(1078) The Antibody Response of an MMF-Containing Immunosuppressive Regimen Aftercovid-19 Vaccination in Asian Heart Transplant Recipient

PURPOSE: Organ transplant recipients have diminished humoral immune responses to COVID-19 vaccination than the general population. The current study have reported the risk factors about the antibody response after vaccination. Data from several studies show that to use of mycophenolate mofetil (MMF) as a major factor associated with poor antibody response after COVID-19 vaccination. But little is known at heart transplant recipients(HTXs) and in Asian race . METHODS: We performed a single-center, prospective observational cohort study of 59 HTXs from National Taiwan University Hospital, Taiwan, was conducted between Jun 1, 2021 and July 31, 2022. We identified the response of antibody titers after vaccination and there were stratified into two categories: with MMF; without MMF. Anti‐spike IgG (S‐IgG) antibody was determined at a specified time point, which is 30 days after each dose of vaccine, and a S‐IgG value of 0.8 U/mL or higher was considered positive (Roche Diagnostics). We enrolled 59 patients (age: 53±13 years;86 % were men) with a negative SARS-CoV-2 anti-nucleocapsid antibody test . 21 patients received an immunosuppressive regimen with MMF, Among these patients, 21 received an immunosuppressive regimen with MMF (36%) throughout the study period. The time period of vaccine administration between the first and the second dose ranged from 28 to 135 days. The time period between the second and the third dose ranged from 34 to 182 days For those recipient, tacrolimus blood levels is 2.6 to 12.1 ng/mL, MMF is given in dose of 250 to 3000 mg QD, the everolimus(EVR) blood level is 1.6 to 5 ng/mL before the first vaccination. RESULTS: The antibody response positive of HTXs on a MMF-containing immunosuppressive regimen were 13% after first vaccination, whereas the response on the no-MMF regimen was significantly higher at 50% (P = 0.002). And the antibody response titer of an MMF-containing group is were significantly lower than no MMF-containing group (P = 0.019 and P = 0.002) after 1 and 2 vaccinations. CONCLUSION: An immunosuppressive regimen with MMF (no/with EVR) is hampered the antibody response after COVID-19 2 vaccinations and no significantly after COVID-19 3 vaccinations(p=0.101) . The result will not affected by the type of vaccination . This finding should be investigated in larger cohorts, including transplant recipients of all races.