What is an effect of a compromised immune system?

The effect of a compromised immune system is vulnerability to diseases.

Explanation: Immune system is the body's defence against infectious organisms and foreign substances invading the body. The immune system attacks organisms and substances that cause diseases in the body by their invasion through a series of actions called immune response. During immune response, the body recognizes the invading organism or substance as foreign or non-self and produce antibodies that fight and eliminate the invader. When the body's immune system is compromised, the body will not be able to trigger an immune response to eliminate the foreign body, therefore the body will be prone to diseases and infections.