How Stuff Works: Immune System - Inside your body there is a mechanism designed to defend you from millions of bacteria, microbes, viruses, toxins and parasites that want to invade your body. Find out how the human immune system works.
NORD-National Organization For Rare Disorders - National Organization for Rare Disorders is dedicated to helping people with rare, orphan diseases. Rarediseases.org contains information on the prevention, treatment and cure of rare diseases.