Vasculitis in hairy-cell leukemia.

Vasculitis associated with hairy-cell leukemia (HCL) has been reported occasionally. We determined the clinical and biological significance of this association by the retrospective study of a series of 50 patients with HCL, including nine patients with vasculitis. The development of vasculitis was not related to a variant of HCL on the basis of hematologic findings and survival. Vasculitis could occur at any time during the course of HCL, and was the circumstance for the diagnosis of HCL in three cases. Clinical and immunohistologic findings were those of hypersensitivity vasculitis in the nine patients. Infection was found to be an associated factor. Thus, eight of nine patients were infected at vasculitis onset, four died of their infection with no remittance of the cutaneous lesions, and three recovered from both infection and vasculitis. The monocyte deficiency in HCL is known to favor intracellular pathogen infection; however, we could not demonstrate that it also correlates with a decrease in the clearance of IgG-sensitized erythrocytes. Finally, vasculitis in HCL appears to be associated with a lasting infection in most cases.