[Effect of Low-Dose Recombinant Interleukin-2 Therapy on Immunocyte Subsets in Children with Solid Tumor]

OBJECTIVE

To evaluate the effect of low-dose recombinant interleukin-2 (rIL-2) therapy on immunocyte subsets and its side effects in children with solid tumor.

METHODS

A total of 22 children (11 males and 11 females) with solid tumor in our department from December 2012 to November 2017 were selected, with a median age of 9 (3-16) years old when starting IL-2 therapy. ALL surgeries and chemotherapy of children had been completed before low-dose rIL-2 therapy, and 17 cases achieved complete remission (CR) and 5 cases achieved partial remission (PR). A low-dose rIL-2 therapy was given 1 month after chemotherapy for 1 year: 4×105 IU/(m2·d), s.c. for every other day, 3 times per week. The immunocyte subsets were detected every 3 months until the end of treatment, meanwhile, disease condition and therapy-related side effects were followed up.

RESULTS

After low-dose rIL-2 therapy in 22 children, the absolute values of CD3+ T cells, CD3-CD56+ natural killer cells, CD3+CD4+ helper T cells (Th) and CD3+CD8+ cytotoxic T cells were up-regulated remarkably, as well as Th/suppressor T cells (all P < 0.05). While, there were no significant differences in absolute value and proportion of CD4+CD25+CD127- Treg cells during therapy. Among the 17 children who achieved CR before rIL-2 therapy, 14 cases continued to maintain CR after therapy, while 3 cases relapsed, and with 2 died after treatment abandonment. The 5 children who achieved PR before low-dose rIL-2 therapy were evaluated CR by PET/CT scan after treatment. In the early stage of low-dose rIL-2 therapy, 1 child developed skin rashes at the injection sites, and 2 children ran a slight to mild transient fever. Their symptoms disappeared without any organ damage after symptomatic treatment.

CONCLUSION

Low-dose rIL-2 therapy has good drug tolerance, and changes the distribution of anti-tumor immune-cell subgroup in peripheral blood of children with solid tumor remarkably without up-regulation of absolute value and ratio of Treg cells.

Wilms Tumor 1 Mutations Are Independent Poor Prognostic Factors in Pediatric Acute Myeloid Leukemia

The prognostic impact of Wilms tumor 1 (WT1) mutations remains controversial for patients with acute myeloid leukemia (AML). Here, we aimed to determine the clinical implication of WT1 mutations in a large cohort of pediatric AML. The clinical data of 870 pediatric patients with AML were downloaded from the therapeutically applicable research to generate effective treatment (TARGET) dataset. We analyzed the prevalence, clinical profile, and prognosis of AML patients with WT1 mutations in this cohort. Our results showed that 6.7% of total patients harbored WT1 mutations. These WT1 mutations were closely associated with normal cytogenetics (P<0.001), FMS-like tyrosine kinase 3/internal tandem duplication (FLT3/ITD) mutations (P<0.001), and low complete remission induction rates (P<0.01). Compared to the patients without WT1 mutations, patients with WT1 mutations had a worse 5-year event-free survival (21.7 ± 5.5% vs 48.9 ± 1.8%, P<0.001) and a worse overall survival (41.4 ± 6.6% vs 64.3 ± 1.7%, P<0.001). Moreover, patients with both WT1 and FLT3/ITD mutations had a dismal prognosis. Compared to chemotherapy alone, hematopoietic stem cell transplantation tended to improve the prognoses of WT1-mutated patients. Multivariate analysis demonstrated that WT1 mutations conferred an independent adverse impact on event-free survival (hazard ratio 1.910, P = 0.001) and overall survival (hazard ratio 1.709, P = 0.020). In conclusion, our findings have demonstrated that WT1 mutations are independent poor prognostic factors in pediatric AML.

Eltrombopag as first-line treatment for thrombocytopenia among paediatric patients after allogeneic haematopoietic stem cell transplantation

AIMS

The purpose of this study is to examine the safety and efficacy of eltrombopag as first-line treatment for thrombocytopenia among paediatric patients after haematopoietic stem cell transplantation (HSCT).

METHODS

Forty-three childhood patients with thrombocytopenia after HSCT who received eltrombopag were retrospectively analysed.

RESULT

Eltrombopag was began at the median of 27 days after HSCT and lasted for 24 days. Thirty-five children responded to eltrombopag therapy, and the cumulative platelet recovery rate was 88.9%. The cumulative incidence of platelet recovery was lower (83.9 vs 100%; P = .035) in patients with decreased numbers of megakaryocytes before starting eltrombopag than in those with normal. Factors associated with a significantly elevated response to eltrobopag from univariate analysis were donor type. Results from the multiple regression analysis found that weight (hazard ratio [HR] = 0.7, 95% confidence interval [CI] 0.5-0.9, P = .022), platelet engraftment time (HR = 1.0, 95%CI 1.0-1.0, P = .012) and bone marrow megakaryocytes (HR = 8.0, 95%CI 1.5-43.3, P = .016) before starting eltrombopag were the independent risk factors. Based on Youden's index algorithm in the receiver-operating characteristic curve, the optimal cut-off value of the maintenance dose of eltrombopag in predicting nonresponders was 4 mg/kg. The area under the receiver-operating characteristic curve was 0.923 with sensitivity of 97.8%, specificity of 87.9%, positive predictive value of 72.3%, and negative predictive value of 92%. None of the paediatric patients stopped using eltrombopag due to side effect or intolerability.

CONCLUSION

Eltrombopag is effective and safe in paediatric patients with thrombocytopenia after HSCT. The number of megakaryocytes in bone marrow before eltrombopag treatment may serve as a predictor of the response to eltrombopag. We recommend that the maintenance dose of eltrombopag should not exceed 4 mg/kg/d.

Prediction, management, and prognosis of mixed chimerism after hematopoietic stem cell transplantation in transfusion-dependent pediatric thalassemia patients

BACKGROUND

Early-onset mixed chimerism (MC) with a high proportion of residual host cells is considered a signal of graft rejection in patients undergoing allogenic hematopoietic stem cell transplantation for transfusion-dependent thalassemia. In order to prevent graft rejection and minimize the risk of treatment-related graft-versus-host disease (GVHD), we established a hierarchical management system based on chimerism analysis.

METHOD

This retrospective study provides a comprehensive review of the characteristics, interventions, and outcomes of the 38 patients who developed MC after transplantation among the 144 pediatric thalassemia patients between July 2007 and January 2019 at our center.

RESULTS

A sibling donor, a blood type-matched donor, conditioning regimens without fludarabine, and transplants containing <10 × 10⁸ total nucleated cells/kg were identified to be associated with the development of MC. Among the 38 patients developing MC, only four patients rejected the grafts. The response rate to donor lymphocyte infusion (DLI, only for patients receiving sibling donor transplantation) and cytokine immunomodulation without DLI was 70.6% and 42.9%, respectively. Patients that developed GVHD after DLI or cytokine therapy had a more significant increase in donor cell chimerism (16%, range 0%-35%) than those without (8.5%, range -21% to 40%, P = .049). However, even when treatment-related GVHD was included, patients with MC had a lower cumulative incidence of total acute GVHD than patients with complete donor chimerism (29.2% vs 48.0%, P = .030).

CONCLUSIONS

Interventions based on chimerism analysis were effective in preventing graft rejection and did not increase treatment-related GVHD in thalassemia patients with MC.

Severe hypertension is an independent risk factor for posterior reversible encephalopathy syndrome post-hematopoietic cell transplantation in children with thalassemia major

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is an increasingly recognized serious complication of cyclosporine A (CSA) and tacrolimus (TAC) use in hematopoietic cell transplantation (HCT) recipients.

PROCEDURE

A retrospective study was carried out, including 84 cases of HCT for TM from January 2012 to January 2017. Eleven cases were diagnosed with PRES.

RESULTS

The cumulative incidence of PRES was 13.4% (95% confidence interval (CI) 9.7%-17.2%). The median onset time of the symptoms was 63 [20, 143] days after transplantation. Lumber puncture found that CSF was normal. Univariate analysis showed that patients who received methylprednisolone (MP) (OR = 10.629 95% CI, 1.360-83.071, P = 0.024), female patients (OR = 4.275, 95% CI, 1.154-15.843, P = 0.032), patients who had severe hypertension (OR = 5.162, 95% CI, 1.042 to 25.559, P = 0.029) had significantly higher risks of PRES. Multivariate analysis showed that severe hypertension (hazard ratio [HR], 12.793; 95% CI, 1.477 to 110.813; P  = 0.021), and Pesaro class 3 (HR, 3.367; 95% CI, 1.210 to 9.368; P  =  0.020) were associated with PRES.

CONCLUSIONS

The severe hypertension is an independent risk factor for PRES post-HCT in children with thalassemia major. Patients of Pesaro class 3 may benefit from optimum control of blood pressure post-HCT for prophylaxis of PRES.

[Clinical Efficacy of NOPHO-AML 2004 Regimen for Treatment of Children with Acute Myelocytic Leukemia (Non-M3)]

OBJECTIVE

To investigate the efficacy and safety of NOPHO-AML 2004 chemotherapy regimen for treatment of children with acute myelocytic leukemia(non-M3).

METHODS

Thirty-three patients aged 1-13 with acute myelocytic leukemia (non-M3) were diagnosed from January 2013 to June 2017. FAB typing showed that 1 case in M0, 4 cases in M1, 12 cases in M2, 5 cases in M4, 8 cases in M5, 1 case in M6, and 2 cases in M7; Risk stratification showed that: 19 cases in standard risk, and 14 cases in high risk. All patients were treated with NOPHO-AML 2004 chemotherapy regimen. SPSS 22.0 software was used, the Kaplan-Meier survival analysis method and Cox regression model were used for statistical analysis.

RESULTS

In the first course of treatment (AIET), among 33 child patients there were 27 cases with complete remission, and 5 cases with non-remission, thus the remission rate was 81.8%. Out of the 5 child patients without remission, 4 cases reached to the complete remission after the second course (AM), and 1 case did not remission, thus the total remission rate was 96.9%.9 cases (27.3%) underwent bone marrow recurrence and the median recurrence time was 30 months after complete continuous remission. Univariate analysis showed that age and erythrocyte transfusion frequency were significant factors to affect the early treatment response; the multiple Cox regression analysis showed that: age >7, MRD positive, erythrocyte transfusion >4 times and poor response to early treatment were independent risk factors for recurrence; Allogeneic hematopoietic stem cell transplantation(HSCT) in 8 high-risk children received enhanced chemotherapy had better efficacy as compared with the chemotherapy alone. The 3-year event-free survival rate was 59.9%, and 3-year overall survival rate was 69.2%. 33 children patients experienced varying degrees of infection and myelosuppression, or drug-related gastrointestinal reactions and allergic reactions, patients were tolerable to these side reactions after active symptomatic treatment.

CONCLUSION

NOPHO-AML 2004 chemotherapy regimen has high response rate and good tolerance, early treatment response is an important factor influencing prognosis. Age and repeated red blood cell infusions are the important factors influencing the prognosis, which promote bone marrow recurrence in AML children. For the children suffered from clinical high-risk AML, the NOPHO-AML 2004 chemotherapy regimen combined with HSCT can improve the prognosis of patients.

Modified conditioning regimen improves outcomes of unrelated donor peripheral blood stem cell transplantation for β-thalassaemia major patients

BACKGROUND

The objective of this study was to evaluate the feasibility of a modified conditioning regimen for the treatment of patients with β-thalassaemia major (TM), using unrelated donor peripheral blood stem cell transplantation (UD-PBSCT).

METHODS

A modified conditioning regimen based on intravenous busulfan, cyclophosphamide, fludarabine, and antithymocyte globulin was performed in 50 consecutive childhood patients with β-TM and a median age of 4.6 years (range, 2-12 years). According to Pesaro's classification, three classes of risk are identified using the criteria of degree of hepatomegaly, portal fibrosis, and quality of the chelation treatment. Patients with three adverse criteria constituted class III, none of the adverse criteria constituted class I, and one or two of the adverse criteria formed class II. Ten patients were class I, 36 class II, and four class III. All patients were transplanted with UDs containing 37 of 10/10 human leukocyte antigen (HLA)-matched pairs, 11 of 9/10 matched pairs, and two of 8/10 matched pairs. The median follow-up was 36 months (range, 9-96 months).

RESULTS

All patients successfully achieved engraftment, two of whom developed persistent thrombocytopaenia. The incidence of acute graft-versus-host disease (aGVHD) grade III-IV and chronic graft-versus-host disease (cGVHD) were 12% and 8%, respectively. However, 8.3% of HLA-matched and 15.4% of HLA-mismatched patients developed aGVHD. The incidence of severe bacterial infections and fungal pneumonia was 12% and 20%, respectively. The 3-year overall survival, disease-free survival, graft rejection, and transplant-related mortality were 94%, 92%, 2%, and 6%, respectively.

CONCLUSION

This modified conditioning protocol effectively improved outcomes of UD-PBSCT for patients with β-TM.

Sagittal alignment of the spine-pelvis-lower extremity axis in patients with severe knee osteoarthritis: A radiographic study

Objectives

Normal sagittal spine-pelvis-lower extremity alignment is crucial in humans for maintaining an ergonomic upright standing posture, and pathogenesis in any segment leads to poor balance. The present study aimed to investigate how this sagittal alignment can be affected by severe knee osteoarthritis (KOA), and whether associated changes corresponded with symptoms of lower back pain (LBP) in this patient population.

Methods

Lateral radiograph films in an upright standing position were obtained from 59 patients with severe KOA and 58 asymptomatic controls free from KOA. Sagittal alignment of the spine, pelvis, hip and proximal femur was quantified by measuring several radiographic parameters. Global balance was accessed according to the relative position of the C7 plumb line to the sacrum and femoral heads. The presence of chronic LBP was documented. Comparisons between the two groups were carried by independent samples t-tests or chi-squared test.

Results

Patients with severe KOA showed significant backward femoral inclination (FI), hip flexion, forward spinal inclination, and higher prevalence of global imbalance (27.1% versus 3.4%, p < 0.001) compared with controls. In addition, patients with FI of 10° (n = 23) showed reduced lumbar lordosis and significant forward spinal inclination compared with controls, whereas those with FI > 10° (n = 36) presented with significant pelvic anteversion and hip flexion. A total of 39 patients with KOA (66.1%) suffered from LBP. There was no significant difference in sagittal alignment between KOA patients with and without LBP.

Conclusions

The sagittal alignment of spine-pelvis-lower extremity axis was significantly influenced by severe KOA. The lumbar spine served as the primary source of compensation, while hip flexion and pelvic anteversion increased for further compensation. Changes in sagittal alignment may not be involved in the pathogenesis of LBP in this patient population.

Cite this article: W. J. Wang, F. Liu, Y.W. Zhu, M.H. Sun, Y. Qiu, W. J. Weng. Sagittal alignment of the spine-pelvis-lower extremity axis in patients with severe knee osteoarthritis: A radiographic study. Bone Joint Res 2016;5:198–205. DOI:10.1302/2046-3758.55.2000538.

Critical role of sensitized serum in rejection of allogeneic bone marrow cells

Objective: Humoral immunity has been clearly implicated in solid organ transplantation, but little is known about the relationship between humoral immunity and hematopoietic stem cell transplantation. This study was designed to investigate that relationship.

Materials and Methods: Sensitized serum was obtained from a sensitized murine model established by allogeneic splenocyte transfusion. Sensitized serum was incubated with allogeneic bone marrow cells (BMCs) in vitro and the cytotoxicity was evaluated by the complement-dependent cytotoxicity method. Mice were transplanted with allogeneic BMCs incubated with sensitized serum after lethal irradiation. The engraftment was assayed by hematopoietic recovery and chimera analysis. Moreover, mice received passive transfer of sensitized serum 1 day prior to transplantation. Mortality was scored daily after bone marrow transplantation.

Results: The in vitro experiments showed that sensitized serum was capable of impairing allogeneic BMCs through the complement-dependent cytotoxicity pathway. The animal studies showed that BMCs incubated with sensitized serum failed to rescue mice from lethal irradiation. The engraftment assay showed that the allogeneic BMCs incubated with sensitized serum were rejected with time in the recipients. Furthermore, the mice died of marrow graft rejection by transfer of sensitized serum prior to transplantation.

Conclusion: Taken together, our results indicated that sensitized serum played a critical role in graft rejection during hematopoietic stem cell transplantation.

[Effects of CD4(+)CD25(+) regulatory T cells on allogeneic hematopoietic stem cell transplantation in sensitized mice]

The aim of this study was to investigate the effects of CD4(+)CD25(+) regulatory T cells (Treg) on allogeneic hematopoietic stem cell transplantation (HSCT) in sensitized mice so as to provide experimental evidence for clinical treatment of allogeneic HSCT rejection in sensitized recipients. The BALB/c mice were divided into 5 groups: group A - mice were sensitized with injection of splenocytes; group B - mice were sensitized with splenocytes and treated with >5×10(5) Treg on day 7 before transplantation; group C - mice were sensitized with splenocytes and treated with 5×10(5) Treg on day 13 and 7 before transplantation; group D - mice were not sensitized, but treated with equal volume of PBS as control; group E - blank control. Each group had 15 mice. On day 0 of transplantation, mice in each group were irradiated lethally with 8 Gy by linear accelerator, and the bone marrow cells of C57BL/6 labeled by fluorescence staining were intravenously injected via the tail vein. The fluorescent cells in peripheral blood and organ tissue were detected by flow cytometry on different time points for homing assessment. Survival rates and hematopoietic reconstitution were also recorded and monitored. The results showed that on 12 and 24 hours after transplantation, as compared with the sensitized group, the number of fluorescence homing cells in different tissue of the applied Treg groups increased significantly and the differences were statistically significant (P < 0.05). The mice in sensitized group and blank control group all died on the 6-13 day, whereas the median survival time of mice in applied Treg once and twice were 15 days and 16 days respectively. Comparing with sensitized group, the difference was statistically significant (P < 0.001), but there was no significant difference between these two groups applied regulatory T cell (P > 0.05). It is concluded that applying Treg can induce immune tolerance of sensitized recipient to allogeneic HSCT and inhibit immune destruction and prolong the survival time, but can not induce full immune tolerance and at last sensitized mice died of rejection of hematopoietic stem cells.

[Effects of blocking co-stimulatory signals on immunotolerance rejection of sensitized recipient after hematopoietic stem cell transplantation]

This research was aimed to explore the effects of blocking B7/CD28 and CD40/CD154 co-stimulatory signals on engraftment of hematopoietic stem cell in the sensitized recipient so as to provide the experimental evidence for the treatment of sensitized recipient's immune rejection after clinical allogeneic hematopoietic stem cell transplantation (HSCT). The BALB/c mice were divided into 4 groups: (1)mice sensitized on 7 day before transplant; (2)mice were sensitized on 7 day before transplant, and injected CTLA4Ig+anti-CD154 applied; (3)normal mice injected by corresponding isotype control IgG of CTLA4Ig and anti-CD154; (4)normal blank control mice. Each group had 15 mice. On day 0, mice of each group were irradiated lethally 8 Gy by linear accelerator, and the bone marrow cells of C57BL/6 labeled by fluorescence staining were injected via the tail vein. The fluorescent cell level in peripheral blood and organ tissue at different time points were detected by flow cytometry (FCM) for homing assessment. Survival rates and hematopoietic reconstitution were also monitored and recorded. The results showed that application of CTLA4Ig anti-CD154 could promote implantation of allogeneic HSC in sensitized recipients, induce the immune tolerance, prolong their survival time and accelerate the hematopoietic reconstitution within 28 days, compared with the sensitized group. It is concluded that applying CTLA4Ig and anti-CD154 can enhance the engraftment of HSCT and induce immune tolerance in the sensitized recipient after allogeneic HSCT and accelerate the hematopoietic reconstitution.

[In vitro amplification of CD4(+) CD25(+) regulatory T cells and identification of amplified T cell immunosuppressive function]

This study was purposed to compare the effect of 3 different cell components for expanding CD4(+) CD25(+) Treg in vitro, and identify their immunosuppressive function. CD4(+) T cells, CD4(+) CD25(-)T cells and CD4(+) CD25(+)T cells were isolated from mouse splenocytes by MACS and then expanded in vitro. Phenotype of the T cell lines and expression of the FOXP3 was determined by flow cytometry. The inhibitory effect of expanded CD4(+) CD25(+) T cells on CD4(+) CD25(-)T cells was tested by MLR method. The results showed that the Treg cells from all the three groups were expanded significantly after culture for 2 weeks. In the CD4(+) T cells group, the proliferation rate was (77.8 ± 5.32) folds with a percentage of Treg cells increasing from (6.61 ± 1.00)% to (15.33 ± 1.31)%. The proliferation rate in the CD4(+) CD25(-) T cells group was (95.20 ± 7.67) folds, with the percentage of CD4(+) CD25(+) T cells raising from (0.37 ± 0.13)% to (9.84 ± 0.98)%. The proliferation rate in the CD4(+) CD25(+) T cells group was (41.20 ± 6.92) folds, the proportion of Treg cells decreased from (86.75 ± 1.25)% to (85.32 ± 1.62)%, and the expression of Foxp3 decreased from (76.92 ± 1.72)% to (75.33 ± 2.11)% during the culture, there were not significant differences in the cell purity and the expression of Foxp3, compared with pre-amplification. The inhibitory test showed that the expanded CD4(+) CD25(+) T cells could inhibit the proliferation of CD4(+) CD25(-) T cells in vitro in a cell dose-dependent manner. It is concluded that the amplification of CD4(+) CD25(+) Treg cells is successful in vitro, especially in the CD4(+) CD25(+) T cells group, the cell purity and Foxp3 gene is not obviously changes after amplification.

Pure red cell aplasia associated with cytomegalovirus and Epstein-Barr virus infection in seven cases of Chinese children

Pure red cell aplasia (PRCA) associated with cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infection is uncommon. Here, we describe the clinical features and management of seven cases of Chinese children with PRCA associated with viral infections. The patients presented with pallor on admission. Blood cell counts and marrow smears showed anemia, reticulocytopenia, and aplasia of erythroblasts. Serological investigation and DNA polymerase chain reactions for CMV were positive in four patients and those tests for EBV were positive in other three patients. All patients received blood transfusion, corticosteroids treatment, and ganciclovir injection. Two patients had a complete response and one had a partial response after the treatments. The other three patients had a complete response to second-line therapies, including high-dose methylprednisolone, cyclosporin A, and intravenous immunoglobulin. Only one patient had no response to the therapies. Our results indicated that it might be important to combine immunosuppressive drugs with an antiviral drug in the management of PRCA associated with CMV and EBV infection.

Homing and engraftment of bone marrow cells derived from different donors in a murine model of sensitization

Sensitized recipients are at a high risk of graft rejection in hematopoietic stem cell transplantation. To explore the trace of donor cells, we tried to explore homing and engraftment of bone marrow cells (BMCs) derived from different donors in a murine model of sensitization. Sensitized BALB/c mice were used as transplanted recipients, which received BMCs derived from C57BL/6 or BALB/c donors after lethal irradiation. The homing study showed that the donor cells decreased along with time in recipients of the C57BL/6 donor group, but the donor cells increased along with time in recipients of the BALB/c donor group. For the engraftment assay, all the sensitized recipients transplanted with BMCs derived from C57BL/6 donors died after lethal irradiation. In contrast, all the recipients transplanted with BMCs derived from BALB/c donors got long-term survival. Our results suggest that it is crucial to have human leukocyte antigen identical donors for sensitized recipients during hematopoietic stem cell transplantation.

Albendazole therapy for coagulation abnormality in children with eosinophilia

Hemorrhage may be associated with eosinophilia. Here, 2 pediatric cases of coagulation abnormality were reported. The 2 children presented ecchymoses and petechiae in the skin. Laboratory investigations revealed hypereosinophilia in the peripheral blood. Moreover, the activity of coagulation factor IX significantly decreased. The serum immunoglobulin G (IgG) antibody to cysticercus was positive in patient 1, and IgG antibodies to cysticercus and plerocercoid were positive in patient 2. These 2 patients received 2 courses of albendazole therapy, at 15 mg/kg/day in divided doses for 10 days for each course. They responded well to the therapy. This report indicates that patients with hypereosinophilia and bleeding abnormalities should undergo evaluation of coagulation pathways, including measurements of coagulation factors.

Autoimmune hemolytic anemia in patients with β-thalassemia major

Hemolysis is a common feature in patients with β-thalassemia major. As a result, autoimmune hemolytic anemia complicating β-thalassemia is easily overlooked. Here, the authors described the clinical features and management of 7 patients with β-thalassemia major and autoimmune hemolytic anemia. These patients had fever, cough, and tea-colored urine on admission. The laboratory investigations showed a significant drop in hemoglobin and increased serum bilirubin. Coombs' tests revealed that anti-immunoglobulin G (IgG) and anti-C3 was positive in 7 and 5 cases, respectively, whereas anti-Rh E alloantibody was positive in 3 cases. All the patients received corticosteroids treatments and blood transfusions. Patients with anti-Rh E alloantibodies also received immunoglobulin treatments. Six of the patients responded well to the management, but 1 patient developed recurrent autoimmune hemolytic anemia that required cyclosporin A treatment. All the patients remained well by following up for more than 6 months.

[Separation and amplification of CD4(+)CD25(+) regulatory T cells from sensitized mice]

The aim of this study was to separate and amplify CD4(+)CD25(+)Treg cells from splenocytes of sensitized mice. The percentage of CD4(+)CD25(+)Treg cells was detected by flow cytometry in sensitized and normal control mice. CD4(+)T, CD4(+)CD25(+)Treg and CD4(+)CD25(-) T cells were isolated from mouse splenocytes by MACS. CD4(+)CD25(+)Treg cells were expanded in vitro cultures in addition of CD3/CD28 MACSiBead and IL-2. The activity of cells was detected with 0.4 trypan blue staining. The purity of cells after sorting, the main surface marker and the level of Foxp3 were detected by flow cytometry. The results showed that CD4(+)CD25(+)Treg cell proportion was higher in sensitized mice than normal control mice (P < 0.05). The average purity of CD4(+)CD25(+)Treg cells was 87. The activity of these cells was more than 97, and the expression of Foxp3 in these cells was high. The amplification multiples achieved 42 times after 2 weeks in vitro. The percentage of CD4(+)CD25(+) regulatory T cells was 85.32, and the expression of Foxp3 decreased from (76.92 ± 1.72) to (75.33 ± 2.11) (P > 0.05). It is concluded that the sorting of CD4(+)CD25(+)Treg cells is isolated successfully by MACS without affecting the vitality of target cells. The amplification of CD4(+)CD25(+)Treg cells is successful in vitro. Expression of surface markers and Foxp3 gene does not obviously change after amplification, so that to establish a practical method to recover and enlarge the amount of CD4(+)CD25(+)Treg cells in good condition.

Evaluation of hepatic iron overload in Chinese children with β-thalassemia major

Patients with β-thalassemia major require long-term blood transfusions, resulting in hepatic iron overload. Thirty-five Chinese children with β-thalassemia major were recruited in the present studies. Hepatic iron overload was evaluated by histological grading. The relationships between hepatic iron overload and both serum biochemical markers and magnetic resonance imaging (MRI) examination were studied. The majority of the patients showed high degrees of hepatic iron overload by histological study. The degree of hepatic iron overload was correlated with serum ferritin (r = .70, P < .01), hyaluronic acid (r = .58, P = .011), and type III precollagen (r = .55, P = .035). Moreover, hepatic iron overload showed a negative correlation with liver to muscle signal intensity ratio (r = -.44, P = .012), and a positive correlation with red marrow area percentage (r = .52, P < .01). These results indicated that hepatic iron overload might be assessed by serum biochemical markers and MRI examination.

[Therapeutic effect of focal adhesion kinase gene silence on leukemia]

This study was aimed to investigate the effects of focal adhesion kinase (FAK) gene silence on leukemia cell growth, leukemogenesis and efficacy of chemotherapy drug. Vector containing lentiviral-FAK-shRNA was constructed and transfected into BCR/ABL-BaF3 leukemic cells, the cell growth and apoptosis were detected in vitro. The effect of FAK shRNA on leukemogenesis was studied in a murine model with leukemia. The apoptosis of leukemia cells and survival of leukemic mice treated by FAK shRNA combined with drug STI571 were monitored. The results showed that FAK gene expression was knocked down by lentiviral-FAK-shRNA. FAK gene silencing inhibited leukemia cell growth in vitro. The apoptosis test results showed that the percentages of Annexin V(+) cells in vector control group and FAK shRNA group were (3.46 ± 0.56)% and (7.3 ± 0.79)%, respectively, and the difference was statistically significant (p < 0.05). The mice in vector control group died at day 21 to 27, while the mice in FAK shRNA group died between day 52 and 60, and the difference was statistically significant (p < 0.05). Moreover, FAK gene silence combined with drug STI571 could enhance the apoptosis of leukemia cells and prolong survival time of leukemic mice. It is concluded that FAK gene silence inhibits leukemogenesis and promotes efficacy of chemotherapy drug on leukemia cells, indicating FAK gene silence may be considered as a new therapeutic strategy for leukemia.

[Transfusion of hematopoietic stem/progenitor cells into marrow cavity in sensitized mouse model]

The study was aimed to investigate the strategy of transfusion of allogeneic hematopoietic stem/progenitor cells (HS/PC) into marrow cavity of mouse model in sensitized transplantation. A sensitized BALB/c mouse model was established by repeated transfusion of allogeneic spleen cells. The normal BALB/c mice were used as non-sensitized controls. The non-sensitized or sensitized recipients were transplanted by transfusion of allogeneic HS/PCs into bone marrow cavity. The survival rate and hematopoietic recovery were monitored. Moreover, non-sensitized and sensitized sera were obtained and incubated with allogeneic HS/PC respectively, the percentage of dead cells was calculated using complement-dependent cytotoxicity (CDC) tests. The results showed that non-sensitized recipients got long-term survival after the transfusion of HS/PC into marrow cavity, and the hematopoietic recovery increased along with time. However, among the sensitized recipients, one mouse died of anesthetic accident, the other 9 mice (9/10) died within 2 weeks after the transfusion of HS/PC in marrow cavity, and the hematopoietic recovery declined along with time. Histopathologic analysis demonstrated that the sensitized recipients died of bone marrow failure. The results of CDC tests showed that the percentage of dead cells in non-sensitized and sensitized group was 7.80 ± 1.93% and 50.80 ± 3.12%, respectively, and the differences were statistically significant (p < 0.05), indicating sensitized sera were capable of impairing allogeneic HS/PC. It is concluded that the strategy of the marrow cavity transfusion of HS/PC can not enhance engraftment of allogeneic donor cells in sensitized recipients.

WITHDRAWN: Therapeutic efficacy of focal adhesion kinase downregulation in REH cells by RNA interference

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Panel reactive antibody in thalassemic serum inhibits proliferation and differentiation of cord blood CD34+ cells in vitro

Thalassemic children are at a high risk of graft rejection in cord blood transplantation. To investigate this possible mechanism, the authors evaluated the effect of panel reactive antibody on the growth of CD34(+) cells in vitro. On semisolid medium, CD34(+) cells derived from cord blood were incubated with thalassemic serum, and colony-forming units were counted after 10 days of culture. After incubation with serum-specific panel reactive antibody, profound decreases were found in the numbers of CFU-GM, CFU-GEMM and BFU-E compared with controls. The results indicated that serum-specific panel reactive antibody might have an apparent inhibition effect on proliferation and differentiation of cord blood CD34(+) cells.

[Establishment of sensitized animal models and their sensitization effects on engraftment of hematopoietic stem cells]

This study was aimed to establish sensitized animal models, explore the changes of immune function in these sensitized recipients, and investigate effects of sensitization on the engraftment of hematopoietic stem cells (HSCs). Different doses of spleen cells (1x10(5), 1x10(6) and 1x10(6)x2 at intervals of 7 days) from C57BL/6 were infused into BALB/c, the immunity function of sensitized models was tested by complement-dependent cytotoxicity method, mixed lymphocyte reaction and ELISA. After irradiation with gamma-ray of 60Co in dose 8 Gy, sensitized mice were transplanted 1x10(7) C57BL/6 bone marrow cells via tail vein or intra-bone marrow, and survival rate was detected daily. The results showed that different levels of donor reactive antibody were induced in all sensitized models. Comparing with normal mice, profound proliferation of spleen cells were found in groups of injected 1x10(6) and 1x10(6), continuous injections at intervals of 7 days. Sensitized model received bone marrow cells of C57BL/6 via tail vein died on day 10 to 14 after transplantation, and sensitized model mice received bone marrow cells of 1x10(6)x2 at intervals of 7 days via intra-bone marrow also died within two weeks after transplantation. It is concluded that different sensitized mouse models are established by different doses of allogeneic spleen cells infusion, the changes of immune function in sensitized mice are correlative with sensitization. Donor HSCs are rejected in sensitized models, and the engraftment can not be improved by intra-bone marrow injection.

[Experimental study on the effect of sensitized sera on engraftment of hematopoietic stem cells]

OBJECTIVE

To evaluate the effect of sensitized sera on engraftment of hematopoietic stem cells (HSCs) and its mechanism.

METHODS

Bone marrow cells (BMCs) from C57BL/6 mice were incubated with sensitized sera (group I) or normal sera (group II), and then washed and transplanted into irradiated BALB/c mice. The survival analysis and engraftment evaluation of the recipients were observed. The incubated BMCs were bound with goat anti mouse IgG for and labeled with Annexin V for apoptosis detection.

RESULTS

Seven out of ten recipient mice in group I died of bone marrow failure at day 10 after transplantation, while all of those in group II were long-term survived. Engraftment assay showed recipients blood count and BMCs progressively decreased along with time passing in group I; in addition, the chimeric percentage of donor cells progressively decreased as well. The percentage of BMCs binding with goat anti mouse IgG in group I or group II were (90.3 +/- 5.1)% and (5.2 +/- 2.4)%, respectively, and the difference was statistically significant (P < 0.01). However, no significant difference was found in the apoptosis detection between the two groups (P > 0.05).

CONCLUSION

The engraftment capacity of HSCs is significantly impaired by sensitized sera, the antibodies in sensitized sera may bind to antigens expressed on HSCs but do not induce apoptosis.

Marrow graft rejection by repeated transfusions of allogeneic donor spleen cells

Many hematological diseases require long-term transfusion support, which causes production of donor-reactive antibodies in sensitized recipients. Sensitized patients are at an increased risk for graft rejection when they undergo allogeneic hematopoietic stem cell transplantation (allo-HSCT). Here, we established a highly sensitized murine model to investigate the mechanism of donor graft rejection. After BALB/c mice were repeatedly transfused with allogeneic spleen cells from C57BL/6 mice, there was a significant increase in complement-dependent cytotoxicity in the serum of sensitized mice. For transplantation, 1 x 10(7) bone marrow cells (BMCs) from C57BL/6 mice were injected into lethally irradiated recipient BALB/c mice. Sensitized mice died between 12 and 15 days post-transplantation, while non-sensitized mice remained alive after 28 days. The hematopoietic recovery rate declined over time in sensitized recipients. The homing trace assay showed a rapid disappearance of donor BMCs in the spleen and bone marrow of sensitized recipients. In addition, the recipient cells and antibodies in the sensitized serum were capable of inducing high level of cell- and complement-mediated cytotoxicity to the donor graft. Our finding may explain the impaired hematopoietic stem cell homing and poor hematopoietic engraftment observed in highly sensitized allo-HSCT patients.