Characterization of Antigenic Relatedness Among GI Norovirus Genotypes Using Serum Samples From Norovirus-Infected Patients and Mouse Sera.

Characterizing diversity and the antigenic relatedness of norovirus remains a primary focus in understanding its biological properties and vaccine designs. The precise antigenic and serological features of GI genotypes have not been studied. The study represented an investigation on a gastroenteritis outbreak related to GI.3 norovirus and the three most detected GI genotypes, GI.2 (belonging to immunotype B), GI.3 and GI.9 (belonging to immunotype C), were selected to characterize their phylogenetic relationship, HBGA binding profiles and antigenic relatedness within (intra-immunotype), and between (inter-immunotypes) genotypes using mouse sera and patient's serum samples from the GI.3 related outbreak. Wide HBGA binding profiles and evolution of binding affinity were observed in the three GI genotypes studied. A low specific blockade antibody to GI.3 in the population generated the pool of susceptible individuals and supported virus spread in the outbreak. We found strong blockade immune response in homologous strains, moderate intra-immunotype blockade but weak inter-immunotypes blockade in humans following GI.3 norovirus infections. These findings further support the immunotypes grouping and will be valuable for optimizing the design of norovirus vaccine.

[Effect of cyclophosphamide on hematopoietic stem cells in mice with iron overload].

OBJECTIVE: To explore the effect of cyclophosphamide on hematopoietic stem cells (HSCs) in mice with iron overload. METHODS: Mouse models of iron overload were established in 30 male C57BL/6 mice by intraperitoneal injections of iron dextran at low (0.25 g/kg), moderate (0.5 g/kg), and high (1 g/kg) doses (n=10), with another 10 PBS-treated mice as the control group. The changes in body weight, liver, spleen and bone marrow of the mice were recorded, and serum level of ferritin was detected. The mice receiving a moderate dose of iron dextran were further divided into 8 groups for observation at different time points (D1, D2, D3, D4, D5, D6, D7, and D14 groups) and were given intraperitoneal injection of 50 mg/kg cyclophosphamide (Cy) for 2 consecutive days. Peripheral blood cells, bone marrow mononuclear cells (BMMNCs), and the frequencies of different HSCs (HPCs, HSCs, LT-HSCs) in the BMMNCs were monitored. The cell cycle distribution in the HSCs, level of reactive oxygen species and the microenvironment of the HSCs were analyzed using flow cytometry. RESULTS: Compared with the control mice, the mice with iron overload showed obvious weight loss with significantly increased serum ferritin level, enlargement of the liver and spleen, and iron deposition in the organs (P < 0.05). No significant changes were noted in the peripheral blood of the mice with iron overload. The cyclophosphamide-treated mice exhibited significantly decreased number of WBCs and lymphocyte ratio at days 1 to 4 (P < 0.05). The numbers of BMMNCs and HPCs in mice with iron overload did not show significant changes as compared with those in the control mice, but the numbers of HSCs and LTHSCs decreased significantly in the mice with iron overload (P < 0.05). In cyclophosphamide-treated mice, the number of HSCs increased since day 1 and reached the peak level on day 3 (P < 0.05). Compared with those in the control group, the HSCs did not exhibit significant changes in cell cycle distribution in mice with iron overload, but the proportion of G0/G1 cells decreased significantly in cyclophosphamide group since day 1 and reached the lowest level on day 3 (P < 0.05). CONCLUSIONS: Iron deposition in the bone marrow causes long- term damages of the HSCs in the bone marrow but does not induce obvious changes in the peripheral blood. In mice with iron overload, intraperitoneal injection of 50 mg/kg cyclophosphamide for two days promotes cell cycle changes of the resting HSCs to mobilize the HSCs, and this effect is the most obvious on day 4.

Transplant Outcomes in Beta-Thalassemia Major Patients Receiving Combined Granulocyte Colony-Stimulating Factor-Primed Bone Marrow and Cord Blood Graft Compared to Granulocyte Colony-Stimulating Factor-Primed Bone Marrow Alone.

BACKGROUND: Hematopoietic stem cell transplantation (HSCT) is currently the only curative treatment for thalassemia majorTM. Graft rejection (GR) and graft-versus-host disease (GVHD) are the primary obstacles to a successful outcome. METHODS: We conducted a retrospective study of HSCT in 29 children (median age at transplantation: 6 years) with Beta-thalassemia (ß-TM) after the combined infusion of granulocyte colony-stimulating factor-primed bone marrow (G-BM) and cord blood (CB) from the human leukocyte antigen (HLA)-identical sibling donors. We also compared the outcomes of the co-transplanted children with those of children with ß-TM who received G-BM alone from an HLA-identical sibling donor (n = 26). RESULTS: Compared to the G-BM transplant (G-BMT) recipients, those who received a co-transplant had a lower incidence of grade ≥II acute (17.24 vs. 30.7%, p = 0.047) and limited chronic (0 vs.15.4%, p = 0.022) GVHD as well as a lower incidence of GR (0 vs. 7.7%, p = 0.132). Neutrophil recovery time was faster in the co-transplant group (18.5 vs. 21 days, p = 0.04). All the patients were monitored until December 31, 2016; the median follow-up time was 74 months, and the 5-year thalassemia-free survival rate was 89.7% in the co-transplant group and 84.6% in the G-BMT-alone group (p = 0.590). CONCLUSIONS: A combined CB and G-BM graft from an HLA-identical sibling donor is an effective treatment option for TM in children, with less acute and chronic GVHD.

Apoptosis of CD19+ chimeric antigen receptor T cells after treatment with chemotherapeutic agents.

The use of chemotherapeutic agents prior to treatment with infusion of cluster of differentiation (CD)19-chimeric antigen receptor (CAR)­T cells is important for the efficacy of clinical therapies against hematological malignancies. However, the effect of chemotherapeutic agents on CD19­CAR­T cells and the associated underlying mechanisms remain unknown. The first aim of the present study was to determine the effect of chemotherapeutic agents on CAR­T cells using the in vitro Cell Counting kit 8 assay. The second aim was to evaluate the abilities of fludarabine (FDR) and mafosfamide (MFA; a metabolite of cyclophosphamide) to induce apoptosis of CD19­CAR­T cells via the use of Annexin V/propidium iodide double staining. In addition, a JC­1 fluorescent probe was used to detect alterations in cell membrane potential, and flow cytometry analysis was used to measure concentrations of caspase­3/7 to identify apoptotic pathways of CD19­CAR­T cells. The data of the present study suggested that FDR and MFA inhibit the activities of CD19­CAR­T cells. Alterations to the mitochondrial membrane potential and an increase in the concentration of caspase­3/7 indicated early apoptosis of FDR­ and MFA­treated CD19­CAR­T cells. The present study laid a theoretical foundation for the development of programs for clinical treatment.

[Nosocomial septicemia in the early stage after stem cell transplantation in children with major ß-thalassemia].

OBJECTIVE: To explore the clinical characteristics of nosocomial septicemia in the early stage after hematopoietic stem cell transplantation (HSCT) in children with major ß-thalassemia. METHODS: The clinical data were retrospectively analyzed of 55 consecutive children with major ß-thalassemia who developed septicemia early after HSCT between January, 2011 and June, 2016. RESULTS: Among the total of 416 consecutive children with major ß-thalassemia undergoing allogeneic HSCT, the incidence of nosocomial infection early after transplantation was 77.16% (321/416), and 55 (17.13%) children showed positive findings in blood culture test. The infections occurred most commonly in the oral cavity (65.5%), followed by the respiratory tract, intestinal tract and skin. Gram-negative bacteria, including Escherichia coli (27.3%), Klebsiella pneumoniae (21.8%) and Pseudomonas aeruginosa (9.1%), were the most common causes of infections. Fungal (Candida tropicalis) infection caused septicemia in 1 case. Of all the pathogens, extended-spectrum ß-lactamase (ESBL)-producing bacteria were found in 6 cases, methicillin-resistant Staphylococcus aureus (MRSA) in 2 cases, and multidrug-resistant (MDR) bacteria in 2 cases. CONCLUSION: Gram-negative bacteria are the major pathogens causing septicemia in children early after HSCT for major ß-thalassemia, and the bacteria show a high level of drug resistance. Adequate preventive use of antibiotics and care of the oral cavity, the respiratory tract, and the perianal region following the transplantation are important measures to control nosoconial infection in these children.

[Outcome of childhood high-risk acute lymphoblastic leukemia treated with the ALL-BFM 95 protocol].

OBJECTIVE: To evaluate the effectiveness and the practicability of the Acute Lymphoblastic Leukemia Berlin-Frankfurt-Münster 95 (ALL-BFM 95) protocol in treating childhood high-risk acute lymphoblastic leukemia (HR-ALL). METHODS: A retrospective analysis of 47 children with newly diagnosed HR-ALL between July 2003 and August 2013 was performed. These children were treated by the ALL-BFM 95 protocol. Survival was evaluated by Kaplan Meier analysis and Log-Rank test. RESULTS: Relapse-related death occurred in 12 of 47 patients (26%), and 5 of 47 patients (11%) were treatment-related mortality. Five-year probability of event-free-survival (pEFS) was 62%. Children with hematopoietic stem cell transplantation (HSCT) after chemotherapy achieved significantly better pEFS than those with chemotherapy alone (77% vs 52%; P=0.035). The patients who were only poor responders to prednisone had a better outcome (5-year pEFS 80%) than the Days 15 and 33 bone marrow M3 subgroups (5-year pEFS 60% and 0 respectively). CONCLUSIONS: ALL-BFM 95 protocol can improve the outcome of children with high-risk ALL. The major cause of death is attributed to relapse. Chemotherapy plus HSCT can produce a better outcome than chemotherapy alone. The Days 15 and 33 bone marrow M3 subgroups have a poor prognosis.

[Value of magnetic resonance imaging T2* tests in detecting heart and liver iron overload in patients with ß-thalassemia major].

OBJECTIVE: To assess the value of magnetic resonance imaging T2* tests in the detection of myocardial and liver iron overload in patients with ß-thalassemia major (ß-TM). METHODS: From 2010 to 2011, 28 ß-TM patients over 10 years old under blood transfusion therapy and chelation care with serum ferritin (SF)>1000 µg/L underwent myocardial and liver MRI T2* tests on a voluntary basis. The results were analyzed in relation with age, SF, and left ventricular ejection fraction (LVEF). RESULTS: Fourteen out of the 28 cases (50%) were found to have myocardial iron overload, including 7 severe cases, 2 moderate cases, and 5 mild cases. All the 28 cases had liver iron overload, including 2 mild cases, 7 moderate cases, and 19 severe cases. Two out of the 28 cases had lowered LVEF (7.14%), and one of them had severe myocardial iron overload. There was a negative correlation between myocardial MRI T2* and SF (r=-0.479, P=0.01). Myocardial MRI T2* was positively correlated with liver MRI T2* (r=0.378, P=0.047). Age was not significantly correlated with SF, LVEF, or liver MRI T2*. CONCLUSION: Magnetic resonance imaging (T2*) detection is an effective and non-invasive means for detecting myocardial and liver iron overload in patients with ß-thalassemia major receiving blood transfusion. T2* combined with SF is the main diagnostic indicator to assess iron overload in the vital organs.

A novel conditioning regimen improves outcomes in ß-thalassemia major patients using unrelated donor peripheral blood stem cell transplantation.

We used a novel NF-08-TM transplant protocol based on intravenous busulfan, cyclophosphamide, fludarabine, and thiotepa in 82 consecutive patients with ß-thalassemia major (TM), including 52 with allogeneic peripheral blood stem cell transplantation (PBSCT) from unrelated donors (UDs) with well-matched human leukocyte antigens and 30 with hematopoietic stem cell transplantation (HSCT) from matched sibling donors (MSDs). The median age at transplantation was 6.0 years (range, 0.6-15.0 years), and the ratio of male-to-female patients was 56:26. The median follow-up time was 24 months (range, 12-39 months). The estimated 3-year overall survival and TM-free survival were 92.3% and 90.4% in the UD-PBSCT group and 90.0% and 83.3% in the MSD-HSCT group. The cumulative incidences of graft rejection and grades III-IV acute graft-versus-host disease were 1.9% and 9.6%, respectively, in the UD-PBSCT group and 6.9% and 3.6%, respectively, in the MSD-HSCT group. The cumulative incidence of transplant-related mortality was 7.7% in the UD-PBSCT group and 10.0% in the MSD-HSCT group. In conclusion, UD-PBSCTs using the well-tolerated NF-08-TM protocol show similar results to MSD-HSCTs and can be used to treat ß-thalassemia patients in the absence of MSDs.

[Impact of cytomegalovirus infections on T lymphocyte subsets in children with ß-thalassemia major early after allogeneic hematopoietic stem cell transplantation].

OBJECTIVE: To investigate the effect of human cytomegalovirus (HCMV) infection on T lymphocyte subsets in children with ß-thalassemia major (TM) during the initial 6 months after allogeneic hematopoietic stem cell transplantation (Allo-HSCT). METHODS: From January, 2010 to January, 2011, 35 children with TM underwent Allo-HSCT. Peripheral blood samples were obtained from the children 6 month after the transplantation to examine the changes of T lymphocytes subsets in relation to HCMV seropositivity. RESULTS: Thirteen children were found seropositive and 22 were seronegative for HCMV. The HCMV-seropositive children had a higher CD8⁺ cell percentage but a lower CD4⁺ cell percentage than those without HCMV infection. Compared with those seronegative for HCMV, the children with HCMV seropositivity showed increased percentages of CD8⁺ cells and CD8⁺CD28⁻ cells with a decreased percentage of CD8⁺CD28⁺ cells. A positive linear correlation was found between the percentages of CD8⁺CD28⁻ cells and CD8⁺ cells. CONCLUSION: HCMV infection can lead to the accumulation of CD8⁺CD28 cells to cause increased CD8⁺ T cells in the peripheral blood in TM children after Allo-HSCT. The percentages of CD8⁺CD28⁻ cells has a positive linear correlation to that of CD8⁺ cells.

[Pretreatment doses of antithymocyte globubin-fresenius for allogeneic hematopoietic stem cell transplantation for beta-thalassemia major].

OBJECTIVE: To investigate the effects of different doses of antithymocyte globubin-fresenius (ATG-F) for allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with beta-thalassemia Major. METHODS: Sixty-four children with beta-thalassemia major undergoing allo-HSCT were divided into two equal groups to receive ATG-F pretreatments at high (30 mg/kg) or low (15 mg/kg) doses as part of the conditioning regimen including mainly cyclophosphamide, busulfan, fludarabine, and thiotepa. The outcomes of the patients were compared between the two groups. RESULTS: No obvious difference were noted in the time to leukocyte and platelet engraftment between the two groups. The incidence of grade II-IV acute graft-versus-host disease (aGVHD) appeared to be higher in the low-dose group than in the high-dose group (12.5% vs 9.4%). The incidence of grade III-IV aGVHD was also higher in the low dose group (12.5% vs 6.3%), but the difference was not statistically significant. Application of high-dose ATG-F was associated with a higher rate of probable and possible fungal infection (P<0.05). CONCLUSION: The two doses of ATG-F is feasible as a part of the conditioning regimen for allo-HSCT in children with beta-thalassemia major.

[Analysis of the risk factors for hemorrhagic cystitis after allogeneic hematopoietic stem cell transplantation for beta-thalassemia in children].

OBJECTIVE: To analyze the risk factors of hemorrhagic cystitis after allogeneic hematopoietic stem cell transplantation for beta-thalassemia in children. METHODS: The clinical records of 30 children with beta-thalassemia undergoing allogeneic hematopoietic stem cell transplantation between December, 2008 and November, 2009 were analyzed. RESULTS: Hemorrhagic cystitis occurred in 8 of the 33 patients with an incidence of 24.24%, including 1 with grade I, 6 with grade II and 1 with grade III hemorrhagic cystitis. The median time of hemorrhagic cystitis onset was 22.9 days (range 6-35 days) and the median duration was 11.9 days(range 3-27 days). Univariate analysis indicated that the different types of transplantation and acute graft-versus-host disease affect the occurrence of hemorrhagic cystitis. The children with Allo-PBSCT had higher incidence than those receiving Allo-PBSCT+Allo-UBT and Allo-BMT (P<0.05). The children at an age >or=6 years had obviously higher incidence of hemorrhagic cystitis than those at younger ages. CONCLUSION: Age is the major factor that affects the occurrence of hemorrhagic cystitis in children undergoing allogeneic hematopoietic stem cell transplantation for beta-thalassemia.

Mixed hematopoietic chimerism for preventing graft-versus-host disease in mice receiving rat bone marrow transplantation.

OBJECTIVE: To find a method for preventing graft-versus-host disease (GVHD) in BALB/c mice receiving rat bone marrow transplantation. METHODS: Firstly 12 SD rats were conditioned with 5.0 Gy sublethal total body irradiation(TBI), followed by infusion of 8 x 10(7) bone marrow cells from 28 BALB/c mice within 4 h and intraperitoneal administration of 100 mg/kg cyclophosphamide (Cy) 2 d later, for the purpose of inducing chimeric SD rats with specific immunological tolerance. Secondly, 24 BALB/c mice were exposed to 9.0 Gy lethal TBI and divided randomly into 3 equal groups designated respectively as groups A, B and C. Mice in group A were injected with 4 x 10(7) bone marrow cells from 4 normal rats, and mice in group B were injected with 4 x 10(7) bone marrow cells and 2 x 10(7) spleen cells from 4 normal rats, while those in group C were given 4 x 10(7) bone marrow cells and 2 x 10(7) spleen cells from 6 chimeric rats. The mice were then observed for 150 d for GVHD. RESULTS: In the second procedure, 2 mice in group A failed to survive due to infection and radiation injury respectively, and none of the rest mice presented signs of GVHD. The mice in group B all developed GVHD of varied degrees with symptoms as wasting, diarrhea, fur loss, arched body posture, and even bloody stool, and all died within 5 to 15 d with an average survival of 10.0 d (95% confidence interval 8,12). Pathological examination of the liver and intestinal tissues revealed inflammatory lymphocyte infiltration and necrosis. The majority of the mice in group C, in contrast, survived for more than 150 d with only two died on the postoperative days 18 and 31 respectively. The survival time of group B was significantly shorter than that of the other two groups. CONCLUSION: Donor/recipient chimerism may help prevent GVHD in xenogeneic bone marrow transplantation.