Hairy Cell Leukemia [DBA.44]

Hairy cell leukemia (HCL) is a rare type of chronic lymphoid leukemia. The disease is characterized by abnormal white blood cells bearing hair-like projections from the cytoplasm. These cancerous cells are larger than normal and positive for CD19, CD20, CD22, CD11c, CD25, CD103 and FMC7. HCL commonly causes infection, anemia and/or easy bleeding in patients. Some of the leukemic cells may gather in the spleen and cause it to swell, leading to massive splenomegaly. Patients with a high tumor burden may also have significantly reduced levels of cholesterol. There are two variants of hairy cell leukemia: hairy cell leukemia-variant, which is usually diagnosed in older men; and a Japanese variant. HCL markers are important research tools as they allow for the functional and behavioral analysis of this type of leukemia. DBA.44, a B subset antibody, reacts with very few normal cells. 50-97% of HCL cases are positive; about 35% of low grade B-cell lymphomas are positive; and about 30-80% of splenic lymphomas are positive. The antibody maybe also positive in some marginal cell lymphomas (MZL) and large cell lymphomas. Combining with TRAcP (tartrate-resistant acid phosphatase) is a good way to detect HCL.