In addition, genetic association studies have shown that CCR5Δ32 homozygotes are resistant to HIV infection, whereas heterozygotes display delayed progression of disease.185, 186, 187 It was therefore hypothesized that ex vivo disruption of CCR5 in patient-derived T cells, followed by reinfusion, could mimic the curative outcome of the Berlin patient. Here, CCR5 is linked to HIV infectious disease.