Wei-Qun Xu

Diagnostic Accuracy of a Specific Cytokine Pattern in Hemophagocytic Lymphohistiocytosis in Children

OBJECTIVE The study goal was to determine the diagnostic accuracy of a specific cytokine pattern including interferon-gamma (IFN-γ), interleukin (IL)-10, and IL-6 for hemophagocytic lymphohistiocytosis (HLH) in febrile children. STUDY DESIGN In this prospective study, 756 patients with fever admitted to a hematology-oncology unit were enrolled. The causes of fever were documented and the serum cytokines, including IFN-γ, tumor necrosis factor-alpha (TNF-α), IL-10, IL-6, IL-4, and IL-2, were determined using cytometric bead array techniques. RESULTS Of 1474 episodes of fever that were analyzed, 71 episodes of HLH manifested a specific cytokine pattern of highly increased levels of IFN-γ (median level: 1088.5 pg/mL) and IL-10 (623.5 pg/mL) but a moderately increased level of IL-6 (51.1 pg/mL). IL-6 was predominantly increased to varied extents in patients in the sepsis group (244.6 pg/mL) and the nonsepsis infection group (34.7 pg/mL). The diagnostic accuracy of IFN-γ and IL-10 for HLH was 99.5% and 92.8%, respectively. By applying the cutoff point of 100 pg/mL, IFN-γ had a sensitivity of 94.4% and a specificity of 97.2% for HLH. When using the criteria of IFN-γ >75 pg/mL and IL-10 >60 pg/mL, the specificity reached 98.9% and the sensitivity was 93.0%. CONCLUSIONS The specific cytokine pattern of markedly elevated levels of IFN-γ and IL-10 with only modestly elevated IL-6 levels has high diagnostic accuracy for HLH and may be a useful approach to differentiate HLH from infection.

Evaluation of Th1/Th2 cytokines as a rapid diagnostic tool for severe infection in paediatric haematology/oncology patients by the use of cytometric bead array technology

Haematology/oncology children are usually at risk for various infections after intensive chemotherapy. We evaluated the quantification of Th1/Th2 cytokines with a flow cytometric bead array (CBA) in 795 hospitalized haematology/oncology children (309 febrile and 486 afebrile patients) to seek for a diagnostic method for determination of the type and the severity of infection. Three hundred and nine febrile patients developed a total of 505 febrile episodes. Microbiological examination demonstrated a positive blood culture (microbiologically documented infection (MDI)) in 145/505 febrile episodes. The controls included 550 healthy children, 43 haemophagocytic lymphohistiocytosis (HLH) patients, 35 cytomegalovirus infection patients and 19 Epstein-Barr virus infection patients. Interleukin (IL)-4, IL-6, IL-10, tumour necrosis factor (TNF)-α and interferon (IFN)-γ levels in febrile episodes were significantly higher than those in healthy children, and the cytokine profile was different from that of the HLH controls or the viral infection controls. IL-6 levels were much higher in MDI patients (usually >1000.0 pg/mL, 60/145) than in HLH patients (2/43); however, IFN-γ levels were only slightly increased in MDI patients, rarely being more than 100.0 pg/mL (8/145 vs. 39/43 in HLH patients). The median levels of IL-4, IL-6, IL-10, TNF-α and IFN-γ in febrile patients before antibiotic therapy were 3.9, 660.1, 122.7, 6.9 and 11.4 pg/mL, respectively, and returned to 3.3, 22.8, 9.6, 4.1 and 6.4 pg/mL, respectively, after infection was controlled. IL-6 and IL-10 levels were positively associated with septic shock and mortality rates. In conclusion, our results have demonstrated the usefulness of IL-6/IL-10/TNF-α/IFN-γ determination with CBA technology for the early rapid diagnosis, severity evaluation and assessment of therapy effect in febrile haematology/oncology children.

A multiplex cytokine score for the prediction of disease severity in pediatric hematology/oncology patients with septic shock.

Although many inflammatory cytokines are prognostic in sepsis, the utility of cytokines in evaluating disease severity in pediatric hematology/oncology patients with septic shock was rarely studied. On the other hand, a single particular cytokine is far from ideal in guiding therapeutic intervention, but combination of multiple biomarkers improves the accuracy. In this prospective observational study, 111 episodes of septic shock in pediatric hematology/oncology patients were enrolled from 2006 through 2012. Blood samples were taken for inflammatory cytokine measurement by cytometric bead array (CBA) technology at the initial onset of septic shock. Interleukin (IL)-6 and IL-10 were significantly elevated in majority of patients, while tumor necrosis factor (TNF)-α and interferon (IFN)-γ were markedly increased in patients with high pediatric index of mortality 2 (PIM2) score and non-survivors. All the four cytokines paralleled the PIM2 score and differentially correlated with hemodynamic disorder and fatal outcomes. The pediatric multiplex cytokine score (PMCS), which integrated the four cytokines into one score system, was related to hemodynamic disorder and mortality as well, but showed more powerful prediction ability than each of the four cytokines. PMCS was an independent predictive factor for fatal outcome, presenting similar discriminative power with PIM2, with accuracy of 0.83 (95% CI, 0.71-0.94). In conclusion, this study develops a cytokine scoring system based on CBA technique, which performs well in disease severity and fatality prediction in pediatric hematology/oncology patients with septic shock.

Absolute lymphocyte count is associated with minimal residual disease level in childhood B-cell precursor acute lymphoblastic leukemia.

The prognostic value of absolute lymphocyte count (ALC) has been a recent matter of debate in childhood acute lymphoblastic leukemia (ALL). In the current study, ALCs at the time of diagnosis (ALC-0), after 7 days of initial therapy (ALC-8) and at interim of the induction therapy (ALC-22) were examined in Chinese children with B-cell precursor (BCP) ALL and correlated with the level of minimal residual disease (MRD) at day 22 of induction therapy. Medical and laboratory records of 140 patients diagnosed with childhood BCP ALL were retrieved and analyzed. ALC-22 is significantly correlated with MRD level at day 22 of therapy and can be a good prognostic factor for childhood BCP-ALL. Furthermore, lymphocyte count at initial diagnosis is correlated with MRD level at day 22 in childhood BCP-ALL with the immnunophenotype of CD19(pos)/CD10(pos)/CD34(pos)/CD45(neg) and role as a new prognostic factor was determined.

Day 22 of induction therapy is important for minimal residual disease assessment by flow cytometry in childhood acute lymphoblastic leukemia

This study was aimed to illustrate the significance of minimal residual disease (MRD) assessment on day 22 in childhood acute lymphoblastic leukemia. MRD were measured on day 22, day 36, week 12, month 6 and month 12 by four-color flow cytometry. The 5-year cumulative incidence of relapse was significantly different for patients with MRD levels of <0.01%, 0.01-0.1%, 0.1-1.0% and ≥ 1.0% on day 22: 6.9 ± 2.6%, 16.7 ± 5.5%, 25.8 ± 6.2% and 58.4 ± 13.4% (P < 0.001). MRD on day 22 was more powerful than other parameters including NCI risk. However, other time points after induction, although predictive as well, were not accurate enough due to false positivity.

Rapid detection of neoplastic cells in serous cavity effusions in children with flow cytometry immunophenotyping.

Abstract The aim of the study was to evaluate the role of flow cytometric immunophenotyping (FCI) as a rapid diagnostic tool for pediatric malignancy in serous cavity effusions (SCEs). FCI results for 103 SCEs in a pediatric population were compared with retrospective clinical outcomes (RCOs). Among 41 patients assessed as having malignancies by RCO, 36 patients were diagnosed with lymphoma (n =25), acute myeloid leukemia (n =2), neuroblastoma (n =8) and retinoblastoma (n =1) by FCI, respectively. The sensitivity and specificity of FCI for detecting neoplastic cells were 87.8% and 98.4%, respectively. The concordance of FCI data with final diagnoses of the patients was 94.2%. FCI data for lymphoma was concordant with the final diagnosis in 89.3% of cases. When Hodgkin lymphoma was excluded, the overall correlation increased to 96.1%. FCI is a useful tool for rapid and reliable diagnosis of pediatric non-Hodgkin lymphoma in SCE samples and also to suggest the presence of non-lymphoid malignancies, especially neuroblastoma.

A new in-frame deletion in ribosomal protein S19 in a Chinese infant with Diamond-Blackfan anemia

Diamond-Blackfan anemia (DBA) is a congenital erythroid aplasia that usually presents as macrocytic anemia during infancy. Ribosomal protein S19 (RPS19) is identified as the first gene associated with DBA. RPS19 is mutated in 25% of DBA patients, but its role in DBA pathogenesis remains to be elucidated. We have identified a novel heterozygous frameshift mutation in RPS19 gene in a DBA child presenting with profound anemia after birth. A single nucleotide heterozygous deletion (C.251delG) results in frameshift in RPS19 gene in exon 4 at codon 84 with possible premature stop codon (p.Arg84LysfsX21). The mutant allele was not detected in her parents, indicating de novo mutation. Both alleles were expressed at the same level. Using an immunofluorescence technique, the mutated-type RPS19 expressions were mostly localized to entire nuclei with little staining for nucleoli and its intracellular localization significantly differed from the wild-type RPS19, which was localized to both nuclei and nucleoli. This type of a mutation could be very helpful in further understanding the role of the RPS19 protein in DBA pathogenesis.

The ratio of absolute lymphocyte count at interim of therapy to absolute lymphocyte count at diagnosis predicts survival in childhood B-lineage acute lymphoblastic leukemia

Absolute lymphocyte count (ALC) after therapy has been reported to be an independent prognostic factor for clinical outcome in leukemia. This study mainly analyzed ALC at interim of therapy on day 22 (ALC-22) and the ratio of ALC-22 to ALC at diagnosis (ALC-0) on the impact of survival and the relation of ALC to lymphocyte subsets in 119 pediatric B-lineage acute lymphoblastic leukemia (B-ALL) patients. Univariate analysis revealed that ALC-22/ALC-0 ratio <10% was significantly associated with inferior overall survival (OS) (hazard ratio (HR)=12.24, P=0.0014) and event-free survival (EFS) (HR=3.3, P=0.0046). In multivariate analysis, ALC-22/ALC-0 ratio remained an independent prognostic factor for OS (HR=6.92, P=0.0181) and EFS (HR=2.78, P=0.0329) after adjusting for age, white blood cell (WBC) count and minimal residual disease (MRD) status. A Spearman correlation test showed that CD3+ T cells had a negative correlation with ALC-0 (r=-0.7204, P<0.0001) and a positive correlation with ALC-22 (r=0.5061, P=0.0071). These data suggest that ALC-22/ALC-0 ratio may serve as a more effective biomarker to predict survival in pediatric B-ALL and ALC is mainly associated with CD3+ T cells.

Successful Construction and Massive Expression of a Novel Anti-CD19 Human-Mouse Chimeric Antibody Hm2E8b

CD19 antigen is a major target for human B cell malignancies. Many studies have shown that the antibodies recognizing this antigen hold clinical therapeutic potential, while CD19 antibody of mouse origin requires genetic engineering to reduce the potential side effects of the antibody for their clinical use. There are many clones of CD19 antibodies available with different subclasses of immunoglobulin. IgM type antibody holds a high affinity and high complement activating capacities facilitating the targeting efficacy when it is used in targeting therapy. However, engineering the murine IgM antibody into a functional humanized antibody remains a challenge. The aim of this study was to construct a chimeric antibody composed of a CD19 specific murine IgM antibody 2E8 single-chain antibody fragment (scFv) and human IgG1 Fc region, which was named 2E8scFv-Fc or Hm2E8b. The function and the biological activities of this engineered antibody were characterized using a variety of approaches including cellular, immunological, flow cytometric, and molecular biological approaches. After switching from IgM- to IgG-like type antibody, Hm2E8b retained full antigen-binding activity to membrane CD19 antigen as its parental antibody 2E8, and the immune effector function analysis revealed that it could mediate complement-dependent cytotoxicity (CDC) to kill the target cells via IgG1 Fc domain. The yield of the engineered antibody Hm2E8b in the supernatant was 13.3 μg/mL expressed and secreted in the CHO cell system, which reached the secretory quantity of a regular mouse hybridoma cells. Our conclusion is that the IgM type of CD19 mouse antibody can be successfully engineered into an IgG1 type human-mouse chimeric antibody with similar affinity and biological activity. The yield of the Hm2E8b expression and secretion in CHO cell system was adequate to facilitate further development for therapeutic purpose.

Prognostic significance of flow cytometric minimal residual disease assessment after the first induction course in Chinese childhood acute myeloid leukemia.

Flow cytometry based minimal residual disease (MRD) was evaluated for outcome prediction in childhood acute myeloid leukemia (AML). The median levels of MRD in relapsed and nonrelapsed patients were different after the first induction (0.64% vs. 0.18%, P=0.030). A cutoff level of ≥ 0.25% after the first course of induction was correlated with a high risk of relapse in both univariate analysis (5-year cumulative incidence of relapse: 66.8% vs. 21.2%, P=0.002) and multivariate analyses (hazard ratio: 3.70, 95% CI, 1.23-11.08, P=0.020). Our results showed that MRD level after the first induction therapy provides important information for risk assessment in childhood AML.