[A multi-center epidemiological study on pneumococcal meningitis in children from 2019 to 2020]. / 2019­2020å¹´160ä¾‹å„¿ç«¥è‚ºç‚Žé“¾çƒèŒè„‘è†œç‚Žä¸´åºŠæµè¡Œç— å­¦å¤šä¸­å¿ƒç ”ç©¶.

OBJECTIVES: To investigate the clinical characteristics and prognosis of pneumococcal meningitis (PM), and drug sensitivity of Streptococcus pneumoniae (SP) isolates in Chinese children. METHODS: A retrospective analysis was conducted on clinical information, laboratory data, and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country. RESULTS: Among the 160 children with PM, there were 103 males and 57 females. The age ranged from 15 days to 15 years, with 109 cases (68.1%) aged 3 months to under 3 years. SP strains were isolated from 95 cases (59.4%) in cerebrospinal fluid cultures and from 57 cases (35.6%) in blood cultures. The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87) and 27% (21/78), respectively. Fifty-five cases (34.4%) had one or more risk factors for purulent meningitis, 113 cases (70.6%) had one or more extra-cranial infectious foci, and 18 cases (11.3%) had underlying diseases. The most common clinical symptoms were fever (147 cases, 91.9%), followed by lethargy (98 cases, 61.3%) and vomiting (61 cases, 38.1%). Sixty-nine cases (43.1%) experienced intracranial complications during hospitalization, with subdural effusion and/or empyema being the most common complication [43 cases (26.9%)], followed by hydrocephalus in 24 cases (15.0%), brain abscess in 23 cases (14.4%), and cerebral hemorrhage in 8 cases (5.0%). Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old, with rates of 91% (39/43) and 83% (20/24), respectively. SP strains exhibited complete sensitivity to vancomycin (100%, 75/75), linezolid (100%, 56/56), and meropenem (100%, 6/6). High sensitivity rates were also observed for levofloxacin (81%, 22/27), moxifloxacin (82%, 14/17), rifampicin (96%, 25/26), and chloramphenicol (91%, 21/23). However, low sensitivity rates were found for penicillin (16%, 11/68) and clindamycin (6%, 1/17), and SP strains were completely resistant to erythromycin (100%, 31/31). The rates of discharge with cure and improvement were 22.5% (36/160) and 66.2% (106/160), respectively, while 18 cases (11.3%) had adverse outcomes. CONCLUSIONS: Pediatric PM is more common in children aged 3 months to under 3 years. Intracranial complications are more frequently observed in children under 1 year old. Fever is the most common clinical manifestation of PM, and subdural effusion/emphysema and hydrocephalus are the most frequent complications. Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates. Adverse outcomes can be noted in more than 10% of PM cases. SP strains are high sensitivity to vancomycin, linezolid, meropenem, levofloxacin, moxifloxacin, rifampicin, and chloramphenicol.

[Prognostic significance of coagulation disorders in children with hemophagocytic syndrome].

OBJECTIVE: To study the prognostic significance of coagulation disorders in children with hemophagocytic syndrome (HPS). METHODS: Thirty-five children with HPS were retrospectively studied to analyze the etiology, clinical characteristics, laboratory results and treatment outcomes. RESULTS: After treatment, 27 of the 35 HPS patients survived, and the other 8 cases died. All cases were treated according to the HLH-2004 protocol, but etoposide (VP-16) was not used in 10 of them. The response rate in patients who received VP-16 (22/25, 88%) was significantly higher than that in those not receiving VP-16 (5/10, 50%) (P<0.05). Compared with the survival group, the dead group had significantly lower platelet count, fibrinogen level, and VP-16 utilization rate (P<0.05) but significantly longer activated partial thromboplastin time and prothrombin time (P<0.05). CONCLUSIONS: Coagulation function can be used as an indicator of disease outcome. It is essential for improving the clinical outcome of HPS to monitor the coagulation function during treatment, detect and correct abnormalities in time, and provide treatment strictly according to the HLH-2004 protocol.

[Clinical efficacy of desmopressin in the treatment of mild hemophilia A in children].

OBJECTIVE: To study the effects of desmopressin (DDAVP) on coagulation factor Ⅷ (FⅧ) and activated partial thromboplastin time (APTT) in children with mild hemophilia A. METHODS: Eighteen children with mild hemophilia A were enrolled. DDAVP (0.3 µg/kg•d) was injected intravenously for 5 days. Plasma FⅧ levels and APTT were measured before and after DDAVP treatment. RESULTS: In 16 of 18 children with mild hemophilia A, the bleeding symptoms, including the articular or musclar hematoma, were significantly alleviated as a result of DDAVP treatment. The plasma FⅧ levels increased significantly to (27±4)% and APTT was shortened to (66±10)s 60 minutes after the first dose of DDAVP treatment. The plasma FⅧ remained at the levels of 25%-30% during 3-4 days of DDAVP treatment. Five days after DDAVP treatment, the plasma FⅧ levels decreased [(21±3)%], and APTT was prolonged when compared with 1-4 days of DDAVP treatment. CONCLUSIONS: DDAVP treatment can increase plasma FⅧ levels and shorten APTT in children with mild hemophilia A. DDAVP is effective in the treatment of mild hemophilia A. The duration of DDAVP therapy for mild hemophilia A is recommended as 3 to 4 days.

[Levels of Toll-like receptors-2,-4 on platelets in children with idiopathic thrombocytopenic purpura].

OBJECTIVE: To study the changes and significance of Toll-like receptor-2 (TLR2) and Toll-like receptor-4 (TLR4) on platelets, CD86 on lymphocytes and concentrations of IL-2, IFN-gamma, IL-4 and IL-10 in serum in children with idiopathic thrombocytopenic purpura (ITP). METHODS: Peripheral blood samples were collected from 24 children with acute idiopathic thrombocytopenic purpura (AITP), 21 children with chronic idiopathic thrombocytopenic purpura (CITP) and 20 normal children (control group). Expression of TLR2 and TLR4 on platelets and CD86 on lymphocytes were detected by flow cytometry. Serum concentrations of IL-2, IL-4, IL-10 and IFN-gamma were measured using ABC-ELISA. RESULTS: The expression of CD41+TLR2+ and CD61+TLR4+ in the AITP and the CITP groups were significantly lower than those in the control group (p<0.01). The AITP group had lower expression of CD41+TLR2+ and CD61+TLR4+ than the CITP group (p<0.01). The expression of CD86+ in the AITP and the CITP groups was significantly higher than that in the control group (p<0.01). The serum concentrations of IL-2, IL-4, IL-10 and IFN-gamma in the AITP and the CITP groups were significantly higher than those in the control group (p<0.05). There was a positive correlation between CD41+TLR2+ and CD61+TLR4+ expression. CD41+TLR2+ and CD61+TLR4+ expression were negatively correlated with CD86+ expression and serum concentrations of IL-2, IL-4 and IL-10. CONCLUSIONS: The detections of TLR2 and TLR4 on platelets, CD86 on lymphocytes and serum concentrations of IL-2, IFN-gamma, IL-4 and IL-10 are of great value in understanding the pathogenesis and predicting types of ITP in children.

[Effects of FMS-like tyrosine kinase 3 targeted RNA interference on proliferation and apoptosis of acute monocytic leukemia cell line THP-1].

OBJECTIVE: FMS-like tyrosine kinase 3 (FLT3) is a receptor tyrosine kinase that is constitutively activated in (70-90)% pediatric patients with acute myeloid leukemia (AML) and appears to confer an adverse prognosis. Although several FLT3-selective small molecule inhibitors and antibodies were developed with varied degrees of success, to address the specificity and resistance, new approaches for specifically targeted FLT3 are needed and RNA interference is a promising choice. The aim of the present study was to investigate the efficacy of suppression of FLT3 induced by small hairpin interfering RNA (shRNA) on myeloproliferation and apoptosis in an acute monocytic leukemia (AMOL) cell line THP-1. METHODS: FLT3-targeted small hairpin interfering RNA (FLT3-shRNA) was designed and synthesized by transcription system in vitro was transfected into THP-1 cells. Firstly FLT3 mRNA level was detected by semi-quantitative RT-PCR and FLT3 protein level was detected by flow cytometry (FCM) to verify the efficacy on FLT3-shRNA interference at 48 h after transfection. Cell growth viability was measured at 24 h, 48 h and 72 h after treatment with CCK-8. The distribution of cell cycle was assayed by FCM, and apoptosis was analyzed by DNA Ladder and Annexin V-FITC Staining at 48 h. RESULTS: FLT3 targeted shRNAs was synthesized successfully and the concentration of 15 nmol/L for 48 h could obtain desirable downregulation of FLT3 expression, the inhibitory percentages of FLT3 mRNA and protein were (72.95 +/- 2.07)% and (65.39 +/- 5.57)%, respectively. The suppression of FLT3 induced by FLT3-shRNA resulted in marked inhibition of cell growth and the inhibitory percentages were (36.66 +/- 3.67)% at 48 h, (35.56 +/- 0.73)% at 72 h. FLT3-shRNA induced the inhibition of cell cycle from G(0)/G(1) phase to S phase, the percentage of sub-G(0)/G(1) phase (65.71 +/- 4.47)% was higher than those in the PBS-control group (52.23 +/- 2.98)%, NC-shRNA control group (51.81 +/- 1.44)%, P < 0.01; the percentage of S phase (25.11 +/- 2.70)% was lower than those in the PBS-control group (34.41 +/- 4.07)% and NC-shRNA control group (32.50 +/- 1.46)%, P < 0.05. Furthermore treatment with FLT3-shRNA for 48 h resulted in clear apoptosis ladder, the percentage of early apoptosis detected by Annexin V-FITC was (18.59 +/- 2.07)% which was significantly higher than that in the PBS-control group (4.00 +/- 0.50)% and the NC-shRNA control group (6.06 +/- 0.70)%, P < 0.001. CONCLUSION: The suppression of FLT3 induced by the shRNA can effectively inhibit cell proliferation, and apoptosis induction on THP-1 cells, which indicates that this approach may bear the therapeutic potential on childhood AMOL.

[In vitro transcription synthesis and effects of FLT3 targeted short hairpin RNA].

FMS-like tyrosine kinase 3 (FLT3) is a receptor of tyrosine kinase that is constitutively activated in most of acute myeloid leukemia patients and seems to give an adverse prognosis. In order to explore the silencing effect of FLT3 targeted short hairpin RNA (FLT3-shRNA) on acute leukaemia cell line THP-1, three FLT3-shRNAs (shRNA1, shRNA2, shRNA3) were designed and synthesized by transcription system in vitro and then transfected into THP-1 cells. FLT3 mRNA was analyzed by semi-quantitative RT-PCR, FLT3 protein was detected by Flow cytometry and immunofluorescence. The results indicated that FLT3 expression was downregulated by shRNA1 and shRNA3, and shRNA1 showed stronger inhibitory effect. At 48 hours following transfection, the inhibitory rate of 25 nmol/L shRNA1 was 72.95 +/- 2.07%, lasting 72 hours. The 5 nmol/L and more concentration of FLT3 shRNA1 could downregulate FLT3 mRNA level, which displayed a quantity-effect relation; the inhibitory rate of 15 nmol/L shRNA1 was 67.53 +/- 0.66%. FLT3 protein was located on THP-1 cell membrance, its expression was downregulated obviously by shRNA1, at 72 hours following transfection the inhibitory rate of shRNA1 was 79.67 +/- 0.66%. shRNA1 showed the best inhibitory effect on FLT3 protein, the optimal time of which was 72 hours with an inhibitory rate of 79.67%. It is concluded that FLT3-shRNA1 shows a desireable FLT3-targeted inhibitory effect, which can be used for further investigation of FLT3 mechanism or FLT3 targeting treatment.

[Expression levels of CXCR4 on megakaryocytes and its ligand in bone marrow in children with acute idiopathic thrombocytopenic purpura].

OBJECTIVE: Chemokine receptor CXCR4 and its ligand stromal-derived factor 1 alpha (SDF-1alpha) have been paid increasing attention for their involvement in megakaryocytic hematopoiesis. It has been revealed in recent years that they can induce mature and immature megakaryocytes (MKs) to migrate through bone marrow endothelial cells (BMEC) by increasing the affinity of MKs for BMEC. Thus MKs maturity and eventual release of platelet from MKs ensues. While maturity disturbance of MKs and impaired production of platelets have been regarded as the main pathogenesis of ITP, the mechanism of which still remains unclear. Therefore, a clear understanding of the levels of CXCR4 and SDF-1alpha within bone marrow in children with ITP will help us to elucidate further the mechanism of ITP as well as to provide direct theoretical evidence for predicting treatment effect and evaluating prognosis. METHODS: Bone marrow were aspirated from 28 children with AITP and 12 normal children. Percoll density gradient and immunomagnetic beads method were used to purify megakaryocytes from the bone marrow. The immune cytochemistry was used to detect CXCR4 on megakaryocytes. The levels of SDF-1alpha were detected by ELISA. SPSS10.0 statistical software was used to deal with the experimental data. RESULTS: Before the treatment in children with AITP, both the CXCR4 expression on megakaryocytes and the SDF-1alpha level in bone marrow plasma were markedly decreased compared with the normal controls (P < 0.05). As to the cases who were sensitive to the high-dose intravenous immunoglobulin (HDIVIgG), the CXCR4 and SDF-1alpha levels were much higher in children after the treatment than those before the treatment (P < 0.05). In 6 cases insensitive to HDIVIgG, before the treatment the CXCR4 level was much lower than the children sensitive to HDIVIgG (P < 0.05). CONCLUSIONS: The low levels of CXCR4/SDF-1alpha system in bone marrow may be one of the factors which contribute to the maturity disturbance of megakaryocytes and disturbance of platelets production in AITP, while decreased CXCR4/SDF-1alpha system may be caused by the effect of autoantibody against platelet. The mechanism of HDIVIgG in the treatment of AITP may involve in the increasing expression of CXCR4/SDF-1alpha system. The level of CXCR4 on megakaryocytes may play a certain role in predicting the treatment effect of immunoglobulin.