T- and B-cell Immune Response to COVID Vaccination in Liver Transplant Recipients Based on Interferon-gamma Release Assay and Serum Antibody Levels

Abstract

Background and Aim: This study aimed to assess T- and B-cell-mediated immune response following administration of two doses of COVID-19 vaccine in liver transplant (LT) recipients. Subjects and Methods: Twenty-eight liver transplant recipients and seven healthy volunteers without prior history of COVID-19 infection were enrolled. All individuals received two doses of COVID-19 vaccine (either Covishield or Covaxin), with the LT recipients receiving them at least 3 months after LT. The results of humoral (COVID-specific IgG) and cell-mediated immune response (interferon [INF]-gamma assay) following vaccination in the LT recipient group were compared with the control group. Results: Both LT recipients and control individuals developed COVID-specific antibodies following vaccination. The LT recipient group showed marginally higher INF-gamma levels with an average of 61.3 pg/ml compared to the control group 42.7 pg/ml (P = 0.051). There was no difference in the immunological response between patients who received the vaccination before or after 6 months posttransplant. There was no difference in response between the two vaccines. Conclusion: LT recipients mounted an immunological response comparable to the control group with both inactivated and viral vector vaccines for COVID-19, when vaccinated with an interval period of 3 months from transplant.