Browsing by Author "Vilkki, Ville Veikko"

Immunotherapy, especially with PD-L1 and PD-1 blockers, has transformed the treatment landscape for melanoma, offering renewed hope to many. However, some patients respond well while others do not, which remains a critical challenge in immunotherapy. Peripheral blood mononuclear cells (PBMCs) play a key role in the immune system, making them good candidates for exploring the differences between good responders and bad responders. In this study, the pre-treatment PBMC profiles of melanoma patients receiving PD-1 blockers were investigated to uncover differences in the PBMC populations between good responders and bad responders. An extensive optimization process was undertaken to ensure the robustness and reproducibility of the PBMC cell suspension protocol. Single-cell RNA sequencing (scRNA-seq) was used to profile the cellular composition and gene expression patterns of the PBMCs. Chromium X microfluidics technology was used for more precise cell sorting and to obtain higher quality scRNA-seq data. After sequencing, computational techniques were applied to process the scRNA-seq data, identifying unique PBMC populations and differentially expressed genes through differential expression analysis and clustering. The analysis revealed distinct PBMC populations and demonstrated variations in cell type distributions, such as T cells, monocytes, and B cells, between good and bad responders. Multiple differentially expressed genes were identified not only in the combined scRNA-seq data but also within specific cell types. Notably, genes such as IL7R and IFI44L were predominantly upregulated in good responders, suggesting their potential roles as biomarkers for an effective immune response. Conversely, genes like CD83 were more highly expressed in bad responders, potentially indicating mechanisms of immune suppression. These findings highlight the complexity of immune interactions in response to PD-1 blockade and underscore the potential of scRNA-seq analysis of PBMCs to discover biomarkers for predicting treatment outcomes. Future studies are required to further refine cell suspension protocols and enhance data robustness. Additionally, larger cohort studies are needed to validate these findings and further clarify the cellular mechanisms influencing responses to PD-L1 blockade in melanoma, aiming to enhance the predictive power of liquid biopsies and refine immunotherapeutic strategies.