Our study aimed to evaluate the levels of MDSCs and Tregs in pediatric B-cell acute lymphoblastic leukemia (B-ALL), their relation to patients’ clinical and laboratory features, and the impact of these cells on the induction response. This study included 31 pediatric B-ALL patients and 27 healthy controls. All patients were treated according to the protocols of the modified St. Jude Children’s Research Hospital total therapy study XIIIB for ALL. Levels of MDSCs and Tregs were analyzed using flow cytometry. We observed a reduction in the levels of CD4 + T-cells and an increase in both the polymorphonuclear MDSCs (PMN-MDSCs) and Tregs. The frequencies of PMN-MDSCs and Tregs were directly related to the levels of peripheral and bone marrow blast cells and CD34 + cells. Complete postinduction remission was associated with reduced percentages of PMN-MDSCs and Tregs, with the level of PMN-MDCs in this subpopulation approaching that of healthy controls. PMN-MDSCs and Tregs jointly play a critical role in maintaining an immune-suppressive state suitable for B-ALL tumor progression. Thereby, they could be independent predictors of B-ALL progress, and finely targeting both PMN-MDSCs and Tregs may be a promising approach for the treatment of B-ALL.

Cytotoxic (CD8) T-cells and natural killer (NK) cells have a significant immune function role. The ongoing stimulation of immunity and the excessive release of proinflammatory cytokines observed in pediatric patients with Gaucher disease (GD) can affect immune cells. Few studies have looked at the proportion of cytotoxic CD8 T-cells and their subsets in children with GD. A prospective case–control study was performed involving twenty pediatric patients with type 1 GD and twenty healthy age-matched controls. All patients received regular enzyme replacement therapy (ERT) for at least 6 months before the study. Complete blood count and flow cytometric analyses of CD8 T, Tc1, Tc2, NK, and NK T-cells were performed. GD patients showed significantly increased of CD8 T, Tc1 and significantly decreased NK cells frequencies when compared to healthy controls. However, no significant difference in Tc2 and NK T-cells was found between the studied groups. GD patients on regular ERT have increased CD8+ T-cell frequencies, predominantly Tc1, together with a reduction in NK cells than in healthy controls. These crucial immunological changes may contribute to some extent to the pathogenesis and the progression of GD.

No abstract

Background:The emergence of colistin-resistant strains is considered a great threat for the children suffering from diarrhea. This study aimed to screen for the presence of mcr-1 in Escherichia coli (E. coli) isolates collected from children with diarrhea and to compare between genotypic and phenotypic methods for detection of colisitin resistant E.coli carrying mcr-1gene. Methods: Isolation of E.coli was done followed by antimicrobial susceptibility test. Kirby-Baur disc diffusion was used to determine antimicrobial susceptibility, whereas broth microdilution (BMD) and the double disc synergy test (DDST) were used to determine colistin resistance. The screening for mcr-1 was used to investigate one probable mechanism of colistin resistance by PCR. Results: All mcr-1 E.coli isolates were resistant to ampicillin, while resistance to ampicillin/sulbactam, cefazolin, cefoxitin, ceftazidime and trimethoprimsulphamethoxazol was 94.1% (32/34), 94.1% (32/34), 94.1% (32/34), 85.3% (29/34) and 70.6% (24/34) respectively. All mcr-1carrying E. coli strains were sensitive to tobramycin, amikacin and imipenem. Moderate resistance was noticed to piperacillin/ tazobactam(23/34) 67.6%, gentamycin 47.1% (16/34), and ciprofloxacin 44.1% (15/34). Thirty-one (91.2 %) mcr-1 positive E. coli strains were multidrug resistant (MDR). Forty five out of 95 (47.4%) of E.coli isolates were positive for mcr-1 by DDST and 34 /95 (35.78%) of E. coli isolates were positive for mcr-1 by PCR. Conclusions: This study reported a high prevalence of colistin resistant E. coli harboring mcr-1 gene in young children in Pediatric Hospital of Assiut University. Broth microdilution is more accurate than DDST in detection of colistin resistance.

Background: Early detection of carbapenemase enzymes among Gram negative bacilli (GNB) is mandatory to prevent their spread. Objective: The goal of this study was to evaluate the performance of chromID® CARBA-SMART medium and carbapenemase inhibition method (CIM) for detection of carbapenemases in GNB. Methodology: A total of 142 GNB isolates were collected and tested using Vitek-2 ® system for identification and antimicrobial susceptibility testing The carbapenem resistant (CR) GNB were tested for carbapenemase production by phenotypic methods; chromID ® CARBA-SMART medium and CIM. Carbapenemase genes (𝑏𝑙𝑎NDM-1, blaSIM-1, 𝑏𝑙𝑎VIM-2, 𝑏𝑙𝑎KPC-1, blaGIM-1, blaSPM-1 and 𝑏𝑙𝑎OXA-48) were detected by PCR. Results: By minimal inhibitory concentration (MIC), 111 (78.17 %) of the 142 isolates were shown to be carbapenem resistant. Sensitivity and specificity of CIM and ChromID® CARBA-SMART medium were (100% and 66.7% respectively) for CIM and (86.7% and 100% respectively) for the medium. Resistance to carbapenem was associated with high percentages of resistance to many antibiotic classes. Carbapenemase genes were detected in 82% (91/111) of CR GNB with 𝑏𝑙𝑎NDM-1 (58.6%) and 𝑏𝑙𝑎OXA-48 (55.9 %) having the highest prevalence, followed by 𝑏𝑙𝑎KPC-1 (36 %) then 𝑏𝑙𝑎VIM-2 (10.8%) and lastly blaSPM-1 (3.6 %) and blaSIM-1 (1.8 %). The blaGIM-1 gene was not detected in any isolate. Conclusion: Carbapenemase inhibition method was found to be a very sensitive, easy, and cheap test for carbapenemase detection but needs the addition of ChromID® CARBA-SMART medium to improve the specificity of the test. This study has a high prevalence of carbapenemases among isolates with potential of rapid spread necessitating need for phenotypic tests.