Novel risk stratification of de novo diffuse large B cell lymphoma based on tumour-infiltrating T lymphocytes evaluated by flow cytometry.

The prognostic value of tumour-infiltrating T lymphocytes (TIL-Ts) has been demonstrated in many solid tumours but remained unclear in diffuse large B cell lymphoma (DLBCL). We conducted a retrospective cohort study reviewing the TIL-Ts proportion and CD4:CD8 of 66 de novo DLBCL by flow cytometry to construct a risk stratification based on TIL-Ts-related prognostic factors. In univariate analysis, low TIL-Ts (< 14%) was significantly related to shorter survival (HR = 2.58, 95% CI 1.11-5.99, p = 0.028). In multivariate analysis, low TIL-Ts (HR = 6.48, 95% CI 2.16-19.46, p = 0.001) and high CD4:CD8 (> 1.2) (HR = 4.22, 95% CI 1.43-12.35, p = 0.009) were independent risk factors. For the risk stratification, three groups were defined based on TIL-Ts-related risk factors: low-risk group (high TIL-Ts and low CD4:CD8), intermediate risk group (low TIL-Ts, low CD4:CD8 or high TIL-Ts, high CD4:CD8) and high-risk group (low TIL-Ts and high CD4:CD8). The patients in high-risk group have significantly shorter survival than that in intermediate risk group (p = 0.025) and low-risk group (p = 0.002). This new risk stratification which is independent of performance status and age of the patients could hint the prognosis and may guide treatment of DLBCL.