Serum eosinophil cationic protein is superior to mast cell tryptase as marker for response to topical corticosteroid therapy in eosinophilic esophagitis.

GOALS: We evaluated the serum levels of eosinophil cationic protein (ECP) and mast cell tryptase (MCT) as surrogate markers for response to treatment in adults with eosinophilic esophagitis (EoE) under topical steroid therapy with fluticasone.
BACKGROUND: EoE is a chronic disease characterized histologically by eosinophilic inflammation of the esophagus. Esophageal mastocytosis and mast cell activation have been implicated in EoE pathogenesis. STUDY: Fifteen patients with EoE completed this prospective observational study. Before and after 3 months of therapy with fluticasone, eosinophilic and mast cell counts were analyzed from histologic samples of the esophagus and were correlated with serum markers ECP and MCT.
RESULTS: Fluticasone-therapy significantly decreased mean eosinophils [from 42.2 to 16.2 eosinophils/high-power field (hpf); P=0.004] and mast cells (from 13.9 to 5.1 mast cells/hpf; P=0.001) in the esophageal epithelium. There was a significant decrease of mean ECP (from 15.6 to 5.5 μg/L; P=0.024) and MCT-serum-values (from 4.7 to 3.8 μg/L; P=0.029) under therapy. Serum-ECP correlated significantly with histologic eosinophilic counts after fluticasone-therapy (r=0.54; P=0.038) in contrast to serum-MCT.
CONCLUSIONS: Serum-ECP but not serum-MCT could be a promising noninvasive biomarker to assess response to topical corticosteroid therapy in EoE. These findings should be confirmed by larger studies; ClincialTrials.gov number, NCT01624129.