TRANSPLANT PATIENTS ARE ABLE TO MOUNT SARS-COV-2-REACTIVE T-CELL RESPONSE WITH THE MAGNITUDE AND FUNCTIONALITY COMPARABLE TO NON-IMMUNOSUPPRESSED PATIENTS

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused unprecedented public health and economical challenges worldwide Cellular immunity is known to be crucial for the virus clearance Recent data demonstrate pre-existing SARS-CoV-2-reactive T cells in samples of healthy blood donors collected before SARS-CoV-2 pandemics The presence of these potentially protective T cells in SARS-CoV-2 naive population can be explained by cross-reactivity to the endemic common cold coronavirus Whether such cells are also detectable in immunosuppressed patients is not known so far Methods: We analysed the presence of SARS-CoV-2-cross-reactive T cell immunity in samples of 10 renal transplant patients (RTX) collected in 2019 before the onset of SARS-CoV-2 pandemics Samples of 10 non-immunosuppressed/ immune competent SARS-CoV-2 naive patients matched to transplant patients were analysed as controls T-cell reactivity against Spike-, Nucleocapsid-, and Membrane-SARS-CoV-2 proteins were analysed by multiparameter flow cytometry Results: 50% of analysed RTX showed CD4 + T-cells reactive against at least one SARS-CoV-2 protein CD8 + T cells reactive against at least one SARSCoV2 protein were demonstrated in 30% of RTX Notably, the detected cells were of differentiated memory phenotype producing several Th1 cytokines including IFNg, TNFa, IL-2, as well as Granzyme B The frequencies and cytokine expression pattern of SARS-CoV-2 reactive T-cells did not differ between transplant and non-transplant cohorts Conclusion: Despite immunosuppressive treatment and underlined renal disease, transplant patients were able to generate cellular immunity crossreactive to SARS-CoV-2 The magnitude and functionality of the pre-existing immunity was non-inferior compared to the immune competent cohort Although several pro-inflammatory cytokines were produced by the detected T cells, further studies are required to prove their antiviral protection