A comparison between syphilis patients and healthy individuals revealed a 1.3-fold increase in mean frequency of CD4+ CD25high T cells in primary syphilis patients (3.6%±0.2%, p<0.01), 1.7-fold increase in secondary syphilis patients (4.5%±0.2%, p<0.001), 1.5-fold increase in early latent syphilis patients (4.1%±0.2%, p<0.001), and 1.7-fold increase in serofast syphilis patients (4.7%±0.3%, p<0.001) (Figure 1B). This evidence concerns the gene CD4 and syphilis.