TNF-α has been shown to induce plasma leakage in vitro.[13] Basophils and mast cells infected with dengue virus produce IL-1 and IL-6, while IFN-γ, IL-2, and TNF-α are also produced by virus-specific T lymphocytes upon activation.[12, 14] Lymphocytes infected with the dengue virus produce IFN-α and IFN-γ,[15] IFN-α levels are higher in patients with DHF, though there is no difference in its levels in different grades of DHF.[16] IFN-γ levels are no different in patients with DF and DHF.[15] The precise role played by interferon in the pathogenesis of dengue shock is unclear. This evidence concerns the gene IL1B and Dengue hemorrhagic fever.