Systematic Screening of Kidney Transplant Patients Points Towards Deficits in Neutralizing Antibody Capacity Against Sars-cov-2
1Laboratory of Experimental Medicine and Pediatrics, University of Antwerp, Antwerp, Belgium, 2Department of Biomedical Sciences, Institute of Tropical Medicine and University of Antwerp, Antwerp, Belgium, 3Department of Laboratory Medicine, Antwerp University Hospital, Antwerp, Belgium, 4Department of Nephrology and Hypertension, Antwerp University Hospital, Antwerp, Belgium, 5Biobank, Antwerp University Hospital, Antwerp, Belgium, 6Centre for the Evaluation of Vaccination, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium, 7Department of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
Meeting: 2021 American Transplant Congress
Abstract number: 20
Keywords: Antibodies, Kidney transplantation
Topic: Clinical Science » Infectious Disease » All Infections (Excluding Kidney & Viral Hepatitis)
Session Information
Session Name: COVID-19 Session 1
Session Type: Rapid Fire Oral Abstract
Date: Saturday, June 5, 2021
Session Time: 4:30pm-5:30pm
Presentation Time: 4:35pm-4:40pm
Location: Virtual
*Purpose: The majority of kidney transplant recipients (KTR) is able to develop SARS-CoV-2 antibodies (Abs). Little is known about the virus neutralizing capacity of these Abs.
*Methods: KTR were systematically screened for SARS-CoV-2 at the Antwerp University Hospital by nasopharyngeal swab and serum sampling for the detection of respectively SARS-CoV-2 RNA and SARS-CoV-2 IgG Abs using an in-house Luminex assay. Results of Abs against the nucleocapsid protein (NP) and Receptor-Binding Domain (RBD) of the spike protein were expressed as Median Fluorescence Intensities (MFI). Virus neutralisation assays were performed on serum samples of patients with SARS-CoV-2 Abs or a positive RT-PCR test and on samples of an age and sex matched control group of 23 COVID-19 positive immunocompetent patients.
*Results: 135 KTR were included; 13 were known to be RT-PCR positive. Of these 13, 10 (77%) tested positive for SARS-CoV-2 Abs. Antibody screening revealed two (2%) additional KTR with detectable Abs. Virus neutralizing capacity was observed in 11/12 (92%) antibody positive KTR vs. 22/23 (96%) immunocompetent antibody positive controls (p = 0.63). In patients who showed virus neutralizing capacity (expressed as sample dilution reducing the number of infected wells by 50% (NT50)), significantly higher neutralizing antibody capacity was observed in immunocompetent controls vs. KTR (median NT50 1027 (IQR 395-1601) vs. 217 (IQR 108-534); p=0.01). There was no difference in IgG-NP MFI and IgG-RBD MFI values between both groups (median IgG NP MFI 24554 (IQR 11218-27017) vs. 11387 (IQR 3062-24825); p = 0.13); median IgG RBD MFI 20302 (IQR 13464-24251) vs. 21736 (6288-24993); p = 0.85).
*Conclusions: Our results suggest that KTR have lower neutralizing antibody capacity compared to immunocompetent subjects. The latter might be of high importance for future COVID-19 vaccine trials.
To cite this abstract in AMA style:
Wijtvliet V, Ariën KK, Mariën J, Peeters B, Hellemans R, Massart A, Hees SVan, Moons P, Theeten H, Damme PVan, Goossens H, Winter BYDe, Ledeganck KJ, Abramowicz D. Systematic Screening of Kidney Transplant Patients Points Towards Deficits in Neutralizing Antibody Capacity Against Sars-cov-2 [abstract]. Am J Transplant. 2021; 21 (suppl 3). https://atcmeetingabstracts.com/abstract/systematic-screening-of-kidney-transplant-patients-points-towards-deficits-in-neutralizing-antibody-capacity-against-sars-cov-2/. Accessed May 16, 2025.« Back to 2021 American Transplant Congress