Table 1

Summary of results of clinical trials
Target cells	Vector	Transgene	Anti-HIV method	Results

CD8⁺	Retrovirus	HyTk	Introduction of suicide gene	CTL response cleared modified cells [16].
CD4⁺	Gold-particle-mediated	Rev M10	Transdominant negative protein	Detected Rev M10 until 2 months post infusion, preferential survival [36].
CD4⁺	Retrovirus	Rev M10	Transdominant negative protein	Detected Rev M10 until 6 months post infusion, preferential survival [37].
CD4⁺	Retrovirus	TdRev and/or anti-sense TAR	Transdominant negative proteins and anti-sense RNA	Anti-HIV genes consistently detected for >100 weeks in six of six patients. Preferential survival of transduced cells during a period of high viral load in one patient [47].
CD34⁺	Retrovirus	TdRev	Transdominant negative protein	One patient died due to relapse to Hodgkin's disease. In second patient, detected vector in the progeny for >3 years, remission of leukemia and good viral load control achieved by administering HAART that cannot be attributed to gene therapy [38,39].
CD34⁺	Retrovirus	huM10	Transdominant negative protein	huM10 could be detected in peripheral blood mononuclear cells (PBMC) for 1–3 months and then dropped to at or below the limit of detection over a two year follow-up period. Preferential survival of transduced cells during a period of high viral load in one patient [40].
CD4⁺	Retrovirus	CD4ζ	Chimeric receptor	Decrease of greater than 0.5 log mean in rectal tissue-associated HIV RNA for at least 14 days, detected CD4ζ in 1–3% of PBMCs at 8 weeks [42]
CD4⁺	Retrovirus	CD4ζ	Chimeric receptor	Good expression of CD4ζ for at least 24 weeks in all patients; no difference between control and study group [43].
CD4⁺and CD8⁺	Retrovirus	CD4ζ	Chimeric receptor	In 11 of 12 patients who received higher doses of modified CD8⁺cells (10⁹or 10¹⁰), CD4ζ could be detected post-infusion for at least 15–40 weeks when they received additional infusions of modified cells. The group receiving IL-2 along with modified CD8⁺cells showed a higher persistence of CD4ζ as compared to the group receiving no IL-2. In patients who received modified CD8⁺and CD4⁺cells, the cells were detected in the peripheral blood for at least 1 year post-infusion [41].
CD34⁺	Retrovirus	(RRE) decoy	RNA decoy	RRE-decoy-containing leukocytes could be isolated from peripheral blood even 1 year post-infusion but the numbers were extremely low [44].
CD4⁺	Retrovirus	RRz2	Ribozyme	Over a 4 year period, PBMCs containing both RRz2 and LNL6 were consistently detected [46].
CD34⁺	Retrovirus	tat/vpr ribozyme	Ribozyme	Vector was detected in naïve T cells for >3 years; no correlation between changes in viremia or CD4+ T cell counts with vector expression or its detection in any cell type [45].

Marathe and Wooley Genetic Vaccines and Therapy 2007 5:5 doi:10.1186/1479-0556-5-5