A consequence of the release of histamine and of complement actrivation?

The release of histamine and complement activation leads to increased vascular permeability and vasodilation, resulting in swelling and redness in the affected tissues. Histamine causes smooth muscle contraction and promotes inflammation, while complement activation enhances immune responses by opsonizing pathogens and attracting immune cells to the site of infection. Together, these processes contribute to the body's defense mechanisms during allergic reactions and infections.