CD8+ T-cell PET/CT Imaging in COVID-19 Patients

Terminated

• Conditions: T-cell; Lymphopenia Due to COVID-19; PET Imaging
• Interventions: Diagnostic Test: [89Zr]Df-IAB22M2C PET/CT scan

• Registration Number: NCT04874818
• Lead Sponsor: Radboud University Medical Center

Brief Summary

A subset of patients diagnosed with severe acute respiratory syndrome (SARS)-CoV2 infection present with lymphopenia. The degree of lymphopenia, and in particular reduced cluster of differentiation (CD)8+ T-cell numbers, is correlated with clinical deterioration and intensive care unit (ICU) admission. The underlying reasons for lymphopenia in coronavirus disease (COVID)-19 is currently unclear, We aim to assess differences in the in vivo distribution of CD8+ T-cells in patients with proven SARS-CoV2 presenting with lymphopenia or with normal lymphocyte counts, using Zirconium-89 (\[89Zr\])Df-IAB22M2C positron emission tomography (PET) imaging.

Detailed Description

Rationale: A subset of patients diagnosed with SARS-CoV2 infection present with lymphopenia. The degree of lymphopenia, and in particular reduced CD8+ T-cell numbers, is strongly correlated with clinical deterioration and ICU admission .

The underlying reasons for lymphopenia in COVID-19 is currently unclear, but several hypotheses have been put forward; 1) sequestration of CD8+ T-cells in peripheral tissues (e.g. lung) either during the effector phase of their lifespan or passively by local chemotactic signals, 2) accelerated maturation and apoptosis either induced by storm of inflammatory cytokines or direct infection or 3) resulting from decreased lymphopoiesis induced by reduced levels of stem cell factor. The lack of data on in vivo distribution of CD8+ T-cells hampers a more thorough understanding of this critical prognostic factor.

Aim: We aim to assess differences in the in vivo distribution of CD8+ T-cells in patients with proven SARS-CoV2 presenting with lymphopenia or with normal lymphocyte counts, using \[89Zr\]Df-IAB22M2C PET/CT imaging.

Study design: This is a prospective, observational non-randomized pilot study in 20 patients with microbiologically proven SARS-CoV2 infection. All patients will undergo a whole body \[89Zr\]Df-IAB22M2C PET/CT scan.

Study population: Twenty patients ≥50 years of age with proven COVID-19, who are admitted to the ward will be included, patients will be stratified according to lymphocyte counts on admission to ensure an even distribution: presenting with lymphopenia (\<1.0 x10e9/L) (n=10) and with lymphocyte numbers within normal range (1.0 - 3.5 x10e9/L) (n=10).

Study procedure: All patients will undergo a \[89Zr\]Df-IAB22M2C PET/CT scan 21-27 hours post intravenous injection of 1.5mg protein dose labelled with 37 megabecquerel (MBq) (1 mCi) 89Zr; and one additional blood sample at the day of scanning.

Primary study objective: The primary objective of this study is to assess differences in the in vivo distribution of CD8+ T-cells in patients with proven SARS-CoV-2 presenting with lymphopenia or with normal lymphocyte counts, using \[89Zr\]Df-IAB22M2C PET/CT imaging.

Secondary study objectives:

1. To assess the spatial correlation between \[89Zr\]Df-IAB22M2C uptake and abnormal findings on routine contrast-enhanced CT scan of the chest

2. To assess the correlation between in vivo biodistribution of \[89Zr\]Df-IAB22M2C and concurrent flowcytometric phenotypic and quantitative assessment of lymphocyte populations

3. To explore the correlation between in vivo biodistribution of \[89Zr\]Df-IAB22M2C and clinical course of disease

Study Timeline

• Study First Submitted: 2021-04-28
• Study First Submitted QC: 2021-05-03
• Study First Posted: 2021-05-06
• Study Start: 2022-02-14
• Primary Completion: 2022-12-31
• Study Completion: 2022-12-31
• Status Verified: 2024-06
• Last Update Submitted: 2025-03-28
• Last Update Posted: 2025-04-02

Recruitment & Eligibility

• Status: TERMINATED
• Sex: All
• Target Recruitment: 5

Inclusion Criteria

• a microbiologically proven SARS-CoV2 infection
• More than 50 years of age;
• Ability to provide written informed consent.

Exclusion Criteria

• Contra-indication for PET: Pregnancy, Breast-feeding, Severe claustrophobia.
• Contra-indication for administration of iodine-containing contrast agents
• Other serious illness, e.g. history of malignancies or auto-immune disorders
• Known pre-existing lymphopenia from an unrelated other medical condition
• Estimated creatinine clearance ≤ 30 mL/min according to the Cockcroft-Gault formula (or local institutional standard method) OR oligo-uric patients (<400 mL/24hr)

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
lymphopenia	[89Zr]Df-IAB22M2C PET/CT scan	lymphocyte counts (\<1.0 x10e9/L)
normal lymphocyte numbers	[89Zr]Df-IAB22M2C PET/CT scan	lymphocyte counts ((1.0 - 3.5 x10e9/L))

Primary Outcome Measures

Name	Time	Method
The primary objective of this study is to quantify uptake of [89Zr]Df-IAB22M2C, as a surrogate for the presence of CD8+ T-cells, in major organ systems of patients with proven SARS-CoV-2 presenting with lymphopenia or with normal lymphocyte counts.	18 months	The main study parameter is the SUVmean uptake of \[89Zr\]Df-IAB22M2C in major organs systems, e.g. lungs, spleen, bone marrow, liver and bloodpool

Secondary Outcome Measures

Name	Time	Method
Based on clinical characteristics	18 months	4) In vivo biodistribution of \[89Zr\]Df-IAB22M2C will be correlated with duration of hospital stay (days)
Based on laboratory parameters	18 months	2) In vivo biodistribution of \[89Zr\]Df-IAB22M2C will be correlated to laboratory test 3) In vivo biodistribution of \[89Zr\]Df-IAB22M2C will be correlated with lymphocyte counts (x10e9/L)
Based on imaging	18 months	1) Spatial correlation of SUVmean per lung segment with CORADS score per lung segment

Trial Locations

Locations (1)

Radboud university medical center; 🇳🇱 Nijmegen, Gelderland, Netherlands