Potential Proteomic Biomarkers Associated with Mucosal Healing and Relapse Prediction after IFX Withdrawals in Crohn’s Disease

Introduction and objectives: In Crohn's disease (CD), there is a discrepancy between clinical activity of the disease (symptoms) and intestinal healing. However absence of tissue healing is associated with the risk of relapse and tissue damage progression. Endoscopy is costly and invasive. Hence biomarkers correlating with intestinal healing could improve disease management and potentially decrease the number of endoscopy when patients are in clinical remission.
Aim: We aimed to identify potential biomarkers associated to CD mucosal healing and relapse after IFX withdrawals by a shotgun label-free proteomic study.
Methods: We used the STORI1 clinical trial cohort (n=103) aiming at identifying markers associated to relapse prediction after Infliximab treatment withdrawals. We used serum samples of patients in clinical remission (at base line). We grouped these according to the degree of intestinal healing seen at endoscopy or according to relapse occurrence during the 28 month follow-up and composed pooled samples. We performed depletion of the 20 most abundant plasma proteins on each serum pools and ran a proteomic label-free differential analysis using 2D-nanoUPLC-MSE HDMS Synapt G2 for data acquisition. We performed different statistical analysis. Moreover, a Gene Ontology annotation was also performed for the potential biomarkers highlighted.
Results and Discussion: We identified analysing these depleted serum pools 430 different proteins and 188 proteins common to all samples. Among these, 40 were found with a significant differential abundance in the groups compared. We selected some among the most significant one (ratio>1.3) or being by nature consistent with the context of this study (sample origin and clinical question addressed). For example, the C-reactive protein (CRP) was found with a significant Ratio of 2 between Relapsers and Non Relapsers. The other potential biomarkers associated to mucosal healing or to relapse prediction, were selected for further validation by Western Blot analysis (WB), routine laboratory tests and also by a Mass Spectrometry based technology: multiplexed selected reaction monitoring (SRM). Multiplexed SRM will enable quantitative analysis of these candidates in each individual patient as well as WB tests.
Conclusions: This research strategy and the validation results on potential biomarkers associated to mucosal healing or relapse after treatment cessation in this cohort of CD patients, as well as tests done on other CD patients, might provide new opportunities for patient follow-up test developments. The next step is to perform SRM validation on the STORI cohort and design signatures using these potential biomarkers SRM data for prognosis power evaluation.
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