White blood cells, also called leukocytes, make up a portion of the cells in your blood. There are five major types of leukocytes, known as neutrophils, eosinophils, basophils, monocytes, and lymphocytes, all of which have distict morphological characteristics and functions within the body. In general, leukocytes help fight infection and prevent the development of infectious diseases. A number of diseases involve or affect the leukocytes, each of which can have serious effects on the body.
AIDS
Acquired immune deficiency syndrome (AIDS), is a progressive disease that results from infection of white blood cells by the HIV virus. The virus enters the cell and essentially hijacks cell behavior to force the cell to generate more virus until the cell dies and releases the virus into the bloodstream, where it can infect more white blood cells. Overall, this severely decreases or destroys the number of white blood cells in a patient's body, leaving them without a functioning immune system.
AIDS can be detected by looking for the presence of viral proteins or DNA within the blood. After diagnosis, patients are usually prescribed a cocktail of drugs that prevents the virus from entering the cell or destroys the viral DNA within the cell to prevent replication of the virus. Over time, the virus can become resistant to specific drugs, so people with AIDS must undergo regular testing to monitor their condition.
Leukemia
Leukemia is a cancer that develops in white blood cells. Under normal conditions, blood cells are formed within the bone marrow, which can create a range of blood cell types. In leukemia, the cells that give rise to blood cells are mutated, and too many leukocytes are made. These leukocytes are unable to function properly, so the blood is essentially flooded with useless extra white blood cells. Leukemia is classified as either acute or chronic, with the symptoms of acute leukemia developing rapidly, and chronic leukemia developing more slowly.
Leukemia can be diagnosed and classified based on physical examinations, blood tests and bone marrow tests. Once diagnosed, leukemia is usually treated with chemotherapy, radiation therapy, targeted drugs or by stem cell transplants to replace the mutant cells with normal cells.
Agranulocytosis
Agranulocytosis occurs when the blood does not contain enough neutrophils, a type of white blood cell. The cells responsible for making blood may not produce enough neutrophils to meet the needs of the body or neutrophils may be destroyed too quickly within the body. Since neutrophils help make up a portion of the immune system, people with agranulocytosis are unable to effectively fight off infection.
Agranulocytosis can be caused by tumors or autoimmune diseases that affect the number of white blood cells. It also can be the result of inherited mutations in DNA. The disease can be diagnosed by blood or bone marrow tests or genetic testing. After diagnosis, agranulocytosis can be treated by transfusions, white blood cell-promoting drugs and antibiotics to treat any infections developed as a result of a low white blood cell count.
