identification of sepsis, and it improves outcomes. We aimed to determine its ability to diagnose sepsis and predict its prognosis with continuous measurements.

METHODS

A total of 335 patients admitted to a Chinese PICU were prospectively stratified into two groups according to the presence of sepsis (defined by clinical criteria for sepsis) between 2018 and 2019. Serum concentrations of the nCD64 index, C-reactive protein (CRP), and procalcitonin (PCT) were measured. Sensitivity, specificity and receiver operating characteristic (ROC) curves were calculated to evaluate the diagnostic value for sepsis. A multiple logistic regression model was used to estimate the prognostic value of continuous nCD64 index measurement for in-hospital death.

RESULTS

The baseline nCD64 index and levels of PCT and CRP were significantly higher in septic children than in nonseptic children (P<0.05). The nCD64 index presented a higher sensitivity (0.90), specificity (0.78) and area under the ROC curve [0.91 (0.90, 0.93)] than CRP and PCT in discriminating septic children with an optimal cutoff value of 5.78. The nCD64 index decreased with the progression of sepsis, and the baseline nCD64 index was strongly associated with in-hospital death (OR: 2.18, 95% CI: 1.02-4.74). Moreover, the more rapidly the nCD64 index declined, the lower the in-hospital death rate was (OR: 0.89, 95% CI: 0.63-1.35) after adjusting for the baseline nCD64 index and other confounders.

CONCLUSIONS

The nCD64 index was not only effective for the early diagnosis of childhood sepsis but also positively associated with the prognosis of sepsis. Moreover, the nCD64 decline was inversely associated with the in-hospital death rate.