Abstract 980: Clinical impact of T-cell exhaustion in patients with diffuse large B-cell lymphoma

Abstract

Abstract Introduction: Tumor microenvironment (TME) and limited immune surveillance impact lymphoma pathogenesis and survival. Immune checkpoint receptors, such as programmed cell death-1 (PD1), lymphocyte-activation gene-3 (LAG3) and T-cell immunoglobulin and mucin domain-3 (TIM3), mediate signals leading to T-cell exhaustion and immune escape. Here, we have characterized the immunological profiles of diffuse large B-cell lymphoma (DLBCL) and associated the findings with outcome. Methods: We utilized the NanoString nCounter platform with a 770-gene PanCancer Immune panel to profile gene expression from 81 RNA samples collected from high-risk DLBCL patients. Multiplex immunohistochemistry (mIHC) with digital image analysis was used to characterize the T-cell phenotypes (CD3, CD4, CD8, PD1, LAG3, and TIM3) in two DLCBL patient cohorts (n=52 and n=136). The findings from gene expression profiling and mIHC were correlated with clinical parameters and patient outcome (i.e. progression-free survival (PFS) and overall survival (OS)). Results: Gene expression profiling revealed a high degree of heterogeneity among DLCBL. Unsupervised hierarchical clustering identified gene clusters differentially expressed between the patients. The distinct clusters contained genes for cytolytic factors and immune checkpoint molecules (GZMB, PRF1, IFNG, TIM3, LAG3), T-cells (CD3, CD2, CD28), macrophages (CD68, CD163), B-cells (MS4A1, CD19, CD79A/B), and extracellular matrix (FN1, ITGA1/5/6, VEGFA). mIHC revealed that the proportion of CD3+ T-cells varied markedly between the patients (median 24.8%, range 0.5-65.1%). On average, 8.8% (0-34.3%) of the CD3+ T-cells were positive for TIM3, whereas 0.6% (0-5.4%) were positive for LAG3. High content of TIM3+ cells was associated with poor outcome (PFS: HR 1.06, 95%CI 1.02-1.10, P=0.003; OS: HR=1.12, 95%CI 1.04-1.20, P=0.003) in a cohort of 52 DLBCL patients independent of the international prognostic index (IPI). In addition, high proportion of TIM3+CD3+ cells associated with poor survival independently of IPI (PFS: HR 1.07, 95%CI 1.00-1.14, P=0.040; OS: HR 1.087, 95%CI 1.01-1.17, P=0.019). The prognostic impact of TIM3 on survival was validated in a separate mIHC cohort of 136 DLBCL patients (PFS: HR 1.07, 95%CI 1.02-1.14, P=0.014; OS: HR 1.10, 95%CI 1.03-1.16, P=0.002). Conclusions: Our data demonstrates that the molecular immunological profile of DLBCL is heterogenic and that the expression of T-cell exhaustion marker TIM3 correlates with poor prognosis in patients with DLBCL. A more detailed characterization of immune cell composition in the TME and its impact on survival is ongoing. Citation Format: Suvi-Katri Leivonen, Matias Autio, Oscar Bruck, Satu Mustjoki, Judit M. Joergensen, Marja-Liisa Karjalainen-Lindsberg, Klaus Beiske, Harald Holte, Sirpa Leppä. Clinical impact of T-cell exhaustion in patients with diffuse large B-cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 980.