Diseases of the Immune System

The immune system is a complex system in the body that protects the it from outside organisms. These other organisms, which can cause damage to the body, include viruses, bacteria, fungi and parasites. The immune system also defends the body from poisonous substances and cancer.

In addition to the immune system’s ability to identify foreign bodies, the immune system also has immunological memory, which is one of its defining characteristics. If the immune system is exposed to a disease it has already fought in the past, it will ‘remember’ what to do in order to overcome the disease.