β-Thalassemia is an autosomal recessive genetic disorder caused by defects in the synthesis of the β-globin chains. Due to ineffective erythropoiesis and premature destruction of red blood cells, patients suffer from anemia, iron overload, organ damage, and impaired immune system. The impairment of the immune system is mainly due to the increase in the levels of reactive oxygen species (ROS) caused by iron overload, which induces DNA oxidation and leads to DNA damage. The treatment strategies for β-thalassemia mainly include gene therapy and allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, iron overload in patients cannot be eliminated promptly after gene therapy and transplantation. Therefore, even if allo-HSCT is performed, the patient's hematopoietic function may still be impaired. Iron chelators and antioxidants have been proven to effectively intervene in the immune damage caused by iron overload. This article aims to review the research progress on the effects of iron overload on the immune system in patients with β-thalassemia, and provides relevant treatment recommendations for immune recovery.
Humans ; beta-Thalassemia/immunology* ; Iron Overload/therapy* ; Immune System ; Hematopoietic Stem Cell Transplantation

OBJECTIVES: To investigate the clinical characteristics of cytokine release syndrome (CRS) in children with thalassemia major (TM) after haploidentical hematopoietic stem cell transplantation (haplo-HSCT) and their prognosis. METHODS: A retrospective analysis was performed for the clinical data of 280 children with TM who underwent haplo-HSCT in the Department of Hematology and Oncology, Shenzhen Children's Hospital, from January 2019 to December 2021. According to the CRS criteria, they were divided into two groups: CRS grade <3 (260 children) and CRS grade ≥3 (20 children). The children with TM were analyzed in terms of clinical characteristics of CRS after haplo-HSCT and their prognosis. RESULTS: There were significant differences between the two groups in neutrophil engraftment time, clinical manifestations of CRS, and the rate of use of glucocorticoids within 4 days after haplo-HSCT (P=0.012, 0.040, and <0.001 respectively). For the CRS grade <3 group, the incidence rate of acute graft-versus-host disease (aGVHD) was 9.6% within 3 months after transplantation, while no aGVHD was observed in the CRS grade ≥3 group within 3 months after transplantation, but there was no significant difference in the incidence of aGVHD between the two groups within 3 months after transplantation (P=0.146). No transplantation-related death was observed in either group within 3 months after haplo-HSCT. CONCLUSIONS The children with CRS grade≥3 have an early neutrophil engraftment time, severe and diverse clinical manifestations of CRS, and a high rate of use of glucocorticoids within 4 days after haplo-HSCT. For these children, early use of low-dose glucocorticoids after transplantation may alleviate CRS response and reduce the incidence of aGVHD, thereby bringing more benefits to the children. CRS after haplo-HSCT has no significant impact on the prognosis of the children.
Humans ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Male ; Female ; Child ; Retrospective Studies ; Child, Preschool ; Graft vs Host Disease/prevention & control* ; beta-Thalassemia/therapy* ; Adolescent ; Cytokine Release Syndrome/etiology* ; Transplantation, Haploidentical/adverse effects* ; Infant ; Prognosis ; Glucocorticoids/therapeutic use*

OBJECTIVES: To explore the risk factors for hemorrhagic cystitis (HC) in children with β-thalassemia major (TM) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: A retrospective analysis was conducted on clinical data of 247 children with TM who underwent allo-HSCT at Shenzhen Children's Hospital from January 2021 to November 2022. The children were divided into an HC group (91 cases) and a non-HC group (156 cases) based on whether HC occurred after operation. Multivariable logistic regression analysis was used to explore the risk factors for HC, and the receiver operating characteristic curve was used to analyze the predictive efficacy of related factors for HC. RESULTS: Among the 247 TM patients who underwent allo-HSCT, the incidence of HC was 36.8% (91/247). Univariate analysis showed age, incompatible blood types between donors and recipients, occurrence of acute graft-versus-host disease (aGVHD), positive urine BK virus deoxyribonucleic acid (BKV-DNA), and ≥2 viral infections were associated with the development of HC after allo-HSCT (P<0.05). Multivariable analysis revealed that incompatible blood types between donors and recipients (OR=3.171, 95%CI: 1.538-6.539), occurrence of aGVHD (OR=2.581, 95%CI: 1.125-5.918), and positive urine BKV-DNA (OR=21.878, 95%CI: 9.633-49.687) were independent risk factors for HC in children with TM who underwent allo-HSCT. The receiver operating characteristic curve analysis showed that positive urine BKV-DNA alone or in combination with two other risk factors (occurrence of aGVHD, incompatible blood types between donors and recipients) had a certain accuracy in predicting the development of HC after allo-HSCT (area under the curve >0.8, P<0.05). CONCLUSIONS Incompatible blood types between donors and recipients, occurrence of aGVHD, and positive urine BKV-DNA are risk factors for HC after allo-HSCT in children with TM. Regular monitoring of urine BKV-DNA has a positive significance for early diagnosis and treatment of HC.
Humans ; Child ; Retrospective Studies ; beta-Thalassemia/therapy* ; Cystitis/epidemiology* ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Risk Factors ; Hemorrhage/etiology* ; Graft vs Host Disease/complications* ; DNA ; Polyomavirus Infections/epidemiology*

OBJECTIVE: To investigate the difference of therapeutic effects on children with thalassemia at different age after hematopoietic stem cell transplantation. METHODS: The clinical data of children with thalassemia treated in our hospital were retrospectively analyzed. The children were divided into 2-5 years old group and 6-12 years old group. The success rate of implantation, transplant-related mortality, GVHD incidence, and other transplant-related complications, as well as thalassemia-free survival (TFS) were compared between the two groups. RESULTS: The incidence of GVHD, hemorrhagic cystitis and severe oral mucositis after transplantation in the 2-5 years old group were significantly lower than those in the 6-12 years old group, while there was no statistically significant difference in the TFS between the two groups. CONCLUSION Children in the low age (2-5 years old) group show fewer complications and higher quality of life after transplantation, therefore, stem cell transplantation at 2-5 years old is more conducive to rehabilitation of the children with thalassemia.
Child ; Child, Preschool ; Graft vs Host Disease/complications* ; Hematopoietic Stem Cell Transplantation ; Humans ; Quality of Life ; Retrospective Studies ; Thalassemia/therapy* ; beta-Thalassemia/therapy*

β-thalassemia (β-thal) is one of the most common genetic diseases in the world, its pathogenesis is extremely complex and there is no effective treatment at present. The birth of children with moderate and severe β-thal brings economic pressure to families, social medical and health services. Long noncoding RNA (lncRNA) is a type of noncoding protein transcripts with a length greater than 200 nucleotides, which is involved in a variety of biological processes, such as cell proliferation, differentiation and chromosome variation and plays an important role in the epigenetic and post-transcriptional regulation of genes. It has potential value in the diagnosis, prevention and treatment of β-thal. LncRNA possesses the characteristics such as tissue specificity, cell specificity, developmental stage specificity, space-time specificity and disease specificity, and its complex interaction network has become a challenge to translate research results into clinical practice. Taking lncRNA as an entry point, in-depth understanding of the function of lncRNA in β-thal and explanation of its related regulatory mechanisms will provide theoretical basis for targeting treatment of β-thal, which can improve the diagnosis and treatment of β-thal.
Cell Differentiation ; Child ; Gene Expression Regulation ; Humans ; RNA, Long Noncoding/genetics* ; beta-Thalassemia/therapy*

OBJECTIVE: To provide a research basis for a safe and effective cell therapy for β-thalassemia through optimization of HS4 region of the third generation lentiviral vector for stable expression of β-globin. METHODS: The human β-globin HS4 region in the third generation lentiviral expression vector was optimized to construct the lenti-HBB, and the transcription and translation of β-globin gene were analyzed by RT-PCR and Western blot after the transduction of lenti-HBB in MEL cell line. Furthermore, the erythroid differentiation of CD34⁺ cells which were transduced lentiviral virus carrying human β-globin from normal human umbilical cord blood cells and peripheral blood cells of patients with β-thalassemia major were confirmed by colony formation assay, cell smear assay and flow cytometry. The safety and effectiveness of the optimized lenti-HBB were verified by NSG mouse in vivo test. RESULTS: The human β-globin was expressed stably in the MEL cells, and CD34⁺ cells from health umbilical cord blood as well as PBMC from patient with β-thalassemia major transduced with lenti-HBB could be differentiated to mature red blood cells. The β-globin expression and differentiation in CD34⁺ cells were demonstrated successfully in the NSG mouse for about 35 months after post-transplant. CONCLUSION Stable β-globin expression through the optimization of HS4 from CD34⁺ in the third generation lentiviral vector is safe and effective for patients with severe β-thalassemia and other β-globin abnormal diseases.
Animals ; Genetic Therapy ; Genetic Vectors ; Humans ; Lentivirus/genetics* ; Leukocytes, Mononuclear ; Mice ; beta-Globins/genetics* ; beta-Thalassemia/therapy*

Objective: To investigate the characteristics, risk factors and outcomes of thalassemia major (TM) children with pericardial effusion (PE) after allo-geneic hematopoietic stem cell transplantation (allo-HSCT). Methods: Clinical data of 446 TM children received allo-HSCT at Shenzhen Children's Hospital between January 2012 and December 2020 were analyzed retrospectively. Patients were divided into PE and non-PE group according to the occurrence of PE. Chi-square tests were used to investigate the risk factors that were associated with the development of PE. Kaplan-Meier method was used for survival analysis of the 2 groups. Results: Twenty-five out of 446 patients (5.6%) developed PE at a time of 75.0 (66.5, 112.5) days after allo-HSCT. Among these patients, 22 cases (88.0%) had PE within 6 months after allo-HSCT and 19 patients (76.0%) had PE within 100 days after allo-HSCT. The diagnoses of PE were confirmed using echocardiography. Pericardial tamponade was observed in only 1 patient, who later undergone emergency pericardiocentesis. The rest of patients received conservative managements alone. PE disappeared in all patients after treatment. Risk factors that were associated with the development of PE after allo-HSCT included the gender of patients, the type of transplantation, the number of mononuclear cells (MNC) infuse, pulmonary infection after HSCT and transplantation associated thrombotic microangiopathy (TA-TMA) (χ²=3.99, 10.20, 14.18, 36.24, 15.03, all P<0.05). In 239 patients that received haploidentical HSCT, the development of PE was associated with the gender of patients, pulmonary infection after HSCT and TA-TMA (χ²=4.48, 20.89, 12.70, all P<0.05). The overall survival rates of PE and non-PE groups were 96.0% (24/25) and 98.6% (415/421). The development of PE was not associated with the overall survival of TM children after allo-HSCT (χ²=1.73, P=0.188). Conclusions: PE mainly develop within 100 days after allo-HSCT in pediatric TM recipients. Haploidentical grafts, female gender, pulmonary infection after HSCT and TA-TMA are the main risk factors associated with PE development after transplant. However, the presence of PE don't have a significant impact on the outcomes of pediatric TM patients after allo-HSCT.
Child ; Female ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Humans ; Pericardial Effusion/etiology* ; Retrospective Studies ; Risk Factors ; Thrombotic Microangiopathies/complications* ; beta-Thalassemia/therapy*

β-thalassemia is a monogenetic inherited hemolytic anemia, which results in a series of pathophysiological changes due to partial or complete inhibition of the synthesis of β-globin chain. The curative therapy for this disease is to reconstitute hematopoiesis, and transplantation with genetically modified autologous hematopoietic stem cells can avoid the major difficulties of traditional allogeneic hematopoietic stem cell transplantation，such as HLA matching and immune rejection. β-thalassemia gene therapy strategies mainly include gene integration and genome editing. The former relies on the development of lentiviral vectors and adds a fully functional HBB gene to the chromosome; the latter rapidly develops with the research of specific nuclease which can repair the HBB gene in situ. In this review, the latest progress of the two strategies in gene therapy of β-thalassemia is summarized.
Gene Editing ; Genetic Therapy ; Genetic Vectors ; Humans ; beta-Globins/genetics* ; beta-Thalassemia/therapy*

BACKGROUND: Iron overload is a risk factor affecting all patients with thalassemia intermedia (TI). We aimed to determine whether there is a relationship of serum ferritin (SF) and alanine aminotransferase (ALT) with liver iron concentration (LIC) determined by R2 magnetic resonance imaging (R2-MRI), to estimate the most relevant degree of iron overload and best time to chelate in patients with TI. METHODS: In this cross-sectional study, 119 patients with TI (mean age years) were randomly selected and compared with 120 patients who had a diagnosis of thalassemia major (TM). Correlations of LIC, as determined by R2-MRI, with SF and ALT levels, were assessed in all participants. A P-value < 0.05 was considered statistically significant. RESULTS: SF and LIC levels were lower in patients with TI than in those with TM; only ferritin values were significant. We found a statistically significant relationship between SF and LIC, with cut-off estimates of SF in patients with TI who had splenectomy and those who entered puberty spontaneously (916 and 940 ng/mL, respectively) with LIC >5 mg Fe/g dry weight (P < 0.0001). A significant relationship was also found for patients with TI who had elevated ALT level (63.5 U/L), of 3.15 times the upper normal laboratory limit, using a cut-off for LIC ≥5 mg Fe/g dry weight. CONCLUSION: We determined the cut-off values for ALT and SF indicating the best time to start iron chelation therapy in patients with TI, and found significant correlations among iron overload, SF, and ALT.
Adolescent ; Alanine Transaminase ; beta-Thalassemia* ; Chelation Therapy ; Cross-Sectional Studies ; Diagnosis ; Ferritins* ; Humans ; Iron Overload ; Iron* ; Liver* ; Magnetic Resonance Imaging ; Puberty ; Risk Factors ; Splenectomy ; Thalassemia*

β-Thalassemia is a global health issue, caused by mutations in the HBB gene. Among these mutations, HBB -28 (A>G) mutations is one of the three most common mutations in China and Southeast Asia patients with β-thalassemia. Correcting this mutation in human embryos may prevent the disease being passed onto future generations and cure anemia. Here we report the first study using base editor (BE) system to correct disease mutant in human embryos. Firstly, we produced a 293T cell line with an exogenous HBB -28 (A>G) mutant fragment for gRNAs and targeting efficiency evaluation. Then we collected primary skin fibroblast cells from a β-thalassemia patient with HBB -28 (A>G) homozygous mutation. Data showed that base editor could precisely correct HBB -28 (A>G) mutation in the patient's primary cells. To model homozygous mutation disease embryos, we constructed nuclear transfer embryos by fusing the lymphocyte or skin fibroblast cells with enucleated in vitro matured (IVM) oocytes. Notably, the gene correction efficiency was over 23.0% in these embryos by base editor. Although these embryos were still mosaic, the percentage of repaired blastomeres was over 20.0%. In addition, we found that base editor variants, with narrowed deamination window, could promote G-to-A conversion at HBB -28 site precisely in human embryos. Collectively, this study demonstrated the feasibility of curing genetic disease in human somatic cells and embryos by base editor system.
APOBEC-1 Deaminase ; genetics ; metabolism ; Base Sequence ; Blastomeres ; cytology ; metabolism ; CRISPR-Cas Systems ; Embryo, Mammalian ; metabolism ; pathology ; Female ; Fibroblasts ; metabolism ; pathology ; Gene Editing ; methods ; Gene Expression ; HEK293 Cells ; Heterozygote ; Homozygote ; Humans ; Point Mutation ; Primary Cell Culture ; Promoter Regions, Genetic ; Sequence Analysis, DNA ; beta-Globins ; genetics ; metabolism ; beta-Thalassemia ; genetics ; metabolism ; pathology ; therapy