Raymond Pui On Wong

Proinflammatory and anti-inflammatory cytokine responses in preterm infants with systemic infections.

Objective: A prospective study to investigate the pattern of proinflammatory and anti-inflammatory cytokine responses in preterm infants with systemic infection. Methods: Very low birthweight infants in whom infection was suspected when they were > 72 hours of age were eligible. A full sepsis screen was performed in each episode. Key cytokines of both proinflammatory and anti-inflammatory pathways, including interleukin (IL) 2, IL4, IL5, IL6, IL10, interferon (IFN) γ, and tumour necrosis factor (TNF) α, were measured at 0 (at the time of sepsis evaluation), 24, and 48 hours by flow cytometric analysis or immunoassay. Results: Thirty seven of the 127 episodes of suspected clinical sepsis were proven infection or necrotising enterocolitis. Both proinflammatory (IL2, IL6, IFNγ, TNFα) and anti-inflammatory (IL4, IL10) cytokines were significantly increased in infected infants compared with non-infected infants. Significant correlations were observed between IL6 and TNFα or IL10 as well as IL10 and IFNγ in infected infants. In the subgroup analysis, plasma IL6, IL10, and TNFα concentrations, and IL10/TNFα and IL6/IL10 ratios were significantly elevated in patients with disseminated intravascular coagulation compared with infected infants without. The IL10/TNFα ratios had decreased significantly 48 hours after the onset, whereas the IL6/IL10 ratio showed only a non-significant decreasing trend. Further, the IL6/IL10 ratio in the deceased infant was disproportionally increased at presentation and continued to increase despite treatment. Conclusion: The results indicate that the counter-regulatory mechanism between the proinflammatory and anti-inflammatory cytokine pathways is probably operational in preterm infants of early gestation. High plasma IL6, IL10, and TNFα concentrations, and IL10/TNFα and IL6/IL10 ratios signify severe infection, but transiently elevated plasma IL10 concentration or IL10/TNFα ratio does not necessarily indicate a poor prognosis.

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

This study aims to evaluate the diagnostic utilities of four leukocyte surface antigens—two lymphocyte antigens (CD25 and CD45RO) and two neutrophil antigens (CD11b and CD64)—for identification of late-onset nosocomial bacterial infection in preterm, very low birthweight infants, and to define the optimal cutoff value for each marker so that it may act as a reference with which future studies can be compared. Very low birthweight infants in whom infection was suspected when they were >72 h of age were eligible for the study. A full sepsis screen was performed in each episode. IL-6, C-reactive protein, and leukocyte surface antigens (CD25, CD45RO, CD11b, and CD64) were measured at 0 (at the time of sepsis evaluation), 24, and 48 h by standard biochemical methods and quantitative flow cytometric analysis. The diagnostic utilities including sensitivity, specificity, and positive and negative predictive values of each marker and combination of markers for predicting late-onset neonatal infection were determined. One hundred twenty-seven episodes of suspected clinical sepsis were investigated in 80 infants. Thirty-seven episodes were proven infection. The calculated optimal cutoff values for CD25, CD45RO, CD11b, and CD64 were 3,100, 2,900, 10,450, and 4,000 phycoerythrin-molecules bound per cell, respectively. An interim analysis of data after 68 episodes suggested that CD25 and CD45RO were poor predictors of neonatal infection with sensitivity or specificity <75% during a single measurement. Thus, these two markers were excluded from further investigation. In the final analysis, CD64 has the highest sensitivity (95–97%) and negative predictive value (97–99%) at 0 and 24 h after the onset. The addition of IL-6 or C-reactive protein (0 h) to CD64 (24 h) further enhanced the sensitivity and negative predictive value to 100%, and has the specificity and positive predictive value exceeding 88% and 80%, respectively. Neutrophil CD64 expression is a very sensitive marker for diagnosing late-onset nosocomial infection in very low birthweight infants. If further validated, the use of CD64 as an infection marker should allow early discontinuation of antibiotic treatment at 24 h without waiting for the definitive microbiologic culture results. The quantitative flow cytometric analysis applied in this study could be developed into a routine clinical test with high comparability and reproducibility across different laboratories.

Neutrophil CD64 is a sensitive diagnostic marker for early-onset neonatal infection

This prospective study aimed to evaluate the diagnostic utilities of neutrophil CD64 expression for the identification of early-onset clinical infection and pneumonia in term infants and to define the optimal cutoff value so that it may act as a reference with which future studies can be compared. Term newborns in whom infection was suspected when they were <72 h of age were recruited into the study. C-reactive protein (CRP) and expression of CD64 on neutrophils were measured at 0 h (at the time of sepsis evaluation) and 24 h. The sensitivity, specificity, positive predictive value, and negative predictive value (NPV) of CRP, CD64, and the combination of these two markers for predicting neonatal sepsis were determined. A total of 338 infants with suspected clinical sepsis were investigated, 115 of whom were found to be clinically infected. CRP and CD64 in infected infants were both significantly elevated at 0 and 24 h compared with noninfected infants (p < 0.001). The calculated optimal cutoff value for CD64 was 6136 antibody-phycoerythrin molecules bound/cell. CD64 has a very high sensitivity (96%) and NPV (97%) at 24 h. The addition of CRP only marginally enhanced the sensitivity and NPV (97 and 98%, respectively). In conclusion, neutrophil CD64 is a very sensitive diagnostic marker for the identification of early-onset clinical infection and pneumonia in term newborns. The results strongly suggest that measurement of neutrophil CD64 may allow neonatal clinicians to discontinue antibiotic treatment at 24 h in infants who are clinically stable and whose CD64 expressions are below the optimal cutoff level.

Host-response biomarkers for diagnosis of late-onset septicemia and necrotizing enterocolitis in preterm infants

Preterm infants are highly susceptible to life-threatening infections that are clinically difficult to detect, such as late-onset septicemia and necrotizing enterocolitis (NEC). Here, we used a proteomic approach to identify biomarkers for diagnosis of these devastating conditions. In a case-control study comprising 77 sepsis/NEC and 77 nonsepsis cases (10 in each group being monitored longitudinally), plasma samples collected at clinical presentation were assessed in the biomarker discovery and independent validation phases. We validated the discovered biomarkers in a prospective cohort study with 104 consecutively suspected sepsis/NEC episodes. Proapolipoprotein CII (Pro-apoC2) and a des-arginine variant of serum amyloid A (SAA) were identified as the most promising biomarkers. The ApoSAA score computed from plasma apoC2 and SAA concentrations was effective in identifying sepsis/NEC cases in the case-control and cohort studies. Stratification of infants into different risk categories by the ApoSAA score enabled neonatologists to withhold treatment in 45% and enact early stoppage of antibiotics in 16% of nonsepsis infants. The negative predictive value of this antibiotic policy was 100%. The ApoSAA score could potentially allow early and accurate diagnosis of sepsis/NEC. Upon confirmation by further multicenter trials, the score would facilitate rational prescription of antibiotics and target infants who require urgent treatment.

IP-10 is an early diagnostic marker for identification of late-onset bacterial infection in preterm infants

Very low birth weight (VLBW) infants with suspected late-onset infection requiring sepsis screening were enrolled in a prospective study to evaluate the diagnostic utilities of a comprehensive panel of key chemokines and cytokines, both individually and in combination, to identify diagnostic markers for early recognition of bacterial sepsis and necrotizing enterocolitis (NEC). Plasma chemokines interleukin (IL)-8, interferon-γ–inducible protein 10 (IP-10), monokine induced by interferon-γ (MIG), monocyte chemoattractant protein 1 (MCP-1), growth-related oncogene-α (GRO-α), and regulated upon activation of normal T cell expressed and secreted (RANTES) and cytokines IL-1β, IL-6, IL-10, IL-12p70, and tumor necrosis factor α (TNF-α) were measured at the onset of sepsis (0 h) and 24 h later. Of 155 suspected infection episodes, 44 were classified as infected. Concentrations of all studied inflammatory mediators (except IL-1β and RANTES) were significantly higher in the infected than in the noninfected group at 0 h, but the levels decreased precipitously by 24 h. IP-10 with a plasma cutoff concentration ≥1250 pg/mL could identify all septicemic and NEC cases and had the highest overall sensitivity (93%) and specificity (89%) at 0 h. We conclude that preterm infants have the ability to induce a robust chemokine and cytokine response during sepsis, and IP-10 is a sensitive early marker of infection.

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.

Immunogenicity of a two-dose regime of varicella vaccine in children with cancers

Objective:  Live‐attenuated varicella vaccine is effective and safe in immunocompetent children. In this study, we assess the immunogenicity and adverse events following varicella vaccination in immunosuppressed cancer children.

Quantitative measurement of monocyte HLA-DR expression in the identification of early-onset neonatal infection

Background: This study aimed to evaluate the diagnostic utilities of monocyte HLA-DR as an infection marker in the identification of early-onset clinical infection and pneumonia in newborn infants. Methods: Term newborns in whom infection was suspected when they were <72 h of age were eligible for enrollment in the study. C-reactive protein (CRP), monocyte HLA-DR and neutrophil CD64 expressions were quantitatively measured at the time of sepsis evaluation (0 h) and 24 h afterwards by flow cytometry and standard laboratory method. Results: A total of 288 infants with suspected sepsis were investigated, and 93 were found to be clinically infected. There were no significant differences in monocyte HLA-DR expression between the infected, non-infected and control groups at 0 h (median (interquartile range): 13,986 (10,994–18,544), 14,234 (12,045–17,474) and 18,441 (14,250–21,537) antibody phycoerythrin (PE) molecules bound/cell), and between infected and non-infected infants at 24 h (median (interquartile range): 17,772 (12,933–25,167) and 19,406 (14,885–24,225) antibody PE molecules bound/cell). The areas under the receiver operating characteristics (ROC) curves for HLA-DR, CD64 and CRP were 0.52–0.54, 0.88–0.94 and 0.75–0.77, respectively. We were unable to determine an optimal cutoff value for HLA-DR, as the diagnostic utilities of any cutoff point on the ROC curves were unable to satisfy the criteria (i.e. sensitivity and specificity ≧80%) for consideration as an useful diagnostic marker of infection. Conclusions: Our findings did not support the use of monocyte HLA-DR alone or in combination with other infection markers in the diagnosis of early-onset clinical infection and pneumonia in term newborns.

Early Diagnosis of Intra-Abdominal Inflammation and Sepsis by Neutrophil CD64 Expression in Newborns

Background: Newborn infants with intra-abdominal inflammation/sepsis often present with nonspecific signs in the early stages of the disease, but can rapidly develop life-threatening complications. A reliable ‘early’ biomarker would be invaluable. Objective: To evaluate the effectiveness of neutrophil CD64 as an ‘early’ biomarker of intra-abdominal inflammation/sepsis. Methods: Blood was collected from newborns with suspected intra-abdominal pathology for neutrophil CD64 and C-reactive protein (CRP) determination at the onset of clinical presentation and 24 h later. They were classified into three groups: intra-abdominal inflammation/sepsis (group 1), extra-abdominal sepsis (group 2) and nonsepsis (group 3). Between-group comparisons were made by Kruskal-Wallis and χ2 tests. Receiver-operating characteristic curves and diagnostic utilities for single and combination of tests were determined. Results: 310 infants were recruited (102, 34 and 174 in groups 1, 2 and 3, respectively). CD64 (conventional cutoff = 6,010 antibody-PE molecules bound/cell) had substantially better sensitivity (0.81 vs. 0.56) and negative predictive value (0.90 vs. 0.79) for diagnosing intra-abdominal sepsis than CRP, at presentation. Pairing CD64 with routine abdominal radiograph (AXR) substantially increased the sensitivity and negative predictive value for group 1 to 0.99 and 0.99, respectively. By adjusting the CD64 cutoff to 12,500 units, a substantial improvement in specificity could be achieved (0.62 to 0.80) without significantly compromising sensitivity (0.99 to 0.97). Conclusions: CD64 is a sensitive and ‘early’ biomarker for diagnosing intra-abdominal inflammation/sepsis. Intra-abdominal catastrophes, including necrotizing enterocolitis, intestinal necrosis, perforation and peritonitis can confidently be excluded using CD64 and AXR early in the course of the disease.

Transfusion‐Related Immunomodulation in Chinese Children with Thalassaemia

Background and objectives: Multiple transfusions can induce immunomodulation. This study was carried out to investigate the immunological status of 50 transfusion‐dependent children with β‐thalassaemia, taking into account that lymphocyte characteristics are affected by sex, age and race. We paid particular attention to the influence of transfusion and serum ferritin on the lymphocyte subsets which may be affected by the exposure to foreign antigens. Materials and methods: By multicolour immunofluorescent analysis using flow cytometry, we determined lymphocyte characteristics with regard to major subsets (T lymphocytes, B lymphocytes and NK cells), activation (membrane IL‐2 receptor CD25, HLA‐D) and memory/naive T cells (CD45RO/CD45RA). Data from 51 age‐ and sex‐balanced children served as controls. Results: The normal Chinese children had higher NK levels than the β‐thalassaemia children. The levels of CD25 and HLA‐D indicated a broad‐based increase in activation status. Memory T cells were also increased when compared with their normal counterparts. We found additional and more marked alterations in the lymphocyte subsets of those who had received over 100 transfusions. While levels of NK cells were inversely correlated with the number of transfusions, CD25+ cells increased with transfusions. Conclusion: Many multitransfused β‐thalassaemia children have altered levels of lymphocyte subsets compared with normals. What remains to be investigated is the long‐term consequence of possessing low NK and non‐MHC‐restricted T cells (CD3+CD56+CD16+) and a high activation status in terms of resistance of infections and development of malignancy.