Palmer, Christine D.

Classic Hodgkin Lymphoma (cHL) is characterized by the presence of abnormal large cells known as Hodgkin Reed-Sternberg (HRS) cells. Curative intent chemotherapy has a 90% response rate, but for refractory patients, current immunotherapies remain insufficient. Ongoing research aims to enhance therapy and patient outcomes by focusing on the tumor microenvironment (TME), a complex environment that includes diverse non-malignant cells, including immune cells, which constitute a critical component of the TME. Utilizing multiplex analysis to comprehend these intricate interactions can pave the way for identifying novel strategies to combat cancer more effectively. CD30-targeted therapies and PD1/PDL1 inhibitors are under investigation clinically and could potentially benefit from adding checkpoint markers such as TIM-3 to enhance patient outcomes by addressing T-cell exhaustion. Such combination strategies will require assays and analysis strategies that can describe both spatial and multi-marker data. Multiplex immunofluorescence (mIF) is a valuable tool for analyzing spatial biology, patient selection, mechanism of action, pharmacodynamics and biomarker assays predictive of response. Describing the relationship between T cell exhaustion and response in cHL may guide the development of targeted treatments aimed at restoring the immune system's ability to recognize and eliminate cancer cells. Twenty-five to thirty percent of cHL patients with advanced stages do not respond to standard therapies. To understand the mechanisms of resistance, we developed a mIF panel (CD4, CD8, CD30, PD-1, PD-L1, and TIM3) for formalin-fixed and paraffin-embedded cHL tissues on the OPAL Tyramide Signal Amplification system and the Leica Bond RX. A set of commercially sourced cHL whole tissue samples (n=5) were used to develop and validate the panel, with qualitative evaluations by a Hematopathologist affirming that the mIF and 3, 3'-diaminobenzidine (DAB) staining yielded comparable results. Subsequently, a cohort of cHL samples (n=34) were stained and underwent exploratory image (Halo) and data (Microsoft Excel and R Studio) analyses. The image analysis strategy includes cell segmentation and phenotyping for all markers in the panel, identifying individual cell populations and multi-marker co-expressing cell populations. Additionally, spatial analysis describes the relationships between key phenotypes in the TME. The quantity of exhausted T cells, their average distance to HRS cells and the average count of exhausted T cells within different proximities of HRS cells will be presented. The development of this mIF assay for cHL demonstrates its consistent application at a mid-scale level across a diverse patient population with varying medical backgrounds and treatment histories. This approach provides a deeper understanding of immune response diversity and cellular composition within cHL. Future deployment of the panel against clinical trial samples with outcomes and responses will yield further insights.