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

Abstract

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. 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. 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). 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.