Clinical insights into the role of immunosuppression in solid organ transplant recipients with COVID-19.

Introduction: The COVID-19 pandemic has disproportionately affected patients who have undergone solid organ transplantation (SOT).
Objectives: We aimed to assess a cohort of transplant recipients who developed COVID‑19, with a focus on immunosuppressive regimen, blood tacrolimus levels, clinical course, and patient and graft outcomes.
Patients and Methods: During the first 12 months of the pandemic, we identified ambulatory SOT recipients, including kidney, liver, and heart transplant recipients, diagnosed with SARS‑CoV‑2 infection. Baseline and follow‑up data on graft function, immunosuppression, and patient and graft outcomes were assessed.
Results: Of the 2091 ambulatory patients, we identified 201 transplant recipients (9.6%) with SARS‑CoV‑2 infection (kidney transplant, n = 112; heart transplant, n = 56; liver transplant, n = 33). Patients after recent kidney (during 2015-2020) or heart (during 2020) transplant were significantly more often diagnosed with COVID ‑19 than patients with a longer time since transplant. Additionally, blood trough tacrolimus levels measured during or shortly after COVID‑19 in 23 kidney graft recipients were significantly increased by a median of 76.1% (interquartile range, 47.4%-109.4%) relative to predose trough levels. However, liver function parameters were not elevated, necessitating a tacrolimus dose reduction in 73.9% of the patients.
Conclusions: In our study, kidney transplant recipients showed significant disturbances of tacrolimus metabolism, which may account for kidney function worsening during COVID‑19. Moreover, infection was more common in patients with recent kidney or heart transplant, which suggests that the level of immunosuppression may affect morbidity related to SARS‑CoV‑2 infection.