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Related Diseases

Chronic lymphocytic leukemia (CLL) shares some similar features and symptoms with other closely related types of leukemia. They all have one thing in common: They begin in a lymphocyte that becomes cancerous and accumulates in the blood, bone marrow or spleen. There are distinguishing characteristics that enable the hematologist/oncologist to identify each disease, including the appearance and the immunophenotype of the cancer cells; the cells’ varying effects on normal marrow and blood cell development; and the cells’ varying effects on other parts of the body, such as the kidneys, bowels and nervous system.

The related diseases listed below represent a range of clinical severity. At one end of the range, there are the diseases that may be stable and may not advance in severity for some months or years, or occasionally indefinitely. At the other end of the range, there are diseases associated with difficulties that may be present at diagnosis and possibly get worse, requiring immediate treatment and frequent observation.

Less Rapidly Progressive

 More Rapidly Progressive

Most Rapidly Progressive


CLL with Increased Prolymphocytes (CLL-PL) or Prolymphocytic Leukemia. About 15 percent of people with CLL have leukemia cells that are a mix of lymphocytes and another type of white blood cell, called a “prolymphocyte.” Most people with this type of CLL follow a similar disease course to that of typical CLL. However, for a relatively small group of patients with this type of CLL, the blood cells may become mainly composed of prolymphocytes, the spleen may enlarge further, and the disease may become more aggressive and less responsive to treatment. In these cases, patients are encouraged to talk to their doctors about participating in a clinical trial.


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