Antigranulocyte monoclonal antibody immunoscintigraphy in inflammatory bowel disease in children and young adolescents

Aim: Diagnostic delay for inflammatory bowel disease (IBD) is frequent, especially in paediatric patients. Scintigraphy with labelled leucocytes has been proposed as a very sensitive diagnostic tool for detecting bowel inflammation. The aim of this study was to evaluate the sensitivity and specificity of immunoscintigraphy in the diagnosis and follow-up of children with IBD and to compare this technique with other diagnostic techniques. Methods: Sixty-six children with histologically confirmed IBD were enrolled in the study. Twenty-one children in whom IBD was suspected but subsequently not confirmed were used as controls. A total of 138 immunoscintigraphies were performed using 99mTechnetium-labelled monoclonal anti-granulocyte antibodies. Immunoscintigraphy was also compared with other diagnostic techniques. Results: Overall sensitivity of monoclonal antibody immunoscintigraphy (MoAb-IS) in patients with clinically active disease was 94% for Crohn's disease (CD) and 85% for ulcerative colitis (UC). Ultrasonography, endoscopy and radiology were carried out at the same time in 29 patients with CD and in 6 patients with UC: sensitivity of IS was 90% compared with 76% of colonoscopy, 75% for enemas, and 55% for sonography. IS was negative (specificity) in 24% of patients with CD and in 67% of patients with UC during remission, and in 64% of controls with other causes of intestinal inflammation. Diagnostic delay was significantly shorter when compared with a historical cohort of patients. Conclusion: Immunoscintigraphy is a highly sensitive detector of intestinal inflammation in young patients with IBD and can be useful for reducing diagnostic delay. However, its specificity is low and all positive cases must be confirmed histologically.