Infiltrate of effector regulatory T cells predicts outcome in a cohort of New Zealand colorectal cancer patients – a pilot study

• Published in: The Journal of immunology (1950) Vol. 196; no. 1_Supplement; pp. 212 - 212.3
• Main Authors: Kemp, Roslyn, Hartstonge, Kirsten A Ward, McCulloch, Tim, Kamps, Ann-Kristin, Cretney, Erika, McCall, John
• Format: Journal Article
• Language: English
• Published: 01.05.2016
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.196.Supp.212.3

Abstract Staging of patients with colorectal cancer is currently based on tumour morphology and does not take into account the complexity of the anti-tumour immune response. Early-stage colorectal patients are usually treated with surgery alone and are not recommended additional adjuvant therapy. Up to twenty-five percent of these patients have relapse of disease, indicating that the current staging does not accurately predict disease-free survival. The Immunoscore has been proposed to incorporate the T cell infiltrate in the tumour into current staging protocols to improve estimates of disease-free survival. However, T cell subsets are complex and therefore may have different effects on patient outcome. Immunofluorescence was used to analyse immune cell infiltrates in early stage (II) colorectal cancer patients and to compare those with recurrent and non-recurrent disease (n=33). CD3 and CD8 were used for the Immunoscore. FoxP3, Blimp-1 and CD3 were used to identify effector regulatory T cells. Patients with a high Immunoscore (high T cell infiltrate) had increased disease-free survival than patients with a low Immunoscore (low T cell infiltrate, Log-rank test p>0.001). The ability to predict patient outcome was improved by measuring the infiltrate of CD4+FoxP3+Blimp-1+ cells (effector regulatory T cells, Log-rank test p>0.001). Patients with a low Immunoscore but high infiltrate of CD4+FoxP3+Blimp-1+ cells at the centre of the tumour had increased disease-free survival than those with a low Immunoscore and a low infiltrate of CD4+FoxP3+Blimp-1+ cells. These results show that incorporating the complexity of the local immune response into current practice may improve prediction of patient outcome in colorectal cancer.