Monocyte HLA-DR expression as predictor of poor outcome in neonates with late onset neonatal sepsis

Evaluation of HLA-DR expression in monocytes and CD64 in neutrophils as A predictor of SEPSIS/sirs in the infectious-inflammatory process

Sepsis is a highly fatal disease that affects millions of people worldwide every year. Currently, the diagnosis of sepsis is made by identifying at least two symptoms of systemic inflammatory response syndrome (SIRS), along with confirming the presence of microorganisms using a blood culture examination. Some biomarkers are already used to aid in the diagnosis, such as increased levels of C-reactive protein (CRP), leukocytes, immature granulocytes (IG), and bands. In addition, studies have shown a relationship between the expression of certain antigen receptors in the body's defense cells and its infectious state. CD64 is a receptor expressed in monocytes, and, in cases of infection, its expression is strongly observed in neutrophils. On the other hand, the class II MHC (major histocompatibility complex) marker, HLA-DR (human leukocyte antigen-DR), decreases its expression in monocytes in response to infection. This cohort study was conducted with 77 adult patients from a university hospital, divided into two groups: Non-Sepsis/SIRS and Sepsis/SIRS. The selected samples were analyzed by flow cytometry, identifying the expression of CD64 and HLA-DR according to their MFI, and calculating the sepsis index (SI) for each patient. All three parameters exhibited significant differences in expression between the two groups. When compared to the laboratory tests already in use, the utilization of HLA-DR, CD64, and the new index has shown greater sensitivity and specificity in identifying sepsis. This study contributes to knowledge about the relationship between the expression of antigens on defense cells and sepsis. The use of these biomarkers can help to improve the diagnosis and treatment of sepsis, which may contribute to the reduction of mortality related to the disease.

Prospective multicentre study of host response signatures in neonatal sepsis in Sub Saharan Africa

Few biomarkers for sepsis diagnosis are commonly used in neonatal sepsis. While the role of host response is increasingly recognized in sepsis pathogenesis and prognosis, there is a need for evaluating new biomarkers targeting host response in regions where sepsis burden is high and medico-economic resources are scarce. The objective of the study is to evaluate diagnostic and prognostic accuracy of biomarkers of neonatal sepsis in Sub Saharan Africa. This prospective multicentre study included newborn infants delivered in the Abomey-Calavi region in South Benin and their follow-up from birth to 3 months of age. Accuracy of transcriptional (CD74, CX3CR1), proteic (PCT, IL-6, IL-10, IP-10) biomarkers and clinical characteristics to diagnose and prognose neonatal sepsis were measured. At delivery, cord blood from all consecutive newborns were sampled and analysed, and infants were followed for a 12 weeks' period. Five hundred and eighty-one newborns were enrolled. One hundred and seventy-two newborns developed neonatal sepsis (29.6%) and death occurred in forty-nine infants (8.4%). Although PCT, IL-6 and IP-10 levels were independently associated with sepsis diagnosis, diagnostic accuracy of clinical variables combinations was similar to combinations with biomarkers and superior to biomarkers alone. Nonetheless, CD74, being the only biomarkers independently associated with mortality, showed elevated prognosis accuracy (AUC > 0.9) either alone or in combination with other biomarkers (eg. CD74/IP-10) or clinical criterion (eg. Apgar 1, birth weight). These results suggest that cord blood PCT had a low accuracy for diagnosing early onset neonatal sepsis in Sub Saharan African neonates, while association of clinical criterion showed to be more accurate than any biomarkers taken independently. At birth, CD74, either associated with IP-10 or clinical criterion, had the best accuracy in prognosing sepsis mortality.Trial registration Clinicaltrial.gov registration number: NCT03780712. Registered 19 December 2018. Retrospectively registered.

The value of postoperative HLA-DR expression and high mobility group box 1 level in predictive diagnosis of sepsis in percutaneous nephrolithotomy surgery

OBJECTIVE

To analyze the value of postoperative human leukocyte antigen-DR (HLA-DR) expression and high mobility group box 1 (HMGB1) level in predictive diagnosis of postoperative sepsis for patients with percutaneous nephrolithotomy (PCNL) surgery.

METHODS

The present prospective observational study included 387 patients with renal calculus who received PCNL surgery from January 2017 to October 2020 in our hospital. After exclusion criteria, 33 patients with sepsis and 78 patients with no sepsis remained. All patients received PCNL surgery. Sepsis definition is according to the third international consensus definitions for sepsis and septic shock (Sepsis-3). The data of the HMGB1, c-reactive protein (CRP), interleukin-6 (IL-6), procalcitonin (PCT) and HLA-DR expression were collected within admission and 24 h and 72 h after surgery. Postoperative HMGB1 levels and HLA-DR expression at 24 h and 72 h were respectively compared between the two groups using t test. ROC cure was used to analyze the value of postoperative HLA-DR expression and HMGB1 level in predictive diagnosis of sepsis.

RESULTS

The positive rate of urine culture and the time of hospitalization time in patients with sepsis were significantly higher than those in patients with no sepsis. Sepsis group had higher levels of HMGB1 at post-24 h ((93.07 ± 11.37) ng/mL vs (75.41 ± 4.85) ng/mL), p < 0.05) and 72 h ((96.58 ± 12.12) ng/mL vs (81.16 ± 8.86) ng/mL), p < 0.05) than nosepsis group. Meanwhile, sepsis group had lower expression of HLA-DR at post-24 h ((50.01 ± 7.42) % vs (69.32 ± 10.58) %), p < 0.05) and 72 h ((54.85 ± 9.45) % vs (69.98 ± 11.00) %), p < 0.05) than non-sepsis group. ROC analysis showed that the HLA-DR expression at postoperative 24 h had highest predictive value in the diagnosis of sepsis, the AUC of HLA-DR was 0.934, cutoff value 56.19%, with sensitivity 89.7%, specificity 81.8%.

CONCLUSION

Postoperative HLA-DR and HMGB1 can both be used as a predictive diagnosis of sepsis for patients with renal calculus received PCNL surgery. HighlightsSepsis group had higher levels of high mobility group box 1 at post-24 h and 72 h than nosepsis group.Sepsis group had lower expression of HLA-DR at post-24 h and 72 h than nosepsis group.Postoperative HLA-DR and HMGB1 can both be used as a predictive diagnosis of sepsis for patients with renal calculus received PCNL surgery.

The use of neutrophil CD64 and monocyte HLA-DR sepsis index in the diagnosis of neonatal sepsis

Background

Neonatal septicemia remains one of the main causes of neonatal morbidity and mortality. However, there are challenges hindering the early diagnosis.

Results

nCD64 percent and MFI were not of statistical significance between the confirmed sepsis, clinical sepsis, and control groups (p = 0.453 and 0.149, respectively); meanwhile, the mHLA-DR percent and MFI were both of statistical significance (p = 0.001, 0.0001, respectively) with lower values in the proven sepsis group. Calculating the sepsis index, its value was 74.1% ± 45 SD in the control, 105.5% ± 73 SD probable sepsis group, and 180.6% ± 143 SD in the proven sepsis group; this was of a high statistical significance (p = 0.0001).

Conclusion

HLA-DR expression on monocytes and nCD64/mHLA-DR sepsis index are reliable indices for the early diagnosis of neonatal sepsis. The sepsis index could be feasibly analyzed by automated flow cytometry even in developing countries. In the future, these markers should be widely assessed as their results are rapid, reliable, and of low cost.

Preterm ETs Are Significantly Reduced Compared with Adults and Partially Reduced Compared with Term Infants

The release of DNA by cells during extracellular trap (ET) formation is a defense function of neutrophils and monocytes. Neutrophil ET (NET) formation in term infants is reduced compared to adults. Objective: The aim was to quantify NET and monocyte ET (MET) release and the respective key enzymes myeloperoxidase (MPO) and neutrophil elastase (NE) in preterm infants. In this prospective explorative study, ET induction was stimulated by N-formylmethionine-leucyl-phenylalanine (fMLP), phorbol 12-myristate 13-acetate (PMA), lipopolysaccharide (LPS), and lipoteichoic acid (LTA) in the cord blood of preterm infants (n = 55, 23-36 weeks) compared to term infants and adults. METs were quantified by microscopy, and NETs by microscopy and flow cytometry. We also determined the MPO levels within NETs and the intracellular concentrations of NE and MPO in neutrophils. The percentage of neutrophils releasing ET was significantly reduced for preterm infants compared to adults for all stimulants, and with a 68% further reduction for PMA compared to term infants (p = 0.0141). The NET area was not reduced except for when fMLP was administered. The amount of MPO in NET-producing cells was reduced in preterm infants compared to term infants. For preterm infants, but not term infants, the percentage of monocytes releasing ETs was significantly reduced compared to healthy adults for LTA and LPS stimulation. Conclusion: In preterm infants, ETs are measurable parts of the innate immune system, but are released in a reduced percentage of cells compared to adults.

Flow Cytometry: An Important Diagnostic Tool in Critically Ill Preterm Neonates with Suspected Sepsis

OBJECTIVE

Sepsis is a major cause of neonatal mortality. The gold standard for diagnosis is blood culture which suffers from low sensitivity and huge turn-around time. Flow cytometry has been extensively applied to malignant disorders and is an upcoming tool for diagnosis of nonmalignant disorders due to its rapidity and accuracy in detecting cells, cell products, and their functional states. The aim of this study was to investigate the utility of flow cytometric expression of neutrophil CD64, monocyte human leukocyte antigen (HLA-DR) and CD16 in diagnosis in suspected preterm neonates.

STUDY DESIGN

In total, 100 preterm neonates with clinical signs of sepsis were enrolled in the study. Blood culture, C-reactive protein (CRP) and flow cytometry for nCD64, mHLA-DR, and mCD16 were performed. The neonates were divided into two groups: culture positive and culture negative and CRP and flow cytometric findings compared. ROC analysis was performed to determine the best cut-off for nCD64, mHLA-DR, and mCD16 values along with estimation of sensitivity, specificity, and predictive values. Probability of <0.05 was taken as significant.

RESULTS

Out of the 100 enrolled neonates, 34 (34%) were culture positive. CRP was not found to be significantly different in the two groups. Expression of nCD64 (p = 0.03) was significantly upregulated in the blood culture positive cases with a cut-off mean fluorescence intensity (MFI) value = 4.72 and sensitivity of 92% and specificity of 52%. Expression of mCD16 (p = 0.02) was also upregulated in the blood culture positive cases with a cut-off MFI value = 4.9, with sensitivity of 41%, specificity of 83%.

CONCLUSION

The study concluded that nCD64 and mCD16 can be potential biomarkers for early diagnosis of neonatal sepsis with a high sensitivity and specificity.

KEY POINTS

· Neutrophil CD64 significantly upregulated in septic neonates.. · Monocyte CD16 significantly upregulated in septic neonates.. · C-reactive protein values were not significantly different in septic versus nonseptic neonates..

Immune System Dysfunction Criteria in Critically Ill Children: The PODIUM Consensus Conference

CONTEXT

Immune system dysfunction is poorly represented in pediatric organ dysfunction definitions.

OBJECTIVE

To evaluate evidence for criteria that define immune system dysfunction in critically ill children and associations with adverse outcomes and develop consensus criteria for the diagnosis of immune system dysfunction in critically ill children.

DATA SOURCES

We conducted electronic searches of PubMed and Embase from January 1992 to January 2020, using medical subject heading terms and text words to define immune system dysfunction and outcomes of interest.

STUDY SELECTION

Studies of critically ill children with an abnormality in leukocyte numbers or function that is currently measurable in the clinical laboratory in which researchers assessed patient-centered outcomes were included. Studies of adults or premature infants, animal studies, reviews and commentaries, case series (≤10 subjects), and studies not published in English with inability to determine eligibility criteria were excluded.

DATA EXTRACTION

Data were abstracted from eligible studies into a standard data extraction form along with risk of bias assessment by a task force member.

RESULTS

We identified the following criteria for immune system dysfunction: (1) peripheral absolute neutrophil count <500 cells/μL, (2) peripheral absolute lymphocyte count <1000 cells/μL, (3) reduction in CD4+ lymphocyte count or percentage of total lymphocytes below age-specific thresholds, (4) monocyte HLA-DR expression <30%, or (5) reduction in ex vivo whole blood lipopolysaccharide-induced TNFα production capacity below manufacturer-provided thresholds.

LIMITATIONS

Many measures of immune system function are currently limited to the research environment.

CONCLUSIONS

We present consensus criteria for the diagnosis of immune system dysfunction in critically ill children.

Cardiac steroid ouabain transcriptionally increases human leukocyte antigen DR expression on monocytes

Sepsis is a life-threatening disease characterized by acute multiple organ dysfunction and immunosuppression that is also called as immunoparalysis. Increasing evidence suggests that immunoparalysis largely contributes to the high mortality of sepsis, but the effective remedies are lacking. As an important antigen presentation molecule, human leukocyte antigen DR (HLA-DR) is remarkably down-regulated in sepsis-induced immunoparalysis, therefore, re-stimulation of HLA-DR expression is expected to be useful in reversing immunoparalysis. We previously described that ouabain, as a Na+, K+-ATPase ligand, is able to counteract immunoparalysis by regulating TH1 cytokines expression. Here, we expanded the finding that ouabain not only prevents LPS-induced down-regulation of HLA-DR on monocytes, but also transcriptionally activates HLA-DR α/β expression mediated by CIITA4, IRF1, c-Src, and Stat1 phosphorylation. Since ouabain can improve sepsis-induced immunoparalysis by multiple mechanisms, we propose that ouabain may be a promising agent in septic therapy that deserves further investigation.

Zebrafish larvae as experimental model to expedite the search for new biomarkers and treatments for neonatal sepsis

Neonatal sepsis is a major cause of death and disability in newborns. Commonly used biomarkers for diagnosis and evaluation of treatment response lack sufficient sensitivity or specificity. Additionally, new targets to treat the dysregulated immune response are needed, as are methods to effectively screen drugs for these targets. Available research methods have hitherto not yielded the breakthroughs required to significantly improve disease outcomes, we therefore describe the potential of zebrafish (Danio rerio) larvae as preclinical model for neonatal sepsis. In biomedical research, zebrafish larvae combine the complexity of a whole organism with the convenience and high-throughput potential of in vitro methods. This paper illustrates that zebrafish exhibit an immune system that is remarkably similar to humans, both in terms of types of immune cells and signaling pathways. Moreover, the developmental state of the larval immune system is highly similar to human neonates. We provide examples of zebrafish larvae being used to study infections with pathogens commonly causing neonatal sepsis and discuss known limitations. We believe this species could expedite research into immune regulation during neonatal sepsis and may hold keys for the discovery of new biomarkers and novel treatment targets as well as for screening of targeted drug therapies.

Lymphocyte-Related Immunological Indicators for Stratifying Mycobacterium tuberculosis Infection

Background

Easily accessible tools that reliably stratify Mycobacterium tuberculosis (MTB) infection are needed to facilitate the improvement of clinical management. The current study attempts to reveal lymphocyte-related immune characteristics of active tuberculosis (ATB) patients and establish immunodiagnostic model for discriminating ATB from latent tuberculosis infection (LTBI) and healthy controls (HC).

Methods

A total of 171 subjects consisted of 54 ATB, 57 LTBI, and 60 HC were consecutively recruited at Tongji hospital from January 2019 to January 2021. All participants were tested for lymphocyte subsets, phenotype, and function. Other examination including T-SPOT and microbiological detection for MTB were performed simultaneously.

Results

Compared with LTBI and HC, ATB patients exhibited significantly lower number and function of lymphocytes including CD4⁺ T cells, CD8⁺ T cells and NK cells, and significantly higher T cell activation represented by HLA-DR and proportion of immunosuppressive cells represented by Treg. An immunodiagnostic model based on the combination of NK cell number, HLA-DR⁺CD3⁺ T cells, Treg, CD4⁺ T cell function, and NK cell function was built using logistic regression. Based on receiver operating characteristic curve analysis, the area under the curve (AUC) of the diagnostic model was 0.920 (95% CI, 0.867-0.973) in distinguishing ATB from LTBI, while the cut-off value of 0.676 produced a sensitivity of 81.48% (95% CI, 69.16%-89.62%) and specificity of 91.23% (95% CI, 81.06%-96.20%). Meanwhile, AUC analysis between ATB and HC according to the diagnostic model was 0.911 (95% CI, 0.855-0.967), with a sensitivity of 81.48% (95% CI, 69.16%-89.62%) and a specificity of 90.00% (95% CI, 79.85%-95.34%).

Conclusions

Our study demonstrated that the immunodiagnostic model established by the combination of lymphocyte-related indicators could facilitate the status differentiation of MTB infection.

Ratio of serum procalcitonin to monocytic HLA-DR as a reliable parameter in prognosis prediction of sepsis

BACKGROUND

We evaluated the prognostic potential of the ratio of serum procalcitonin to monocytic HLA-DR for 28-day mortality in sepsis.

METHODS

In this retrospective study, a total of 91 patients with sepsis were enrolled. Clinical and laboratory data detected on admission (D0) and 7 days thereafter (D7) including the Acute Physiology and Chronic Health Evaluation II (APACHE II), the Sequential Organ Failure Assessment (admission SOFA), serum lactate, D-dimer, mHLA-DR, procalcitonin, platelet and white blood cell count, neutrophil-to-lymphocyte ratio were collected. The PCT/mHLA-DR ratio, the changes in mHLA-DR and WBC on day 7 compared with those on the day of admission and PCT clearance were calculated. Receiver operating characteristic curves, Kaplan-Meier survival curves, DeLong test and Cox regression analyses were used to assess and compare their predictive values.

RESULTS

Among all studied parameters, D₇-PCT/mHLA-DR showed the best discriminatory property to differentiate survivors from non-survivors and was identified as an independent predictor of 28-day mortality.

CONCLUSION

The D₇-PCT/mHLA-DR ratio was more sensitive than either biomarker alone in predicting fatal outcome in septic patients. Combining pro-inflammatory and immunosuppression biomarkers might improve the prognostic accuracy in sepsis.

Transient Immune Activation in BCG-Vaccinated Infant Rhesus Macaques Is Not Sufficient to Influence Oral Simian Immunodeficiency Virus Infection

BCG vaccination has been demonstrated to increase levels of activated CD4+ T cells, thus potentially influencing mother-to-child transmission of human immunodeficiency virus (HIV). To assess the risk of BCG vaccination in HIV infection, we randomly assigned newborn rhesus macaques to receive BCG vaccine or remain unvaccinated and then undergo oral simian immunodeficiency virus (SIV) challenges 3 weeks later. We observed elevated levels of activated peripheral CD4+ T cells (ie, HLA-DR+CD38+CCR5+ CD4+ T cells) by week 3 after vaccination. BCG was also associated with an altered immune gene expression profile, as well as with monocyte activation in both peripheral blood and the draining axillary lymph node, indicating significant BCG vaccine-induced immune activation. Despite these effects, BCG vaccination did not increase the rate of SIV oral transmission or disease progression. Our findings therefore identify patterns of T-cell and monocyte activation that occur after BCG vaccination but do not support the hypothesis that BCG vaccination is a risk factor for postnatal HIV transmission or increased pathogenesis in infants.

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.

Independent risk factors associated with higher mortality rates and recurrence of brain abscesses from head and neck sources

OBJECTIVE

The aim of this study was to identify the features and independent risk factors associated with recurrence and mortality in patients with brain abscesses of head and neck origin.

STUDY DESIGN

We designed a retrospective study of patients diagnosed with a brain abscess at the Massachusetts General Hospital between 1980 and 2017. Inclusion criteria were complete medical records, including medical and surgical history; and radiographic and microbiologic data. Multinomial logistic regression and Gray's test were used to evaluate the independent variables associated with recurrence and mortality.

RESULTS

Eighty-eight cases met the inclusion criteria. Of these, 48 patients (54.5%) were men (mean age 50.5 ± 18.8 years). Significant association between etiology and cultured organisms was found only in cases of neurosurgical intervention with staphylococcal or streptococcal isolates (P < .05). Seizure activity was the only significant predictor of recurrence. Predictors of mortality included advanced age (P = .005); staphylococcal infection (P = .029); low monocyte count (P = .004); hyponatremia (P = .002); elevated blood urea nitrogen (P = .000); elevated creatinine (P = .002); hyperglycemia (P = .023); and status at discharge (P = .000).

CONCLUSIONS

Independent risk factors, such as low monocyte count, hyponatremia, renal dysfunction, and hyperglycemia, were found to be associated with higher mortality rates in patients with brain abscesses of head and neck origin. These abnormalities should be promptly recognized and aggressively treated.

Differences in monocyte subsets are associated with short-term survival in patients with septic shock

Sepsis is characterized by dynamic changes of the immune system resulting in deregulated inflammation and failure of homoeostasis and can escalate to septic shock. Circulating monocytes and other innate immune cells are among the first ones to recognize and clear pathogens. Monocytes have an important role in sepsis and septic shock and have been studied as potential diagnostic markers. In total, forty‐two patients with septic shock were recruited and blood samples obtained within first 12 hours of ICU admission. We showed that frequency of classical and intermediate monocytes assessed at the time of admission to the intensive care unit are significantly distinct in patients with septic shock who survived longer that five days from those who died. These parameters correlate significantly with differences in serum levels of inflammatory cytokines MCP‐1, IL‐6, IL‐8, IL‐10, and IL‐18, and with the proportion of helper and cytotoxic T cells. The described changes in frequency of monocyte subsets and their activation status may predict short‐term septic shock survival and help with fast identification of the group of vulnerable patients, who may profit from tailored therapy.

The Impact of a History of Pre-maturity on Viral Respiratory Infections in Children Under 2 Years of Age: A Propensity Score-Matching Analysis of in-hospital Complications and Mortality

Introduction: A history of pre-maturity may be a risk factor for complications in patients under 24 months of age hospitalized for viral respiratory infections (VRIs). Objective: To identify the impact of a history of pre-maturity on in-hospital complications and mortality in patients under 24 months of age who were hospitalized for VRIs over a period of 5 years. Material and Methods: This was a propensity score-matched study. The database was compiled by physicians, electronically validated by engineers, and analyzed by statisticians. Patients diagnosed with VRIs (based on International Classification of Diseases [ICD-10]) codes B974, J12, J120-J129X, J168, J17, J171, J178, J20, J203-J209, J21, J210, J211, J218, J219, J22X, and J189) from 2013 to 2017 were enrolled in the study. The subjects were classified into two groups according to the absence or presence of a history of pre-maturity (P070, P072, P073). Patients with congenital heart disease (CHD) (Q20-Q26) were excluded. Length of hospital stay, in-hospital complications, surgical procedures, and mortality were analyzed. Statistical Analysis: Patients were matched according to age. For comparisons between groups, Student's t-tests and chi² tests were applied. A logistic regression model was constructed to identify factors related to in-hospital complications and mortality. Results: In total, 5,880 patients were eligible for inclusion in the analysis. The average patient age was 14.25 weeks. The presence of pre-maturity (coefficient = 1.16), male sex, bronchopulmonary dysplasia (BPD), in-hospital infectious complications (coefficient = 11.31), and invasive medical procedures (coefficient = 18.4) increased the number of days of hospitalization. Invasive medical procedures (OR = 6.13), a history of pre-maturity (OR = 2.54), and male sex (OR = 1.78) increased the risk for in-hospital complications. In-hospital infectious complications (OR = 84.2) and invasive medical procedures (OR = 58.4) were risk factors for mortality. Conclusions: A history of pre-maturity increased the length of hospital stay and the rate of in-hospital complications but did not increase mortality in patients under 24 months of age hospitalized for VRIs.

Functional analysis of granulocyte and monocyte subpopulations in neonates

BACKGROUND

Neonate immune cell functions lack full protection against pathogens. This could be either defect or protective mechanism against overshooting proinflammatory immune responses. We here analysed the function of classical, pro- and anti-inflammatory monocytes and granulocytes from neonates in comparison with adults to investigate if suppressed functions of subpopulations are causative for the unique neonatal immune status. Therefore, reactive oxygen species (ROS) and surface activation markers were quantified in subpopulations.

METHODS

In a prospective, longitudinal study granulocyte and monocyte subpopulations were analysed in healthy term infants (> 37 week; n = 13) in comparison with healthy young adults (n = 11). Percentage (%) of cells expressing surface marker (HLA-DR, CD11b, CD62L, CD32, Toll-Like-Receptor-2) and expression per cell, determined by mean fluorescence intensity (MFI), were measured by flow cytometry. ROS production was induced by fMLP, PMA and E. coli in term neonates (> 37 week; n = 13).

RESULTS

Classical granulocytes were down- and proinflammatory granulocytes upregulated in neonates compared with adults. Percentage of TLR-2 expressing granulocytes was increased in neonates. Granulocytic ROS production depended on stimulation. The percentage of anti-inflammatory monocytes was increased, while classical monocytes were reduced in neonates. HLA-DR (%, MFI) showed reduction for all monocyte subpopulations, while CD32, CD11b, CD62L and TLR-2 were differently regulated in comparison with adults.

CONCLUSIONS

Differentially regulated granulocyte and monocyte subpopulations indicate a unique state of neonatal immunity to fight infections and prevent dysregulation. Further studies are needed to investigate the role of reduced granulocytic ROS formation and reduced monocytic HLA-DR in active disease.

Flow Cytometry of CD64, HLA-DR, CD25, and TLRs for Diagnosis and Prognosis of Sepsis in Critically Ill Patients Admitted to the Intensive Care Unit: A Review Article

Sepsis is an important health problem with a high burden on health systems. Finding new aspects of immune system function in sepsis showed a new role for flow cytometry in the diagnosis of sepsis. We made a review on the role of CD64, HLA-DR, CD25, and TLRs as more useful flow cytometric tools in diagnosing sepsis, both in adults, and neonates. According to our results, we concluded that for diagnosis and treatment of the septic, flow cytometry can play an important role so that it can be used as a novel method in individualized treatment of septic patients based on their immune system situation.

Association between HLA-DR Expression and Multidrug-resistant Infection in Patients with Severe Acute Pancreatitis

Multidrug-resistant (MDR) bacterial infection is a common complication of severe acute pancreatitis (SAP). This study aimed to explore the association between human leukocyte antigen-antigen D-related (HLA-DR) expression and multidrug-resistant infection in patients with SAP. A total of 24 SAP patients who were admitted to Nanjing Drum Tower Hospital between May 2015 and December 2016 were enrolled in the study. The percentages of CD4+, CD8+, natural killer (NK), and HLA-DR (CD14+) cells and the CD4+/CD8+ cell ratio on days 1,7,14, and 28 after admission were determined by flow cytometry. Eighteen patients presented with the symptoms of infection. Among them, 55.6% patients (10/18) developed MDR infection. The most common causative MDR organisms were Enterobacter cloacae and Acinetobacter baumannii. The CD4+/CD8+ cell ratio and the percentage of NK cells were similar between patients with non-MDR and patients with MDR infections. In patients without infection, the HLA-DR percentage was maintained at a high level throughout the 28 days. Compared to the patients without any infection, the HLA-DR percentage in patients with non-MDR infection was reduced on day 1 but increased and reached similar levels on day 28. In patients with MDR infection, the HLA-DR percentage remained below normal levels at all-time points. It was concluded that persistent down-regulation of HLA-DR expression is associated with MDR bacterial infection in patients with SAP.

Occurrence of marked sepsis-induced immunosuppression in pediatric septic shock: a pilot study

Background

While the process of sepsis-induced immunosuppression is now well described in adults, very little information is available on immune functions in pediatric sepsis. The current study investigated this in children with septic shock by performing immunomonitoring, including both innate (monocyte human leukocyte antigen-DR, mHLA-DR, expression) and adaptive immunity (lymphocyte subsets count), as well as cytokine concentrations (IL-6, IL-8, IL-10, IL-1Ra, TNF-α, IFN-γ). Subsequent objectives were to assess the associations between inflammatory response, potential immunosuppression and secondary acquired infection occurrence.

Methods

Single-center prospective observational study, including children aged between 1 month and 18 years admitted to pediatric intensive care unit (PICU) for septic shock. Age-matched controls were children hospitalized for elective surgery without any infectious criteria. Blood was sampled at day 1–2, 3–5, and 7–9 after sepsis onset. mHLA-DR and lymphocyte subsets count were measured by flow cytometry and cytokine concentrations by Luminex technology.

Results

A total of 26 children and 30 controls were included. Patients had lymphopenia, and mHLA-DR levels were significantly lower than controls at each time point (p < 0.0001). All cytokines peaked at day 1–2. Children with secondary acquired infection had lower day 3–5 mHLA-DR and higher pro-inflammatory cytokine concentrations (IL-6, IL-8 and TNF-α) at day 1–2 compared to children without secondary acquired infection.

Conclusions

The higher initial inflammatory cytokine production was, the more innate immunity was altered, while evaluated by low mHLA-DR expression. Children with decreased mHLA-DR expression developed more secondary acquired infections. Upon confirmation in multicenter cohorts, these results pave the way for immunostimulation for the most immunosuppressed children in order to prevent nosocomial infections in PICU.

Trial registration PedIRIS study NCT02848144. Retrospectively registered 28 July 2016

Electronic supplementary material

The online version of this article (10.1186/s13613-018-0382-x) contains supplementary material, which is available to authorized users.

Sepsis-Induced Immunosuppression in Neonates

Neonates, especially those born preterm, are at increased risk of sepsis and adverse long-term effects associated with infection-related inflammation. Distinct neonatal immune responses and dysregulated inflammation are central to this unique susceptibility. The traditional separation of sepsis into an initial hyper-inflammatory response followed by hypo-inflammation is continually under review with new developments in this area of research. There is evidence to support the association of mortality in the early acute phase of sepsis with an overwhelming hyper-inflammatory immune response. Emerging evidence from adults suggests that hypo- and hyper-inflammation can occur during any phase of sepsis and that sepsis-immunosuppression is associated with increased mortality, morbidity, and risk to subsequent infection. In adults, sepsis-induced immunosuppression (SII) is characterised by alterations of innate and adaptive immune responses, including, but not limited to, a prominent bias toward anti-inflammatory cytokine secretion, diminished antigen presentation to T cells, and reduced activation and proliferation of T cells. It is unclear if sepsis-immunosuppression also plays a role in the adverse outcomes associated with neonatal sepsis. This review will focus on exploring if key characteristics associated with SII in adults are observed in neonates with sepsis.

Unique aspects of the perinatal immune system

The early stages of life are associated with increased susceptibility to infection, which is in part due to an ineffective immune system. In the context of infection, the immune system must be stimulated to provide efficient protection while avoiding insufficient or excessive activation. Yet, in early life, age-dependent immune regulation at molecular and cellular levels contributes to a reduced immunological fitness in terms of pathogen clearance and response to vaccines. To enable microbial colonization to be tolerated at birth, epigenetic immune cell programming and early life-specific immune regulatory and effector mechanisms ensure that vital functions and organ development are supported and that tissue damage is avoided. Advancement in our understanding of age-related remodelling of immune networks and the consequent tuning of immune responsiveness will open up new possibilities for immune intervention and vaccine strategies that are designed specifically for early life.

Immunoparalysis: Clinical and immunological associations in SIRS and severe sepsis patients

INTRODUCTION

This study was designed to identify changes in the monocytic membrane marker HLA-DR and heat shock proteins (HSPs) in relation to T-regulatory cells (T-regs) and other immunological marker changes in patients with systemic inflammatory response syndrome (SIRS) or sepsis/septic shock.

METHODS

Healthy volunteers, intensive care unit (ICU) patients with SIRS due to head injury and ICU patients with severe sepsis/septic shock were enrolled in the current study. Determination of CD14+/HLA-DR+ cells, intracellular heat-shock proteins and other immunological parameters were performed by flow cytometry and RT-PCR techniques as appropriate. Univariate and multivariate analysis examined associations of CD14/HLA-DR, HSPs, T-regs and suppressor of cytokine signalling (SOCS) proteins with SIRS, sepsis and outcome.

RESULTS

Fifty patients (37 with severe sepsis and 13 with SIRS) were enrolled, together with 20 healthy volunteers used as a control group. Compared to healthy individuals, patients with SIRS and severe sepsis showed progressive decline of their CD14/HLA-DR expression (0% to 7.7% to 50% within each study subpopulation, p<0.001). Mean fluorescent intensity (MFI) levels of HSP70 and HSP90 on monocytes and polymorphonuclear cells were significantly higher in SIRS patients compared to controls and fell significantly in severe sepsis/septic shock patients (p<0.05 for all comparisons). There was no statistically significant difference between subgroups for levels of T-regulatory cells or relative copies of Suppressor of Cytokine Signalling 3 (SOCS3) proteins. In univariate models percent of CD14/HLA-DR was associated with mortality (OR: 1.8 95%CI 1.02-3.2, p=0.05), while in multivariate models after adjusting for CD14/HLA-DR only younger age and lower Acute Physiology and Chronic Health Evaluation II (APACHE II) scores were associated with increased chances of survival (beta -0.05, OR 0.9, 95% CI 0.9-0.99, p=0.038 for age and beta -0.11, OR 0.89, 95% CI 0.8-0.99, p=0.037 for APACHE II score).

CONCLUSIONS

Significant associations with SIRS and sepsis were found for CD14/HLA-DR expression and monocyte and polymorphonuclear cell levels of HSP70 and 90. The role of these biomarkers in assessing the prognosis of sepsis needs to be further explored and validated in prospective studies.

In neonates S100A8/S100A9 alarmins prevent the expansion of a specific inflammatory monocyte population promoting septic shock

The high susceptibility of newborn infants to sepsis is ascribed to an immaturity of the neonatal immune system, but the molecular mechanisms remain unclear. Newborn monocytes massively release the alarmins S100A8/S100A9. In adults, these are major regulators of immunosuppressive myeloid-derived suppressor cells (MDSCs). We investigated whether S100A8/S100A9 cause an expansion of monocytic MDSCs (Mo-MDSCs) in neonates, thereby contributing to an immunocompromised state. Mo-MDSCs have been assigned to CD14⁺/human leukocyte antigen (HLA)-DR^-/low/CD33⁺ monocytes in humans and to CD11b⁺/Gr-1^int/Ly6G^-/Ly6C^hi cells in mice. We found monocytes with these phenotypes significantly expanded in their respective newborns. Functionally, however, they did not prove immunosuppressive but rather responded inflammatorily to microbial stimulation. Their expansion did not correlate with high S100A8/S100A9 levels in cord blood. Murine studies revealed an excessive expansion of CD11b⁺/Gr-1^int/Ly6G^-/Ly6C^hi monocytes in S100A9^-/- neonates compared to wild-type neonates. This strong baseline expansion was associated with hyperinflammatory responses during endotoxemia and fatal septic courses. Treating S100A9^-/- neonates directly after birth with S100A8/S100A9 alarmins prevented excessive expansion of this inflammatory monocyte population and death from septic shock. Our data suggest that a specific population of inflammatory monocytes promotes fatal courses of sepsis in neonates if its expansion is not regulated by S100A8/S100A9 alarmins.-Heinemann, A. S., Pirr, S., Fehlhaber, B., Mellinger, L., Burgmann, J., Busse, M., Ginzel, M., Friesenhagen, J., von Köckritz-Blickwede, M., Ulas, T., von Kaisenberg, C. S., Roth, J., Vogl, T., Viemann, D. In neonates S100A8/S100A9 alarmins prevent the expansion of a specific inflammatory monocyte population promoting septic shock.

Reduced Expression of HLA-DR on Monocytes During Severe Respiratory Syncytial Virus Infections

BACKGROUND

Respiratory syncytial virus (RSV) is a common cause of bronchiolitis in infants with a wide spectrum of disease severity. Besides environmental and genetic factors, it is thought that the innate immune system plays a pivotal role. The aim of this study was to investigate the expression of immune receptors on monocytes and the in vitro responsiveness from infants with severe RSV infections.

METHODS

Peripheral blood mononuclear cells (PBMCs) from infants with RSV infections were isolated. Classical, intermediate and nonclassical monocytes were immunophenotyped for the expression of CD14, CD16, human leukocyte antigen (HLA)-ABC and HLA-DR. PBMCs were stimulated with lipopolysaccharide to determine the secretion of tumor necrosis factor and interleukin (IL)-10 with enzyme-linked immunosorbent assay.

RESULTS

During RSV infection, intermediate monocytes are increased in the peripheral blood, whereas classical and nonclassical monocytes are reduced. The expression of CD14 and HLA-ABC is increased on monocytes, whereas the expression of HLA-DR is suppressed. Low HLA-DR expression is correlated with increased disease severity. PBMCs from infants with severe RSV infections show an impaired IL-10 response in vitro.

CONCLUSIONS

Phenotyping subpopulations of monocytes combined with in vitro responsiveness reveals significant differences between nonsevere and severe RSV infections. Reduced HLA-DR expression and impaired IL-10 production in vitro during severe RSV infections indicate that an imbalanced innate immune response may play an important role in disease severity.

Prolonged suppression of monocytic human leukocyte antigen-DR expression correlates with mortality in pediatric septic patients in a pediatric tertiary Intensive Care Unit

INTRODUCTION

Immunoparalysis is a syndrome with no clinical symptoms that occurs in some septic patients. Monocytic human leukocyte antigen-DR (mHLA-DR) expression has been used to identify patients in immunoparalysis and prolonged periods of reduced mHLA-DR expression have been correlated with a poor prognosis in sepsis. However, there is a lack of studies investigating mHLA-DR expression in pediatric septic patients.

AIM

To determine if mHLA-DR expression correlates with mortality in pediatric septic patients using the QuantiBRITE Anti HLA-DR/Anti-Monocyte,a Bechton Dickinson novel reagent that standardizes flow cytometry values.

METHODS

We determined mHLA-DR expression in 30 patients with severe sepsis or septic shock admitted to the pediatric intensive care unit at Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil, between January 2013 and February 2015. mHLA-DR expression was quantified between days 3 to 5 and 5 to 7 after the onset of sepsis and the ΔmHLA-DR (mHLA-DR2 - mHLA-DR1) was calculated. We also measured mHLA-DR levels in 21 healthy control patients.

RESULTS

Mean mHLA-DR expression was significantly lower in septic patients than in controls (P = .0001). Mortality was 46% in patients with negative ΔHLA-DR or <1000 mAb/cell and 7% in patients with positive ΔHLA-DR or >1000 mAb/cell. Mean ΔmHLA-DR levels were significantly different between survivors and non-survivors (P = .023).

CONCLUSION

ΔHLA-DR correlates with mortality in pediatric patients with septic shock or severe sepsis. This is the first study to have used the QuantiBRITE Anti HLA-DR/Anti-Monocyte reagent to quantify monocyte HLA-DR expression in pediatric septic patients.

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.

Sepsis-induced immune alterations monitoring by flow cytometry as a promising tool for individualized therapy

Septic syndromes remain a major although largely under-recognized health care problem and represent the first cause of mortality in intensive care units. While sepsis has, for long, been solely described as inducing a tremendous systemic inflammatory response, novel findings indicate that sepsis indeed initiates a more complex immunologic response that varies over time, with the concomitant occurrence of both pro- and anti-inflammatory mechanisms. As a resultant, after a short proinflammatory phase, septic patients enter a stage of protracted immunosuppression. This is illustrated in those patients by reactivation of dormant viruses (CMV or HSV) or infections due to pathogens, including fungi, which are normally pathogenic solely in immunocompromised hosts. Although mechanisms are not totally understood, these alterations might be directly responsible for worsening outcome in patients who survived initial resuscitation as nearly all immune functions are deeply compromised. Indeed, the magnitude and persistence over time of these dysfunctions have been associated with increased mortality and health-care associated infection rate. Consequently, new promising therapeutic avenues are currently emerging from those recent findings such as adjunctive immunostimulation (IFN-γ, GM-CSF, IL-7, anti-PD1/L1 antibodies) for the most immunosuppressed patients. Nevertheless, as there is no clinical sign of immune dysfunctions, the prerequisite for such therapeutic intervention relies on our capacity in identifying the patients who could benefit from immunostimulation. To date, the most robust biomarkers of sepsis-induced immunosuppression are measured by flow cytometry. Of them, the decreased expression of monocyte HLA-DR appears as a "gold standard." This review reports on the mechanisms sustaining sepsis-induced immunosuppression and its related biomarkers measurable by flow cytometry. The objective is to integrate the most recent facts in an up-to-date account of clinical results, flow cytometry aspects as well as issues in results standardization for multicenter studies. © 2015 International Clinical Cytometry Society.

HLA-A*31 as a marker of genetic susceptibility to sepsis

Objective

The HLA haplotype has been associated with many autoimmune diseases, but no associations have been described in sepsis. This study aims to investigate the HLA system as a possible marker of genetic sepsis susceptibility.

Methods

This is a prospective cohort study including patients admitted to an intensive care unit and healthy controls from a list of renal transplant donors. Patients with less 18 years of age; pregnant or HIV positive patients; those with metastatic malignancies or receiving chemotherapy; or with advanced liver disease; or with end-of-life conditions were excluded. The DNA was extracted from the whole blood and HLA haplotypes determined using MiliPlex^® technology.

Results

From October 2010 to October 2012, 1,121 patients were included (1,078 kidney donors, 20 patients admitted with severe sepsis and 23 with septic shock). HLA-A*31 positive subjects had increased risk of developing sepsis (OR 2.36, 95%CI 1.26-5.35). Considering a p value <0.01, no other significant association was identified.

Conclusion

HLA-A*31 expression is associated to risk of developing sepsis.

Human leukocyte antigen DR surface expression on CD14+ monocytes during adverse events after hematopoietic stem cell transplantation

The human leukocyte antigen DR surface expression on CD14+ monocytes reflects the degree to which these cells have been activated. Given the central role monocytes and macrophages play in the immune system, a decreased human leukocyte antigen DR expression on CD14+ monocytes results in a hallmark of altered immune status during systemic inflammatory response syndrome. We hypothesize that human leukocyte antigen DR expression might be similarly altered after hematopoietic stem cell transplantation and during post-transplant complications. Using flow cytometry, this study investigates the human leukocyte antigen DR surface expression of CD14+ monocytes in 30 pediatric and young adult patients up to 1 year after hematopoietic stem cell transplantation. Normal values were derived from a control group of healthy children, adolescents, and young adults. Human leukocyte antigen DR expression decreased significantly prior and during bacterial infection or sepsis. By contrast, human leukocyte antigen DR expression levels were elevated before and at the time of viremia. Human leukocyte antigen DR expression was also elevated during acute graft-versus-host disease. In contrast, the expression was reduced when patients had hepatic veno-occlusive disease. A significant decrease of human leukocyte antigen DR expression was associated with a relapse of the underlying disease and before death. Human leukocyte antigen DR expression on CD14+ monocytes appears to be a promising parameter that might allow identification of patients at risk after hematopoietic stem cell transplantation.

Macrophage phenotype is associated with disease severity in preterm infants with chronic lung disease

BACKGROUND

The etiology of persistent lung inflammation in preterm infants with chronic lung disease of prematurity (CLD) is poorly characterized, hampering efforts to stratify prognosis and treatment. Airway macrophages are important innate immune cells with roles in both the induction and resolution of tissue inflammation.

OBJECTIVES

To investigate airway innate immune cellular phenotypes in preterm infants with respiratory distress syndrome (RDS) or CLD.

METHODS

Bronchoalveolar lavage (BAL) fluid was obtained from term and preterm infants requiring mechanical ventilation. BAL cells were phenotyped by flow cytometry.

RESULTS

Preterm birth was associated with an increase in the proportion of non-classical CD14(+)/CD16(+) monocytes on the day of delivery (58.9 ± 5.8% of total mononuclear cells in preterm vs 33.0 ± 6.1% in term infants, p = 0.02). Infants with RDS were born with significantly more CD36(+) macrophages compared with the CLD group (70.3 ± 5.3% in RDS vs 37.6 ± 8.9% in control, p = 0.02). At day 3, infants born at a low gestational age are more likely to have greater numbers of CD14(+) mononuclear phagocytes in the airway (p = 0.03), but fewer of these cells are functionally polarized as assessed by HLA-DR (p = 0.05) or CD36 (p = 0.05) positivity, suggesting increased recruitment of monocytes or a failure to mature these cells in the lung.

CONCLUSIONS

These findings suggest that macrophage polarization may be affected by gestational maturity, that more immature macrophage phenotypes may be associated with the progression of RDS to CLD and that phenotyping mononuclear cells in BAL could predict disease outcome.

Early sepsis does not increase the risk of late sepsis in very low birth weight neonates

OBJECTIVE

To examine whether preterm very low birth weight (VLBW) infants have an increased risk of late-onset sepsis (LOS) following early-onset sepsis (EOS).

STUDY DESIGN

Retrospective analysis of VLBW infants (401-1500 g) born September 1998 through December 2009 who survived >72 hours and were cared for within the National Institute of Child Health and Human Development Neonatal Research Network. Sepsis was defined by growth of bacteria or fungi in a blood culture obtained ≤ 72 hours of birth (EOS) or >72 hours (LOS) and antimicrobial therapy for ≥ 5 days or death <5 days while receiving therapy. Regression models were used to assess risk of death or LOS by 120 days and LOS by 120 days among survivors to discharge or 120 days, adjusting for gestational age and other covariates.

RESULTS

Of 34,396 infants studied, 504 (1.5%) had EOS. After adjustment, risk of death or LOS by 120 days did not differ overall for infants with EOS compared with those without EOS [risk ratio (RR): 0.99 (0.89-1.09)] but was reduced in infants born at <25 weeks gestation [RR: 0.87 (0.76-0.99), P = .048]. Among survivors, no difference in LOS risk was found overall for infants with versus without EOS [RR: 0.88 (0.75-1.02)], but LOS risk was reduced in infants with birth weight 401-750 g who had EOS [RR: 0.80 (0.64-0.99), P = .047].

CONCLUSIONS

Risk of LOS after EOS was not increased in VLBW infants. Surprisingly, risk of LOS following EOS appeared to be reduced in the smallest, most premature infants, underscoring the need for age-specific analyses of immune function.

Flow cytometry in the detection of neonatal sepsis

Neonatal sepsis remains a burden problem by showing minimal initial symptoms of subtle character, nonspecific manifestation, and diagnostic pitfalls. The clinical course can be fulminant and fatal if treatment is not commenced promptly. It is therefore crucial to establish early diagnosis and initiate adequate therapy. Besides clinical symptoms, the most reliable laboratory markers in establishing diagnosis is currently the combined measurement of CRP and a cytokine (IL-6 and IL-8). Due to their different kinetics, a diagnostic gap might occur and thus withholding antimicrobial therapy in clinical suspicion of infection is not acceptable. We therefore need parameters which unerringly differentiate between infants in need for antimicrobial therapy and those who are not. Flow cytometry promises to be a useful tool in this field, allowing the determination of different cellular, dissolved, and functional pathophysiological components of sepsis. Despite technical and methodical advances in flow cytometry, its use in clinical routine is still limited. Advantages and disadvantages of promising new parameters in diagnosis of sepsis performed by flow cytometry, particularly CD64, HLA-DR, and apoptosis, are reviewed here. The necessity of tests to be used as an “ideal” parameter is presented.

HLA-DR(hi) and CCR9 Define a Pro-Inflammatory Monocyte Subset in IBD

OBJECTIVES:

It has been demonstrated that circulating monocytes relocate to the intestinal mucosa during intestinal inflammation, but the phenotype and inflammatory mechanisms of these monocytes remain poorly understood. Here, we have investigated blood monocytes expressing high levels of HLA-DR and CCR9 in patients with inflammatory bowel disease (IBD).

METHODS:

Fifty-one patients with mild to severe ulcerative colitis (UC; n=31; UC-DAI 3–12) or Crohn's disease (CD; n=20; Harvey–Bradshaw indices (HBI) 2–16) were included together with 14 controls, during IBD therapy for four consecutive weeks. The frequency of CD14⁺HLA-DR^hi monocytes was monitored weekly in peripheral blood, using flow cytometry. The surface phenotype and cytokine profile of these monocytes were established using flow cytometry and real-time PCR. Clinical parameters were assessed weekly in all patients.

RESULTS:

The frequency of circulating CD14⁺HLA-DR^hi monocytes was significantly higher in IBD patients with moderate to severe disease compared with healthy controls (P<0.001). During treatment with corticosteroids and granulocyte/monocyte apheresis, the proportion of circulating CD14⁺HLA-DR^hi monocytes was significantly reduced. CD14⁺HLA-DR^hi monocytes produced high levels of inflammatory mediators, such as tumor necrosis factor (TNF)-α, and expressed the gut-homing receptor CCR9. Furthermore, we found that the CCR9 ligand, CCL25/TECK, was expressed at high levels in the colonic mucosa in IBD patients with active disease.

CONCLUSIONS:

CD14⁺HLA-DR^hi blood monocytes were increased in patients with active IBD. These monocytes exhibit a pro-inflammatory, gut-homing phenotype with regard to their TNF-α production and expression of CCR9. Our results suggest that these monocytes are important in mediating intestinal inflammation, and provide potential therapeutic targets in IBD.

The three human monocyte subsets: implications for health and disease

Human blood monocytes are heterogeneous and conventionally subdivided into two subsets based on CD16 expression. Recently, the official nomenclature subdivides monocytes into three subsets, the additional subset arising from the segregation of the CD16+ monocytes into two based on relative expression of CD14. Recent whole genome analysis reveal that specialized functions and phenotypes can be attributed to these newly defined monocyte subsets. In this review, we discuss these recent results, and also the description and utility of this new segregation in several disease conditions. We also discuss alternative markers for segregating the monocyte subsets, for example using Tie-2 and slan, which do not necessarily follow the official method of segregating monocyte subsets based on relative CD14 and CD16 expressions.

Very low birth weight neonates who survive early-onset sepsis do not have an increased risk of developing late-onset sepsis

BACKGROUND

Very low birth weight neonates (≤ 1500 g, VLBWs) have a high rate of infection and distinct baseline immune function compared with more mature populations. In critically ill children and adults, sepsis increases subsequent infection risk. It is unknown whether sepsis modifies the risk of subsequent infection in VLBWs.

METHODS

We conducted a retrospective cohort study of VLBWs≤32weeks of gestation at birth cared for in 312 neonatal intensive care units in the United States from 1997 to 2011 (n=103,376). Early-onset sepsis (EOS, culture-positive only) and late-onset sepsis (LOS, culture-positive or clinical) cases were identified. Cox proportional hazard models were used to control for clinical variables between neonates with and without EOS to determine if EOS modified risk of LOS, necrotizing enterocolitis (NEC), or death.

RESULTS

LOS occurred in 12,112/102,317 (11.8%) neonates without EOS and in 133/1059 (12.6%) of those with EOS. After adjustment for clinical variables, the risk of LOS was not different between neonates with or without a history of EOS (hazard ratio [HR]=0.92; 95% confidence interval [CI] 0.74, 1.16). EOS increased the risk of 120-day mortality (HR=1.78; 95% CI 1.49, 2.13).

CONCLUSIONS

In contrast to findings in children and adults, EOS was not associated with an increased risk of LOS in this cohort. Age-specific investigations are needed to determine if post-sepsis immunologic alterations are present.

Assessment of cellular immune parameters in paediatric toxic shock syndrome: a report of five cases

Toxic shock syndrome (TSS) and septic shock (SS) share many clinical signs of an exacerbated inflammatory response. In this report, we investigated whether TSS presents similar features of delayed immunosuppression as described in SS. Five children with TSS from paediatric intensive care units in a university hospital were monitored. TSS cases were defined by the association of standardized clinical signs of TSS and confirmed by measurement of specific Vbeta expansions corresponding to toxin gene profile of the isolated strains. As in SS, an increased percentage of circulating regulatory T cells (Treg) was observed in patients with TSS. However, in contrast to SS, neither lymphopenia nor decreased HLA-DR expression on monocytes was measured. In conclusion, whereas SS and TSS exhibited similar clinical presentation, the present observation suggests that respective pathophysiological mechanisms induce different immune alterations. Future studies must isolate and better characterize the phenotypic and functional properties of Treg subsets during TSS to understand the mechanisms sustaining their increase, especially the putative role of superantigens.

Immune status in very preterm neonates

OBJECTIVES

Preterm neonates are at increased risk of sepsis compared with those born at term. We investigated immune status at birth and early neonatal life in very preterm neonates and its association with short-term outcomes.

METHODS

Prospective observational study conducted at a university hospital recruiting 113 preterm neonates (23-32 weeks) and 78 controls. Monocyte major histocompatibility complex (MHC) class II expression, serum, and ex vivo lipopolysaccharide stimulated levels of six cytokines (tumor necrosis factor α, interleukin (IL)-1β, IL-6, IL-8, IL-10, and IL-12p70) were measured in umbilical cord blood and over the first 7 days. The presence of neonatal sepsis and histologic chorioamnionitis was recorded.

RESULTS

Prematurity (preterm labor and preterm premature rupture of membranes cohorts), neonatal sepsis, and histologic chorioamnionitis were associated with significant reduction in monocyte MHC class II expression. Neonates who had evidence of subsequent protracted sepsis had low levels of MHC class II expression at birth. Serial monocyte MHC class II expression revealed a fall by day 2, in all preterm neonates, with the degree being influenced by both prematurity and sepsis, and incomplete recovery by day 7, suggesting immunoparalysis in preterm premature rupture of membranes and preterm labor cohorts. Whole blood lipopolysaccharide stimulation assay showed significantly lower tumor necrosis factor α, values in preterm neonates who subsequently developed sepsis indicating a degree of immunoparalysis.

CONCLUSIONS

Our data support the concept that fetal exposure to inflammation before preterm delivery leads to subsequent endotoxin hyporesponsiveness (immunoparalysis), which increases the risk of subsequent sepsis and associated organ dysfunction.

Dietary fish oil decreases the proportion of classical monocytes in blood in healthy mice but increases their proportion upon induction of inflammation

Fish oil can have beneficial effects in health and disease. In healthy individuals, reduction of the inflammatory status may be of benefit, whereas in patients with systemic inflammation, such as sepsis, it is important to diminish the immunosuppression that is thought to contribute to poor outcome. The objective of this study was to determine the effects of dietary fish oil on monocytes/macrophages in blood, bone marrow, spleen, and peritoneum and chemokine concentrations in blood and peritoneum in healthy mice and mice with endotoxin-induced inflammation. Mice were fed a Western-type diet without fish oil (C) or with 2.8% fish oil (FO) for 6 wk and then either killed (healthy mice) or injected i.p. with endotoxin (LPS) and killed after 3, 8, 12, 24, or 48 h. Blood, bone marrow, spleen, and peritoneal lavage were collected. Expression of cell surface molecules and chemokine receptors was analyzed by flow cytometry and chemokine concentrations measured by ELISA. Healthy mice in the FO group had lower proportions of classical monocytes in blood than healthy mice in the C group. LPS administration increased the proportion of classical monocytes in blood in mice in the FO group but not in those in the C group. Healthy mice in the FO group had lower serum concentrations of CCL2 than mice in the C group, but in inflamed mice, CCL2 concentrations were higher in the FO group than in the C group. These results indicate that dietary fish oil can attenuate the inflammatory status in homeostasis but intensify the immune response upon inflammation.

Changes of monocyte human leukocyte antigen-DR expression as a reliable predictor of mortality in severe sepsis

INTRODUCTION

Many studies have shown that monocyte human leukocyte antigen-DR (mHLA-DR) expression may be a good predictor for mortality in severe septic patients. On the contrary, other studies found mHLA-DR was not a useful prognostic marker in severe sepsis. Few studies have taken changes of mHLA-DR during treatment into consideration. The objective of this study was to estimate the prognostic value of changes of mHLA-DR to predict mortality in severe sepsis.

METHODS

In this prospective observational study, mHLA-DR was measured by flow cytometry in peripheral blood from 79 adult patients with severe sepsis. mHLA-DR levels were determined on day 0, 3, 7 after admission to the surgical intensive care unit (SICU) with a diagnosis of severe sepsis. ΔmHLA-DR₃ and ΔmHLA-DR₇ were defined as the changes in mHLA-DR value on day 3 and day 7 compared to that on day 0. Data were compared between 28-day survivors and non-survivors. Receiver operating characteristic (ROC) curves were plotted to measure the performance and discriminating threshold of ΔmHLA-DR₃, ΔmHLA-DR₇, ΔmHLA-DR₇-₃, mHLA-DR₀, mHLA-DR₃ and mHLA-DR₇ in predicting mortality of severe sepsis.

RESULTS

ROC curve analysis showed that ΔmHLA-DR₃ and ΔmHLA-DR7 were reliable indicators of mortality in severe sepsis. A ΔmHLA-DR₃ value of 4.8% allowed discrimination between survivors and non-survivors with a sensitivity of 89.0% and a specificity of 93.7%; similarly, ΔmHLA-DR₇ value of 9% allowed discrimination between survivors and non-survivors with a sensitivity of 85.7% and a specificity of 90.0%. Patients with ΔmHLA-DR₃ ≤ 4.8% had higher mortality than those with ΔmHLA-DR₃ > 4.8% (71.4% vs. 2.0%, OR 125.00, 95% CI 13.93 to 1121.67); patients with ΔmHLA-DR7 ≤ 9% had higher mortality than those with ΔmHLA-DR₇ > 9% (52.9% vs. 2.0%, OR 54.00, 95% CI 5.99 to 486.08). The mean change of mHLA-DR significantly increased in the survivor group with the passage of time; from day 0 to day 3 and day 7, changes were 6.45 and 16.90 (P < 0.05), respectively.

CONCLUSIONS

The change of mHLA-DR over time may be a reliable predictor for mortality in patients with severe sepsis.