Published: 25 March, 2004

White blood cells fight infection, help to repair damaged tissue

What if you had no white blood cells?

If you had no white cells, you would get lots of very serious infections. White blood cells can find germs that enter your body and destroy them, which keeps them from making you sick. Some white blood cells make antibodies, which are special molecules that can stick to germs and make them harmless.

White blood cells also help repair damaged tissue, which is important in wound healing. White blood cells can even keep certain types of cancers from developing. A single drop of blood contains nearly half a million white blood cells, so your body has to make lots of them every day.

White blood cells are made in the soft, inner part of your bones called the marrow, and some of them develop further in a special gland in your chest called the thymus. It is very rare for a person to be born unable to make white blood cells.

In the past, such babies usually died of overwhelming infections soon after birth. Some of these babies can now be cured by taking bone marrow or thymus tissue from another person (called a donor) and putting it (transplanting it) into the baby's body. This gives them the ability to make white blood cells of their own, which protects them from infection and lets them live a long life.

Sometimes, people who are given chemotherapy drugs to fight cancer, are exposed to large amounts of radiation, or have an illness that damages their bone marrow, become unable to make white blood cells anymore. They may be given special medicines to try to boost their white blood cells, and antibiotics to prevent or treat infections.

If their bone marrow doesn't start making white blood cells again, then they too may need to be treated with a bone marrow transplant.