IMPAIRED NEUTROPHIL FUNCTIONS IN PATIENTS WITH LEUKOCYTOCLASTIC VASCULITIS

Background Leukocytoclastic vasculitis (LV) is characterized by segmen tal inflammation of small blood vessels, resulting in ischemic damage to the surrounding tissue. It is considered to be related to a type II I hypersensitivity reaction, although the exact etiologic mechanism is not clear. Objective The purpose of this study was to evaluate neutro phil functions in patients with LV in order to understand their role i n the pathogenesis of the disease. Methods Neutrophil functions were e xamined in 25 LV patients. The patients were divided into two groups: Group A consisted of 14 patients with drug-induced LV and Group B cons isted of 11 patients where LV was induced by other factors.Results Bot h groups of patients showed significantly reduced chemotaxis and phago cytosis. Superoxide generation was significantly lower (P < 0.001) onl y in neutrophils from patients in Group A: 5.8 +/- 0.5 nmoles O-2/10(6 ) cells/min compared to 9.08 +/- 0.8 nmoles O-2/10(6) cells/min in the controls. Preincubation on normal neutrophils with the patients' sera caused an increase in their superoxide generation in accordance with the high IL-8 levels in these sera. Conclusions Neutrophil functions w ere significantly impaired in patients with LV. It is likely that fact ors present in LV plasma may chronically activate neutrophils, so that they become refractory to further stimulation. Our study showed that neutrophil superoxide generation is low only in drug-induced LV; this test may assist in distinguishing such patients from those with LV ind uced by other causes.