Neutrophil CD64 as a diagnostic marker of sepsis: impact on neonatal care

Can biomarkers improve the rational use of antibiotics?

PURPOSE OF REVIEW

We aim to review recent literature about the use of biomarkers to guide the initiation and duration of antibiotic treatments for suspected bacterial infections.

RECENT FINDINGS

Several good quality meta-analyses show that procalcitonin can be safely used to guide antibiotic-related decisions, especially for respiratory infections, thereby decreasing unnecessary antibiotic exposure. Furthermore, the use of CRP-based algorithms to guide antibiotic initiation in primary care patients with acute respiratory infections is associated with a reduction in antibiotic use without an increase in adverse events. Regarding neutrophil CD64 and serum amyloid A, more good-quality evidence is needed to assess their utility as biomarkers to tailor antibiotic use. Finally, transcriptomics, metabolomics and proteomics are promising tools for the development of tests to differentiate specific host responses to viral, bacterial and noninfectious stimuli, but such tests still need further validation.

SUMMARY

Evidence shows that the use of biomarkers, procalcitonin and CRP, can safely reduce unnecessary antibiotic prescriptions in certain infectious syndromes. The clinical utility of host-based strategies such as transcriptomics, metabolomics and proteomics for the diagnosis of infectious diseases has yet to be evaluated, as well as considerations such as costs, technical complexity and result turnaround time.

Diagnostic value of neutrophil CD64 combined with CRP for neonatal sepsis: A meta-analysis

BACKGROUND

Sepsis is the leading cause of morbidity and mortality in newborns. CD64 combined with c-reactive protein (CRP) could improve the sensitivity and specificity of neonatal sepsis diagnosis, but the results were still controversial. Therefore, this meta-analysis was conducted to clarify the importance of CD64 combined with CRP in the diagnosis of neonatal sepsis.

METHODS

The researches published as of December 24, 2018 were comprehensively searched in PubMed, Embase (included Embase and Medline), the Cochrane Library and Web of Science. Totally, 8 articles were included, involving 1114 objects. Statistical calculations were performed using Stata14.0 and Review Manager 5.3.

RESULTS

The diagnostic accuracy of all included studies was pooled as follows: sensitivity, 0.95 (95% CI: 0.86-0.98); specificity, 0.86 (95% CI: 0.74-0.93); positive likelihood ratio (PLR), 6.8 (95% CI: 3.50-13.20); negative likelihood ratio (NLR), 0.06 (95% CI: 0.02-0.18); diagnostic odds ratio (DOR), 118.0 (95% CI: 25.00-549.00), and the area under the curve (AUC) was 0.96 (95% CI: 0.94-0.97). It was found that heterogeneity was not caused by threshold effect (P = 0.16), but the results of sensitivity (I² = 87.57%) and specificity (I² = 89.07%) analyses indicated significant heterogeneity between studies.

CONCLUSIONS

The combined application of CD64 and CRP improved the accuracy of neonatal sepsis diagnosis.

Management of Neonates Born at ≤34 6/7 Weeks' Gestation With Suspected or Proven Early-Onset Bacterial Sepsis

Early-onset sepsis (EOS) remains a serious and often fatal illness among infants born preterm, particularly among newborn infants of the lowest gestational age. Currently, most preterm infants with very low birth weight are treated empirically with antibiotics for risk of EOS, often for prolonged periods, in the absence of a culture-confirmed infection. Retrospective studies have revealed that antibiotic exposures after birth are associated with multiple subsequent poor outcomes among preterm infants, making the risk/benefit balance of these antibiotic treatments uncertain. Gestational age is the strongest single predictor of EOS, and the majority of preterm births occur in the setting of other factors associated with risk of EOS, making it difficult to apply risk stratification strategies to preterm infants. Laboratory tests alone have a poor predictive value in preterm EOS. Delivery characteristics of extremely preterm infants present an opportunity to identify those with a lower risk of EOS and may inform decisions to initiate or extend antibiotic therapies. Our purpose for this clinical report is to provide a summary of the current epidemiology of preterm neonatal sepsis and provide guidance for the development of evidence-based approaches to sepsis risk assessment among preterm newborn infants.

Management of Neonates Born at ≥35 0/7 Weeks' Gestation With Suspected or Proven Early-Onset Bacterial Sepsis

The incidence of neonatal early-onset sepsis (EOS) has declined substantially over the last 2 decades, primarily because of the implementation of evidence-based intrapartum antimicrobial therapy. However, EOS remains a serious and potentially fatal illness. Laboratory tests alone are neither sensitive nor specific enough to guide EOS management decisions. Maternal and infant clinical characteristics can help identify newborn infants who are at risk and guide the administration of empirical antibiotic therapy. The incidence of EOS, the prevalence and implications of established risk factors, the predictive value of commonly used laboratory tests, and the uncertainties in the risk/benefit balance of antibiotic exposures all vary significantly with gestational age at birth. Our purpose in this clinical report is to provide a summary of the current epidemiology of neonatal sepsis among infants born at ≥35 0/7 weeks' gestation and a framework for the development of evidence-based approaches to sepsis risk assessment among these infants.

Examining the utility of the CD64 index compared with other conventional indices for early diagnosis of neonatal infection

As specific clinical manifestations and detection tools for early neonatal infections are lacking, early detection and treatment are ongoing challenges. The present study aimed to investigate the role and clinical significance of the CD64 index in comparison with conventional examination indices (WBC, PCT and CRP) for the early diagnosis of neonatal infection. Of 74 in-patient newborns, non-sepsis (non-specific infection but free of sepsis), sepsis and control [newborns with ABO hemolytic disease of the newborn (ABOHDN) but without infection] groups involved 32, 16 and 26 cases, respectively. Peripheral blood WBC, PCT, CRP and CD64 indices were acquired for all groups. The sepsis group showed significantly higher WBC, PCT and CRP levels than the control group. Compared with the non-sepsis group, the sepsis group demonstrated significant increases in PCT but not in WBC or CRP. Compared with the control group, the non-sepsis and sepsis groups had higher CD64 indices. Combined, compared with the WBC, PCT and CRP indices, the CD64 index is unique in its capacity to diagnose neonatal infections early. The CD64 index combined with other conventional indices may lay a basis for the future early diagnosis and effective treatment of neonatal infections.

[Value of combined determination of neutrophil CD64 and procalcitonin in early diagnosis of neonatal bacterial infection]

OBJECTIVE

To investigate the value of combined determination of neutrophil CD64 and procalcitonin (PCT) in the early diagnosis of neonatal bacterial infection.

METHODS

According to discharge diagnosis, 37 neonates with bacterial infection were divided into sepsis (n=15) and ordinary infection (non-sepsis) groups (n=22). Twenty-one neonates without infection who were hospitalized during the same period of time were enrolled as the control group. Venous blood samples were collected immediately after admission. Flow cytometry was used to measure the serum level of neutrophil CD64. Chemiluminescence and immune transmission turbidimetry were used to measure the serum levels of PCT and CRP respectively.

RESULTS

The sepsis group had higher serum levels of neutrophil CD64, PCT, and CRP than the control group (P<0.01), the ordinary infection group had a higher serum level of neutrophil CD64 than the control group (P<0.01), and the sepsis group had higher serum levels of PCT and CRP than the ordinary infection group (P<0.01). The areas under the ROC curve (AUC) of neutrophil CD64, PCT, and CRP in diagnosing bacterial infection were 0.818, 0.818, and 0.704 respectively, and the AUC of combined neutrophil CD64 and PCT was 0.926. A combination of neutrophil CD64 and PCT had a sensitivity of 97.29% and an accuracy of 89.65% in the early diagnosis of neonatal bacterial infection.The sensitivity and accuracy were higher than those of a combination of CRP and neutrophil CD64 or PCT as well as neutrophil CD64, PCT, or CRP alone for the early diagnosis of neonatal bacterial infection.

CONCLUSIONS

The combined determination of neutrophil CD64 and PCT can improve the sensitivity and accuracy in the diagnosis of neonatal bacterial infection, which helps with early identification of bacterial infection.

[Value of combined determination of neutrophil CD64 and procalcitonin in early diagnosis of neonatal bacterial infection]

OBJECTIVE

To investigate the value of combined determination of neutrophil CD64 and procalcitonin (PCT) in the early diagnosis of neonatal bacterial infection.

METHODS

According to discharge diagnosis, 37 neonates with bacterial infection were divided into sepsis (n=15) and ordinary infection (non-sepsis) groups (n=22). Twenty-one neonates without infection who were hospitalized during the same period of time were enrolled as the control group. Venous blood samples were collected immediately after admission. Flow cytometry was used to measure the serum level of neutrophil CD64. Chemiluminescence and immune transmission turbidimetry were used to measure the serum levels of PCT and CRP respectively.

RESULTS

The sepsis group had higher serum levels of neutrophil CD64, PCT, and CRP than the control group (P<0.01), the ordinary infection group had a higher serum level of neutrophil CD64 than the control group (P<0.01), and the sepsis group had higher serum levels of PCT and CRP than the ordinary infection group (P<0.01). The areas under the ROC curve (AUC) of neutrophil CD64, PCT, and CRP in diagnosing bacterial infection were 0.818, 0.818, and 0.704 respectively, and the AUC of combined neutrophil CD64 and PCT was 0.926. A combination of neutrophil CD64 and PCT had a sensitivity of 97.29% and an accuracy of 89.65% in the early diagnosis of neonatal bacterial infection.The sensitivity and accuracy were higher than those of a combination of CRP and neutrophil CD64 or PCT as well as neutrophil CD64, PCT, or CRP alone for the early diagnosis of neonatal bacterial infection.

CONCLUSIONS

The combined determination of neutrophil CD64 and PCT can improve the sensitivity and accuracy in the diagnosis of neonatal bacterial infection, which helps with early identification of bacterial infection.

The usefulness of neutrophil CD64 expression for diagnosing infection after orthopaedic surgery in dialysis patients

BACKGROUND

Dialysis patients undergoing orthopaedic surgery are at high risk for postoperative infection. Diagnosis of postoperative infection is difficult in dialysis patients due to presentation of signs and symptoms similar to infection, such as fever and elevated inflammatory marker levels. Neutrophil CD64 expression (CD64), a marker of infection, is upregulated by microbial wall components and several cytokines (interferon-γ and tumor necrosis factor-α). The purpose of this study is to evaluate the usefulness of CD64 for diagnosing postoperative infection in dialysis patients post orthopaedic surgery.

PATIENTS AND METHODS

Between 2013 and 2014, we prospectively studied 36 dialysis patients (18 men, 18 women; mean age 65.9 years; 49 to 83) who underwent orthopaedic surgery. Dialysis patients were classified into three groups according to their postoperative course as follows; non-infected patients, infection suspected patients, and infected patients. Inflammatory markers such as white blood cell count (WBC), C-reactive protein (CRP) and CD64 were measured before operation and one week after surgery. Using the receiver-operating characteristic (ROC) curve and Akaike's Information Criterion (AIC), the cutoff value of CD64 and CRP was calculated leading to a determination of which inflammatory marker is best accurate for detecting postoperative infection.

RESULTS

We found that postoperative CD64 and CRP levels presented a statistically significant difference between infected patients and non-infected patients (p < 0.05). Furthermore, comparison of the ROC curve and AIC value between postoperative CD64 and CRP levels exhibited that CD64 was more accurate infectious marker than CRP.

CONCLUSION

CD64 is a useful marker for detecting postoperative infection after orthopaedic surgery in dialysis patients.

[Diagnostic values of plasma CD64 and sTREM-1 for pediatric pneumonia]

OBJECTIVE

To determine the diagnostic values of plasma CD64 and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in children with pneumonia.

METHODS

Sixty children with pneumonia between August 2014 and October 2015 were classified into bacterial pneumonia group (25 cases), viral pneumonia group (17 cases), and Mycoplasma pneumonia group (18 cases) according to their clinical manifestations, pathogen cultures, and X-ray findings. Another 30 healthy children who underwent physical examination during the same period were selected as the control group. The concentrations of CD64 and sTREM-1 in blood samples were determined using ELISA. The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic sensitivity and specificity of plasma CD64 and/or sTREM-1 for bacterial pneumonia.

RESULTS

The expression of CD64 and sTREM-1 in the bacterial pneumonia group was significantly higher than that in the viral pneumonia, Mycoplasma pneumonia, and control groups (P<0.05). The areas under the ROC curves of CD64, sTREM-1, and a combination of the two markers for diagnosing bacterial pneumonia were 0.878, 0.805, and 0.956, respectively. The sensitivity and specificity of CD64 for diagnosing bacterial pneumonia were 81.30% and 92.32%, respectively, when the cut-off value was 641 pg/mL. The sensitivity and specificity of sTREM-1 for diagnosing bacterial pneumonia were 78.65% and 84.67%, respectively, when the cut-off value was 1 479 pg/mL. The sensitivity and specificity of a combination of the two markers for diagnosing bacterial pneumonia were 93.15% and 91.54%, respectively.

CONCLUSIONS

Plasma CD64 and sTREM-1 can be used as markers for diagnosing pediatric bacterial pneumonia, and a combination of the two markers results in better diagnosis.

nCD64 index as a prognostic biomarker for mortality in acute exacerbation of chronic obstructive pulmonary disease

BACKGROOUND

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of mortality and morbidity worldwide. However, there are still no easily obtained biomarkers for prognosis. As a high-affinity Fc receptor, CD64 is an early marker of immune response to bacterial infection, but its role in acute exacerbation of COPD (AECOPD) remains incompletely understood.

OBJECTIVE

We investigated the prognostic role of the neutrophial CD64 (nCD64) index in AECOPD patients.

DESIGN

Retrospective cross-sectional study of all patient admitted between January 2013 to May 2014.

SETTING

Provincial hospitals affiliated with a university.

PATIENTS AND METHODS

Clinical and laboratory data were collected in patients admitted for AECOPD and stable COPD patients, in whom nCD64 index was obtained. A receiver operating characteristics curve was used to determine the optimal cut-off levels for the nCD64 index that discriminated survivors versus nonsurvivors during index hospitalization, and during a post-discharge period of 12 months.

MAIN OUTCOME MEASURES

nCD64 index level.

RESULTS

The white blood cell count, CRP (C-reactive protein (CRP) and PCT (procalcitonin) in AECOPD subjects (n=31) were all significantly higher than in controls (n=18) (P= 3.3 predicted in-hospital mortality with a sensitivity and specificity of 80% and 83%, respectively (area under the ROC=0.887; 95% confidence interval [CI]=0.721-0.972, P < .001). An nCD64 index of 3.3 upon admission as the optimal cut-off level to predict post-discharge mortality had a sensitivity and specificity of 83% and 75%, respectively (area under the ROC=0.842; 95% confidence interval [CI]=0.667-0.948, P < .001).

CONCLUSIONS

An elevated nCD64 index was a reliable prognostic biomarker for both short-term and long-term mortality in patients admitted for AECOPD.

LIMITATIONS

Retrospective design prevented collection of enough evidence to demonstrate infectious origin for COPD in every patient. Unsure whether nCD64 differed between bacterial and viral exacerbation.

Monocyte HLA-DR expression and neutrophil CD64 expression as biomarkers of infection in critically ill neonates and infants

BACKGROUND

Reduced monocyte HLA-DR expression and increased neutrophil CD64 expression have been proposed as biomarkers of infection.

METHODS

From 2009-2011, blood samples from neonatal intensive care unit (NICU) and pediatric intensive care unit (ICU) patients <1 y of age were collected at enrollment and during subsequent evaluation for suspected infection, if it occurred. Samples were analyzed for monocyte HLA-DR and neutrophil CD64 expression levels by flow cytometry.

RESULTS

Forty-seven infants had study samples collected at enrollment; 26 infants had study samples collected at the time of a suspected infection. At enrollment, there was an inverse relationship between neutrophil CD64 expression and age (P ≤ 0.047). At the time of suspected infection, infants with an infection demonstrated a lower percentage of HLA-DR+ monocytes (P = 0.02, area under the curve (AUC) 0.78), higher percentage of CD64+ neutrophils (P = 0.009, AUC 0.81), and higher neutrophil CD64 expression levels (P = 0.04, AUC 0.75).

CONCLUSION

Monocyte HLA-DR and neutrophil CD64 expression in critically ill infants are related to age and infection.

What was old is new again: using the host response to diagnose infectious disease

A century of advances in infectious disease diagnosis and treatment changed the face of medicine. However, challenges continue to develop including multi-drug resistance, globalization that increases pandemic risks and high mortality from severe infections. These challenges can be mitigated through improved diagnostics, focusing on both pathogen discovery and the host response. Here, we review how 'omics' technologies improve sepsis diagnosis, early pathogen identification and personalize therapy. Such host response diagnostics are possible due to the confluence of advanced laboratory techniques (e.g., transcriptomics, metabolomics, proteomics) along with advanced mathematical modeling such as machine learning techniques. The road ahead is promising, but obstacles remain before the impact of such advanced diagnostic modalities is felt at the bedside.