(61) Prevalence and Determinants of Cellular Immunity Against Sars-Cov-2 in Heart Transplant Recipients: A Cross-Sectional Study

PURPOSE: Serology studies provide limited information on immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This cross-sectional study aimed to assess prevalence and determinants of anti-SARS-CoV-2 cellular immunity in a cohort of heart transplant (HT) recipients. METHODS: All consecutive HT recipients followed-up at our outpatient clinic between February and June 2022 providing informed consent were included in this observational cross-sectional study. We quantified SARS-CoV-2 Spike (S)-reactive and Nucleocapsid (N)-reactive T cells using enzyme-linked immunospot assay. A positive response was defined as S or N reactivity >8 spots/2 × 10(5) lymphocytes. Clinical characteristics, laboratory data, immunosuppressive regimen and vaccination status were compared between patients with and without SARS-CoV-2 S-reactive T cells. Categorical variables were described as number (%) and continuous variables with median [IQR]. RESULTS: Among 201 patients (age 58 [45-65] years, 77% males, time since transplantation 51 months [24-81]), 97 (48%) exhibit S-specific T cells, of which 58 had in addition N-reactive T cells. CD4 and CD8 T lymphocyte count, glomerular filtration rate, immunosuppressive regimen were associated with T cell response (Table). Among patients with detectable SARS-Co-V-2 cellular immunity, numbers of S-reactive T cells were higher in patients who had detectable N-reactive T cells (277 vs 93 /10(6) T cells) (Figure). CONCLUSION: Our study provides new information on cellular immunity against SARS-CoV-2 in HT recipients.