The T Cell Receptor (TCR) Repertoire Is a Key Determinant of the Tumour Microenvironment (TME) in Diffuse Large B Cell Lymphoma (DLBCL)

• Published in: Blood 2015-12, Vol.126 (23), p.3893-3893
• Main Authors: Keane, Colm, Jones, Kimberly, Gould, Clare, Hamm, David, Wood, Peter, Birch, Simone, Crooks, Pauline, Green, Michael R, Taulaulikar, Dipti, Jain, Sanjiv, Tobin, Josh, Gandhi, Maher K
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V126.23.3893.3893

Background: We have recently demonstrated that an 'immune score' is strongly and independently prognostic in de novo DLBCL treated with R-CHOP immuno-chemotherapy. The score quantifies the relative composition of immune effectors (T cells) and checkpoints (e.g. PD-1 axis molecules and M2 macrophages), as a measure of net anti-tumoral immunity within the TME. It is also known that a diverse TCR repertoire is a hallmark of a robust anti-HIV T cell immune response; conversely in metastatic melanoma treated with anti-PD-1 checkpoint blockade, narrow more clonal TCR repertoires are associated with favorable response. The relationship between the intra-tumoral TCR repertoire and the TME in DLBCL following R-CHOP immuno-chemotherapy is unknown. Methods High-throughput unbiased TCR β chain sequencing was performed on 116 nodal tissues (101 de novo DLBCL patients treated with R-CHOP with long-term follow-up including 8 EBV+DLBCL; and 15 age/gender matched healthy lymph nodes). Outcomes included measurement of productive uniques (a measure of the number of functional T cells with a distinct TCR rearrangement or 'richness'); entropy (a measure of TCR 'diversity'), 'clonality' (a measure of clonal expansions) and the 'maximal frequency' of the most highly expressed clone within tumor biopsies. Results were compared to digital quantification (by nanoString) of key immune effector and checkpoint genes within the TME, the immune score, malignant cell-of-origin (COO), R-IPI and patient survival. Results: First we compared the TCR repertoire in lymphomatous and healthy nodes. There was a marked increase in clonality, reduced diversity and high maximal frequency within DLBCL nodes relative to healthy nodal tissue (both p