Impact of the inflammatory microenvironment on T-cell phenotype in the progression from reflux oesophagitis to Barrett oesophagus and oesophageal adenocarcinoma

• Profiled T-cells in oesophageal tissue across the GORD–BO–OAC sequence.
• Assessed the impact of secreted factors from oesophageal tissue on T cell profile.
• Higher proportion of CD8−IL-4+ T cells in Barrett's tissue suggests Th2 profile.
• Higher levels of secreted IL-6 in Barrett's environment reveal promising target.
• Decreased T cell activation in OAC tissue suggests diminished immunity.

The incidence of oesophageal adenocarcinoma (OAC), arising from reflux-induced Barrett oesophagus (BO), is increasing dramatically. T-cells have recently been implicated in the initiation of oesophagitis; however, their role in the progression from oesophagitis to BO and OAC has not been fully elucidated. Previous studies have examined the secreted cytokines from oesophageal tissue during disease progression but this study is the first to examine the activation phenotype and the inflammatory profile of CD4+ and CD8+ T-cells in human oesophagitis, BO and OAC tissue. Results demonstrated significantly higher levels of IL-4 producing CD4+ T-cells and secreted levels of IL-6, confirming a Th2 phenotype in BO. In OAC tissue, both pro- and anti-inflammatory cytokines were secreted, with significantly higher levels of IL-6, IL-1β, TNF-α, IFN-γ, IL-2 and IL-10 compared with normal oesophageal tissue. In addition, CD4+ T-cells infiltrating OAC tissue displayed a decreased activation profile, with significantly lower CD45RO and CD69 expression compared with normal tissue. Data from this study suggest that factors in the tissue microenvironment may alter T-cell phenotype and function early during oesophageal disease progression and may represent targets for immune intervention.