Successful correction of the human beta-thalassemia major phenotype using a lentiviral vector.
beta-thalassemias are the most common single gene disorders and are potentially amenable to gene therapy. However, retroviral vectors carrying the human beta-globin cassette have been notoriously unstable. Recently, considerable progress has been made using lentiviral vectors, which stably transmit the beta-globin expression cassette. Thus far, mouse studies have shown correction of the beta-thalassemia intermedia phenotype and a partial, variable correction of beta-thalassemia major phenotype. We tested a lentiviral vector carrying the human beta-globin expression cassette flanked by a chromatin insulator in transfusion-dependent human thalassemia major, where it would be ultimately relevant. We demonstrated that the vector expressed normal amounts of human beta-globin in erythroid cells produced in in vitro cultures for unilineage erythroid differentiation. There was restoration of effective erythropoiesis and reversal of the abnormally elevated apoptosis that characterizes beta-thalassemia. The gene-corrected human beta-thalassemia progenitor cells were transplanted into immune-deficient mice, where they underwent normal erythroid differentiation, expressed normal levels of human beta-globin, and displayed normal effective erythropoiesis 3 to 4 months after xenotransplantation. Variability of beta-globin expression in erythroid colonies derived in vitro or from xenograft bone marrow was similar to that seen in normal controls. Our results show genetic modification of primitive progenitor cells with correction of the human thalassemia major phenotype.
Saban Research Institute, Division of Hematology-Oncology, Childrens Hospital Los Angeles, Mail Stop 54, 4650 Sunset Blvd, Los Angeles, CA 90027, USA.
Geetha
G
Puthenveetil
Jessica
J
Scholes
Denysha
D
Carbonell
Naveen
N
Qureshi
Ping
P
Xia
Licheng
L
Zeng
Shulian
S
Li
Ying
Y
Yu
Alan L
AL
Hiti
Jiing-Kuan
JK
Yee
Punam
P
Malik
D000818:Animals; D002454:Cell Differentiation; D002470:Cell Survival; D015672:Erythroid Precursor Cells / Q000378:metabolism / Q000637:transplantation; D004920:Erythropoiesis; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D005914:Globins / Q000008:administration & dosage* / Q000235:genetics; D006801:Humans; D016086:Lentivirus / Q000235:genetics; D051379:Mice; D016513:Mice, SCID; D010641:Phenotype; D014183:Transplantation, Heterologous; D016896:Treatment Outcome; D017086:beta-Thalassemia / Q000628:therapy*
D005914:Globins