Arne Røseth

This study describes methods for extraction and quantification of calprotectin (L1 protein) in feces by enzyme immunoassay. This protein is a prominent antimicrobial component of neutrophils, monocytes, macrophages, and squamous epithelia. Calprotectin was stable in feces during storage for 7 days at room temperature. Small fecal samples taken from a 24-h feces collection gave a reliable estimate of calprotectin. Within-assay precision was 1.9%, and between-assay precision 14.8%. In healthy subjects (n = 33) median fecal calprotectin was 2025 micrograms/l and in hospital controls (n = 40) 10,500 micrograms/l. Median values in patients with Crohn's disease (n = 21) was 43,000 micrograms/l and in ulcerative colitis (n = 17) 40,000 micrograms/l. Fecal calprotectin was significantly correlated to fecal alpha 1-antitrypsin in the patients with Crohn's disease. Ten of 11 patients with gastrointestinal carcinomas had calprotectin level above the suggested reference limit of 6740 micrograms/l.

BACKGROUND: Several studies have suggested that clinical indices of disease activity in inflammatory bowel disease (IBD) do not adequately reflect the degree of inflammation in most such patients. Faecal excretion of indium-111-labelled neutrophilic granulocytes has been suggested as the gold standard of disease activity, but its complexity and high cost and the exposure of patients to ionizing irradiation have limited the use of this technique. The aim of this study was to investigate the correlation between the faecal excretion of the granulocyte marker protein calprotectin and that of 111In-labelled granulocytes. METHODS: Calprotectin in stool extracts from 19 patients with Crohn's disease (CD), 10 with ulcerative colitis (UC), and 9 presumably healthy controls was assessed with a simple enzyme-linked immunosorbent assay. Simultaneously, the faecal excretion of autologous 111In-labelled granulocytes was measured. RESULTS: There was a strong correlation between the average daily excretion of calprotectin and that of the total 3-day excretion of 111In-labelled granulocytes (r = 0.87, P < 0.0001). Furthermore, the concentration of calprotectin, assessed in a small stool sample on day 1, also correlated well with the excretion 111In-labelled granulocytes (r = 0.80, P < 0.0001). CONCLUSION: The results suggest that faecal calprotectin reflects the granulocyte migration through the gut wall in patients with IBD and hence might serve as a simple, inexpensive alternative to the indium-111 technique.

This study comprised 62 outpatients with ulcerative colitis who underwent 64 colonoscopies. The disease activity was evaluated according to endoscopic and histological criteria. The results revealed a significant correlation between both the endoscopic as well as the histological gradings of disease activity and faecal calprotectin. The median faecal calprotectin levels in the control group (6 mg/l) and in the patients with no or low disease activity (11.5 mg/l) were significantly different (p < 0.0001). The median calprotectin level among patients with active disease was 68 mg/l which was significantly different from the latter group (p < 0.0001). Furthermore, we suggest that the degree of inflammation rather than the extent of the disease determined the faecal calprotectin levels. In conclusion, assessment of faecal calprotectin seems to be a marker of disease activity in patients with ulcerative colitis.

BACKGROUND: The diagnosis of non-steroidal anti-inflammatory drug (NSAID) induced enteropathy is difficult, requiring enteroscopy or the use of four day faecal excretion of (111)In labelled white cells. AIMS: To assess faecal calprotectin (a non-degraded neutrophil cytosolic protein) as a method for diagnosing NSAID enteropathy. METHODS: Single stool faecal calprotectin concentrations were compared with the four day faecal excretion of (111)In labelled white cells in 47 patients taking NSAIDs. The prevalence and severity of NSAID enteropathy was assessed using this method in 312 patients (192 with rheumatoid arthritis, 65 with osteoarthritis, 55 with other conditions) taking 18 different NSAIDs. RESULTS: The four day faecal excretion of (111)In white cells correlated significantly with faecal calprotectin concentrations. In the group of 312 patients on NSAIDs faecal calprotectin concentrations were significantly higher than in controls, the prevalence of NSAID enteropathy being 44%. The prevalence and severity of NSAID enteropathy was independent of the particular type or dose of NSAID being taken or other patient variables. CONCLUSIONS: Assay of faecal calprotectin provides a simple practical method for diagnosing NSAID enteropathy in man. Forty four per cent of patients receiving these drugs had NSAID induced enteropathy when assessed by this technique; 20% of these had comparable levels of inflammation to that previously reported in patients with inflammatory bowel disease.

(2004). Normalization of faecal calprotectin: a predictor of mucosal healing in patients with inflammatory bowel disease. Scandinavian Journal of Gastroenterology: Vol. 39, No. 10, pp. 1017-1020.