The Trajectory of the COVID-19 Vaccine Antibody Titers Over Time and the Association of Mycophenolate Mofetil in Solid Organ Transplant Recipients

Abstract

The coronavirus disease 2019 vaccines will be safe and effective in solid organ transplant recipients (SOTs). However, the blunted antibody responses were also of concern. Few studies have reported prolonged serological follow-up after two doses of BNT162b2 vaccine in SOTs. We performed a single-center, prospective observational study of 78 SOTs who received two doses of BNT162b2 vaccine. We identified the trajectory of antibody titers after vaccination among SOTs with or without mycophenolate mofetil (MMF), or withdrawn from MMF.We found low seroconversion rates (29/42: 69%) and low antibody titers in SOTs treated with MMF. An inverse linear relationship between neutralizing antibody titers and MMF concentration was confirmed in restricted cubic spline plots (P for effect <0.01, P for non-linearity = 0.08). For the trajectory of antibody responses, seroconversion and improved antibody titers were observed after withdrawal from MMF in SOTs who showed seronegative or low antibody titers at the first visit after two doses of vaccine (P for effect <0.01, P for non-linearity <0.05 and P for interaction <0.01). We identified increased B-cell counts after withdrawal from MMF (P <0.01).Recovery of antibody responses was seen in SOTs withdrawn from MMF. Trajectories of antibody responses were modified by MMF administration.