Targeting Lymphoma Associated Myeloid-Monocytic Cells through CSF1R Blockade Enhances CAR-T Cell Response in Aggressive B Cell Lymphoma
Bibliographic record
Abstract
Introduction: Chimeric antigen receptor (CAR) T cell therapy has substantially improved the outcome of patients suffering from relapsed and/or refractory (r/r) aggressive B cell lymphoma. However, around 60% of patients do not show long-term remissions after CAR-T cell therapy. Recent studies have indicated a relevant role of the lymphoma microenvironment (LME) in response and resistance to CAR-T cell therapy. However, targeting the LME in aggressive B cell lymphoma to boost CAR-T cell efficacy has not yet been sufficiently explored. We therefore aimed to unravel the immunosuppressive capacity of the LME and its myelo-monocytic cell compartment with the ultimate goal to identify potential therapeutic targets and enhance CAR-T cell response. Methods: To elucidate hallmarks associated with an immunosuppressive LME and CAR-T cell resistance in patients with r/r B cell lymphoma, we applied multi-dimensional analyses to pre- and post-CAR-T cell-treated human lymphoma specimens (n = 41), including bulk RNA sequencing, single-cell RNA sequencing of 47,078 live cells and Imaging Mass Cytometry (IMC). To validate our findings and explore the potential of new therapeutic targets, we utilized ex vivo co-culture experiments, a fully murine CD19 CAR-T cell therapy platform in an immunocompetent, autochthonous DLBCL mouse model and performed bulk RNA sequencing and IMC of diseased spleens. Results: In our cohort of CAR-T cell treated patients (n = 104) durable response, defined as complete remission six months after CAR-T cell therapy, resulted in prolonged progression-free and overall survival. In CAR-T cell non-durable responding lymphoma patients, we identified a prognostically relevant lymphoma-associated myelo-monocytic (LAMM) signature including genes such as CD14, CD68, MARCO, ITGAM, IL1B, IL10 and S100A9. Furthermore, non-durable response was characterized by increased hypoxia and reduced (CD8+) T cell infiltration. In particular, in-depth profiling using single-cell RNA sequencing and IMC revealed a distinct CSF1R+CD14+CD68+ LAMM cell population associated with non-durable response and poor clinical outcome in CAR-T cell-treated patients with r/r B cell lymphoma. Importantly, high LAMM and low CD8+ T cell infiltration prior to CAR-T cell therapy showed a reduced progression-free survival when compared to low LAMM and high CD8+ T cell infiltration in r/r B cell lymphoma samples. Next, in ex vivo co-culture experiments we demonstrated that CSF1R+ LAMM cells strongly inhibit the proliferation and the cytotoxic capacity of CAR-T cells. To elaborate on LAMM-T cell interaction at a molecular level, we performed inference analysis of cell-cell communication in our single-cell RNA sequencing dataset using CellphoneDB which revealed that LAMM cells exert their immunosuppressive function by direct interaction with T cells via prostaglandin E2 (PGE2) and EP2/EP4 receptor signaling. Most strikingly, applying a fully autochthonous DLBCL CAR-T cell mouse model, we demonstrated that the combination of CD19 CAR-T cell therapy with CSF1R blockade switches an immunosuppressive LME into a T cell-enriched LME, which was accompanied by a follicular architecture and blood vessel normalization of diseased spleens indicated by IMC analysis. Finally, we showed that the combination of CSF1R inhibition and CD19 CAR-T cell therapy displayed synergistic treatment effects and prolonged survival with long-lasting, complete remissions. Conclusion: Our multiomic data and preclinical models provide strong evidence that CSF1R+ LAMM cells contribute to CAR-T cell failure in r/r aggressive B cell lymphoma and that CSF1R inhibition synergistically improves CD19 CAR-T cell response, promotes an immunosupportive microenvironment and restores anti-lymphoma immunity. Given that CSF1R inhibitors have already been clinically evaluated and FDA-approved in other malignancies, this therapeutic combination has the potential for rapid clinical translation. Based on our findings, we propose to test the combination of CAR-T cell therapy and CSF1R inhibitors in patients with r/r aggressive B cell lymphoma within prospective clinical trials.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".