Novel tumour-infiltrating lymphocyte-related risk stratification based by flow cytometry for patients with de novo angioimmunoblastic T cell lymphoma.

Tumour-infiltrating lymphocytes (TILs) account for a large proportion of tumour microenvironment (TME) in angioimmunoblastic T cell lymphoma (AITL), and at present the significance of TIL in TME of AITL remains unclear. Overall, 50 de novo AITL patients undergoing lymph node flow cytometry from 2014 to 2019 were retrospectively analysed to assess the relationship between TILs and AITL prognosis. We found that high TIL-Bs (≥ 42.4%, p = 0.004) and high CD4:CD8 (≥ 0.85, p = 0.024) were independent favourable prognostic factors for de novo AITL in univariate or multivariate analyses. New TIL-related risk stratification was established based on TIL-Bs and CD4:CD8 factors. Patients in the low-risk group (TIL-Bs ≥ 42.4% and CD4:CD8 ≥ 0.85) had significantly better overall survival than the high-risk (TIL-Bs < 42.4% and CD4:CD8 < 0.85) (p < 0.001) or intermediate-risk group (TIL-Bs ≥ 42.4% and CD4:CD8 < 0.85 or TIL-Bs < 42.4% and CD4:CD8 ≥ 0.85) (p = 0.011). To our knowledge, our cohort is the largest one focusing on the TILs in de novo cases of AITL by analysing lymph node samples using flow cytometry, which is the first time to comprehensively consider humoral immunity and cellular immunity influence on AITL. Our new risk stratification was valuable and useful in evaluating prognosis of AITL and guiding immunotherapy strategies.