Infusion of autologous retrodifferentiated stem cells into patients with beta-thalassemia

Alternative options for DNA-based experimental therapy of β-thalassemia

INTRODUCTION

Beta-thalassemias are caused by more than 200 mutations of the β-globin gene, leading to low or absent production of adult hemoglobin. Achievements have been made with innovative therapeutic strategies for β-thalassemias, based on research conducted at the levels of gene structure, transcription, mRNA processing and protein synthesis.

AREAS COVERED

The objective of this review is to describe the development of therapeutic strategies employing viral and non-viral DNA-based approaches for treatment of β-thalassemia.

EXPERT OPINION

Modification of β-globin gene expression in β-thalassemia cells has been achieved by gene therapy, correction of the mutated β-globin gene and RNA repair. In addition, cellular therapy has been proposed for β-thalassemia, including reprogramming of somatic cells to generate induced pluripotent stem cells to be genetically corrected. Based on the concept that increased production of fetal hemoglobin (HbF) is beneficial in β-thalassemia, DNA-based approaches to increase HbF production have been optimized, including treatment of target cells with lentiviral vectors carrying γ-globin genes. Finally, DNA-based targeting of α-globin gene expression has been applied to reduce the excess of α-globin production by β-thalassemia cells, one of the major causes of the clinical phenotype.

A novel autologous stem cell procedure for the treatment of aplastic anaemia using reprogrammed mature adult cells: a pilot study

BACKGROUND & OBJECTIVES

Aplastic anaemia is a life threatening rare bone marrow failure disorder. The underlying haematopoietic cellular deficit leads to haemorrhage, infection and severe anaemia. The treatment of choice for this haematological condition is allogeneic bone marrow transplantation from fully matched HLA sibling. Though this procedure is curative in the majority of young patients with aplastic anaemia, extending this benefit to older patients or those lacking a family donor remains a major challenge. Herein, the safety and efficacy of infusing autologous retrodifferentiated haematopoietic stem cells (RHSC) into four patients with aplastic anaemia without the use of any pre- or post-conditioning regimen including immunosuppression is described.

METHODS

Un-mobilized, mononuclear cells were harvested from four patients with acquired aplastic anaemia by aphaeresis. Mononuclear cells of patients were cultured with purified monoclonal antibody against the monomorphic regions of the beta chain of MHC class II antigens (Clone CR3/43) for 3 h, to obtain autologous RHSC. Autologous RHSC were washed and infused into the four patients without the use of any pre- or post-conditioning regimen. Thereafter, the efficacy (engraftment) of autologous RHSC was assessed in these patients.

RESULTS

Following single infusion of the autologous RHSC, two of the four patients with aplastic anaemia become transfusion independent for more than seven years. Karyotyping and G-banding analysis prior and post-procedure in all patients remained the same.

INTERPRETATION & CONCLUSIONS

The findings of this pilot study demonstrated the functional utility of reprogrammed fully differentiated adult cells into pluripotent stem cells with extensive repopulation potentials in a human setting and without any pre- or post-conditioning regimen, including immunosuppression. This autologous approach of stem cell creation may broaden the curative potentials of stem cell therapy to a wider population of patients with aplastic anaemia, including many patients suffering from other haematological and non-haematological disorders.