(Pardon the "duh" headline.)
I found this article interesting mainly because I like to let my fevers run -- "bake out the infection". Works for me, but then I've never had a really high, convulsion-inducing fever.
Anyway, interesting tidbits from the article:
It has been found that fevers help the body’s immune system identify an infection and raise an army of white blood cells (lymphocytes) against it. ...[Researchers] artificially created a fever-like state in a group of mice... This had the effect of doubling the number of lymphocytes visiting lymph nodes... Lymphocytes arriving at the nodes are screened for "killer efficiency" using fragments of potentially infectious material. Lymphocytes that respond to the fragments are found, are then selectively multiplied, and then swarm into the bloodstream to seek out and destroy the invader.
Apparently the extra heat of a fever activates high endothelial venule cells ("gatekeeper" cells, as the article calls them) in lymph nodes. They produce extra surface proteins that capture passing lymphocytes and draw them into the lymph nodes.
Evans says that although it fell out of fashion with the development of modern medicine, the idea of treating disease with heat has a long history: "Hippocrates used to heat patients with cancer," she says. And a century ago the physician William Coley discovered a cocktail of bacteria, dubbed "Coley's toxins", which appeared to combat cancer by producing a fever.