Expression Levels of 4 Genes in Colon Tissue Might be Used to Predict Which Patients Will Enter Endoscopic Remission After Vedolizumab Therapy for Inflammatory Bowel Diseases.
Clin Gastroenterol Hepatol. 2019 Aug 22;:
Authors: Verstockt B, Verstockt S, Veny M, Dehairs J, Arnauts K, Van Assche G, De Hertogh G, Vermeire S, Salas A, Ferrante M
BACKGROUND & AIMS: We aimed to identify biomarkers that might be used to predict responses of patients with inflammatory bowel diseases (IBD) to vedolizumab therapy.
METHODS: We obtained biopsies from inflamed colon of patients with IBD who began treatment with vedolizumab (n=31) or tumor necrosis factor (TNF) antagonists (n=20) and performed RNA-sequencing analyses. We compared gene expression patterns between patients who did and did not enter endoscopic remission (absence of ulcerations at month 6 for patients with Crohn’s disease or Mayo endoscopic sub-score ≤1 at week 14 for patients with ulcerative colitis) and performed pathway analysis and cell deconvolution for training (n=20) and validation (n=11) datasets. Colon biopsies were also analyzed by immunohistochemistry. We validated a baseline gene expression pattern associated with endoscopic remission after vedolizumab therapy using 3 independent datasets (n=66).
RESULTS: We identified significant differences in expression levels of 44 genes between patients who entered remission after vedolizumab and those who did not; we found significant increases in leukocyte migration in colon tissues from patients who did not enter remission (P<.006). Deconvolution methods identified a significant enrichment of monocytes (P=.005), M1-macrophages (P=.05), and CD4+ T cells (P=.008) in colon tissues from patients who did not enter remission, whereas colon tissues from patients in remission had higher numbers of naïve B-cells before treatment (P=.05). Baseline expression levels of PIWIL1, MAATS1, RGS13, and DCHS2 identified patients who did vs did not enter remission with 80% accuracy in the training set and 100% accuracy in validation dataset 1. We validated these findings in the 3 independent datasets by microarray, RNA sequencing and quantitative PCR analysis (P=.003). Expression levels of these 4 genes did not associate with response to anti-TNF agents. We confirmed the presence of proteins encoded by mRNAs using immunohistochemistry.
CONCLUSIONS: We identified 4 genes whose baseline expression levels in colon tissues of patients with IBD associate with endoscopic remission after vedolizumab, but not anti-TNF, treatment. We validated this signature in 4 independent datasets and also at the protein level. Studies of these genes might provide insights into the mechanisms of vedolizumab.
PMID: 31446181 [PubMed – as supplied by publisher]