Among 27 cytokine proteins included in this study, 9 cytokines (TNF-α, IL-8, MIP-1α, MIP-1b, MCP-1, RANTES, IL-1rα, IL-9, IP-10) were found at measurable levels in culture supernatants of PHHs following mock infection and/or DENV-2 infection at MOI of 5 for 48 h (Fig 5A–5F). Here, IL9 is linked to infection.