IL6 and Zika virus infectious disease: As a proof of concept, isolated HB cells from healthy term placenta secreted elevated pro-inflammatory cytokines such as IL-6, MCP-1, IP-10, and IFN-α upon in vitro infection with Zika Virus (ZIKV) [26], even if HB cells are permissive for ZIKV infection and replication [27,28,29].