Gene therapy, combined with reduced-intensity conditioning, is a safe and effective treatment for SCID in patients with ADA deficiency. (ClinicalTrials.gov numbers, NCT00598481 and NCT00599781.)
Hematopoietic stem cell (HSC) gene therapy for adenosine deaminase (ADA)-deficient severe combined immunodeficiency (SCID) has shown limited clinical efficacy because of the small proportion of engrafted genetically corrected HSCs. We describe an improved protocol for gene transfer into HSCs associated with nonmyeloablative conditioning. This protocol was used in two patients for whom enzyme replacement therapy was not available, which allowed the effect of gene therapy alone to be evaluated. Sustained engraftment of engineered HSCs with differentiation into multiple lineages resulted in increased lymphocyte counts, improved immune functions (including antigen-specific responses), and lower toxic metabolites. Both patients are currently at home and clinically well, with normal growth and development. These results indicate the safety and efficacy of HSC gene therapy combined with nonmyeloablative conditioning for the treatment of SCID.
Key Points
Survival was 100% for 18 patients with ADA-SCID treated with genetically modified CD34+ cells (2.3-13.4 years follow up; median, 6.9 years). Long-term engraftment, immune reconstitution, and fewer severe infections were observed in 15 out of 18 patients without leukemic transformation.
We tested whether rat liver preservation performed by machine perfusion (MP) at 20°C can enhance the functional integrity of steatotic livers versus simple cold storage. We also compared MP at 20°C with hypothermic MP at 8°C, and 4°C. Obese and lean male Zucker rats were used as liver donors. MP was performed for 6 hours with a glucose and N-acetylcysteine-supplemented Krebs-Henseleit solution. Both MP and cold storage preserved livers were reperfused with Krebs-Henseleit solution (2 hours at 37°C). MP at 4°C and 8°C reduced the fatty liver necrosis compared with cold storage but we further protected the organs using MP at 20°C. Necrosis did not differ in livers from lean animals submitted to the different procedures; the enzymes released in steatotic livers preserved by MP at 20°C were similar to those showed in nonsteatotic organs. The adenosine triphosphate/adenosine diphosphate ratio and bile production were higher and the oxidative stress and biliary enzymes were lower in steatotic livers preserved by MP at 20°C as compared with cold storage. In livers from lean rats, the adenosine triphosphate/adenosine diphosphate ratio appears better conserved by MP at 20°C as compared with cold storage. In steatotic livers preserved by cold storage, a 2-fold increase in tumor necrosis factor-alpha levels and caspase-3 activity was observed as compared with organs preserved by MP at 20°C. These data are substantiated by better morphology, higher glycogen content, and lower reactive oxygen species production by sinusoidal cells in steatotic liver submitted to MP at 20°C versus cold storage. MP at 20°C improves cell survival and leads to a marked improvement in hepatic preservation of steatotic livers as compared with cold storage. Liver Transpl 15:20-29, 2009.
Adenosine deaminase (ADA) deficiency is a disorder of the purine metabolism leading to combined immunodeficiency and systemic alterations, including skeletal abnormalities. We report that ADA deficiency in mice causes a specific bone phenotype characterized by alterations of structural properties and impaired mechanical competence. These alterations are the combined result of an imbalanced receptor activator of nuclear factor-B ligand (
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