MYD88 and syphilis: Additionally, PBMCs from healthy individuals and either primary or <i>MyD88</i> knock-out keratinocytes were exposed to live <i>Treponema pallidum</i> cells to define initial skin responses to the bacteria.<h4>Results</h4>Immunohistochemistry of secondary syphilis skin lesions showed a polymorphous immune infiltrate with colocalization of T cells, B cells and antigen-presenting cells.