CDKN2B and syphilis: We also compared the levels of serum antibodies against TP15, TP17, and TP47 in the patients at different stages of syphilis and found that they were relatively low in the patients of primary syphilis while high levels of antibodies against TP15, TP17, and TP47 were observed in the patients of secondary syphilis, early latent syphilis, and late latent syphilis, although subtle differences existed (Supplemental Figure 2).