Model to improve specificity for identification of clinically-relevant expanded T cells in peripheral blood.

Bibliographic Details
Title: Model to improve specificity for identification of clinically-relevant expanded T cells in peripheral blood.
Authors: Julie Rytlewski, Shibing Deng, Tao Xie, Craig Davis, Harlan Robins, Erik Yusko, Jadwiga Bienkowska
Source: PLoS ONE, Vol 14, Iss 3, p e0213684 (2019)
Publisher Information: Public Library of Science (PLoS), 2019.
Publication Year: 2019
Collection: LCC:Medicine
LCC:Science
Subject Terms: Medicine, Science
More Details: Current methods to quantify T-cell clonal expansion only account for variance due to random sampling from a highly diverse repertoire space. We propose a beta-binomial model to incorporate time-dependent variance into the assessment of differentially abundant T-cell clones, identified by unique T Cell Receptor (TCR) β-chain rearrangements, and show that this model improves specificity for detecting clinically relevant clonal expansion. Using blood samples from ten healthy donors, we modeled the variance of T-cell clones within each subject over time and calibrated the dispersion parameters of the beta distribution to fit this variance. As a validation, we compared pre- versus post-treatment blood samples from urothelial cancer patients treated with atezolizumab, where clonal expansion (quantified by the earlier binomial model) was previously reported to correlate with benefit. The beta-binomial model significantly reduced the false-positive rate for detecting differentially abundant clones over time compared to the earlier binomial method. In the urothelial cancer cohort, the beta-binomial model enriched for tumor infiltrating lymphocytes among the clones detected as expanding in the peripheral blood in response to therapy compared to the binomial model and improved the overall correlation with clinical benefit. Incorporating time-dependent variance into the statistical framework for measuring differentially abundant T-cell clones improves the model's specificity for T-cells that correlate more strongly with the disease and treatment setting of-interest. Reducing background-level clonal expansion, therefore, improves the quality of clonal expansion as a biomarker for assessing the T cell immune response and correlations with clinical measures.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 1932-6203
Relation: https://doaj.org/toc/1932-6203
DOI: 10.1371/journal.pone.0213684
Access URL: https://doaj.org/article/8be2100aa85f4227b39f285fd1408e16
Accession Number: edsdoj.8be2100aa85f4227b39f285fd1408e16
Database: Directory of Open Access Journals
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More Details
ISSN:19326203
DOI:10.1371/journal.pone.0213684
Published in:PLoS ONE
Language:English