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

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

Peripheral blood tumor-infiltrating lymphocytes in a neuroblastoma model. / Linfocitos infiltrantes de tumor en sangre periférica en un modelo de neuroblastoma.

OBJECTIVE: To detect tumor-infiltrating lymphocytes (TILs) in the peripheral blood (PB) of a preclinical neuroblastoma model. MATERIALS AND METHODS: Two types of preclinical models - immunodeficient mice and immunocompetent mice - were generated by injecting a cell suspension of neuroblastoma cell line NB36769 with MYCN gene (TH-MYCN+) overexpression. Spleen, tumor, and peripheral blood were studied using flow cytometry to detect PD-1+ T-cells. TCR-ß immunosequencing was performed in matched samples (tumor and peripheral blood). RESULTS: Most PB T-cells of immunodeficient mice were CD4 (control: 83.1%; tumor: 86.1%), with a small proportion of PD-1+ T-cells (control: 0.4%; tumor: 0.3%). However, the percentage of PD-1+ T-cells in the spleen was higher (control: 6.5%; tumor: 6.2%), and it was expressed in the CD4+ subset only. Regarding the TCR repertoire of immunocompetent mice, the proportion of the 10 most frequent sequences was significantly higher in tumors (11.09% ± 2.83%) than in the peripheral blood (1.59% ± 0.59%) (p=0.024). These findings are suggestive of clonotype enrichment within the tumor. 9 out of the 10 most frequent tumor clones were identified in the matched peripheral blood sample in 2 mice, and 6 out of 10 in one mouse. In addition, TILs with shared sequences from different animals were found. CONCLUSIONS: Our results in terms of immunophenotype and clonality suggest the presence of PB T-cells which could include TILs in a preclinical neuroblastoma model.

OBJETIVO: Comprobar la existencia de linfocitos T que incluyen linfocitos infiltrantes de tumor (TILs) en la sangre periférica (SP) de un modelo preclínico de neuroblastoma. MATERIAL Y METODOS: Utilizamos un modelo en ratones inmunodeficientes y otro en inmunocompetentes mediante inyección de suspensiones de la línea tumoral NB36769 con mutación de MYCN (TH-MYCN+). Se realizaron análisis por citometría de flujo (bazo, SP y tumor) y secuenciación del TCR-ß en el ADN de muestras pareadas de tumor y SP. RESULTADOS: En los ratones inmunodeficientes el componente principal en SP fue CD4: 83,1% (control) y 86,1% (tumor), siendo PD-1+ el 0,4 y el 0,3%. En el bazo obtuvimos un mayor porcentaje de linfocitos T PD-1+ que en SP, siendo similar en el control (6,5%) y en el ratón con tumor (6,2%), en subpoblación CD4+ exclusivamente. En los ratones inmunocompetentes observamos que la proporción de los 10 clones más frecuentes en los tumores constituía el 11,09% ± 2,83% del repertorio del TCR, mientras en SP representaba el 1,59% ± 0,59% (p= 0,024). Estos resultados sugieren un enriquecimiento de clonotipos dentro del tumor. De los 10 clones más frecuentes en las muestras tumorales, localizamos 9 también en la SP en dos ratones y 6 en el tercero. Además, encontramos secuencias compartidas por TILs de animales diferentes. CONCLUSIONES: Nuestros resultados de inmunofenotipo y clonalidad apuntan a la existencia de linfocitos en SP que podrían contener TILs en un modelo experimental de neuroblastoma.

[Twenty years of treating childhood acute lymphoblastic leukemia]. / Veinte años de experiencia en el tratamiento de la leucemia linfoblástica aguda.

BACKGROUND: Conventional prognostic factors for relapse in patients with acute lymphoblastic leukemia (ALL) are the main basis of risk-stratified treatments. OBJECTIVES: To analyze conventional risk factors for relapse and design a predictive model for relapse in our series, after 20 years of experience in treating ALL. PATIENTS AND METHOD: We performed a multivariate analysis of conventional prognostic factors in the treatment of ALL in our unit and compared them with the risk groups in the Berlin-Frankfurt-Münster (BFM-ALL) treatment protocols. RESULTS: Between 1984 and 2004, 232 children were diagnosed with ALL and treated according to the different versions of the BFM protocols (BFM83, BFM86, BFM90 and BFM95) at the Hospital Niño Jesús, Madrid, Spain. The event-free survival for all patients was 79.4 % (95 % CI: 72.7-85.4). Overall survival among patients who relapsed was 10.72 % (95 % CI: 6-27.3). The only significant prognostic factor for relapse identified by multivariate analysis was leukocyte [white blood cell (WBC)] count higher than 80,000/ml at diagnosis (hazard ratio [HR]: 4.63; 95 % CI: 1.61-13.3; p 5 0,004). The sensitivity and specificity of WBC in predicting relapses were 31.4 % and 87.5 %, respectively. The sensitivity and specificity of BFM risk group stratification in predicting relapses were 25 and 85.9 respectively. CONCLUSIONS: A leukocyte count at diagnosis higher than 80,000/ml and BFM risk-stratified treatment have insufficient sensitivity and specificity to identify relapses.

[Allogeneic bone marrow transplantation in children with severe acquired aplastic anemia. The long-term results. The Spanish Group for Bone Marrow Transplantation in Children (GETMON)]. / Transplante alogénico de médula ósea en niños con aplasia medular grave adquirida. Resultados a largo plazo. Grupo Español para el Trasplante de Médula Osea en Niños (GETMON).

OBJECTIVE: The objective of this study was to evaluate retrospectively the efficacy of allogeneic BMT in the treatment of childhood severe acquired aplastic anemia (SAAA). PATIENTS AND METHODS: Twenty-seven children aged 2 to 16 years (median 11 years) received a BMT from an HLA identical sibling. Conditioning consisted in irradiation (total, nodal or thoraco-abdominal) plus cyclophosphamide (120-200 mg/kg) in 15 patients and cyclophosphamide alone (200 mg/kg) in the rest. Prophylaxis for graft-versus-host disease (GVHD) was cyclosporine and methotrexate in most patients. RESULTS: Twenty-four children achieved the bone marrow graft at a median of 18 days (neutrophils) and 21 days (platelets). Two patients failed engraftment and 1 had a late graft rejection. Three patients developed acute GVHD grades 3-4 and six chronic GVHD, which was extensive in 4 of them. Twenty patients/71%) are alive and disease-free at a median follow-up of 110 months and the estimated disease free survival at 6 years is 67%. CONCLUSIONS: Our results confirm that allogeneic bone marrow transplantation from an HLA identical sibling is the best treatment modality for children with SAAA. Acute GVHD associated with infections and graft rejection were responsible for treatment failures.