Serum Protein Profiling of Adults and Children With Crohn Disease

ABSTRACT Objectives: Crohn disease (CD) and ulcerative colitis (UC), known collectively as inflammatory bowel diseases (IBDs), are chronic immunoinflammatory pathologies of unknown aetiology. Despite the frequent use of biomarkers in medical practice, there is a relative lack of information regarding validated paediatric biomarkers for IBD. Furthermore, biomarkers proved to be efficacious in adults are frequently extrapolated to the paediatric clinical setting without considering that the pathogenesis of many diseases is distinctly different in children. In the present study, proteomics technology was used to monitor differences in protein expression among adult and young patients with CD, identify a panel of candidate protein biomarkers that may be used to improve prognostic–diagnostic accuracy, and advance paediatric medical care. Methods: Male and female serum samples from 12 adults and 12 children with active CD were subjected to 2‐dimensional gel electrophoresis. Following the relative quantitation of protein spots exhibiting a differential expression between the 2 groups by densitometry, the spots were further characterized by matrix‐assisted laser desorption tandem time‐of‐flight mass spectrometer. The results were confirmed by Western blot analysis. Results: Clusterin was found to be significantly overexpressed in adults with CD, whereas ceruloplasmin and apolipoprotein B‐100 were found to be significantly overexpressed in children, indicating that the expression of these proteins may be implicated in the onset or progression of CD in these 2 subgroups of patients. Conclusions: Interestingly, we found a differential expression of several proteins in adults versus paediatric patients with CD. Undoubtedly, future experiments using a larger cohort of patients with CD are needed to evaluate the relevance of our preliminary findings.