Multivariate analysis at 2 years after seroconversion indicated that CD4 T cell counts below 500 cells per μl blood, viral RNA load above 104.5 copies per ml plasma, the presence of X4-variants and homozygosity for the Trim5 H43Y genotype (43YY) were independent predictors for progression to AIDS (Table 3). The gene discussed is TRIM5; the disease is AIDS.