CD4 and infection: At the time of secondary infection (i.e., infection after 1-2 days of fever onset), high concentration of interferon-alpha (IFN-α) is found, while high levels of soluble interferon γ (IFN-γ), interleukin 2 receptor (IL-2R), and soluble CD4 and CD8 were reported throughout the outset of vascular permeability [80, 81].