scholarly journals Efficient transduction of pigtailed macaque hematopoietic repopulating cells with HIV-based lentiviral vectors

Blood ◽  
2008 ◽  
Vol 111 (12) ◽  
pp. 5537-5543 ◽  
Author(s):  
Grant D. Trobridge ◽  
Brian C. Beard ◽  
Christina Gooch ◽  
Martin Wohlfahrt ◽  
Philip Olsen ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Ex Vivo ◽  
High Titer ◽  
Lentiviral Vectors ◽  
Macaca Nemestrina ◽  
Hematopoietic Stem ◽  
Host Restriction ◽  
Vector Integration ◽  
High Level

AbstractLentiviral vectors are attractive for hematopoietic stem cell (HSC) gene therapy because they do not require mitosis for nuclear entry, they efficiently transduce hematopoietic repopulating cells, and self-inactivating (SIN) designs can be produced at high titer. Experiments to evaluate HIV-derived lentiviral vectors in nonhuman primates prior to clinical trials have been hampered by low transduction frequencies due in part to host restriction by TRIM5α. We have established conditions for efficient transduction of pigtailed macaque (Macaca nemestrina) long-term repopulating cells using VSV-G–pseudotyped HIV-based lentiviral vectors. Stable, long-term, high-level gene marking was observed in 3 macaques using relatively low MOIs (5-10) in a 48-hour ex vivo transduction protocol. All animals studied had rapid neutrophil engraftment with a median of 10.3 days to a count greater than 0.5 × 109/L (500/μL). Expression was detected in all lineages, with long-term marking levels in granulocytes at approximately 20% to 30%, and in lymphocytes at approximately 12% to 23%. All animals had polyclonal engraftment as determined by analysis of vector integration sites. These data suggest that lentiviral vectors should be highly effective for HSC gene therapy, particularly for diseases in which maintaining the engraftment potential of stem cells using short-term ex vivo transduction protocols is critical.

scholarly journals Long-Term Transfer and Expression of the Human β-Globin Gene in a Mouse Transplant Model

Blood ◽  
1997 ◽  
Vol 90 (9) ◽  
pp. 3414-3422 ◽  
Author(s):  
Harry Raftopoulos ◽  
Maureen Ward ◽  
Philippe Leboulch ◽  
Arthur Bank
Keyword(s):  
Gene Therapy ◽  
Gene Transfer ◽  
Bone Marrow Cells ◽  
High Titer ◽  
Globin Gene ◽  
High Level Expression ◽  
Hematopoietic Stem ◽  
High Level ◽  
Transplant Model

Abstract Somatic gene therapy of hemoglobinopathies depends initially on the demonstration of safe, efficient gene transfer and long-term, high-level expression of the transferred human β-globin gene in animal models. We have used a β-globin gene/β-locus control region retroviral vector containing several modifications to optimize gene transfer and expression in a mouse transplant model. In this report we show that transplantation of β-globin–transduced hematopoietic cells into lethally irradiated mice leads to the continued presence of the gene up to 8 months posttransplantation. The transferred human β-globin gene is detected in 3 of 5 mice surviving long term (>4 months) transplanted with bone marrow cells transduced with high-titer virus. Southern blotting confirms the presence of the unrearranged 5.1-kb human β-globin gene-containing provirus in 2 of these mice. In addition, long-term expression of the transferred gene is seen in 2 mice at levels of 5% and 20% that of endogenous murine β-globin at 6 and 8 months posttransplantation. We further document stem cell transduction by the successful transfer and high-level expression of the human β-globin gene from mice transduced 9 months earlier into irradiated secondary recipient mice. These results demonstrate high-level, long-term somatic human β-globin gene transfer into the hematopoietic stem cells of an animal for the first time, and suggest the potential feasibility of a retroviral gene therapy approach to sickle cell disease and the β thalassemias.

Prolonged High-Level Detection of Retrovirally Marked Hematopoietic Cells in Nonhuman Primates after Transduction of CD34+ Progenitors Using Clinically Feasible Methods.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1137-1137
Author(s):  
Tong Wu ◽  
Hyeoung Joon Kim ◽  
Stephanie E. Sellers ◽  
Kristin E. Meade ◽  
Brian A. Agricola ◽  
...  
Keyword(s):  
Stem Cell ◽  
Gene Transfer ◽  
Nonhuman Primates ◽  
Ex Vivo ◽  
Hematopoietic Stem ◽  
Retroviral Transduction ◽  
Colony Pcr ◽  
High Level

Abstract Low-level retroviral transduction and engraftment of hematopoietic long-term repopulating cells in large animals and humans remain primary obstacles to the successful application of hematopoietic stem cell(HSC) gene transfer in humans. Recent studies have reported improved efficiency by including stromal cells(STR), or the fibronectin fragment CH-296(FN), and various cytokines such as flt3 ligand(FLT) during ex vivo culture and transduction in nonhuman primates. In this work, we extend our studies using the rhesus competitive repopulation model to further explore optimal and transduction in the presence of either preformed autologous STR or immobilized FN. Long-term clinically relevant gene marking levels in multiple hematopoietic lineages from both conditions were demonstrated in vivo by semiquantitative PCR, colony PCR, and genomic Southern blotting, suggesting that FN could replace STR in ex vivo transduction protocols. Second, we compared transduction on FN in the presence of IL-3, IL-6, stem cell factor(SCF), and FLT(our best cytokine combination in prior studies)with a combination of megakaryocyte growth and development factor(MGDF), SCF, and FLT. Gene marking levels were equivalent in these animals, with no significant effect on retroviral gene transfer efficiency assessed in vivo by the replacement of IL-3 and IL-6 with MGDF. Our results indicate that SCF/G-CSF-mobilized PB CD34+ cells are transduced with equivalent efficiency in the presence of either STR or FN, with stable long-term marking of multiple lineages at levels of 10–15% and transient marking as high as 54%. These results represent an advance in the field of HSC gene transfer using methods easily applied in the clinical setting.

Development of Megakaryocyte-Specific Lentiviral Vectors for Gene Therapy of Platelet Disorders.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 5143-5143
Author(s):  
Liesbeth De Waele ◽  
Kathleen Freson ◽  
Chantal Thys ◽  
Christel Van Geet ◽  
Désiré Collen ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Transgene Expression ◽  
Ex Vivo ◽  
Phosphoglycerate Kinase ◽  
Lentiviral Vectors ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Platelet Disorders

Abstract The prevalence of congenital platelet disorders has not been established but for some life-threatening bleeding disorders the current therapies are not adequate, justifying the development of alternative strategies as gene therapy. In the case of platelet dysfunction and thrombocytopenia as described for GATA1 deficiency, potentially lethal internal bleedings can occur. The objective of the study is to develop improved lentiviral vectors for megakaryocyte(MK)-specific long term gene expression by ex vivo transduction of hematopoietic stem cells (HSC) to ultimately use for congenital thrombopathies as GATA1 deficiency. Self-inactivating lentiviral vectors were constructed expressing GFP driven by the murine (m) or human (h) GPIIb promoter. These promoters contain multiple Ets and GATA binding sites directing MK-specificity. To evaluate the cell lineage-specificity and transgene expression potential of the vectors, murine Sca1+ and human CD34+ HSC were transduced in vitro with Lenti-hGPIIb-GFP and Lenti-mGPIIb-GFP vectors. After transduction the HSC were induced to differentiate in vitro along the MK and non-MK lineages. The mGPIIb and hGPIIb promoters drove GFP expression at overall higher levels (20% in murine cells and 25% in human cells) than the ubiquitous CMV (cytomegalovirus) or PGK (phosphoglycerate kinase) promoters, and this exclusively in the MK lineage. Interestingly, in both human and murine HSC the hGPIIb promoter with an extra RUNX and GATA binding site, was more potent in the MK lineage compared to the mGPIIb promoter. Since FLI1 and GATA1 are the main transcription factors regulating GPIIb expression, we tested the Lenti-hGPIIb-GFP construct in GATA1 deficient HSC and obtained comparable transduction efficiencies as for wild-type HSC. To assess the MK-specificity of the lentiviral vectors in vivo, we transplanted irradiated wild-type C57Bl/6 mice with Sca1+ HSC transduced with the Lenti-hGPIIb-GFP constructs. Six months after transplantation we could detect 6% GFP positive platelets without a GFP signal in other cell lineages. Conclusion: In vitro and in vivo MK-specific transgene expression driven by the hGPIIb and mGPIIb promoters could be obtained after ex vivo genetic engineering of HSC by improved lentiviral vectors. Studies are ongoing to study whether this approach can induce phenotypic correction of GATA1 deficient mice by transplantation of ex vivo Lenti-hGPIIb-GATA1 transduced HSC.

scholarly journals Designing Lentiviral Vectors for Gene Therapy of Genetic Diseases

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1526
Author(s):  
Valentina Poletti ◽  
Fulvio Mavilio
Keyword(s):  
Gene Therapy ◽  
Ex Vivo ◽  
Genetic Diseases ◽  
Lentiviral Vectors ◽  
Clinical Applications ◽  
Clinical Development ◽  
Development Phase ◽  
Hematopoietic Stem ◽  
Monogenic Diseases ◽  
Immunotherapy Of Cancer

Lentiviral vectors are the most frequently used tool to stably transfer and express genes in the context of gene therapy for monogenic diseases. The vast majority of clinical applications involves an ex vivo modality whereby lentiviral vectors are used to transduce autologous somatic cells, obtained from patients and re-delivered to patients after transduction. Examples are hematopoietic stem cells used in gene therapy for hematological or neurometabolic diseases or T cells for immunotherapy of cancer. We review the design and use of lentiviral vectors in gene therapy of monogenic diseases, with a focus on controlling gene expression by transcriptional or post-transcriptional mechanisms in the context of vectors that have already entered a clinical development phase.

scholarly journals Lentiviral Hematopoietic Stem Cell Gene Therapy in Patients with Wiskott-Aldrich Syndrome

Science ◽  
2013 ◽  
Vol 341 (6148) ◽  
pp. 1233151 ◽  
Author(s):  
Alessandro Aiuti ◽  
Luca Biasco ◽  
Samantha Scaramuzza ◽  
Francesca Ferrua ◽  
Maria Pia Cicalese ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Lentiviral Vector ◽  
Ex Vivo ◽  
Conditioning Regimen ◽  
Immune Functions ◽  
Gene Encoding ◽  
Hematopoietic Stem ◽  
Wiskott Aldrich Syndrome ◽  
Vector Integration ◽  
Lentiviral Gene Therapy

Wiskott-Aldrich syndrome (WAS) is an inherited immunodeficiency caused by mutations in the gene encoding WASP, a protein regulating the cytoskeleton. Hematopoietic stem/progenitor cell (HSPC) transplants can be curative, but, when matched donors are unavailable, infusion of autologous HSPCs modified ex vivo by gene therapy is an alternative approach. We used a lentiviral vector encoding functional WASP to genetically correct HSPCs from three WAS patients and reinfused the cells after a reduced-intensity conditioning regimen. All three patients showed stable engraftment of WASP-expressing cells and improvements in platelet counts, immune functions, and clinical scores. Vector integration analyses revealed highly polyclonal and multilineage haematopoiesis resulting from the gene-corrected HSPCs. Lentiviral gene therapy did not induce selection of integrations near oncogenes, and no aberrant clonal expansion was observed after 20 to 32 months. Although extended clinical observation is required to establish long-term safety, lentiviral gene therapy represents a promising treatment for WAS.

The Immunogenicity of Platelet-Derived FVIII in Hemophilia a Mice with or without Pre-Existing Anti-FVIII Immunity

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2809-2809
Author(s):  
Yingyu Chen ◽  
Jocelyn Schroeder ◽  
Juan Chen ◽  
Xiaofeng Luo ◽  
Christina Baumgartner ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Immune Response ◽  
Hemophilia A ◽  
Conflicts Of Interest ◽  
Ex Vivo ◽  
High Titer ◽  
Hematopoietic Stem ◽  
Inhibitory Antibodies ◽  
Platelet Infusion

Abstract Recent studies from our group and others have demonstrated that FVIII ectopically targeted to platelets under control of the platelet-specific αIIb promoter (2bF8) can efficiently restore hemostasis in hemophilia A mice even in the presence of high-titer inhibitory antibodies directed against FVIII (inhibitors). Our studies have demonstrated that platelet-targeted FVIII gene therapy can not only correct the hemophilic phenotype, but also induce FVIII-specific immune tolerance. In the platelet gene therapy model, hematopoietic stem cells (HSCs) are ex vivo transduced with lentivirus carrying 2bF8 and transplanted into the recipient. Sufficient preconditioning has to be employed to create space for therapeutic engraftment of the transduced HSCs. It is not clear whether preconditioning affects the potential for an immune response in the context of platelet-derived FVIII. Furthermore, if current efforts to generate platelets in vitro succeed, genetically manipulated platelets containing FVIII may be used therapeutically, as potential transfusion alternative, in hemophilia A patients even with inhibitors. One important question that has not been explored, however, is the immunogenicity of platelet-derived FVIII. To investigate whether platelet-derived FVIII can act as an immunogen in hemophilia A mice, we infused transgenic mouse platelets with a level of platelet-FVIII of 6 mU/108 platelets into naïve FVIIInull mice without any preconditioning weekly for 8 weeks. These platelets were transfused to a level between 20 to 57% of total platelets upon infusion, and all animals survived the tail-clip survival test 13-hours after platelet infusion. The level of platelet-FVIII in the infused animals was 0.11 ± 0.01 mU/108 platelets (n = 6) even one week after infusion. Neither inhibitory nor non-inhibitory anti-FVIII antibodies were detected in the infused mice during the study course (n = 9). All animals developed inhibitors following further challenge with recombinant human FVIII (rhF8) at a dose of 50 U/kg by intravenous injection weekly for 4 weeks, indicating that infusion of platelets containing FVIII does not trigger an immune response in hemophilia A mice. We then explored whether platelets containing FVIII can act as an immunogen in FVIIInull mice with pre-existing anti-FVIII immunity. FVIIInull mice were immunized with rhF8 to induce anti-FVIII antibodies. Four week after the last immunization, 2bF8 transgenic platelets were transfused into rhF8-primed FVIIInull mice (n = 4) weekly for 4 weeks and anti-FVIII antibody titers were monitored. There was not significant augmentation of FVIII-specific antibodies as determined by Bethesda assay for inhibitory antibodies and ELISA assay for total anti-FVIII IgG, indicating that infusion of platelets containing FVIII does not stimulate an anti-FVIII memory response in the inhibitor model. To investigate whether preconditioning affects the anti-FVIII immune response, animals were pre-conditioned with a sub-lethal 660 cGy total body irradiation (TBI) followed by 2bF8 transgenic platelet infusion weekly for 8 weeks. No anti-FVIII antibodies were detected in recipients (n = 6) after 2bF8 transgenic platelet infusion. Following further challenge with rhF8, the inhibitor titer in this group was significantly lower (75 ± 42 BU/ml) than in the naïve FVIIInull mice without preconditioning when the same infusion protocol was employed (270 ± 76 BU/ml), indicating that 660 cGy TBI plus 2bF8 transgenic platelet infusion may suppress anti-FVIII immune response. In conclusion, our data demonstrate that infusion of platelets containing FVIII triggers neither primary nor memory anti-FVIII immune response in hemophilia A mice. Disclosures No relevant conflicts of interest to declare.

scholarly journals Proteasome activity restricts lentiviral gene transfer into hematopoietic stem cells and is down-regulated by cytokines that enhance transduction

Blood ◽  
2006 ◽  
Vol 107 (11) ◽  
pp. 4257-4265 ◽  
Author(s):  
Francesca Romana Santoni de Sio ◽  
Paolo Cascio ◽  
Anna Zingale ◽  
Mauro Gasparini ◽  
Luigi Naldini
Keyword(s):  
Gene Therapy ◽  
Gene Transfer ◽  
Cell Cycle Progression ◽  
Therapeutic Potential ◽  
Ex Vivo ◽  
Proteasome Activity ◽  
Hematopoietic Stem ◽  
Vector Integration ◽  
Cytokine Stimulation

AbstractThe therapeutic potential of hematopoietic stem cell (HSC) gene therapy can be fully exploited only by reaching efficient gene transfer into HSCs without compromising their biologic properties. Although HSCs can be transduced by HIV-derived lentiviral vectors (LVs) in short ex vivo culture, they display low permissivity to the vector, requiring cytokine stimulation to reach high-frequency transduction. Using stringent assays of competitive xenograft repopulation, we show that early-acting cytokines synergistically enhanced human HSC gene transfer by LVs without impairing engraftment and repopulation capacity. Using S-phase suicide assays, we show that transduction enhancement by cytokines was not dependent on cell cycle progression and that LVs can transduce quiescent HSCs. Pharmacologic inhibition of the proteasome during transduction dramatically enhanced HSC gene transfer, allowing the reach of very high levels of vector integration in their progeny in vivo. Thus, LVs are effectively restricted at a postentry step by the activity of this proteolytic complex. Unexpectedly, cytokine stimulation rapidly and substantially down-regulated proteasome activity in hematopoietic progenitors, highlighting one mechanism by which cytokines may enhance permissiveness to LV gene transfer. These findings demonstrate that antiviral responses ultimately mediated by proteasomes strongly limit the efficiency of HSC transduction by LVs and establish improved conditions for HSC-based gene therapy.

Characterization of Regulatory Elements in the Slc4a1 (Band 3) Locus To Create Safe and Effective Vectors for Globin Gene Therapy

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3740-3740
Author(s):  
Faith Harrow ◽  
Stephanie Battle ◽  
Nancy E. Seidel ◽  
Amanda P. Cline ◽  
Patrick G. Gallagher ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Progenitor Cells ◽  
High Titer ◽  
Globin Gene ◽  
Lentiviral Vectors ◽  
Band 3 ◽  
Hematopoietic Stem ◽  
Intron 1 ◽  
Blocking Activity ◽  
Enhancer Blocking

Abstract Effective gene therapy for hemoglobin β-chain disorders, β-thalassemia and sickle cell disease, requires efficient, safe delivery of globin genes into hematopoietic stem cells (HSCs). Engraftment of ∼25% of HCSs expressing a globin gene at ∼20% the level of endogenous α-globin would be sufficient to improve both diseases. The β-globin promoter is inefficient, requiring sequences from the locus control region (LCR) to increase expression. LCR enhancers are included in globin gene therapy vectors, but unfortunately are prone to cryptic splicing and polyadenylation, resulting in low virus titer. In addition, the LCR enhancers are, in theory, capable of activating neighboring oncogenes. To improve safety and efficiency of globin vectors we have developed a novel strategy by fusing the γ-globin gene to LCR-independent, erythroid-specific promoters. Band 3/AE1 is an erythrocyte membrane protein expressed from the Slc4a1 gene. We have previously shown in transgenic mice that a 1750-bp Slc4a1 promoter linked to γ-globin gene (pSlc4a1/γ) and flanked by the chicken β-globin insulator 5′HS4 (ch5′HS4), which contains both barrier and enhancer-blocking elements, is capable of erythroid-specific, uniform γ-globin expression at therapeutic levels (∼19.8% α-globin/transgene copy). Without ch5′HS4, the pSlc4a1/γ gene was prone to silencing. Lentiviral vectors with two copies of ch5′HS4 either internal or in the Long Terminal Repeat cannot be produced at high titer. We hypothesized that flanking the pSlc4a1/γ-globin gene with distinct barrier elements would prevent recombination and gene silencing. Using this strategy, we developed first generation lentiviral vectors in which pSlc4a1/γ is flanked by combinations of the ch5′HS4 insulator and barrier elements we have identified in the ankyrin and α-spectrin loci. To test the effectiveness of these lentivirus vectors in mouse models, we pseudotyped each one with an ecotropic envelope. All three were produced at high titer (>1x106 infectious units/ml). We transduced primitive mouse hematopoietic progenitor cells and detected γ-globin mRNA in >20% of spleen foci at levels as high as 17% of endogenous α-globin. In mice repopulated with transduced stem and progenitor cells, 11–15% of peripheral blood erythrocytes were positive for γ-globin 8 to 21 weeks post-transplantation. To establish the safety of the Slc4a1 promoter we used a high throughput real-time PCR-based assay to identify DNaseI hypersensitive sites (HS) in a 119kb region including Slc4a1. We have identified 6 HS and tested each for enhancer and enhancer-blocking activity. One HS (−355 to −112) increases reporter gene expression in a position- and orientation-independent fashion consistent with the properties of an enhancer. A second HS (−112 to 0) is active in enhancer-blocking assays, and deletion analyses indicate that this region may also contain a transcriptional silencer. A third HS in intron 1 (+910 to +1581) displays enhancer-blocking activity. Three HS have no activity. We are testing a second generation of pSlc4a1/γ lentiviruses in which the Slc4a1 enhancer and silencer are deleted. A third generation of vectors flank pSlc4a1/γ upstream with ch5′HS4, and downstream with either the ankyrin or α-spectrin barrier elements plus the Slc4a1 intron 1 enhancer-blocker to prevent activation of neighboring genes. We hypothesize that these new vectors will allow safe expression of therapeutic levels of γ-globin.

scholarly journals Hematopoietic Stem Cell Gene Therapy for Cystinosis: From Bench-to-Bedside

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3273
Author(s):  
Stephanie Cherqui
Keyword(s):  
Clinical Trial ◽  
Gene Therapy ◽  
Lentiviral Vector ◽  
Ex Vivo ◽  
The Body ◽  
Hematopoietic Stem ◽  
Tissue Integration ◽  
Toxicological Studies ◽  
The Impact

Cystinosis is an autosomal recessive metabolic disease that belongs to the family of lysosomal storage disorders. The gene involved is the CTNS gene that encodes cystinosin, a seven-transmembrane domain lysosomal protein, which is a proton-driven cystine transporter. Cystinosis is characterized by the lysosomal accumulation of cystine, a dimer of cysteine, in all the cells of the body leading to multi-organ failure, including the failure of the kidney, eye, thyroid, muscle, and pancreas, and eventually causing premature death in early adulthood. The current treatment is the drug cysteamine, which is onerous and expensive, and only delays the progression of the disease. Employing the mouse model of cystinosis, using Ctns−/− mice, we first showed that the transplantation of syngeneic wild-type murine hematopoietic stem and progenitor cells (HSPCs) led to abundant tissue integration of bone marrow-derived cells, a significant decrease in tissue cystine accumulation, and long-term kidney, eye and thyroid preservation. To translate this result to a potential human therapeutic treatment, given the risks of mortality and morbidity associated with allogeneic HSPC transplantation, we developed an autologous transplantation approach of HSPCs modified ex vivo using a self-inactivated lentiviral vector to introduce a functional version of the CTNS cDNA, pCCL-CTNS, and showed its efficacy in Ctns−/− mice. Based on these promising results, we held a pre-IND meeting with the Food and Drug Administration (FDA) to carry out the FDA agreed-upon pharmacological and toxicological studies for our therapeutic candidate, manufacturing development, production of the GMP lentiviral vector, design Phase 1/2 of the clinical trial, and filing of an IND application. Our IND was cleared by the FDA on 19 December 2018, to proceed to the clinical trial using CD34+ HSPCs from the G-CSF/plerixafor-mobilized peripheral blood stem cells of patients with cystinosis, modified by ex vivo transduction using the pCCL-CTNS vector (investigational product name: CTNS-RD-04). The clinical trial evaluated the safety and efficacy of CTNS-RD-04 and takes place at the University of California, San Diego (UCSD) and will include up to six patients affected with cystinosis. Following leukapheresis and cell manufacturing, the subjects undergo myeloablation before HSPC infusion. Patients also undergo comprehensive assessments before and after treatment to evaluate the impact of CTNS-RD-04 on the clinical outcomes and cystine and cystine crystal levels in the blood and tissues for 2 years. If successful, this treatment could be a one-time therapy that may eliminate or reduce renal deterioration as well as the long-term complications associated with cystinosis. In this review, we will describe the long path from bench-to-bedside for autologous HSPC gene therapy used to treat cystinosis.

Ten years of gene therapy for primary immune deficiencies

Hematology ◽  
2009 ◽  
Vol 2009 (1) ◽  
pp. 682-689 ◽  
Author(s):  
Alessandro Aiuti ◽  
Maria Grazia Roncarolo
Keyword(s):  
Gene Therapy ◽  
Gene Transfer ◽  
Insertional Mutagenesis ◽  
Ex Vivo ◽  
Lentiviral Vectors ◽  
Hematopoietic Stem ◽  
Benefit Evaluation ◽  
Immune Deficiencies ◽  
Substantial Progress ◽  
Ex Vivo Gene Transfer

Abstract Gene therapy with hematopoietic stem cells (HSC) is an attractive therapeutic strategy for several forms of primary immunodeficiencies. Current approaches are based on ex vivo gene transfer of the therapeutic gene into autologous HSC by vector-mediated gene transfer. In the past decade, substantial progress has been achieved in the treatment of severe combined immundeficiencies (SCID)-X1, adenosine deaminase (ADA)-deficient SCID, and chronic granulomatous disease (CGD). Results of the SCID gene therapy trials have shown long-term restoration of immune competence and clinical benefit in over 30 patients. The inclusion of reduced-dose conditioning in the ADA-SCID has allowed the engraftment of multipotent gene-corrected HSC at substantial level. In the CGD trial significant engraftment and transgene expression were observed, but the therapeutic effect was transient. The occurrence of adverse events related to insertional mutagenesis in the SCID-X1 and CGD trial has highlighted the limitations of current retroviral vector technology. For future applications the risk-benefit evaluation should include the type of vector employed, the disease background and the nature of the transgene. The use of self-inactivating lentiviral vectors will provide significant advantages in terms of natural gene regulation and reduction in the potential for adverse mutagenic events. Following recent advances in preclinical studies, lentiviral vectors are now being translated into new clinical approaches, such as Wiskott-Aldrich Syndrome.

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