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.

[Preliminary Study of Chidamide Combined with Hematopoietic Stem Cell Transplantation in the Treatment of Childhood Acute T-Lymphoblastic Leukemia].

OBJECTIVE: To investigate the efficacy and safety of combination chidamide and hematopoietic stem cell transplantation (HSCT) in the treatment of childhood acute T lymphoblastic leukemia (T-ALL). METHODS: Seven children with acute T lymphoblastic leukemia received hematopoietic stem cell transplantation in SUN Yat-Sen Memorial Hospital of SUN Yat-Sen University were selected. 7 cases of T-ALL were divided into 2 groups: HSCT plus chidamide-treated group (4 cases) and traditional HSCT-treated group (3 cases) as control. The incidence of GVHD and other related complications, as well as implantation, recurrence and survival were compared between the two groups, and the side effects of chidamide were observed. All the patients were follow-up until January 2019. RESULTS: All the 7 patients were alive and, there was no difference in the incidence of acute GVHD between the HSCT plus chidamides treated group and the traditional HSCT-treated group. The implantation rate of HSCT was 100%, and there were no recurrence occurred. During the application of chidamide, 3 cases showed adverse reactions, of which 2 cases had adverse reactions of grade 3 or higher, and 2 cases were hematological adverse reactions (neutropenia, thrombocytopenia), other adverse reactions were non-hematologic adverse reactions (transaminase elevation, fatigue, nausea, vomiting), there were no serious adverse reactions occurred. In the HSCT plus chidamide-treated group, 2 cases were found that mature lymphocytes were not expressed by tumors, during examing for minimal redidaul disease (MRD). Compared with the immunophenotype and TCR rearrangement at first diagnosis, the results did not support the source of residual T-ALL tumor cells. During the review of MRD, it was found that the abnormal T cells showed an increasing trend, indicating that chidamide might induce leukemia cell differentiation through some pathways. CONCLUSION: Hematopoietic stem cell transplantation is still an effective method to cure children's T-ALL. In some cases, abnormal T-cell nonclonal amplification occurs during the application of chidamide, and the children with T-ALL can tolerable adverse reactions of chidamide.

[Efficacy of BMMSCs on aGVHD and Its Correlation with SerumInflammatory Cytokines in Pediatric Patients with Severe Refractory Acute Graft-Versus-Host Disease].

OBJECTIVE: To investigate the efficacy of bone marrow mesenchymal stem cells (BMMSC) on children with refractory graft-versus-host disease (GVHD) and to judge the efficacy of BMMSC by dynamically monitoring the changes of cytokines in children with GVHD before and after infusion of BMMSC, so as to provide a theoretical basis for clarifying the mechanism of BMMSC. METHODS: 17 children with refractory aGVHD including 7 of grade II, 6 cases of grade III and 4 cases of grade IV after allo-HSCT were enrolled. All the children with aGVHD, who received routine immunosuppressive therapy, but the state of disease not improved, were treated with immunosuppressive drugs combined with BMMSC infusion. Study endpoints included safety of BMMSC infusion, response to BMMSC, and overall response of aGVHD. The serum levels of IL-2α, IL-6, IL-10, IL-8 and TNF-α in aGVHD patients were measured by chemiluminescence before infusion of BMMSCs and Day 7, Day 14 after infusion of BMMSCs. RESULTS: The cumulative median dose of BMMSCs was 5.5 (3.4-11.1) × 106/kg for average of 3.7 times, and the median time of 16.5 (4-95) days for the first infusion of MSCs. In 17 cases of refractory GVHD, 14 responded to treatment, whereas 3 patients failed. The total effective rate was 82.4% and no adverse reactions occurred. Of the 14 survived cases (82.4%), the median follow-up time was 944 (559-1245) days from the first infusion of MSCs. The levels of TNF-α in children with grade II, III and IV GVHD before treatment were 9.5±4.3 pg/ml, 16.3±10.9 pg/ml and 35.8±21.2 pg/ml respectively. The difference between grade II and IV, III and IV was statistically significant (P<0.05). Compared with the ineffective group of BMMSC infusion, the serum TNF-αlevel in the BMMSCs treatment effective group was 10.8±5.6 pg/ml vs 40.6±14.8 pg/ml (t=-3.901, P<0.05) before treatment. In the effective group of BMMSCs infusion, IL-10 20±17.4 pg/ml of day 14 was significantly higher than that 7.3±3.1 pg/ml before the treatment (t=-2.850, P<0.05), while , the serum levels of IL-2α, IL-6, IL-8, TNF-α were not statistically significantly different (P＞0.05). CONCLUSION: The infusion of BMMSC is safe and effective in the treatment of refractory GVHD in children. TNF-αlevel relates with the severity of GVHD. BMMSC may play an anti-GVHD role by up regulating the level of cytokine IL-10 in vivo.

Reassessment of the Risk-stratified GD-2008 ALL Protocol.

OBJECTIVE: To explore the clinical features and outcomes of relapsed childhood acute lymphoblastic leukemia (ALL) at our center, achieve the early detection of risk factors for recurrence and assess the risk-stratified Guangdong (GD)-2008 ALL protocol. MATERIALS AND METHODS: In total, 59 Chinese childhood ALL patients treated with the GD-2008 ALL protocol who relapsed between July 2008 and March 2015 were enrolled in this study. Their clinical features and outcomes were retrospectively analyzed and compared with those of 218 patients who achieved continuous complete remission. RESULTS: Of the 285 study participants, 8 died of treatment-related infections or other complications before remission, 218 achieved continuous complete remission, and 59 patients relapsed, yielding a relapse rate of 20.7%. The number of relapsed patients in the standard-risk, intermediate-risk, and high-risk groups were 15 (17.0%), 27 (19.7%), and 17 (32.7%), respectively. Risk factors included age 10 years and above at first diagnosis, white blood cell (WBC) count ≥50×10/L, poor prednisone response, failure to achieve bone marrow complete remission at day 15 of induction chemotherapy. High-risk stratification and a high level (≥0.1%) of minimal residual disease at day 33 were the risk factors for relapse. Multivariate analysis showed that a high WBC at first diagnosis was an independent risk factor for relapse (P=0.000). CONCLUSION: For the GD-2008 ALL risk stratification based on age and initial WBC, 10 years of age and WBC 50×10/L can be used as cut-offs. Patients at high risk benefited from the GD-2008 ALL protocol. In addition, the impact of minimal residual disease on prognosis should be considered.

Indoleamine 2,3-dioxygenase and inducible nitric oxide synthase mediate immune tolerance induced by CTLA4Ig and anti-CD154 hematopoietic stem cell transplantation in a sensitized mouse model.

Cytotoxic T-lymphocyte-associated protein 4 immunoglobulin (CTLA4Ig) and anti-cluster of differentiation 154 (anti-CD154) are able to block B7/CD28 and CD40/CD154 co-stimulatory signals in T cells. Additionally, they promote hematopoietic stem cell transplantation (HSCT) in sensitized recipients and are able to induce immune tolerance and complete hematopoietic reconstitution. Indoleamine 2, 3-dioxygenase (IDO) and nitric oxide (NO) have been implicated in T cell immune tolerance. The aim of the present report was to study the in vivo tolerogenic mechanisms by which CTLA4Ig and anti-CD154 induce transplantation survival in mice receiving HSCT. BALB/c mice were sensitized via splenocyte transfusion and pretreated with CTLA4Ig plus anti-CD154 on day-7. IDO and inducible nitric oxide synthase (iNOS) inhibitors were applied on days-7 to 0 and the mice were divided into 4 groups (n=10) and injected with IDO every other day. The mice were sacrificed on day 0, and splenocytes were separated to identify CD11c+ antigen-presenting cells, which were subsequently assessed for IDO expression and activity. The concentration of NO was tested using a nitrate reductase kit. Following the acceptance of allogeneic HSCT, mice were tested for homing and engraftment, as well as survival rate. Application of the IDO inhibitor increased the concentration of NO, whereas a decrease in NO resulted in increased IDO activity. Immune tolerance was abrogated in the presence of both IDO and iNOS inhibitors, whereas this effect was not observed with either compound alone. CTLA4Ig and anti-CD154 may induce immune tolerance by affecting the activity of IDO and iNOS. This tolerance was abrogated in the presence of both IDO and iNOS inhibitors. A cross-regulatory pathway was observed between the IDO and NO pathways, in which the inhibition of IDO stimulated the iNOS pathway and vice versa.

[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.