The immune system is the body’s defence against pathogens, infectious organisms and other substances that may harm the body and the individual.
It comprises special cells and organs to keep the entire body system healthy. The primary cells involved are the leukocytes or the white blood cells. These are produced in bone marrows.
Certain conditions, such as leukaemia, can cause the bone marrow to produce insufficient amounts of leukocytes in the body. That can lead to easy susceptibility to infection and sickness.