CCR5Δ32 heterozygous genotype was associated with reduced risk of CD4+ T cell depletion (univariate analysis) and with increased risk of death after AIDS diagnosis (multivariate analysis; potentially due to the emergence of CXCR4-tropic HIV strains); CCR5Δ32 was a protective factor on disease progression in survival curve analysis. The gene discussed is CXCR4; the disease is AIDS.