Long term SARS-CoV-2-specific cellular immunity after COVID-19 in liver transplant recipients

Abstract

Abstract Purpose: Long-term immunity after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in immunosuppressed patients is not well characterized. We aimed to explore the long-term natural immunity against SARS-CoV-2 in liver transplant (LT) recipients compared to the non-transplanted population (control group). Methods: Fifteen LT recipients and 15 controls matched according to variables associated with disease severity were included at 12 months following the coronavirus disease 2019 (COVID-19) onset. Peripheral blood mononuclear cells were stimulated with peptide pools covering spike (S), nucleocapside (N), and membrane (M) proteins. Reactive CD4þ and CD8þ T cells were identified using flow cytometry, and cytokine production was evaluated in the culture supernatants using cytometric bead array. Serum anti-N and anti-S IgG antibodies were detected with chemiluminescence. Results: The percentage of patients with a positive response in both CD4þ and CD8þ T cells against each viral protein and IL2, IL10, TNF-a, and IFN-g levels was similar between LT recipients and controls. IFN-g levels were positively correlated with the percentage of reactive CD4þ (p Z 0.022) and CD8þ (p Z 0.043) T cells to a mixture of M þ N þ S peptide pools. The prevalence and levels of anti-N and anti-S IgG antibodies were slightly lower in the LT recipients, but the difference was not statistically significant. Conclusion: LT recipients exhibited a similar T cell response compared to non-transplanted individuals one year after COVID-19 diagnosis.