Models, mechanisms & therapies

Monday September 12, 2022 from 17:35 to 18:35

Room: CF-7

246.1 Antibody response and cellular phenotyping in kidney transplant recipients following SARS-CoV-2 vaccination

Robert Montgomery, United States

H. Leon Pachter Chair and Professor of Surgery
Director, NYU Langone Transplant Institute
NYU Langone Health

Abstract

Antibody response and cellular phenotyping in kidney transplant recipients following SARS-CoV-2 vaccination

Nicole Ali1, Zoe Stewart1, Jake Miles2, Sapna Mehta1, Vasishta Tatapudi1, Bonnie Lonze1, Elaina Weldon1, Charles Dimaggio1, S Gray-Gaillard1, Jeanette Leonard1, S Tuen1, Robert Montgomery1, Herati Ramin1.

1Transplant Institute, NYU Langone Health, New York, NY, United States; 2CareDx, CareDx, Brisbane, CA, United States

Introduction: Correlates of protection for SARS-CoV-2 vaccines are not yet well-established in kidney transplant recipients (KTRs). Studies have highlighted the importance of neutralizing antibodies (Abs), however data suggests T cell responses may play a secondary role in preventing reinfection. We performed a longitudinal assessment of immunogenicity and T and B cell responses in KTRs following SARS-CoV-2 vaccination.

Methods: KTRs eligible for SARS-CoV-2 vaccination were screened through medical records from March 12, 2021. Baseline and weekly blood samples were collected for routine assessment, SARS-CoV-2 spike protein Ab titers and cellular phenotyping for 12 weeks. Ab response was defined as a 10-fold increase in total binding IgG titers. To determine if T cell responses were induced by vaccination, we considered the proportion of activated non-naive CD4+ and CD8+ T cells after vaccination.

Results: 49 KTRs with a mean age of 54 years were enrolled (Table 1). 10 patients (20.4%) mounted an Ab response following completed vaccination. A history of COVID-19 was associated with an increased likelihood of developing an Ab response (OR: 18.3, 95% CI 3.2, 105.0, p=0.0005). For non-naive CD8+ T cells, a subset co-expressing CD38+Ki67+ was induced 1 week after the 1st immunization in some SARS-CoV-2-naiive patients (P=0.12 versus P=0.14 for SARS-CoV-2-experienced adults, Figure 1A/B). For non-naive CD4+ T cells, induction of a subset co-expressing CD38+Ki67+ was observed at 1 week after the 1st immunization for SARS-CoV-2-naïve participants (P = 0.09 for SARS-CoV-2-naïve, P=0.03 for SARS-CoV-2-experienced adults, Figure 1C/D). For CD8+ and CD4+ T cells, dose 2 stimulated weak induction of the CD38+Ki67+ subset in the SARS-CoV-2-naïve patients only (Figure 1A-D).

Conclusions: Quantitative Ab responses were strongly associated with prior SARS-CoV-2 infection. Activated CD4+ and CD8+ T cell responses were evident in most patients, with wide variation, irrespective of COVID-19 history. Further studies are needed to determine whether these activated CD4+ and CD8+ T cell responses were antigen-specific or confer immunity.



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