Hydrophobic complementarity-determining region 3 (CDR3) sequences elucidate the cardiotoxic effects

Sep 30, 2026

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Immune checkpoint inhibitors (ICIs) improve cancer outcomes but can cause serious immune-related adverse events, especially cardiotoxicity. Researchers investigated peripheral blood mononuclear cells and T cells from heart tissue of patients who developed cardiotoxicity during ICI therapy. Using spectral flow cytometry, single-cell RNA sequencing, and TCR sequencing, they identified altered immune profiles, including increased circulating FOXP3+ CD4+ and PRF1+ CD8+ T cells at disease onset. Findings also show effector CD8 T cells in heart tissue and pericardial fluid, TCR expansions with activation markers, and shorter, more hydrophobic CDR3 sequences supporting a hydrophobic TCR mechanism for myocarditis. Overall, the work informs strategies targeting TCR physical properties to reduce risk and enable more precise therapies.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages33

Reading Time1 h 23 min

AccessFree to download

Background

Clinical challenge and diagnosis of irAE cardiotoxicity

Study design and methods

Patient cohorts and sample collection

Single-cell analysis and TCR sequencing

Key findings

Immune cell changes at disease onset

Effector CD8 T cells in myocarditis tissues

TCR expansion and activation markers

Hydrophobic, shorter CDR3 sequences

Implications and future directions

Columbia University Medical Center F. Hoffmann-La Roche Columbia University Medical Center Columbia University Medical Center Columbia University Medical Center Genentech, Inc Genentech, Inc Genentech, Inc Columbia University Medical Center F. Hoffmann-La Roche Columbia University Medical Center Cardiotoxicity, myocarditis, effector T cells, immune-related adverse events, perforin 1, and T cell receptor, CDR3, hydrophobic TCR December 16th, 2025 [https://doi.org/10.21203/rs.3.rs-8320867/v1](https://doi.org/10.21203/rs.3.rs-8320867/v1) 􀁱 􀅏 This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License The authors declare no competing interests. Immune checkpoint inhibitors (ICIs) have signi«cantly changed cancer treatment, demonstrating strong e cacy across multiple cancers. However, their use also carries the risk of serious immune-related side effects (irAEs), especially cardiotoxicity. To understand how these adverse effects occur, we studied peripheral blood mononuclear cells and T cells taken from the heart tissue of cancer patients who experienced cardiotoxicity during ICI therapy. Using spectral ¬ow cytometry, single-cell RNA sequencing, and T cell receptor (TCR) sequencing, we found key differences in the immune pro«les of affected patients. Those with cardiotoxicity had a noticeable increase in circulating CD4 + FOXP3 + and CD8 + PRF1 + T cells at disease onset. Our results also show that effector CD8 T cells are present in the heart tissue and pericardial ¬uid of patients with myocarditis, highlighting their role in starting the disease. TCR sequencing revealed expansions of CD8 GZMK + GZMA + and CD8 PRF1 + GZMA + T cells in myocarditis patients, along with increased activation markers CD69 and KLRG1, supporting the idea that speci«c cytotoxic CD8 T cell groups promote in¬ammation. Notably, we also found that T cells from patients with irAE myocarditis have shorter TCR CDR3 sequences, with a higher proportion of hydrophobic residues. This discovery suggests a new mechanism for TCR involvement in irAEmyocarditis, focusing on T cell activation through the TCR's functional promiscuity, which relies more on TCR-MHC interactions than on speci«c peptide features. Overall, this research provides a foundation for new strategies targeting TCR physical properties to reduce risks and develop more precise therapies for vulnerable patients. Immune checkpoint inhibitors (ICIs) have signi«cantly improved outcomes for patients with cancer ( 1– 5) . However, they can also lead to immune-related adverse events (irAEs), including cardiotoxicity. This ICI-related cardiotoxicity is a serious condition, with a mortality rate of up to 50% for myocarditis ( 6), and often necessitates the permanent discontinuation of ICI therapy (6–8) . ICIs enhance the immune system's ability to combat cancer by targeting immune checkpoints that regulate immune responses. While effective against tumors, ICIs may inadvertently trigger autoimmune-like responses, resulting in in¬ammation in various organs, including the heart (9–11) . The onset of irAE cardiotoxicity, particularly myocarditis, is complex and involves T cell activation, cytokine release, and potential autoantibody formation. These mechanisms result in heart muscle in¬ammation, which can lead to chest pain and shortness of breath. In half of the cases, myocarditis can lead to heart failure, arrhythmias, and death ( 6–8) . Diagnosing irAE myocarditis can be di cult due to symptom overlap with other cardiac conditions. Con« rmation generally requires clinical evaluation, cardiac biomarkers, electrocardiograms, imaging tests such as cardiac MRI, and occasionally an endomyocardial biopsy. There is no consensus on how to treat these patients. New experimental, targeted, biologically informed therapies, such as abatacept and ruxolitinib, are under investigation (12) . Timely diagnosis and intervention are essential for a

FAQs

What question does the study address about ICI-related cardiotoxicity?

How T-cell involvement occurs in ICI-induced cardiotoxicity, with a focus on whether TCR CDR3 sequence characteristics mechanistically contribute to the pathogenesis of irAE myocarditis.

Which experimental approaches were used to profile immune and TCR features?

Spectral flow cytometry, single-cell RNA sequencing, and T cell receptor (TCR) sequencing were used to compare immune profiles and define TCR repertoire changes in affected patients.

What was distinctive about the TCR CDR3 sequences in irAE myocarditis patients?

T cells from irAE myocarditis patients had shorter TCR CDR3 sequences with a higher proportion of hydrophobic residues, suggesting a role for hydrophobicity and TCR functional promiscuity in promoting inflammation.

Sep 30, 2026

Uploaded by Putri