The spleen is crucial to the function of the immune system. The spleen filters the blood, removing and destroying bacteria and other infectious organisms in the bloodstream. It also produces antibodies (immunoglobulins). (See also Overview of Immunodeficiency Disorders.)
For people whose spleen is absent at birth or has been damaged or removed because of disease, the risk of developing severe bacterial infections is increased.
People who have a spleen disorder or no spleen are given antibiotics at the first sign of infection. Children who do not have a spleen should take antibiotics, usually penicillin or ampicillin, continuously until at least age 5 to prevent an infection in the bloodstream. If they also have an immunodeficiency disorder, they may take these antibiotics indefinitely.