111In-oxine-labelled white blood cells in the diagnosis and follow-up of Crohn's disease.

Prospectively, 43 patients with Crohn's disease (41 clinically active, 2 clinically inactive) and 7 patients with irritable bowel syndrome were examined by 111In-oxine-labelled leukocytes ('mixed' leukocyte preparations, n = 8; 'pure' granulocyte preparations, n = 42). The number of scintigraphically diagnosed inflamed bowel segments correlated significantly (r = 0.95, p less than 0.001) with the number of radiologically and endoscopically diagnosed segments. The exact localization of the diseased ileum may be difficult by scintigraphy. One complicating abscess and two fistulas were correctly diagnosed. The percentage of fecal excretion of radiolabelled leukocytes is highly specific for intestinal inflammations. It correlates significantly with the erythrocyte sedimentation rate (r = +0.69, p less than 0.001), serum albumin (r = -0.54, p less than 0.001), orosomucoid (r = +0.65, p less than 0.001), and with the A.I. (van Hees) (r = +0.67, p less than 0.001). In the follow-up of 9 patients, the percentage of fecal excretion decreased or increased more rapidly, but in correlation with the CDAI, A.I., or ESR. The authors conclude that this method is an alternative to common methods and that it is superior in primary diagnosis in patients with severe disease, bowel stenosis, abscesses, and after surgery. After clinical and biopsy-proven diagnosis of Crohn's disease, the special value of the leukocyte scan lies in the noninvasive follow-up of patients and its potential of localizing inflamed bowel segments and assessing disease activity.