CCL4 and sexually transmitted disease: The proposed mechanism of enhanced STI/HIV susceptibility is via the induction of pro-inflammatory cytokines (MIP-1α, MIP-1β, IL-1α, IL-1β, TNF-α, IFN-γ, IL-10, IL-8, IL-23, and IL-17) and recruitment of HIV-1 target cells [14, 52], and recent clinical studies demonstrated a 17 fold increase in HIV target cells (CD4+CCR5+CD38+HLA-DR+) in the cervix of women with highly diverse vaginal microbiota, compared to L. crispatus dominant women [52].