A retrospective study of radiolabeled granulocyte kinetics in patients with systemic vasculitis.

Patients with systemic vasculitis, including Wegener's granulomatosis (WG) and microscopic polyarteritis (MP), may undergo white cell scanning for the investigation of infective complications and/or occult fever. In a retrospective study of 12 patients with systemic vasculitis (six each of WG and MP), all with renal disease, we observed increase diffuse lung radioactivity soon after the injection of 111In-labeled granulocytes or 99mTc-HMPAO-labeled leukocytes in all patients with WG and in three with MP. Lung activity was quantified by comparison with the liver or spleen. The lung:liver count rate ratio per pixel, 1-1.5 hr after injection, in patients with systemic vasculitis was 0.87 (s.d. 0.25), significantly higher (p less than 0.001) than the ratio 0.38 (0.13) in patient controls who had normal white cell scans. The majority of patients with systemic vasculitis had scintigraphic evidence of abnormal splenic function. Two had focal splenic defects, while 7 had increased labeled cell uptake. Nine of the patients with vasculitis showed cell migration into the gut, presumably as a result of vasculitis, and in 6 it was prominent. Focal nasal uptake was found in 5/7 patients with systemic vasculitis who had their heads imaged, and may be specific for WG. Although all patients had renal disease, there was scintigraphic evidence of diffuse parenchymal renal uptake of 111In-labeled granulocytes in only one (with MP). The presence of anti-neutrophil cytoplasmic antibodies did not correlate with any abnormality or with lung uptake. Systemic vasculitis is associated with abnormalities of granulocyte kinetics, particularly involving the lung and spleen.