Detection of pre-existing SARS-CoV-2-reactive T cells in unexposed renal transplant patients

Abstract

Background Recent data demonstrate potentially protective pre-existing T cells reactive against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in samples of healthy blood donors, collected before the SARS-CoV-2 pandemic. Whether pre-existing immunity is also detectable in immunosuppressed patients is currently not known. Methods Fifty-seven patients were included in this case–control study. We compared the frequency of SARS-CoV-2-reactive T cells in the samples of 20 renal transplant (RTx) patients to 20 age/gender matched non-immunosuppressed/immune competent healthy individuals collected before the onset of the SARS-CoV-2 pandemic. Seventeen coronavirus disease 2019 (COVID-19) patients were used as positive controls. T cell reactivity against Spike-, Nucleocapsid-, and Membrane- SARS-CoV-2 proteins were analyzed by multi-parameter flow cytometry. Antibodies were analyzed by neutralization assay. Results Pre-existing SARS-CoV-2-reactive T cells were detected in the majority of unexposed patients and healthy individuals. In RTx patients, 13/20 showed CD4+ T cells reactive against at least one SARS-CoV-2 protein. CD8+ T cells reactive against at least one SARS-CoV-2 protein were demonstrated in 12/20 of RTx patients. The frequency and Th1 cytokine expression pattern of pre-formed SARS-CoV-2 reactive T cells did not differ between RTx and non-immunosuppressed healthy individuals. Conclusions This study shows that the magnitude and functionality of pre-existing SARS-CoV-2 reactive T cell in transplant patients is 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. Graphic abstract

Concurrent vaccination of kidney transplant recipients and close household cohabitants against COVID-19

“…In line with previous reports (e.g., Anft et al. 9 ), preexisting T-cell immunity to SARS-CoV-2 spike was detected in both KTRs and cohabitants (35% and 60%, respectively). T-cell responses were increased upon vaccination in 49% of transplant recipients compared with 93% of cohabitants.…”

What has vaccination against COVID-19 in CKD patients taught us?

“…These T cells exhibited strong cross-reactivity with the nucleocapsid protein of SARS-CoV-2. The presence of T-cell cross-reactivity in patients with a previous coronavirus infection (also reported by others [ 48 ]) could confer some immunoprotection against SARS‐CoV‐2, and thus explain the variable severity of COVID-19 clinical syndromes, which ranges from asymptomatic or mild influenza-like disease to severe pneumonia and acute respiratory distress syndrome. Moreover, they hypothesised that patients with SARS-CoV-2 infection could develop long-term T-cell immunity (Table 1 ).…”

Differential regulatory T cell signature after recovery from mild COVID-19

“…Interestingly, our data also showed a significant increase in Tregs expressing LAP and co-expressing perforin and granzyme B in Pool CoV-2-stimulated PBMC from HC. Samples of patients not previously exposed to the virus showed the presence of reactive T cells to SARS-CoV-2, probably due to exposure to other endemic coronaviruses ( 58 ). Therefore, our findings may point to immunological cross-reactivity caused by prior infections by other pathogens.…”