Hairy cell leukemia is a rare, slow-growing cancer of the blood in which your bone marrow makes too many B cells (lymphocytes), a type of white blood cell that fights infection. It is recognized as a clonal B-cell malignancy, as identified by immunoglobulin gene rearrangements that result in a phenotype B-cell expression of surface antigens. These reflect the differentiation between the immature B-cell of chronic lymphocytic leukemia and the plasma cell of multiple myeloma.
These excess B cells are abnormal and look "hairy" under a microscope. Common symptoms of HCL includes persistently feeling tired, weakness, weight loss for no reason, shortness of breath, excessive sweating (most often at night), swollen lymph nodes, frequent infections and fevers, small red spots on the skin. The main treatment for hairy cell leukemia is chemotherapy, purine analog drugs either cladribine (2-CdA) or pentostatin, monoclonal antibody rituximab, surgery or interferon alpha.
Survivals at 5 and 10 years were 34.4% and 29.6% respectively for untreated patients, 58.8% and 44.1% for patients receiving chemotherapy, steroids or other drugs, 64.1% and 56.1% for splenectomized patients and 88.9% (at 5 years) for alpha interferon (IFN)-treated patients.