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Updated: Jun 3, 2026
Separation of Immune Cell Subpopulations in Peripheral Blood Samples from Children with Infectious Mononucleosis
Published on: September 7, 2022
EBV-specific CD8+ T cells from asymptomatic pediatric thoracic transplant patients carrying chronic high EBV loads
Camila Macedo1, Steven A Webber, Albert D Donnenberg
1Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
Insights
Monitoring Epstein-Barr virus (EBV) loads in pediatric transplant patients reveals distinct T cell responses. High EBV loads correlate with exhausted T cells, increasing risks for post-transplant lymphoproliferative disorders.
Area of Science:
- Immunology
- Transplant Medicine
- Virology
Background:
- Epstein-Barr virus (EBV) monitoring is crucial in pediatric organ transplant recipients.
- Asymptomatic patients can harbor varying EBV loads, influencing immune responses.
- Late-onset post-transplant lymphoproliferative disorders (LTD) are a significant risk in high EBV load patients.
Purpose of the Study:
- To investigate the characteristics of EBV-specific CD8(+) T cells in asymptomatic pediatric organ transplant patients with different EBV loads.
- To determine the relationship between EBV load levels and T cell activation, exhaustion, and cytokine profiles.
- To assess the implications for immunologic monitoring and risk stratification for LTD.
Main Methods:
- Serial monitoring of EBV viral loads in peripheral blood.
- Flow cytometry analysis of EBV-specific CD8(+) T cells for activation (CD38), exhaustion (PD-1, CD127), and cytokine production (IFN-γ, IL-5, IL-10).
- Categorization of patients into undetectable, chronic low, and chronic high EBV load groups.
Main Results:
- Asymptomatic patients with detectable EBV loads (low and high) showed increased EBV-specific CD8(+) T cells compared to undetectable groups.
- Low EBV load patients had moderately activated T cells with some PD-1 upregulation and IFN-γ secretion.
- High EBV load patients exhibited significant CD38 upregulation, T cell exhaustion (PD-1+/CD127-), reduced IFN-γ, and skewed immunopolarization towards IL-5 and IL-10.
Conclusions:
- Chronic EBV load and antigenic pressure significantly shape EBV-specific memory CD8(+) T cell phenotypes and functions.
- High EBV loads are associated with exhausted T cell signatures, indicating a higher risk for LTD.
- Combined phenotypic and functional monitoring of EBV-specific CD8(+) T cells is essential for accurate immunologic assessment and clinical management.
Abstract:
Serial EBV load monitoring of clinically asymptomatic pediatric thoracic organ transplant patients has identified three groups of children who exhibit undetectable (<100 copies/ml), chronic low (100-16,000 copies/ml), or chronic high (>16,000 copies/ml) EBV loads in peripheral blood. Chronic high EBV load patients have a 45% rate of progression to late-onset posttransplant lymphoproliferative disorders. In this article, we report that asymptomatic patients carrying EBV loads (low and high) expressed increased frequencies of EBV-specific CD8(+) T cells, as compared with patients with undetectable EBV loads. Although patients with low viral load displayed EBV-specific CD8(+) T cells with moderate signs of activation (CD38(+/-)/CD127(+/-)), programmed death 1 upregulation and effective IFN-γ secretion, high EBV load carriers showed significant CD38(+) upregulation, features of cellular exhaustion (programmed death 1(+)/CD127(-)) accompanied by a decline in IFN-γ release. Immunopolarization of EBV-specific CD8(+) T cells was skewed from the expected type 1 (IFN-γ) toward type 0 (IFN-γ/IL-5) in patients, and Tr1 (IL-10) in high load carriers. These results indicate the importance of chronic EBV load and of the levels of antigenic pressure in shaping EBV-specific memory CD8(+) T cells. Concomitant phenotypic and functional EBV monitoring is critical for identifying the complex "functional" versus "exhausted" signature of EBV-specific CD8(+) T cells, with implications for immunologic monitoring in the clinic.
