What is different in the immune system from other systems? The immune system creates its own organs as it is needed.

The immune system is only present when needed, if there is not an attack, there are no defenses in action.

The immune system stands apart from other organ systems because it does not really have its own system of organs.

The immune system has the same basic organs as the digestive system but performs a different function.

The immune system is a mental system, since the body really never gets sick. The brain (thought of being sick) leads the body to defend itself and
allows the creation of new glands and cells for defense.