Expression of costimulatory molecule CD80 in colonic dysplasia in ulcerative colitis: an immunosurveillance mechanism against colorectal cancer?

ABSTRACT

BACKGROUND AND AIMS: Ulcerative colitis is an established risk factor for colorectal cancer but dysplasia reports are much more frequent than invasive neoplasm diagnosis. The effective activation of T lymphocytes that provide antitumor surveillance requires the presence of costimulation molecules such as CD80 and CD86 on the surface of antigen-presenting cells. The aim of our study was to verify the presence of an in vivo immunosurveillance mechanism in the early stages of colon tumorigenesis. PATIENTS AND METHODS: Expression of CD80, CD86, and IFN-gamma in the colonic mucosa of 21 consecutive ulcerative colitis (UC) patients was quantified using reverse transcription polymerase chain reaction. After a 7-year follow-up period, we reviewed the histology of all surveillance colonoscopy specimens for colonic dysplasia. Correlation, frequency, and survival analyses were performed. RESULTS: CD80 was detectable in seven patients while expression of CD86 and IFN-gamma was evident in all patients. Histology confirmed the presence of dysplasia in eight patients. Patients who had dysplasia showed higher CD80 levels compared to those without dysplasia (p=0.02). Survival analysis demonstrated that cumulative dysplasia rates of CD80-positive patients were significantly higher than those of CD80-negative patients (p=0.04). CONCLUSION: Even if partially limited by a relatively small sample size, our study seems to show an association between CD80 expression and colonic dysplasia in UC patients that may suggest a role for CD80 in the immunosurveillance against colorectal cancer in this early stage of tumorigenesis. On the contrary, CD86 seems to be involved in the inflammatory pathogenesis of UC.