Expression of PD-1/PD-L1 pathway molecules in human cardiac allograft according to acute cellular rejection status: insights from a Korean Heart Transplant Cohort.
{"title":"Expression of PD-1/PD-L1 pathway molecules in human cardiac allograft according to acute cellular rejection status: insights from a Korean Heart Transplant Cohort.","authors":"Jeemin Yim, Yoon Kyung Jeon, Doo Hyun Chung, Jaemoon Koh","doi":"10.4132/jptm.2026.01.02","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Acute cellular rejection (ACR) following heart transplantation (TPL) compromises graft function and survival. The programmed cell death-1 (PD-1)/PD-1 ligand-1 (PD-L1) pathway represents an immune checkpoint that maintains peripheral immune tolerance, but its expression and significance in human cardiac allografts with ACR remain unclear. Thus, we investigated PD-1/ PD-L1 expression in endomyocardial biopsies from heart TPL recipients to clarify the role of this pathway in the ACR of human cardiac allografts and explore the potential of therapeutic modulation of PD-1/PD-L1 in this setting.</p><p><strong>Methods: </strong>Endomyocardial biopsies of 78 patients with heart TPL were subjected to immunohistochemistry for PD-L1, PD-1, CD4, and CD8. PD-L1 expression and quantities of PD-1+, CD4+, and CD8+ infiltrating lymphocytes were evaluated according to clinicopathological features, ACR presence, and clinical outcomes.</p><p><strong>Results: </strong>Allografts with high-grade ACR (International Society for Heart and Lung Transplantation grades 2R and 3R) demonstrated markedly higher PD-L1 expression than did those without ACR (62.5% vs. 16.1%, p < .001). PD-L1 expression was positively associated with CD4+ lymphocyte infiltration (p = .025), whereas CD8 and PD-1+ lymphocyte counts were higher in PD-L1-positive allografts without reaching statistical significance (p = .059 and p = .390, respectively). Serial biopsies revealed that PD-L1 expression was upregulated in patients with high-grade ACR compared with that in previous non-ACR tissues, and follow-up biopsies were performed after ACR resolution.</p><p><strong>Conclusions: </strong>The PD-1/PD-L1 pathway is involved in ACR regulation in human cardiac allografts. Increased PD-L1 expression during ACR may represent a counteractive mechanism to limit alloimmune-mediated tissue injury, supporting PD-1/PD-L1 as a potential therapeutic target in heart TPL recipients.</p>","PeriodicalId":46933,"journal":{"name":"Journal of Pathology and Translational Medicine","volume":" ","pages":""},"PeriodicalIF":3.0000,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Pathology and Translational Medicine","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.4132/jptm.2026.01.02","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PATHOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Background: Acute cellular rejection (ACR) following heart transplantation (TPL) compromises graft function and survival. The programmed cell death-1 (PD-1)/PD-1 ligand-1 (PD-L1) pathway represents an immune checkpoint that maintains peripheral immune tolerance, but its expression and significance in human cardiac allografts with ACR remain unclear. Thus, we investigated PD-1/ PD-L1 expression in endomyocardial biopsies from heart TPL recipients to clarify the role of this pathway in the ACR of human cardiac allografts and explore the potential of therapeutic modulation of PD-1/PD-L1 in this setting.
Methods: Endomyocardial biopsies of 78 patients with heart TPL were subjected to immunohistochemistry for PD-L1, PD-1, CD4, and CD8. PD-L1 expression and quantities of PD-1+, CD4+, and CD8+ infiltrating lymphocytes were evaluated according to clinicopathological features, ACR presence, and clinical outcomes.
Results: Allografts with high-grade ACR (International Society for Heart and Lung Transplantation grades 2R and 3R) demonstrated markedly higher PD-L1 expression than did those without ACR (62.5% vs. 16.1%, p < .001). PD-L1 expression was positively associated with CD4+ lymphocyte infiltration (p = .025), whereas CD8 and PD-1+ lymphocyte counts were higher in PD-L1-positive allografts without reaching statistical significance (p = .059 and p = .390, respectively). Serial biopsies revealed that PD-L1 expression was upregulated in patients with high-grade ACR compared with that in previous non-ACR tissues, and follow-up biopsies were performed after ACR resolution.
Conclusions: The PD-1/PD-L1 pathway is involved in ACR regulation in human cardiac allografts. Increased PD-L1 expression during ACR may represent a counteractive mechanism to limit alloimmune-mediated tissue injury, supporting PD-1/PD-L1 as a potential therapeutic target in heart TPL recipients.
期刊介绍：
The Journal of Pathology and Translational Medicine is an open venue for the rapid publication of major achievements in various fields of pathology, cytopathology, and biomedical and translational research. The Journal aims to share new insights into the molecular and cellular mechanisms of human diseases and to report major advances in both experimental and clinical medicine, with a particular emphasis on translational research. The investigations of human cells and tissues using high-dimensional biology techniques such as genomics and proteomics will be given a high priority. Articles on stem cell biology are also welcome. The categories of manuscript include original articles, review and perspective articles, case studies, brief case reports, and letters to the editor.
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号
