Neutrophil CD64 expression: a sensitive diagnostic marker for late-onset nosocomial infection in very low birthweight infants

The Role of Neutrophil CD11b Compared to Neutrophil CD64 as an Early Diagnostic, Monitoring, and Prognostic Sepsis Marker in Neonatal ICUs: Case-Control-Methodological Study

Background: Early diagnosis and treatment of neonatal sepsis are crucial to cut off its major medical consequences: lifelong morbidities, neurodevelopmental disabilities, and a high number of neonatal mortalities. Aim of the Work: This study is aimed at determining the diagnostic and prognostic performance of CD11b as a sepsis biomarker for detecting neonatal sepsis at early stages compared to nCD64 and the other conventional sepsis parameters. Methods: Two hundred eleven neonates were enrolled from three Egyptian neonatal ICUs (NICUs), and they were classified into two main groups: the control group (n = 101) and the sepsis group (n = 110). Enrolled neonates were subjected to full sepsis screening, including complete blood count (CBC), C-reactive protein (CRP), blood cultures, and flow cytometry analysis for both CD64 and CD11b on the neutrophil surface (results represented as a percentage (percent) and mean fluorescent intensity (MFI) units for either biomarker). Results: nCD64% (median = 44.15%) was significantly enhanced in the sepsis group compared to the controls (median = 25%), achieving 90.8% specificity, 92.8% sensitivity, and AUC = 0.894, respectively. CD64 MFI and CD11b MFI could differentiate between sepsis and control groups but with low undesirable diagnostic performance (sensitivity: 72.5% and 59.1%; specificity: 54.4% and 69.4%; AUC: 0.634 and 0.144, respectively). CD11b% could not discriminate between sepsis and control neonates (sensitivity and specificity of 31.8% and 73.6%, respectively) with an AUC of 0.405. hs-CRP had moderate diagnostic performance, achieving sensitivity and specificity of 69% and 78.15%, respectively, and AUC = 0.586. ROC analysis showed that combined hs-CRP and CD64% results had the highest sensitivity and specificity in the current study, being 93.9% and 97.2%, with AUC = 0.938, respectively. Conclusion: CD64%, CD64 MFI, CD11b MFI, and hs-CRP are increased in neonates with sepsis comparable to the controls. CD64% has a superior diagnostic performance comparable to nCD11b and hs-CRP. Combined nCD64 with hs-CRP measurement can provide rapid and accurate diagnostic modality for sepsis diagnosis in correlation with the patient's clinical condition and context with the results of other hematological indices; neutrophil CD64 can be routinely applicable in NICUs for better sepsis management. It is statistically evident that nCD11b is less ideal compared to nCD64 as a diagnostic, prognostic, or monitoring sepsis marker.

Reliability of IL-6 Alone and in Combination for Diagnosis of Late Onset Sepsis: A Systematic Review

Diagnosis of neonatal sepsis is difficult due to nonspecific signs and symptoms. Interleukin-6 (IL-6) is a promising marker for neonatal sepsis. We aimed to test the accuracy of IL-6 in neonates after 72 h of life in case of late onset sepsis (LOS). We searched for studies regarding IL-6 accuracy for the diagnosis of LOS between 1990 and 2020 using the PubMed database. Following study selection, the reported IL-6 sensitivities and specificities ranged between 68% and 100% and 28% and 100%, with median values of 85.7% and 82% and pooled values of 88% and 78% (respectively) in the 15 studies including 1306 infants. Subgroup analysis revealed a better sensitivity (87% vs. 82%), but not specificity (both 86%), in preterm infants compared to term infants or mixed populations. Early sample collection revealed the highest sensitivity (84%), but had the lowest specificity (86%). To assess quality, we used a STARD checklist adapted for septic neonates and the QUADAS criteria. Limitations of this review include the heterogeneous group of studies on the one side and the small number of studies on the other side that analyzed different combinations of biomarkers. We concluded that IL-6 demonstrated good performance especially in the preterm infant population and the best results were achieved by measurements at the time of LOS suspicion.

Biomarkers of Neonatal Sepsis: Where We Are and Where We Are Going

Neonatal sepsis is a bacterial bloodstream infection leading to severe clinical manifestations frequently associated with death or irreversible long-term deficits. Antibiotics are the drug of choice to treat sepsis, regardless of age. In neonates, the lack of reliable criteria for a definite diagnosis and the supposition that an early antibiotic administration could reduce sepsis development in children at risk have led to a relevant antibiotic overuse for both prevention and therapy. The availability of biomarkers of neonatal sepsis that could alert the physician to an early diagnosis of neonatal sepsis could improve the short and long-term outcomes of true sepsis cases and reduce the indiscriminate and deleterious use of preventive antibiotics. The main aim of this narrative review is to summarize the main results in this regard and to detail the accuracy of currently used biomarkers for the early diagnosis of neonatal sepsis. Literature analysis showed that, despite intense research, the diagnosis of neonatal sepsis and the conduct of antibiotic therapy cannot be at present decided on the basis of a single biomarker. Given the importance of the problem and the need to reduce the abuse of antibiotics, further studies are urgently required. However, instead of looking for new biomarkers, it seems easier and more productive to test combinations of two or more of the presently available biomarkers. Moreover, studies based on omics technologies should be strongly boosted. However, while waiting for new information, the use of the clinical scores prepared by some scientific institutions could be suggested. Based on maternal risk factors and infant clinical indicators, sepsis risk can be calculated, and a significant reduction in antibiotic consumption can be obtained.

Diagnostic value of mid-regional pro-Adrenomedullin as a biomarker of invasive bacterial infection in children: a systematic review

Background

Invasive bacterial infections (IBI) in children present a difficult clinical challenge. They are often life-threatening, however in the early stages they can be hard to differentiate from benign viral infections. This leaves clinicians with the risk of missing a serious IBI diagnosis or inappropriately using antimicrobials in a child with a viral infection- contributing to the ongoing development of increased antimicrobial resistance. Hence, biomarkers which could aid in early detection of IBI and differentiation from viral infections are desirable. Mid-Regional pro-Adrenomedullin (MR-proADM) is a biomarker which has been associated with IBI. The aim of this systematic review was to determine its diagnostic accuracy in identifying children with IBI.

Methods

A strategy was devised to search online databases MEDLINE, Embase, Web of Science and Scopus for human clinical trials reporting the accuracy of MR-proADM in children. Against predesigned inclusion and exclusion criteria full texts were selected for inclusion and data extraction. True positives, false positives, true negatives and false negatives were extracted from each included study to fill 2 × 2 tables. Using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool methodological quality of each study was assessed.

Results

A total of 501 articles were initially identified. After the removal of duplicates and abstract screening 11 texts were fully reviewed and four texts (totaling 1404 patients) were included in the systematic analysis. Only one study was of a high quality and that study accounted for the vast majority of patients. A single study reported the diagnostic accuracy of MR-proADM for invasive bacterial infection reporting an Area under the Curve of 0.69. The paucity of available studies made meta-analysis and studies of heterogeneity impossible.

Conclusion

There is a paucity of research regarding the diagnostic accuracy of MR-proADM in the diagnosis of invasive bacterial infections in children. Initial results would suggest that MR-proADM testing alone is poor at identifying IBI in young children. It remains unclear if MR-proADM performs differently in older children or in children with signs and symptoms of IBI.

Trial registration

PROSPERO CRD42018096295.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03255-9.

Diagnosis of Neonatal Sepsis: The Role of Inflammatory Markers

This is a narrative review on the role of biomarkers in the diagnosis of neonatal sepsis. We describe the difficulties to obtain standardized definitions in neonatal sepsis and discuss the limitations of published evidence of cut-off values and their sensitivities and specificities. Maternal risk factors influence the results of inflammatory markers as do gestational age, the time of sampling, the use of either cord blood or neonatal peripheral blood, and some non-infectious causes. Current evidence suggests that the use of promising diagnostic markers such as CD11b, CD64, IL-6, IL-8, PCT, and CRP, either alone or in combination, might enable clinicians discontinuing antibiotics confidently within 24-48 h. However, none of the current diagnostic markers is sensitive and specific enough to support the decision of withholding antibiotic treatment without considering clinical findings. It therefore seems to be justified that antibiotics are often initiated in ill term and especially preterm infants. Early markers like IL-6 and later markers like CRP are helpful in the diagnosis of neonatal sepsis considering the clinical aspect of the neonate, the gestational age, maternal risk factors and the time (age of the neonate regarding early-onset sepsis) of blood sampling.

C-Reactive Protein, Interleukin-6, and Procalcitonin in Diagnosis of Late-Onset Bloodstream Infection in Very Preterm Infants

BACKGROUND

Late-onset bloodstream infection (LOBSI) is common in very preterm infants. Early and accurate diagnosis is crucial for prognosis and outcome. We aimed to analyze the accuracy of routinely used inflammatory biomarkers in the diagnosis of LOBSI as compared to uninfected controls.

METHODS

In this single-center, retrospective case-control study, interleukin-6 (IL-6), procalcitonin (PCT), and C-reactive protein (CRP) were routinely measured, when infection was clinically suspected. The definition of LOBSI was based on positive blood culture, clinical signs of infection, and onset more than 72 hours after birth.

RESULTS

Among 285 enrolled infants, 66 developed LOBSI. IL-6 was superior to other markers, and levels greater than 100 ng/L had a sensitivity of 94% and a specificity of 99% for the presence of LOBSI. Receiver operating characteristic curve of IL-6 had area under the curve of 0.988 (95% CI = 0.975-1.00, P < .001). The negative predictive value of IL-6, CRP, and PCT for optimal cutoff values was 99%, 95%, and 93%, respectively. The logistic regression model of IL-6 > 100 ng/L or CRP > 10 mg/L were successfully predicted LOBSI in 97.9% of cases.

CONCLUSIONS

The combination of IL-6 and CRP seems to have great potential in routine rapid diagnosis of LOBSI development. High negative predictive value of all tested markers could encourage the early discontinuation of antibiotic treatment.

Neonatal sepsis at point of care

Sepsis, which includes infection followed by inflammation, is one of the leading causes of death among neonates worldwide. The major attribute of this disease process is dysregulated host response to infection leading to organ dysfunction and potentially death. A comprehensive understanding of the host response as well as the pathogen itself are important factors contributing to outcome. Early diagnosis is paramount, as it leads to accurate assessment and improved clinical management. Accordingly, a number of diagnostic platforms have been introduced to assess the presence of blood stream pathogens in septic neonates. Unfortunately, current point-of-care (POC) methods rely on a single parameter/biomarker and thus lack a comprehensive evaluation. The emerging field of biosensing has, however, resulted in the development of a wide range of analytical devices that may be useful at POC. This review discusses currently available methods to screen the inflammatory process in neonatal sepsis. We describe POC sensor-based methods for single platform multi-analyte detection and highlight the latest advances in this evolving technology. Finally, we critically evaluate the applicability of these POC devices clinically for early diagnosis of sepsis in neonates.

Cell-Surface Biomarkers, C-Reactive Protein and Haematological Parameters for Diagnosing Late Onset Sepsis in Pre-term Neonates

OBJECTIVE

To compare the diagnostic accuracy of white blood cell-surface biomarkers (CD64, CD11b and HLA-DR), C-reactive protein (CRP) and hematological parameters to diagnose definite sepsis among pre-term neonates presenting with suspected late-onset neonatal sepsis (LONS).

DESIGN

This was a prospective, single-gate, diagnostic study in a Level III neonatal unit. Fifty-three neonates (gestation, <34 weeks) with LONS (onset, >72  age), were enrolled. Cell-surface biomarkers, CRP and haematological parameters were assayed at 0 and 48 h after onset. The reference standard was definite sepsis, defined as a positive blood culture with a non-contaminant organism. The index tests (cell-surface biomarkers, CRP and haematological parameters) were compared between subjects with or without 'definite sepsis'. The area under the receiver operator characteristics curves (AUC) generated for each index test at 0 and 48 h was compared.

SETTING

Level III neonatal unit in a tertiary care institute.

RESULTS

Of 53 enrolled pre-term infants, 24 had definite sepsis. Among all the index tests evaluated, CRP at 48 h had the highest AUC [0.82 (95% confidence interval, 0.69, 0.92)]. The expression of CD11b and HLA-DR was significantly reduced among the septic neonates. Among the cell-surface biomarkers, the maximum AUC was recorded for HLA-DR at 48  [0.68 (95% CI, 0.54, 0.81)]. Comparisons between index tests were not statistically significant.

CONCLUSION

C-reactive protein is superior to other sepsis screen biomarkers and white blood cell-surface biomarkers in diagnosing culture-positive LONS among pre-term infants. CD64, CD11b and HLA DR as diagnostic tests in this group have limited discriminatory value.

LAY SUMMARY

The diagnosis of neonatal blood stream infections is a challenge. In response to bacterial blood stream infections, white blood cells are known to produce an excess of certain types of specialized proteins on their surface, including CD64, CD11b and HLA-DR. In this study we evaluated the concentration of these cell-surface proteins for diagnosing blood stream infections in pre-mature newborn babies, whose onset of infection was beyond 72 h of life. We compared these tests against standard tests that are currently in clinical use, such as C-reactive protein and blood white cell counts. All tests were performed at the time of initially suspecting the infection and 48 h later. The gold standard against which all these tests were evaluated was blood culture, in which the offending bacteria are grown in specialized laboratory media. Of 53 pre-mature babies with suspected infection, 24 had blood culture-proven infection. Among all tests, C-reactive protein at 48 h had the best ability to distinguish definite infection from no infection. The expression of CD11b and HLA-DR was significantly reduced among infected neonates. We conclude that C-reactive protein is superior to white blood cell-surface proteins and white cell count in diagnosing definite late-onset infections among pre-term infants.

Procalcitonin Clearance, CD64, and HLA-DR as Predictors of Outcome in Febrile Neutropenic Children With Lymphoreticular Malignancies

BACKGROUND

Febrile neutropenia (FN) is a dreaded complication of cancer chemotherapy. There has been a lot of improvement in supportive care in FN that has drastically reduced the infection-related mortality in these patients. The focus now is on reducing infection-related morbidity, healthcare costs and optimizing the quality of life of the child as well as their family during these episodes. In this study, biomarkers were studied as predictors of outcome so that outcome can be predicted earlier, and treatment modified accordingly.

OBJECTIVE

To measure procalcitonin levels (at baseline and day 3), procalcitonin clearance, neutrophil CD64 expression levels (at baseline) and monocyte HLA-DR expression levels (at baseline), and their correlation with outcome.

SETTING

Tertiary care hospital.

STUDY TYPE

Cross-sectional observational study.

POPULATION/PARTICIPANTS

Sixty-five episodes of FN in children below 12 years with lymphoreticular malignancies. Children receiving antibacterial and/or antifungal treatment within the last 7 days were excluded from the study.

METHODS

The subjects recruited into the study had undergone complete clinical and laboratory evaluation as per hospital protocol. Procalcitonin (day 0 and 3), neutrophil CD64 expression, and monocytic HLA-DR expression levels were measured in these patients.

RESULTS

Sixty-five episodes of FN were studied in children with lymphoreticular malignancy. It was found that procalcitonin and HLA-DR are very good markers of outcome, whereas CD64 although a good marker, was inferior to procalcitonin and HLA-DR in predicting outcome. Procalcitonin clearance was found to be superior to single value of procalcitonin. Furthermore, procalcitonin on day 3 was found to be a better predictor of outcome compared with its baseline value. Also, it was found that procalcitonin and HLA-DR had a significant correlation with baseline C-reactive protein levels.

CONCLUSIONS

On the basis of the findings of the study we suggest that serial monitoring of procalcitonin levels be used in febrile neutropenic children with cancer. Procalcitonin levels on day 3 alone can be offered in resource poor setting. The role of HLA-DR and CD64 also seems promising and needs to be further explored in larger multicentric studies.

Neutrophil and monocyte receptor expression in patients with sepsis: implications for diagnosis and prognosis of sepsis

Understanding the complex immune responses in sepsis is crucial to provide insight into the clinical syndrome. We evaluated the changes in the surface receptors of the cells of innate immunity, neutrophils and monocytes, in patients with sepsis. Since sepsis remains a clinical challenge, we aimed to assess the significance of altered receptor expression in diagnosis and prognosis. Critically ill patients with sepsis (n=31) were investigated for the expression of receptors for IgG heavy chain CD64 and CD16 on neutrophils and CD64 and the lipopolysaccharide receptor CD14 on monocytes by flow cytometry and compared to 23 patients with no sepsis. Patients with sepsis had increased expression of neutrophil CD64. Neutrophil CD64 was specific for discriminating patients with sepsis but showed weak sensitivity. When integrated in a scoring system, neutrophil CD64 in combination with C-reactive protein (CRP) and SOFA score showed a diagnostic accuracy of 0.93 for sepsis and significantly predicted increased mortality risk. While neutrophil CD16 did not discriminate for sepsis, decreased expression was associated with increased mortality risk. In contrast, monocyte CD64 and CD14 expression was unaltered in sepsis and was not associated with mortality risk. Our study demonstrates that unlike monocytes, neutrophil receptor expression is altered in patients with sepsis receiving intensive care. It is promising to apply a combination approach to diagnose sepsis especially in time-limited conditions.

Expression, Role, and Regulation of Neutrophil Fcγ Receptors

Neutrophils are best known for their critical role in host defense, for which they utilize multiple innate immune mechanisms, including microbe-associated pattern recognition, phagocytosis, production of reactive oxygen species, and the release of potent proteases, mediators, antimicrobials, and neutrophil extracellular traps. Beyond their well-established contribution to innate immunity, neutrophils were more recently reported to interact with various other cell types, including cells from the adaptive immune system, thereby enabling neutrophils to tune the overall immune response of the host. Neutrophils express different receptors for IgG antibodies (Fcγ receptors), which facilitate the engulfment of IgG-opsonized microbes and trigger cell activation upon cross-linking of several receptors. Indeed, FcγRs (via IgG antibodies) confer neutrophils with a key feature of the adaptive immunity: an antigen-specific cell response. This review summarizes the expression and function of FcγRs on human neutrophils in health and disease and how they are affected by polymorphisms in the FCGR loci. Additionally, we will discuss the role of neutrophils in providing help to marginal zone B cells for the production of antibodies, which in turn may trigger neutrophil effector functions when engaging FcγRs.

Biomarkers for Infection in Children: Current Clinical Practice and Future Perspectives

Biomarkers have become an integral part of the clinical decision-making process of clinicians dealing with febrile children. C-reactive protein, procalcitonin and white blood cell count are probably the most studied ones. Crucial to using biomarkers is the understanding of how a test result will alter post-test probabilities and then impact on clinical decision making. Improved analytical and computational platforms have enabled the next generation of advanced biomarker discovery studies. Promising combinations of candidate biomarkers for a diverse spectrum of febrile illnesses, such as viral and bacterial infections, have been identified using proteomics, RNA gene expression and metabolomics.

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.

Is neutrophil CD11b a special marker for the early diagnosis of sepsis in neonates? A systematic review and meta-analysis

OBJECTIVES

Our study aimed to synthesise and analyse the early diagnostic value of neutrophil CD11b (nCD11b) for neonatal sepsis.

DESIGN

Systematic review and meta-analysis.

METHODS

Pubmed, Embase, the Cochrane Library and Web of Science Databases were searched up to June 2018. We used Stata software (V.14.0) to conduct the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic OR (DOR), pretest probability, post-test probability and summary receiver operating characteristic (SROC) curve for diagnostic efficiency of n CD11b.

RESULTS

Nine studies, accounting for 843 neonates, were included. The overall pooled sensitivity, specificity, PLR, NLR, DOR, post-test positive probability and post-test negative probability and the area under the SROC curve were 0.82 (95% CI 0.71 to 0.90), 0.93 (95% CI 0.62 to 0.99), 11.51 (95% CI 1.55 to 85.62), 0.19 (95% CI 0.10 to 0.36), 59.50 (95% CI 4.65 to 761.58), 74%, 5% and 0.90, which had accuracy in diagnosing neonatal sepsis.

CONCLUSION

The present evidence indicated that nCD11b is a promising biomarker for the early diagnosis of neonatal sepsis.

Accuracy of CD64 expression on neutrophils and monocytes in bacterial infection diagnosis at pediatric intensive care admission

The CD64 receptor has been described as an interesting bacterial infection biomarker. Its expression has not been studied in previously healthy children admitted to pediatric critical care unit (PICU). Our objective was firstly to describe the CD64 expression and secondly study its diagnostic accuracy to discriminate bacterial versus viral infection in this children. We made a prospective double-blind observational study (March 2016-February 2018). A flow cytometry (FC) was done from peripheral blood at PICU admission. We studied the percentage of CD64+ neutrophils and the CD64 mean fluorescence intensity (MFI) on neutrophils (nCD64) and monocytes (mCD64). Statistical analyses were performed with non-parametric tests (p < 0.05). Twenty children in the bacterial infection group (BIG) and 25 in the viral infection group (VIG). Children in BIG showed higher values of CD64+ neutrophils (p = 0.000), nCD64 (p = 0.001), and mCD64 (p = 0.003). In addition, CD64+ neutrophils and nCD64 expression have positive correlation with procalcitonin and C reactive protein. The nCD64 area under the curve (AUC) was 0.83 (p = 0.000). The %CD64+ neutrophils showed an AUC of 0.828 (p = 0.000). The mCD64 AUC was 0.83 (p = 0.003). The nCD64 and %CD64+ neutrophils also showed higher combined values of sensitivity (74%) and specificity (90%) than all classical biomarkers.In our series CD64 expression allows to discriminate between bacterial and viral infection at PICU admission. Future studies should confirm this and be focused in the study of CD64 correlation with clinical data and its utility as an evolution biomarker in critical care children.

Plasma miR-1290 Is a Novel and Specific Biomarker for Early Diagnosis of Necrotizing Enterocolitis-Biomarker Discovery with Prospective Cohort Evaluation

OBJECTIVE

To discover specific circulating microRNA (miRNA) biomarkers for the early differentiation of necrotizing enterocolitis (NEC) from neonatal sepsis and inflammatory conditions.

STUDY DESIGN

The study comprised 3 distinct phases: differential microarray analysis to compare plasma miRNA expression profiles of NEC vs sepsis and non-NEC/nonsepsis cases, a case-control study to quantify dysregulated miRNAs as potential specific biomarkers of NEC, and a prospective cohort study to assess the diagnostic usefulness of the best miRNA biomarker(s).

RESULTS

A distinct miRNA expression profile was observed in the NEC compared with the sepsis and non-NEC/nonsepsis groups. miR-1290, miR-1246, and miR-375 were discovered to be specific biomarkers of NEC in the case-control study. In the cohort study (n = 301), plasma miR-1290 (day 0; >220 copies/µL) provided the greatest diagnostic usefulness for identifying both mild medical and severe surgical NEC cases. Of 20 infants with miR-1290 >650 copies/µL, 15 were diagnosed with NEC. Incorporating C-reactive protein (day 1; >15.8 mg/L) for cases with intermediate levels (220-650 copies/µL) in a 2-stage algorithm further optimized the diagnostic profile with a sensitivity of 0.83, a specificity of 0.96, a positive predictive value of 0.75, and a negative predictive value of 0.98. Importantly, 7 of 36 infants with NEC (19.4%) could be diagnosed 7.8-32.2 hours earlier (median, 13.3 hours) using miR-1290.

CONCLUSIONS

Plasma miR-1290 is a novel and specific biomarker that can effectively differentiate NEC cases from neonatal sepsis. miR-1290 facilitates neonatologists to confidently and timely reach a decision for early transfer of sick infants with NEC from community-based hospitals to tertiary surgical centers.

Comparison of the accuracy of neutrophil CD64, procalcitonin, and C-reactive protein for sepsis identification: a systematic review and meta-analysis

Background

Neutrophil CD64 is widely described as an accurate biomarker for the diagnosis of infection in patients with septic syndrome. We performed a systematic review and meta-analysis to evaluate the diagnostic accuracy of neutrophil CD64, comparing it with C-reactive protein (CRP) and procalcitonin (PCT) for the diagnosis of infection in adult patients with septic syndrome, based on sepsis-2 criteria. We searched the PubMed and Embase databases and Google Scholar. Original studies reporting the performance of neutrophil CD64 for sepsis diagnosis in adult patients were retained. The pooled sensitivity, specificity, diagnostic odds ratio (DOR), and hierarchical summary receiver operating characteristic (SROC) curve were calculated.

Results

We included 14 studies (2471 patients) from 2006 to 2017 in the meta-analysis. The pooled sensitivity and specificity of neutrophil CD64 for diagnosing infection in adult patients with septic syndrome were 0.87 (95% CI 0.80–0.92) and 0.89 (95% CI 0.82–0.93), respectively. The area under the SROC curve and the DOR were 0.94 (95% CI 0.92–0.96) and 53 (95% CI 22–128), respectively. There was significant heterogeneity between the studies included. Subgroup analyses showed that this heterogeneity was due to differences in sample size and the proportions of patients with sepsis included in the studies. Six studies (927 patients) compared neutrophil CD64 and CRP determinations, and six studies (744 patients) compared neutrophil CD64 and PCT determinations. The area under the SROC curve was larger for neutrophil CD64 than for CRP (0.89 [95% CI 0.87–0.92] vs. 0.84 [95% CI 0.80–0.88], P < 0.05) or PCT (0.89 [95% CI 0.84–0.95] vs. 0.84 [95% CI 0.79–0.89], P < 0.05).

Conclusions

In adult patients with septic syndrome, neutrophil CD64 levels are an excellent biomarker with moderate accuracy outperforming both CRP and PCT determinations.

Electronic supplementary material

The online version of this article (10.1186/s13613-018-0479-2) contains supplementary material, which is available to authorized users.

Decreased levels of regulatory B cells in patients with acute pancreatitis: association with the severity of the disease

Early stratification of the severity of acute pancreatitis (AP) is clinically important. Regulatory B cells have been found to be associated with disease activity of autoimmune diseases. However, the role of Regulatory B cells in AP remains unknown. We investigate the dynamic longitudinal changes in circulating IL-10-producing B cells (B10) and memory CD19+CD24hiCD27hi cells in patients with AP to evaluate their prediction utility for AP severity. B10, CD19+CD24hiCD27hi cells, inflammatory markers and cytokines were detected in patients with AP immediately after admission to the hospital (day 1), then on the third and seventh days. We observed decreases in lymphocytes, CD19+, B10, CD19+CD24hiCD27hi cells and lower mean fluorescence intensity (MFI) of CD80 and CD86 on B10 or CD19+CD24hiCD27hi cells in patients with AP, especially in those with severe acute pancreatitis (SAP). CD19+CD24hiCD27hi cells from patients with AP suppressed the cytokine productions of CD4+ T cells and CD14+ monocytes, but had impaired ability to induce regulatory T cells response. B10 and CD19+CD24hiCD27hi cells significantly increased in patients with mild acute pancreatitis (MAP) from day 1 to day 7, whereas these indexes remained stable in patients with SAP. B10 or CD19+CD24hiCD27hi cells were negatively correlated with the severity index (APACHE II score), inflammatory markers (C-reactive protein, CD64 index), and cytokines (IL-6, IL-17, TNF-α). Furthermore, receiver operating characteristic (ROC) curve analysis revealed that B10 and CD19+CD24hiCD27hi cells could predict the development of SAP. Thus, the detection of B10 and CD19+CD24hiCD27hi cells may be a practical way to improve the early assessment of AP severity.

Application of Electronic-Nose Technologies and VOC-Biomarkers for the Noninvasive Early Diagnosis of Gastrointestinal Diseases †

Conventional methods utilized for clinical diagnosis of gastrointestinal (GI) diseases have employed invasive medical procedures that cause stress, anxiety and pain to patients. These methods are often expensive, time-consuming, and require sophisticated chemical-analysis instruments and advanced modeling procedures to achieve diagnostic interpretations. This paper reviews recent applications of simpler, electronic-nose (e-nose) devices for the noninvasive early diagnosis of a wide range of GI diseases by collective analysis of headspace volatile organic compound (VOC)-metabolites from clinical samples to produce disease-specific aroma signatures (VOC profiles). A different "metabolomics" approach to GI disease diagnostics, involving identifications and quantifications of disease VOC-metabolites, are compared to the electronic-nose approach based on diagnostic costs, accuracy, advantages and disadvantages. The importance of changes in gut microbiome composition that result from disease are discussed relative to effects on disease detection. A new diagnostic approach, which combines the use of e-nose instruments for early rapid prophylactic disease-screenings with targeted identification of known disease biomarkers, is proposed to yield cheaper, quicker and more dependable diagnostic results. Some priority future research needs and coordination for bringing e-nose instruments into routine clinical practice are summarized.

Diagnosis and Management of Necrotizing Enterocolitis: An International Survey of Neonatologists and Pediatric Surgeons

BACKGROUND

Necrotizing enterocolitis (NEC) is a serious complication of prematurity. Currently, there is limited evidence to guide investigation and treatment strategies.

OBJECTIVES

To evaluate the parameters used to diagnose or exclude NEC, and to identify differences between neonatologists and pediatric surgeons.

METHODS

A scenario-based survey was sent to neonatologists and pediatric surgeons.

RESULTS

173 physicians from 26 countries completed the survey (55% neonatologists and 45% pediatric surgeons). Bloody stools, abdominal tenderness, low platelet counts, and increased lactate levels increased the likelihood of NEC for 82, 72, 56, and 45% of respondents, respectively. Intestinal pneumatosis, portal venous gas, and pneumoperitoneum on X-ray increased the likelihood of NEC for 99, 98, and 92% of respondents, respectively. Clinical examination and laboratory tests were insufficient to exclude NEC, but normal intestinal movements and normal gut wall thickness on ultrasonography decreased the likelihood of NEC for 38 and 33% of respondents, respectively. Neonatologists more frequently relied on increased gastric residuals and abdominal distension to diagnose NEC (p = 0.04 and p = 0.03, respectively), whereas pediatric surgeons more frequently reported that absence of bloody stools helped to exclude NEC (p = 0.04). In a deteriorating patient with suspected NEC, 39% of respondents would broaden the antibiotic spectrum, and 42% would recommend a laparotomy.

CONCLUSION

Our results indicate a wide variation in the management of NEC, with significant differences between neonatologists and pediatric surgeons. A better appreciation of the relative significance and weighting that should be applied to the clinical features and investigations should reduce the variation in interpretation that appears to exist.

Diagnostics for neonatal sepsis: current approaches and future directions

Progress has been made in the reduction of morbidity and mortality from neonatal sepsis. However, diagnosis continues to rely primarily on conventional microbiologic techniques, which can be inaccurate. The objective of this review is to provide the clinician with an overview of the current information available on diagnosing this condition. We review currently available diagnostic approaches for documenting neonatal sepsis and also describe novel approaches for diagnosing infection in neonates who are under development and investigation. Substantial progress has been made with molecular approaches and further development of non-culture-based methods offer promise. The potential ability to incorporate antimicrobial resistance gene testing in addition to pathogen identification may provide a venue to incorporate a predominantly molecular platform into a larger program of neonatal care.

Biomarkers for the diagnosis of neonatal sepsis and necrotizing enterocolitis: Clinical practice guidelines

Sepsis and necrotizing enterocolitis are major contributors to morbidity and mortality in neonates, especially in those born preterm. While therapeutic interventions are available for both (for e.g. antibiotics), a major dilemma is early diagnosis so that these interventions can be done in a timely manner. As clinical evaluation alone is unreliable in identifying infants in the early stages of neonatal sepsis or necrotizing enterocolitis, there is a need to find specific biomarkers associated with these conditions to improve diagnostic capabilities. Optimal use of biomarkers in the identification and management of affected neonates requires an understanding of the properties of each marker within the timeline of the inflammatory response. We propose that early- and mid-phase markers such as neutrophil CD64 and procalcitonin should be combined with the late-phase biomarker C-reactive protein for maximal diagnostic benefit. Appropriately powered trials evaluating the serial measurements of these markers in decisions related to antibiotic stewardship in the neonatal population are indicated, in addition to more studies investigating other potentially useful biomarkers.

Early detection of neonatal group B streptococcus sepsis and the possible diagnostic utility of IL-6, IL-8, and CD11b in a human umbilical cord blood in vitro model

Background

Group B streptococcus (GBS) infection remains a major cause of neonatal morbidity and mortality, and GBS III is the predominant strain in early-onset GBS neonatal sepsis. To avoid both over- and undertreatment of infants with nonspecific signs of infection, early diagnostic tools are warranted. The aim of this study was to identify biomarkers with high sensitivity and specificity in an early stage of GBS infection. A secondary aim was to assess the utility of a human umbilical cord blood (HUCB) model system of early-onset neonatal sepsis.

Methods

Umbilical cord blood samples from 20 healthy term pregnancies were stimulated for 2 hours with a GBS III isolate from a patient and a commercially available GBS Ia strain. Nonstimulated samples served as controls. Leukocyte surface markers (CD11b, CD64, toll-like receptor [TLR] 2, TLR4, and TLR6) were analyzed by flow cytometry and soluble biomarkers by enzyme-linked immunosorbent assay (interleukin [IL]-6 and -8; interferon-γ-inducing protein [IP]-10; and S100b). The area under the receiver operating characteristic curve (AUC) was calculated for the markers.

Results

GBS III gave the highest responses and AUC values for all biomarkers. Only IL-6 and IL-8 displayed an AUC approaching 0.8 for both GBS serotypes (P<0.001). IL-8 >5,292 pg/mL had both a sensitivity and a specificity of 1.00. IL-6 >197 pg/mL had both a sensitivity and a specificity of 0.95 for GBS III stimulation. CD11b on granulocytes and monocytes was the leukocyte surface marker with the highest AUC values for both GBS serotypes.

Conclusion

In agreement with previous studies, IL-6, IL-8, and potentially CD11b could be useful in diagnosing neonatal GBS infection in an early stage. Our HUCB early-onset neonatal sepsis model may be useful for evaluating biomarkers of neonatal sepsis. The HUCB of neonates with risk factors for sepsis might even be used for diagnostic purposes, but requires further study.

Diagnosing sepsis - The role of laboratory medicine

Sepsis is the host response to microbial pathogens resulting in significant morbidity and mortality. An accurate and timely diagnosis of sepsis allows prompt and appropriate treatment. This review discusses laboratory testing for sepsis because differentiating systemic inflammation from infection is challenging. Procalcitonin (PCT) is currently an FDA approved test to aid in the diagnosis of sepsis but with questionable efficacy. However, studies support the use of PCT for antibiotic de-escalation. Serial lactate measurements have been recommended for monitoring treatment efficacy as part of sepsis bundles. The 2016 sepsis consensus definitions include lactate concentrations >2mmol/L (>18mg/dL) as part of the definition of septic shock. Also included in the 2016 definitions are measuring bilirubin and creatinine to determine progression of organ failure indicating worse prognosis. Hematologic parameters, including a simple white blood cell count and differential, are frequently part of the initial sepsis diagnostic protocols. Several new biomarkers have been proposed to diagnose sepsis or to predict mortality, but they currently lack sufficient sensitivity and specificity to be considered as stand-alone testing. If sepsis is suspected, new technologies and microbiologic assays allow rapid and specific identification of pathogens. In 2016 there is no single laboratory test that accurately diagnoses sepsis.

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.

Meta-analysis of diagnostic accuracy of neutrophil CD64 for neonatal sepsis

Background

The aim of this study was to systematically evaluate the diagnostic performance of nCD64 for neonatal sepsis.

Methods

Computer retrieval was conducted for the databases of PubMed, Embase, and Springer databases up to March 18, 2015 to select the relevant studies on nCD64 and neonatal sepsis. Sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and 95 % confidence intervals (CI) for diagnostic efficiency of nCD64 were pooled. In addition, the summary receiver operating characteristic (SROC) curve was also conducted based on the sensitivity and specificity.

Results

Seventeen studies including 3478 participants were included in this meta-analysis. The overall pooled sensitivity, specificity, PLR, NLR and DOR were 0.77 (95 % CI: 0.74–0.79), 0.74 (95 % CI: 0.72–0.75), 3.58 (95 % CI: 2.85–4.49), 0.29 (95 % CI: 0.22–0.37) and 15.18 (95 % CI: 9.75–23.62), respectively. In addition, the area under the SROC curve (AUC) was 0.8666, and no threshold effect was found based on the Spearman correlation analysis (P = 0.616). Besides, subgroup analysis showed higher sensitivity, specificity and AUC in term infants and proven infection group than those in preterm infants and clinical infection group, respectively.

Conclusions

The n CD64 expression alone is not a satisfactory marker for diagnosing neonatal sepsis with relatively low sensitivity, specificity, PLR and NLR, in spite of relatively high SROC area. Therefore, the n CD64 expression used in diagnosis of neonatal sepsis should be treated with caution.

Neutrophil CD64 as a Marker of Bacterial Infection in Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are responsible for most mortality in patients with chronic obstructive pulmonary disease (COPD) and are caused mainly by bacterial infection. We analyzed and compared neutrophil CD64 expression (using the ratio of CD64 level in neutrophils to that in lymphocytes as an index), serum C-reactive protein (CRP), procalcitonin (PCT) levels, white blood cell (WBC) count, and neutrophil percentage among healthy subjects and patients with stable COPD or AECOPD. Compared with patients with COPD and healthy subjects, patients with AECOPD demonstrated significantly increased CD64 index, CRP, PCT, WBC count, and neutrophil percentage. Interestingly, CD64 index and PCT were both significantly higher in patients with AECOPD with positive bacterial sputum culture than those with negative culture. Furthermore, CD64 index and PCT were positively correlated in AECOPD, and there was also correlation between CD64 index and CRP, WBC, and neutrophil percentage. These data suggest that CD64 index is a relevant marker of bacterial infection in AECOPD. We divided patients with AECOPD into CD64-guided group and conventional treatment group. In CD64-guided group, clinicians prescribed antibiotics based on CD64 index; while in the conventional treatment group, clinicians relied on experience and clinical symptoms to determine the necessity for antibiotics. We found that the efficacy of antibiotic treatment in CD64-guided group was significantly improved compared with the conventional treatment group, including reduction of hospital stays and cost and shortened antibiotic treatment duration. Thus, the CD64 index has important diagnostic and therapeutic implications for antibiotic treatment of patients with AECOPD.

Diagnostic value of C-reactive protein in neonatal sepsis: A meta-analysis

The aim of this study was to determine the value of C-reactive protein (CRP) in the diagnosis of patients with neonatal sepsis by a meta-analysis. Potential relevant studies were searched through the PubMed, Embase, and Cochrane Library databases before February 2016. We combined estimates of sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) with their 95% confidence intervals (CIs) of CRP for neonatal sepsis diagnosis. Summary receiver operating characteristic (SROC) curve was applied to evaluate the diagnostic value of CRP. The meta-regression and subgroup analysis were performed when heterogeneity was significant. In total, 31 studies were included in our meta-analysis with 5698 participants. The overall estimates for CRP in the diagnosis of neonatal sepsis were: sensitivity 0.69 (95% CI, 0.66–0.71), specificity 0.77 (95% CI, 0.76–0.78), PLR 3.83 (95% CI, 3.03–4.84), NLR 0.38 (95% CI, 0.31–0.45), and DOR 12.65 (95% CI, 8.91–17.94). The area under the curve (AUC) and Q* index were 0.8458 and 0.7773. Meta-regression analysis showed that heterogeneity was irrelevant to test time, cutoff value, assay method of CRP, neonates, and sepsis type. Heterogeneity still existed but decreased after subgroup analysis. CRP might be a valuable approach for the diagnosis of neonatal sepsis.

[Analysis of Cases with Elevated Blood (1->3)-β-D-glucan in Relation to an Infection Marker, Neutrophil CD64 Expression]

(1->3)-β-D-glucan (BDG) is a constituent of the fungal cell wall and its blood level is known as a marker of fungal infection including pneumocystis pneumonia (PCP). Meanwhile, peripheral blood neutrophil CD64 expression (CD64) is upregulated in various infections. We analyzed patients with positive BDG (cut off 11.0 pg/mL) and those whose CD64 was measured simultaneously. In patients who visited our hospital from 2005 to 2011, BDG was measured in 3,960 samples. The number of positive samples were 441 obtained from 185 patients. In patients with positive BDG, the initial BDG was 24.3 [16.4-70.5] pg/mL (median [interquartile range]). Positive BDG samples were derived mainly from the department of Rheumatology or that of Allergy and Respirology. Common primary diseases were rheumatoid arthritis (RA) or other connective tissue diseases, followed by malignancy, none (only abnormal chest X-ray) and bronchial asthma. The rates of afebrile patients, patients on immunosuppressive therapy and those with a normal range of white blood cell count were 63.7%, 50.9% and 40.8%, respectively. The main causes of positive BDG were PCP (n = 38, 20.5%) and non-PCP mycosis (n = 48, 25.9%, including 26 cases of aspergillosis). Others (99 patients, 53.6%) had positive BDG of unknown origin and 53 of them ameliorated spontaneously, most of whom could have been examples of pseudo-positive BDG. The number of deceased patients was 57 (30.8%) consisting of 9 PCP, 16 non-PCP mycosis and others. The median initial positive BDG levels in patients with PCP, non-PCP mycosis and others were 49.9, 28.9 and 19.7pg/mL, respectively. The positive rate of CD64 (cut off 2,000 molecules/cell) measured simultaneously with initial positive BDG was 77.8%. In RA patients with PCP, 94.7% of them had positive CD64 and the levels of CD64 were significantly higher than those in RA patients with bacterial pneumonia (median 9,386 vs 4,399 molecules/cell) in that same period. The positive rate of CD64 was lower in patients with positive BDG of unknown origin than those with PCP or non-PCP mycosis, which implies positive CD64 can exclude pseudo-positive BDG. Immunosuppressed patients often exhibit positive BDG. Simultaneous measurement of BDG and CD64, a quick pan-infection marker, assists the decision whether the positive BDG is true or false-positive.

Immune cell subsets at birth may help to predict risk of late-onset sepsis and necrotizing enterocolitis in preterm infants

BACKGROUND

Parameters predicting late-onset sepsis (LOS) and necrotizing enterocolitis (NEC) in preterm infants would be valuable. Ten-color flow-cytometry enables the estimation of cellular immune status requiring only small sample volumes.

AIMS

Identifying predictive parameters for LOS and NEC in the cellular immune status of preterm infants.

STUDY DESIGN AND SUBJECTS

In this prospective study in 40 preterm infants (week 26+0 to 30+6) and 10 healthy full-term newborn infants (control group, week 37+0 to 40+6), flow cytometric analyses of lymphocyte subpopulations were performed between the 2nd and the 6th day of life, with a follow-up until the preterm infant reached the calculated gestational age of week 40. Patients' episodes of infections and NEC were analyzed according to the NEO-KISS criteria of the German National Reference Center.

RESULTS

Ten preterm infants showed events within the first week of life and were excluded from the analysis. Of the other 30, five developed NEC, twelve LOS. In patients with LOS, the proportion of double-negative (DN) T cells was significantly elevated compared to patients without LOS, while immune-regulatory CD56bright and CD56negCD16+ NK cells were significantly decreased (p<0.05). Patients with NEC showed a reduction in the NK cell proportion (<3.7%) and significantly decreased naïve cytotoxic CD45RA+CD62L+ T cells (p<0.05).

CONCLUSION

NK cells and DN-T cell counts within the first week of life may be predictors for NEC and LOS in preterm infants. In order to identify patients at risk early, further analysis of these populations might be of interest.

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.

Neutrophil CD64 is upregulated in RA patients with lymphoma but not in other solid cancers

OBJECTIVE

To evaluate the utility of quantifying CD64 expression on neutrophils in rheumatoid arthritis patients with malignancy, especially its diagnostic role in lymphoma.

METHODS

We used flow cytometry to quantify CD64 expression on neutrophils from patients diagnosed with malignancy during the follow-up period prior to initiating treatment.

RESULTS

Neutrophils from 18 patients with lymphoma expressed significantly higher levels of CD64 (9635.6 ± 2123.7 molecules/cell) than those from 32 patients with other solid cancers (carcinoma) (1250.5 ± 91.1 molecules/cell) (p < 0.001). When the cutoff value was set at 2060 molecules/cell, the sensitivity and specificity of CD64 for diagnosing lymphoma was 88.9% and 94.4%, respectively.

CONCLUSIONS

The quantitative measurement of neutrophil CD64 by flow cytometry may be useful as a subsidiary diagnostic marker in patients with suspected lymphoma. Although neutrophil CD64 is currently a well-known marker of infection, it is necessary to bear in mind that lymphoma is also a candidate in differential diagnosis when CD64 expression on neutrophils is upregulated.

The use of laboratory biomarkers for surveillance, diagnosis and prediction of clinical outcomes in neonatal sepsis and necrotising enterocolitis

Biomarkers have been used to differentiate systemic neonatal infection and necrotising enterocolitis (NEC) from other non-infective neonatal conditions that share similar clinical features. With increasing understanding in biochemical characteristics of different categories of biomarkers, a specific mediator or a panel of mediators have been used in different aspects of clinical management in neonatal sepsis/NEC. This review focuses on how these biomarkers can be used in real-life clinical settings for daily surveillance, bedside point-of-care testing, early diagnosis and predicting the severity and prognosis of neonatal sepsis/NEC. In addition, with recent development of 'multi-omic' approaches and rapid advancement in knowledge of bioinformatics, more novel biomarkers and unique signatures of mediators would be discovered for diagnosis of specific diseases and organ injuries.

Role of Neutrophil CD64 Index as a Screening Marker for Late-Onset Sepsis in Very Low Birth Weight Infants

Introduction

The role of CD64 in late onset sepsis (LOS) in preterm infants has been described in several studies. Aim of this study was to investigate whether CD64 expression is increased in the days before clinical manifestation of LOS.

Methods

Patients with birth weight below 1,500g were eligible for study participation. During routine blood sampling CD64 index was determined between day of life 4 and 28. Patients were allocated to one of four groups: (1) blood-culture positive sepsis, (2) clinical sepsis, (3) symptoms of infection without biochemical evidence of infection, or (4) patients without suspected infection. Kinetics of CD64 expression were compared during a period before and after the day of infection in the respective groups.

Results

50 infants were prospectively enrolled and allocated to each group as follows: group (1) n = 7; group (2) n = 10; group (3) n = 8; and group (4) n = 25. CD64 index was elevated in 57% of patients in group (1) at least two days before infection. In contrast only 20% in the clinical sepsis group and 0% in group (3) had an elevated CD64 index in the days before infection. 10 of the 25 patients in the control group (4) presented increased CD64 index values during the study period.

Conclusions

The CD64 index might be a promising marker to detect LOS before infants demonstrate signs or symptoms of infection. However, larger prospective studies are needed to define optimal cut-off values and to investigate the role of non-infectious inflammation in this patient group.

A mathematical algorithm for detection of late-onset sepsis in very-low birth weight infants: a preliminary diagnostic test evaluation

OBJECTIVE

To study the diagnostic ability of RALIS (computerized mathematical algorithm and continuous monitoring device) to detect late onset sepsis among very low birth weight preterm neonates.

METHODS

Randomly chosen 24 very low birth weight infants with proven sepsis were compared to 22 infants without sepsis. The clinical parameters were retrospectively collected from the medical records. The ability of RALIS to detect late onset sepsis was calculated.

RESULTS

RALIS positively identified 23 of the 24 infants with sepsis (sensitivity 95.8%). It indicated sepsis alert median 2.0 days earlier than clinical suspicion. A false positive alert was indicated in 23% (5/22) infants. The specificity, and positive and negative predictive ability of RALIS were 77.3%. 82.1% and 94.4%, respectively.

CONCLUSION

RALIS may aid in the early diagnosis of late onset sepsis in very low birth weight preterm infants.

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

OBJECTIVE

The aim of this study is to determine the validity and reliability of neutrophil CD64 in identifying infected infants and to evaluate the impact of this marker on clinical care.

STUDY DESIGN

Neutrophil CD64 index was incorporated in 371 infection evaluations in 234 infants (ages 1-293 days) from 2005 to 2009 and the impact of this change on clinical care was evaluated.

RESULTS

The sensitivity of the neutrophil CD64 assay was 87% in identifying 31 episodes of culture positive sepsis and 83% in identifying 12 infants with ventilator-associated pneumonia. There was no difference in the mean number of antibiotic days in infants with a normal CD64 versus those with a normal complete blood count (CBC) (p = 0.89), but twofold more infants were identified as "not infected" by CD64 than by CBC.

CONCLUSION

CD64 had a high sensitivity for identifying infected infants while also decreasing the number of infants that were exposed to unnecessary antibiotic use.

Neutrophil CD64 level as a rapid and promising diagnostic tool for infectious diseases in elderly patients

AIM

We examined the utility of the neutrophil CD64 level as a rapid and sensitive diagnostic marker for infections in febrile aged patients.

METHODS

The expression level of CD64 per neutrophil was quantitatively measured with flow cytometry using a QuantiBrite kit in samples from febrile (aged >65 years) patients. Information about the presence or absence of infectious disease was retrospectively obtained from each patient's medical record in which attending physicians were obliged to write down a tentative diagnosis after resolution of manifestations.

RESULTS

With receiver operating characteristic curve evaluation using the results, a CD64 level >2000 molecules per neutrophil was sensitive and specific for detecting infection. Among 102 patients suspected of having infection, 72 patients were diagnosed with infectious diseases, and 30 patients had non-infectious diseases. The sensitivity and specificity of determination of the neutrophil CD64 level were 88% and 63%, respectively. However, considering the high frequency of infections in elderly patients (71% in the present study), the post-test probability reached as high as 93%. The positive likelihood ratio was 2.4, and the negative likelihood ratio was 0.2.

CONCLUSIONS

Considering the frequency of infectious diseases in elderly patients, determination of the neutrophil CD64 level helps detect infectious diseases.

Diagnostic utility of biomarkers for neonatal sepsis--a systematic review

Neonatal sepsis is a major cause of morbidity and mortality. Early diagnosis and treatment of the neonate with suspected sepsis are essential to prevent life-threatening complications. Diagnosis of neonatal sepsis is a challenge due to non-specific clinical signs and the fact that infection markers are difficult to interpret in the first and critical phase of neonatal sepsis. The objective of the present study was to systematically evaluate existing evidence of the diagnostic utility of biomarkers for prediction of sepsis in neonates. We conducted a systematic literature search performed in PubMed and Embase. The study population was neonates with gestation age > 24 weeks in their first 28 days of life with suspected sepsis. The included manuscripts were rated due to criteria from a modified rating scale developed by Douglas Altman. Of 292 potentially relevant manuscripts, 77 fulfilled the inclusion and exclusion criteria; 16 (21%) were rated as high-quality studies. C-reactive protein (CRP) was the most extensively studied biomarker evaluated. The high-quality studies indicated that the acute phase protein serum amyloid A had high sensitivity, both at onset of symptoms and 2 days after. The studies evaluating serum amyloid A presented a variable positive predictive value (PPV, 0.67 and 0.92) with a high negative predictive value (NPV, 0.97 and 1.00). The existing evidence of the diagnostic value of serum amyloid A for neonatal sepsis showed promising results, and should be further investigated in clinical settings.

Effective Biomarkers for Diagnosis of Neonatal Sepsis

Infection in neonates continues to be a global problem with significant morbidity and mortality. The diagnosis of neonatal sepsis is complicated by nonspecific clinical symptomatology, a high-false negative rate, and a delay in obtaining blood culture results. An ideal biomarker needs to have a high degree of accuracy in recognizing the presence or absence of definite infection at an early stage, to guide the initiation and duration of antibiotic therapy. The diagnostic utility of the following biomarkers seems to be most practical in the early (interleukin [IL]-6, IL-8, tumor necrosis factor-alpha, neutrophil CD64), mid (procalcitonin) and late (C-reactive protein) phases of neonatal sepsis. Future research studies to assess reliability of these biomarkers should be (1) adequately powered for sample size and (2) use the gold-standard definition of blood-culture proven pathogen-specific sepsis. Significant advances in diagnostic accuracy of novel biomarkers to allow early, accurate, and cost-effective identification of pathogens responsible for neonatal sepsis is anticipated in the next 5 years.

Diagnostic utility of neutrophil CD64 as a marker for early-onset sepsis in preterm neonates

Introduction

Neutrophil CD64 has been proposed as an early marker of sepsis. This study aims to evaluate the diagnostic utility of neutrophil CD64 for identification of early-onset sepsis in preterm neonates.

Methods

The prospective study was conducted in a neonatal intensive care unit between November 2010 and June 2011. Preterm neonates in whom infection was suspected when they were <12 hours of age were enrolled. Complete blood count with differential, blood culture, neutrophil CD11b and CD64 measurement were performed. Receiver operating characteristic curve analysis was performed to evaluate the performance of neutrophil CD64 as biomarker of sepsis.

Results

A total of 158 preterm neonates was enrolled, 88 of whom were suspected infection. The suspected sepsis group was of lesser gestational age (P<0.001) and lower birth weight (P<0.001), compared with controls. The hematologic profiles of the suspected sepsis group were characterized by higher white blood cell count, neutrophil counts and C-reactive protein. The suspected sepsis neonates had significantly higher neutrophil CD64 expression compared with controls. Neutrophil CD64 had an area value under the curve of 0.869 with an optimal cutoff values of 1010 phycoerythrin molecules bound/cell and it had a high sensitivity (81.82%) and negative predictive value (77.4%). The level of neutrophil CD64 was independent of antibiotic therapy within 24 hours after the onset of sepsis in preterm neonates.

Conclusions

Neutrophil CD64 is a highly sensitive marker for suspected early-onset sepsis in preterm neonates. Our study suggests that neutrophil CD64 may be incorporated as a valuable marker to diagnose infection.

CD64 expression is increased in patients with severe acute pancreatitis: clinical significance

BACKGROUND/AIMS

Upregulated CD64 expression on neutrophils is the most useful marker for acute bacterial infections and systemic inflammation. However, it is unknown whether CD64 is involved in the pathogenesis of acute pancreatitis (AP). This study was designed to determine whether CD64 is implicated in severe acute pancreatitis (SAP), and thus, is a suitable marker for SAP.

METHODS

SAP was induced in rats with an intraperitoneal injection of L-arginine. CD64 expression in the rat pancreas was determined by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry. Additionally, the CD64 mRNA expression in peripheral blood leukocytes from 21 patients with mild acute pancreatitis (MAP) and 10 patients with SAP was investigated at the time of admission and during remission by qRT-PCR.

RESULTS

CD64 mRNA and protein expression in the pancreas was significantly higher in rats with SAP, compared to the controls. The CD64 expression was higher in the patients with SAP than in the patients with MAP. During remission, CD64 mRNA decreased in both the MAP and SAP patients. The area under the curve of CD64 expression for the detection of SAP was superior to both the Ranson and the Acute Physiology and Chronic Health Evaluation II scores.

CONCLUSIONS

The CD64 level was significantly increased in correlation with the disease severity in SAP and may act as a useful marker for predicting the development of SAP.

Biomarkers of necrotising enterocolitis

Different categories of biomarkers of necrotising enterocolitis (NEC), including (i) non-specific mediators of the inflammatory cascade, e.g. acute phase reactants, chemokines, cytokines, and cell surface antigens, (ii) enhanced non-specific biomarkers, and (iii) specific gut-associated proteins, have distinctive biochemical characteristics and properties. The appropriateness of using these mediators in specific clinical situations, and the pros and cons of their applications as indicators or predictors of intestinal injury and NEC are highlighted. Many potentially new biomarkers such as micro-RNA, volatile organic compounds and gut microbiomes are currently under investigation. A stringent protocol for biomarker discovery is revealed so that investigators can consider this methodology as a reference for future discovery of organ-specific and/or disease-specific biomarkers for preterm infants.

Gut-associated biomarkers L-FABP, I-FABP, and TFF3 and LIT score for diagnosis of surgical necrotizing enterocolitis in preterm infants

OBJECTIVES

To evaluate the use of gut barrier proteins, liver-fatty acid binding protein (L-FABP), intestinal-fatty acid binding protein (I-FABP), and trefoil factor 3 (TFF3), as biomarkers for differentiating necrotizing enterocolitis (NEC) from septicemic/control infants and to identify the most severely affected surgical NEC from nonsurgical NEC infants.

BACKGROUND

Clinical features and routine radiologic investigations have low diagnostic utilities in identifying surgical NEC patients.

METHODS

The diagnostic utilities of individual biomarkers and the combination of biomarkers, the LIT score, were assessed among the NEC (n = 20), septicemia (n = 40), and control groups (n = 40) in a case-control study for the identification of proven NEC and surgical NEC infants.

RESULTS

Plasma concentrations of all gut barrier biomarkers and the LIT score were significantly higher in the NEC than in the septicemia or control group (P < 0.01). Using median values of biomarkers and the LIT score in the NEC group as cutoff values for identifying NEC from septicemic/control cases, all had specificities of 95% or more and sensitivities of 50%. Significantly higher levels of biomarkers and the LIT score were found in infants with surgical NEC than in nonsurgical NEC cases (P ≤ 0.02). The median LIT score of 4.5 identified surgical NEC cases with sensitivity and specificity of 83% and 100%%, respectively. A high LIT score of 6 identified nonsurvivors of NEC with sensitivity and specificity of 78% and 91%, respectively.

CONCLUSIONS

The LIT score can effectively differentiate surgical NEC from nonsurgical NEC infants and nonsurvivors of NEC from survivors at the onset of clinical presentation. Frontline neonatologists and surgeons may, therefore, target NEC infants who are most in need of close monitoring and those who may benefit from early surgical intervention.