Overexpression of programmed death ligand 1 in refractory inflammatory bowel disease

Jessica Nguyen, Brian S. Finkelman, David Escobar, Yue Xue, Kristy Wolniak, Maryam Kherad Pezhouh*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Programmed death ligand 1 (PD-L1) dysregulation has been implicated in chronic inflammatory diseases, but its role in regulating intestinal mucosa inflammation is still unclear. The aim of this study was to assess PD-L1 expression in the intestinal mucosa of patients with refractory inflammatory bowel disease (IBD) compared to controls. We evaluated PD-L1 expression by immunohistochemistry in colectomy specimens of patients with ulcerative colitis (UC) and Crohn disease (CD) compared to controls. PD-L1 expression was assessed in colonic epithelium and inflammatory cells, along with the location of the inflammatory cells expressing PD-L1. All cases were stained with CD3, CD4, CD8, FOXP3, CD20, CD68, and CD90 immunostains to determine the types of cells expressing PD-L1. The UC group showed significantly higher PD-L1 expression in the colonic epithelium than both CD and control groups (both P < 0.001), and CD was also significantly higher than the control group (P = 0.004). Both UC and CD groups showed similar PD-L1 expression in the inflammatory infiltrate but significantly higher than the control group (both P < 0.001). Among both IBD groups, higher IBD activity was associated with higher levels of PD-L1 expression in the colonic epithelium (P < 0.05) and inflammatory infiltrate (P < 0.001). When comparing PD-L1 expression to lineage-specific markers, CD3+, CD4+ T cells, CD68+ macrophages, and CD90+ colonic stromal cells appeared to be expressing PD-L1. These findings implicate a role for PD-L1 in the dysregulation of the immune response in refractory IBD. Further studies are warranted to better understand the role of the immune regulatory pathways in intestinal mucosa.

Original languageEnglish (US)
Pages (from-to)19-27
Number of pages9
JournalHuman pathology
StatePublished - Aug 2022


  • Crohn disease
  • IBD
  • Inflammatory bowel disease
  • PD-L1
  • Program death ligand 1
  • Ulcerative colitis

ASJC Scopus subject areas

  • Pathology and Forensic Medicine


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