9 research outputs found
Lentiviral hematopoietic stem cell gene therapy for X-linked severe combined immunodeficiency
-linked severe combined immunodeficiency (SCID-X1) is a profound deficiency of T, B, and natural killer (NK) cell immunity caused by mutations in IL2RG encoding the common chain (γc) of several interleukin receptors. Gamma-retroviral (γRV) gene therapy of SCID-X1 infants without conditioning restores T cell immunity without B or NK cell correction, but similar treatment fails in older SCID-X1 children. We used a lentiviral gene therapy approach to treat five SCID-X1 patients with persistent immune dysfunction despite haploidentical hematopoietic stem cell (HSC) transplant in infancy. Follow-up data from two older patients demonstrate that lentiviral vector γc transduced autologous HSC gene therapy after nonmyeloablative busulfan conditioning achieves selective expansion of gene-marked T, NK, and B cells, which is associated with sustained restoration of humoral responses to immunization and clinical improvement at 2 to 3 years after treatment. Similar gene marking levels have been achieved in three younger patients, albeit with only 6 to 9 months of follow-up. Lentiviral gene therapy with reduced-intensity conditioning appears safe and can restore humoral immune function to posthaploidentical transplant older patients with SCID-X1
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Lentiviral hematopoietic stem cell gene therapy for X-linked severe combined immunodeficiency.
X-linked severe combined immunodeficiency (SCID-X1) is a profound deficiency of T, B, and natural killer (NK) cell immunity caused by mutations inIL2RGencoding the common chain (γc) of several interleukin receptors. Gamma-retroviral (γRV) gene therapy of SCID-X1 infants without conditioning restores T cell immunity without B or NK cell correction, but similar treatment fails in older SCID-X1 children. We used a lentiviral gene therapy approach to treat five SCID-X1 patients with persistent immune dysfunction despite haploidentical hematopoietic stem cell (HSC) transplant in infancy. Follow-up data from two older patients demonstrate that lentiviral vector γc transduced autologous HSC gene therapy after nonmyeloablative busulfan conditioning achieves selective expansion of gene-marked T, NK, and B cells, which is associated with sustained restoration of humoral responses to immunization and clinical improvement at 2 to 3 years after treatment. Similar gene marking levels have been achieved in three younger patients, albeit with only 6 to 9 months of follow-up. Lentiviral gene therapy with reduced-intensity conditioning appears safe and can restore humoral immune function to posthaploidentical transplant older patients with SCID-X1
Severe congenital neutropenia resulting from G6PC3 deficiency with increased neutrophil CXCR4 expression and myelokathexis
Mutations in more than 15 genes are now known to cause severe congenital neutropenia (SCN); however, the pathologic mechanisms of most genetic defects are not fully defined. Deficiency of G6PC3, a glucose-6-phosphatase, causes a rare multisystem syndrome with SCN first described in 2009. We identified a family with 2 children with homozygous G6PC3 G260R mutations, a loss of enzymatic function, and typical syndrome features with the exception that their bone marrow biopsy pathology revealed abundant neutrophils consistent with myelokathexis. This pathologic finding is a hallmark of another type of SCN, WHIM syndrome, which is caused by gain-of-function mutations in CXCR4, a chemokine receptor and known neutrophil bone marrow retention factor. We found markedly increased CXCR4 expression on neutrophils from both our G6PC3-deficient patients and G6pc3−/− mice. In both patients, granulocyte colony-stimulating factor treatment normalized CXCR4 expression and neutrophil counts. In G6pc3−/− mice, the specific CXCR4 antagonist AMD3100 rapidly reversed neutropenia. Thus, myelokathexis associated with abnormally high neutrophil CXCR4 expression may contribute to neutropenia in G6PC3 deficiency and responds well to granulocyte colony-stimulating factor