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.

BACKGROUND:

The COVID-19 pandemic has uniquely affected the United States. We hypothesize that transplantation would be uniquely affected.

METHODS:

In this population-based cohort study, adult transplantation data were examined as time series data. Autoregressive-integrated-moving-average models of transplantation rates were developed using data from 1990 to 2019 to forecast the 2020 expected rates in a theoretical scenario if the pandemic did not occur to generate observed-to-expected (O/E) ratios.

RESULTS:

32,594 transplants were expected in 2020, and only 30,566 occurred (O/E 0.94, CI 0.88-0.99). 58,152 waitlist registrations were expected and 50,241 occurred (O/E 0.86, CI 0.80-0.94). O/E ratios of transplants were kidney 0.92 (0.86-0.98), liver 0.96 (0.89-1.04), heart 1.05 (0.91-1.23), and lung 0.92 (0.82-1.04). O/E ratios of registrations were kidney 0.84 (0.77-0.93), liver 0.95 (0.86-1.06), heart 0.99 (0.85-1.18), and lung 0.80 (0.70-0.94).

CONCLUSIONS:

The COVID-19 pandemic was associated with a significant deficit in transplantation. The impact was strongest in kidney transplantation and waitlist registration.

Long-term adaptive immune memory has been reported among immunocompetent individuals up to eight months following SARS-CoV-2 infection. However, limited data is available in convalescent patients with a solid organ transplant. To investigate this, we performed a thorough evaluation of adaptive immune memory at different compartments (serological, memory B cells and cytokine [IFN-γ, IL-2, IFN-γ/IL12 and IL-21] producing T cells) specific to SARS-CoV-2 by ELISA and FluoroSpot-based assays in 102 convalescent patients (53 with a solid organ transplants (38 kidney, 5 liver, 5 lung and 5 heart transplant) and 49 immunocompetent controls) with different clinical COVID-19 severity (severe, mild and asymptomatic) beyond six months after infection. While similar detectable memory responses at different immune compartments were detected between those with a solid organ transplant and immunocompetent individuals, these responses were predominantly driven by distinct COVID-19 clinical severities (97.6%, 80.5% and 42.1%, all significantly different, were seropositive; 84% vs 75% vs 35.7%, all significantly different, showed IgG-producing memory B cells and 82.5%, 86.9% and 31.6%, displayed IFN-γ producing T cells; in severe, mild and asymptomatic convalescent patients, respectively). Notably, patients with a solid organ transplant with longer time after transplantation did more likely show detectable long-lasting immune memory, regardless of COVID-19 severity. Thus, our study shows that patients with a solid organ transplant are capable of maintaining long-lasting peripheral immune memory after COVID-19 infection; mainly determined by the degree of infection severity.

Response to two doses of a nucleoside-modified messenger ribonucleic acid (mRNA) vaccine was evaluated in a large solid-organ transplant program. mRNA COVID-19 vaccine was administered to transplant candidates and recipients who met study inclusion criteria. Qualitative anti-SARS-CoV-2 Spike Total Immunoglobulin (Ig) and IgG-specific assays, and a semi-quantitative test for anti-SARS-CoV-2 Spike protein IgG were measured in 241 (17.2%) transplant candidates and 1163 (82.8%) transplant recipients; 55.2% of whom were non-Hispanic White and 44.8% identified as another race. Transplant recipients were a median (IQR) of 3.2 (1.1, 6.8) years from transplantation. Response differed by transplant status: 96.0% versus 43.2% by the anti-SARS-CoV-2 Total Ig (candidates vs. recipients, respectively), 93.5% versus 11.6% by the anti-SARS-CoV-2 IgG assay, and 91.9% versus 30.1% by anti-spike titers after two doses of vaccine. Multivariable analysis revealed candidates had higher likelihood of response versus recipients (odds ratio [OR], 14.6; 95 %CI 2.19, 98.11; P = .02). A slightly lower response was demonstrated in older patients (OR .96; 95 %CI .94, .99; P = .002), patients taking antimetabolites (OR, .21; 95% CI .08, .51; P = .001). Vaccination prior to transplantation should be encouraged.