ABSTRACT
Background: In patients with end-stage renal disease (ESRD), mean antibody concentrations following SARS-CoV-2 vaccination are lower than in the general population, which correlates with the risk of COVID-19 disease. For a high-affinity antibody response, germinal centre responses in lymph nodes (LN) are critical. However, current knowledge on SARS-CoV-2 specific B and T cell responses is almost exclusively based on peripheral blood (PB) mononuclear cells (MNC). Previous studies have shown that LN MNC differ substantially from their PB counterparts. We aim to study the functional and phenotypical differences between PB-and LN-derived SARS-CoV-2 specific B and T cells after vaccination in ESRD patients and compare these with their counterparts after infection. Method(s): MNC were isolated from PB and paired non-draining LN of ESRD patients, retrieved during kidney transplantation. Ten patients who received SARS-CoV-2 vaccination and five who suffered COVID-19 disease were included. SARS-CoV-2 spike specific T cells were phenotyped using HLA class I dextramers and for SARS-CoV-2 spike specific B cells spike-tetramers were used. Also, antibody levels and functions like neutralization of infectivity, phagocytosis, antibody-dependent cellular cytotoxicity and complement-mediated lysis of pathogens of infected cells were measured. Result(s): An example of the SARS-CoV-2 specific T and B cell phenotyping in PB MNC of healthy controls is shown. Whether these cells are detectable in the non-draining LN of ESRD patients after SARS-CoV-2 vaccination or infection and if they functionally and phenotypically correlate with paired PB MNC is yet to be determined. Conclusion(s): We aim to gain an invaluable insight into the underlying T-and B-cellcentred immunological processes in LN of ESRD patients in order to understand and optimize vaccine response.