We have genetically engineered CD4+ and CD8+ T cells with human immunodeficiency virus (HIV) specificity by inserting a gene, CD4ζ, containing the extracellular domain of human CD4 (which binds HIV env) linked to the zeta (ζ) chain of the T-cell receptor (which mediates T-cell activation). Twenty-four HIV-positive subjects received a single infusion of 2 to 3 × 1010 autologous CD4ζ-modified CD4+and CD8+ T cells administered with (n = 11) or without (n = 13) interleukin-2 (IL-2). Subjects had CD4 counts greater than 50/μL and viral loads of at least 1000 copies/mL at entry. T cells were costimulated ex vivo through CD3 and CD28 and expanded for approximately 2 weeks. CD4ζ was detected in 1% to 3% of blood mononuclear cells at 8 weeks and 0.1% at 1 year after infusion, and survival was not enhanced by IL-2. Trafficking of gene-modified T cells to bulk rectal tissue and/or isolated lamina propria lymphocytes was documented in a subset of 5 of 5 patients at 14 days and 2 of 3 at 1 year. A greater than 0.5 log mean decrease in rectal tissue–associated HIV RNA was observed for at least 14 days, suggesting compartmental antiviral activity of CD4ζ T cells. CD4+ counts increased by 73/μL at 8 weeks in the group receiving IL-2. There was no significant mean change in plasma HIV RNA or blood proviral DNA in either treatment arm. This sustained, high-level persistence of gene-modified T cells demonstrates the feasibility of ex vivo T-cell gene therapy in HIV-infected adults and suggests the importance of providing HIV-specific T-helper function.

A phase I gene transfer clinical study was undertaken to examine the ability to introduce a potential anti-human immunodeficiency virus (HIV) gene therapeutic into hematopoietic progenitor cells (HPC), thereby contributing to multilineage engraftment. The potential therapeutic effect of genetically modifying HPC with protective genes in HIV-infected adults depends in part on the presence of adult thymic activity and myeloid capacity in the setting of HIV replication. Herein we report the presence and expression of a retroviral vector encoding an anti-HIV-1 ribozyme in mature hematopoietic cells of different lineages, and de novo T-lymphocyte development ensuing from genetically engineered CD34(+) HPC. Sustained output of vector-containing mature myeloid and T-lymphoid cells was detected even in patients with multidrug-resistant infection. In addition, the study showed that the degree of persistence of gene-containing cells was dependent on transduced HPC dose. These novel findings support the concept of gene therapy as a modality to effect immune reconstitution with cells engineered to inhibit HIV replication and this report represents the first demonstration of long-term maintenance of a potential therapeutic transgene in HIV disease.

We have genetically engineered CD4+ and CD8+ T cells with human immunodeficiency virus (HIV) specificity by inserting a gene, CD4ζ, containing the extracellular domain of human CD4 (which binds HIV env) linked to the zeta (ζ) chain of the T-cell receptor (which mediates T-cell activation). Twenty-four HIV-positive subjects received a single infusion of 2 to 3 × 1010 autologous CD4ζ-modified CD4+and CD8+ T cells administered with (n = 11) or without (n = 13) interleukin-2 (IL-2). Subjects had CD4 counts greater than 50/μL and viral loads of at least 1000 copies/mL at entry. T cells were costimulated ex vivo through CD3 and CD28 and expanded for approximately 2 weeks. CD4ζ was detected in 1% to 3% of blood mononuclear cells at 8 weeks and 0.1% at 1 year after infusion, and survival was not enhanced by IL-2. Trafficking of gene-modified T cells to bulk rectal tissue and/or isolated lamina propria lymphocytes was documented in a subset of 5 of 5 patients at 14 days and 2 of 3 at 1 year. A greater than 0.5 log mean decrease in rectal tissue–associated HIV RNA was observed for at least 14 days, suggesting compartmental antiviral activity of CD4ζ T cells. CD4+ counts increased by 73/μL at 8 weeks in the group receiving IL-2. There was no significant mean change in plasma HIV RNA or blood proviral DNA in either treatment arm. This sustained, high-level persistence of gene-modified T cells demonstrates the feasibility of ex vivo T-cell gene therapy in HIV-infected adults and suggests the importance of providing HIV-specific T-helper function.