P196 Laboratory assessment of inflammation activity in pediatric inflammatory bowel disease

Abstract

method to image inflammatory activity, novel state-of-the-art scintigraphy including SPECT-CT has not been validated for the measurement of inflammatory load in UC in comparison with other inflammatory markers. We aimed to prospectively validate leukocyte SPECT-CT as a tool to measure and quantify inflammatory load in patients with different extent and severity of UC. Methods: UC patients with an indication for ileocolonoscopy were included. Within 1 week and without any changes in therapy both colonoscopy (Mayo score, UCEIS) with biopsies (Geboes score) and leukocyte scintigraphy were performed. In addition, serum C-reactive protein and fecal calprotectin (Buhlmann ELISA) were measured and clinical questionnaires (CCAI, Mayo) were collected. Patients’ peripheral blood leukocytes were isolated and labelled with 200 (188 220) MBq technetium-99m HMPAO. SPECT combined with a low-dose CT was performed 60 min after reinjection of labelled cells. To quantify inflammation in each colon segment the maximum uptake of leukocytes was calculated as a ratio to the mean uptake in bone marrow of 4 lumbar vertrebrae and expressed as SPECT inflammation classification of each colon segment and a Summed Activity Score (SAS) for the inflammatory activity in all 5 colonic segments. Results: Twenty-six UC patients were studied. 3/26 were using anti-TNF, 4/26 thiopurines, 3/26 prednisone and 20/26 5-ASA at inclusion. At endoscopy 12/26 (46%) of patients had pancolitis, 8/26 (31%) left-sided colitis and 6/26 (23%) proctitis. According to endoscopic Mayo score, 1/26 (4%) of patients had inactive, 5/26 (19%) mild, 8/26 (31%) moderate or 12/26 (46%) severe disease. The median (IQR) full Mayo score was 7 (5 10), CCAI: 6 (2 9), serum CRP 4.1mg/L (1.7 12.5) and fecal Calprotectin 449 ug/g (245 1142). According to SPECT-CT patients were classified as having 9/26 Mild, 12/26 Moderate, 5/26 Severe disease for their most affected colon segment. Significant correlations (Spearman) were observed between this SPECT inflammation classification and endoscopic Mayo: r 0.54 (P< 0.01), UCEIS r 0.56 (P< 0.01) and histologic Geboes score r 0.59 (P< 0.01). The Summed Activity Score correlated better with fecal calprotectin r 0.55 (P< 0.01) than with CRP: r 0.24 (P= 0.24), CCAI: r 0.43 (P< 0.05) or clinical Mayo: r 0.54 (P< 0.01). Conclusions: SPECT-CT classification of disease severity of the most inflamed colon segment is correlated with both endoscopic and histologic scores for UC. The total inflammatory load in Ulcerative Colitis at SPECT-CT is better reflected by fecal calprotectin compared to serum CRP.