Non-hemic autoimmunity in CLL.

Non-hemic autoimmune complications of chronic lymphocytic leukemia are very rare compared to autoimmune haemolytic anemia, which occurs in between 10% and 20% of patients and immune thrombocytopenia, which occurs in between 1% and 2% of patients. A clear relationship has only been established with three non-hemic syndromes: acquired angioedema, glomerulonephritis and paraneoplastic pemphigus. The first is a result of a secreted product of the tumor, but the last two seem to be a product of the disordered immune system, and may be triggered by treatment with purine analogues suggesting a mechanism involving regulatory T cells. Apart from Herpes Zoster infections, neurological syndromes are rare in CLL and most have been attributed to either leukemic infiltration of the CNS or progressive multifocal leukoencephalopathy.