Leveraging Single Cell Multiomics to Dissect Longitudinal and Spatial Heterogeneity in Follicular Lymphoma
View/ Open
PhD Thesis
Embargoed until: 2026-07-23
Reason: Author Request
Embargoed until: 2026-07-23
Reason: Author Request
Publisher
Metadata
Show full item recordAbstract
Follicular lymphoma (FL) exhibits substantial clinical heterogeneity, presenting a distinct challenge for the prognostication and treatment of patients. Transformation of FL to aggressive diffuse large B-cell lymphoma (tFL) substantially negatively impacts outcome; yet the biological determinants of these phenotypes and the co-evolution of the tumour and immune compartments are incompletely understood. Therefore, the goal of this thesis was to dissect the complex landscape of FL through the application of high-resolution single cell methodologies. Multiomic single cell sequencing of the transcriptome, B-cell receptor (BCR) and T-cell receptor (TCR) in FL revealed divergent tumour-intrinsic and extrinsic features which discriminated patients with or without transformation. FL tumour cells exhibited a broader spectrum of B-cell differentiation states beyond the classical germinal centre (GC) cell-of-origin, with every tumour composed of a range of states. Tumours from patients without transformation predominantly harboured GC-like states whilst those who transform were characterized by an enrichment of memory-like states. Analyses of the TME identified substantial heterogeneity, with prominent CD4+ TFH populations in ntFL tumours compared to increasingly dysfunctional and exhausted CD8+ and NK cell states, progressing from pFL to tFL. Alongside, the T-cell states, the T-cell clonotypic dynamics from pFL to tFL indicated the expansion of novel CD8+ clonotypes that were predominantly exhausted. Longitudinal analyses revealed distinct transitions in malignant and immune cell states over the course of transformation and revealed features detectable prior to the occurrence of transformation which demonstrated utility in accurately predicting adverse outcome and transformation in bulk RNA-seq FL cohorts. Alterations in the immune landscape of FL were not confined to the local tumour microenvironment, but instead immune alterations extended to the peripheral blood (PB) immune landscape. FL patients exhibited expanded peripheral CD8+ T cell populations which expressed activation and immune checkpoint markers and increased proportions of TREG cells, mimicking the immune subversions identified in the tumour microenvironment, highlighting the potential of the PB immunome to provide a window into the FL immune landscape which may have relevance for prognosis in FL. Collectively, this thesis provides new insights into the evolutionary B-cell and immune cell dynamics shaping FL and its evolution towards transformation, and serves as a critical resource for further discovery and therapeutic evaluation.
Authors
Perrett, MCollections
- Theses [4223]