Background: Patients with hairy cell leukaemia (HCL)
have an increased susceptibility to intracellular pathogens, such as mycobacteria and Listeria. Although several abnormalities of T-cell populations have been described in HCL, the effector mechanism responsible for the increased susceptibility to infections is not known.
Methods: Blood was collected from 11 patients with
HCL and 22 age- and gender-matched volunteers.
Proinflammatory cytokine production by freshly isolated
mononuclear cells was stimulated with either lipopolysaccharide or various heat-killed microorganisms. Cytokine concentrations were assessed by specific ELISAs.
Results: We demonstrate that mononuclear cells harvested from HCL patients have a specific defect of IFNγ production when stimulated with a broad panel of bacterial stimuli. In contrast, the production of other proinflammatory cytokines, such as TNF, IL-1β and IL-6, did not differ between HCL patients and controls.
Conclusion: The specific defect in IFNγ production may play a role in the susceptibility of patients with hairy cell leukaemia towards intracellular pathogens.