In situ detection of PD1-PD-L1 interactions as a functional predictor for response to immune checkpoint inhibition in NSCLC.
Amanda Lindberg, Lars Muhl, Hui Yu, Louise Hellberg, Rebecca Artursson, Jakob Friedrich, Max Backman, Neda Hekmati, Johanna Mattsson, Cecilia Lindskog, Hans Brunnström, Johan Botling, Artur Mezheyeuski, Erika Broström, Miklos Gulyas, Klas Kärre, Johan Isaksson, Patrick Micke, Carina Strell
Author Information
Amanda Lindberg: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Lars Muhl: Department of Medicine, Huddinge, Karolinska Institutet, Stockholm, Sweden; Centre of Cancer Biomarkers CCBIO, Department of Clinical Medicine, University of Bergen, Bergen, Norway.
Hui Yu: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Louise Hellberg: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Rebecca Artursson: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Jakob Friedrich: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Max Backman: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Neda Hekmati: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Johanna Mattsson: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Cecilia Lindskog: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Hans Brunnström: Division of Pathology, Lund University, Lund, Sweden.
Johan Botling: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Artur Mezheyeuski: Vall d'Hebron Institute of Oncology, Molecular oncology group, Barcelona, Spain; Vall d'Hebron Institute of Research, Barcelona, Spain.
Erika Broström: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Miklos Gulyas: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Klas Kärre: Department of Microbiology, Cell and Tumor Biology, Karolinska Institutet, Stockholm, Sweden.
Johan Isaksson: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Patrick Micke: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Carina Strell: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden; Centre of Cancer Biomarkers CCBIO, Department of Clinical Medicine, University of Bergen, Bergen, Norway. Electronic address: carina.strell@igp.uu.se.
BACKGROUND: Immune checkpoint inhibitors (ICIs) have transformed lung cancer treatment, yet their effectiveness appears restricted to certain patient subsets. Current clinical stratification based on PD-L1 expression offers limited predictive value. Given the mechanism of action, directly detecting spatial PD1-PD-L1 interactions might yield more precise insights into immune responses and treatment outcomes. METHODS: We applied a second-generation in situ proximity ligation assay (PLA) to detect PD1-PD-L1 interactions in diagnostic tissue samples from 16 different cancer types, a tissue microarray from 352 surgically resected early-stage non-small cell lung cancer (NSCLC) patients, and finally diagnostic biopsies from 242 advanced NSCLC patients with and without ICI treatment. RNAseq analysis was used to identify potential resistance mechanisms. RESULTS: In the early-stage NSCLC, only about half of the cases with detectable PD-L1 and PD1 expression showed PD1-PD-L1 interactions, with significantly lower levels in EGFR-mutated tumors. Interaction levels varied across cancer types, aligning with reported ICI response rates. In ICI-treated NSCLC patients, higher PD1-PD-L1 interactions were linked to complete responses and longer survival, outperforming standard PD-L1 expression assays. Patients who, despite high PD1-PD-L1 interactions, did not respond to ICIs, showed additional expression of stromal immune mediators (EOMES, HAVCR1/TIM-1, JAML, FCRL1). CONCLUSION: Our study proposes a diagnostic shift from static biomarker quantification to assessing active immune pathways, providing more precise ICI treatment. This functional concept applies to tiny lung biopsies and can be used to further immune checkpoints. Accordingly, our results indicate concerted ICI resistance mechanisms, highlighting a need for combination diagnostics and therapies.
