Usefulness of peripheral blood monocyte count to predict relapse in patients with inflammatory bowel disease: a prospective longitudinal cohort study.

BACKGROUND

monocytes play an important role in the pathogenesis of inflammatory bowel disease but data are scarce regarding activity biomarkers, above all in patients under biologic therapies.

OBJECTIVE

the aim of this study was to evaluate the value of monocyte measurements in predicting flares in inflammatory bowel disease patients under maintenance treatment with anti-TNF.

METHODS

a prospective, observational cohort study was designed. Relapse was defined as a Harvey-Bradshaw score > 4 in Crohn's disease, and a partial Mayo score ≥ 2 in ulcerative colitis. Monocyte concentration was quantified at 4-month intervals for twelve months. A total of 95 consecutive patients were included. Median age was 42 years, 50.5 % were female, and 75 % had Crohn's disease.

RESULTS

sixteen months after inclusion, 65 (68.4 %) patients remained in clinical remission. Mean monocyte count preceding a relapse was 563 (standard deviation: 144) compared to 405 (standard deviation: 177) in patients who remained in remission. Final monocyte count was significantly different between relapse and remission in Crohn's disease (0.82; 95 % CI: 0.71-0.90; p < 0.005). According to the multivariate analysis, only monocytes and fecal calprotectin were related to more relapses.

CONCLUSION

in conclusion, in inflammatory bowel disease patients under anti-TNF therapy, repeat monocyte counts could help monitor patients, at least in Crohn's disease.