Immunohistochemistry and real time-PCR analysis of biopsy specimens obtained from primary and secondary syphilis lesions demonstrate that syphilitic skin lesions are also composed of macrophages and lymphocytes that express mRNAs for IL-1β, Interferon-γ and IL-12 in experimentally infected rabbit tissues [16] and human primary syphilitic lesions [17]. Here, IL1B is linked to syphilis.