Cellular and humoral immune response after mRNA-1273 SARS-CoV-2 vaccine in liver and heart transplant recipients

Recently published studies have found an impaired immune response after SARS-CoV-2 vaccination in solid organ recipients. However, most of these studies have not assessed immune cellular responses in liver and heart transplant recipients. We prospectively studied heart and liver transplant recipients eligible for SARS-CoV-2 vaccination. Patients with past history of SARS-CoV-2 infection or SARS-CoV-2 detectable antibodies (IgM or IgG) were excluded. We assessed IgM/IgG antibodies and ELISpot against the S protein 4 weeks after receiving the second dose of the mRNA-1273 (Moderna) vaccine. Side effects, troponin I, liver tests and anti-HLA donor-specific antibodies (DSA) were also assessed. A total of 58 liver and 46 heart recipients received two doses of mRNA-1273 vaccine. Median time from transplantation to vaccination was 5.4 years (IQR 0.3–27). Sixty-four percent of the patients developed SARS-CoV-2 IgM/IgG antibodies and 79% S-ELISpot positivity. Ninety percent of recipients developed either humoral or cellular response (87% in heart recipients and 93% in liver recipients). Factors associated with vaccine unresponsiveness were hypogammaglobulinemia and vaccination during the first year after transplantation. Local and systemic side effects were mild or moderate, and none presented DSA or graft dysfunction after vaccination. Ninety percent of our patients did develop humoral or cellular responses to mRNA-1273 vaccine. Factors associated with vaccine unresponsiveness were hypogammaglobulinemia and vaccination during the first year after transplantation, highlighting the need to further protect these patients.

     

Very late relapse of hepatitis C virus infection immediately after liver transplant

Late relapse of hepatitis C virus (HCV) infection is very rare in the era of modern direct‐acting antiviral therapy. We report here the first case of a late relapse, after direct‐acting antiviral therapy, occurring immediately after liver transplant (LT), with 93 weeks of sustained virologic response before LT. HCV RNA in serum and in liver biopsy was negative the day of LT, and relapse was diagnosed 11 days after LT. HCV NS5A sequencing was performed on samples before and after LT, with 99% of homology demonstrating a true late relapse rather than a reinfection. This late relapse could be explained by extrahepatic reservoirs of HCV and the high immunosuppressive therapy, including bolus of steroids, within the first days post LT. In conclusion, our case suggests that monitoring HCV RNA after LT could be recommended to detect and treat early relapse, even after a long virologic response.     

Cellular and humoral response after MRNA-1273 SARS-CoV-2 vaccine in kidney transplant recipients

According to preliminary data, seroconversion after mRNA SARS-CoV-2 vaccination might be unsatisfactory in Kidney Transplant Recipients (KTRs). However, it is unknown if seronegative patients develop at least a cellular response that could offer a certain grade of protection against SARS-CoV-2. To answer this question, we prospectively studied 148 recipients of either kidney (133) or kidney-pancreas (15) grafts with assessment of IgM/IgG spike (S) antibodies and ELISpot against the nucleocapside (N) and the S protein at baseline and 2 weeks after receiving the second dose of the mRNA-1273 (Moderna) vaccine. At baseline, 31 patients (20.9%) had either IgM/IgG or ELISpot positivity and were considered to be SARS-CoV-2-pre-immunized, while 117 (79.1%) patients had no signs of either cellular or humoral response and were considered SARS-CoV-2-naïve. After vaccination, naïve patients who developed either humoral or cellular response were finally 65.0%, of which 29.9% developed either IgG or IgM and 35.0% S-ELISpot positivity. Factors associated with vaccine unresponsiveness were diabetes and treatment with antithymocytes globulins during the last year. Side effects were consistent with that of the pivotal trial and no DSAs developed after vaccination. In conclusion, mRNA-1273 SARS-CoV-2 vaccine elicits either cellular or humoral response in almost two thirds of KTRs.     

Fatal outcome in a liver transplant recipient with COVID‐19

Liver injury is common in patients with COVID‐19, but little is known about its clinical presentation and severity in the context of liver transplant. We describe a case of COVID‐19 in a patient who underwent transplant 3 years ago for hepatocellular carcinoma. The patient came to clinic with symptoms of respiratory disease; pharyngeal swabs for severe acute respiratory syndrome coronavirus 2 were positive. His disease progressed rapidly from mild to critical illness and was complicated by several nosocomial infections and multiorgan failure. Despite multiple invasive procedures and rescue therapies, he died from the disease. The management of COVID‐19 in the posttransplant setting presents complex challenges, emphasizing the importance of strict prevention strategies.     

Clinical course of COVID‐19 in a liver transplant recipient on hemodialysis and response to tocilizumab therapy: A case report

The novel coronavirus disease 2019 (COVID‐19) is a highly infectious and rapidly spreading disease. There are limited published data on the epidemiology and outcomes of COVID‐19 infection among organ transplant recipients. After initial flulike symptoms, progression to an inflammatory phase may occur, characterized by cytokine release rapidly leading to respiratory and multiorgan failure. We report the clinical course and management of a liver transplant recipient on hemodialysis, who presented with COVID‐19 pneumonia, and despite completing a 5‐day course of hydroxychloroquine, later developed marked inflammatory manifestations with rapid improvement after administration of off‐label, single‐dose tocilizumab. We also highlight the role of lung ultrasonography in early diagnosis of the inflammatory phase of COVID‐19. Future investigation of the effects of immunomodulators among transplant recipients with COVID‐19 infection will be important.     

Bacteremia in solid organ transplant recipients as compared to immunocompetent patients: Acute phase cytokines and outcomes in a prospective,matched cohort study

We undertook a prospective, matched cohort study of patients with Staphylococcus aureus bacteremia (SAB) and gram-negative bacteremia (GNB) to compare the characteristics, outcomes, and chemokine and cytokine response in transplant recipients to immunocompetent, nontransplant recipients. Fifty-five transplant recipients (GNB n = 29; SAB n = 26) and 225 nontransplant recipients (GNB n = 114; SAB n = 111) were included for clinical analysis. Transplant GNB had a significantly lower incidence of septic shock than nontransplant GNB (10.3% vs 30.7%, p = .03). Thirty-day mortality did not differ significantly between transplant and nontransplant recipients with GNB (10.3% vs 15.8%, p = .57) or SAB (0.0% vs 11.7%, p = .13). Next, transplant patients were matched 1:1 with nontransplant patients for the chemokine and cytokine analysis. Five cytokines and chemokines were significantly lower in transplant GNB vs nontransplant GNB: IL-2 (median [IQR]: 7.1 pg/ml [7.1, 7.1] vs 32.6 pg/ml [7.1, 88.0]; p = .001), MIP-1β (30.7 pg/ml [30.7, 30.7] vs 243.3 pg/ml [30.7, 344.4]; p = .001), IL-8 (32.0 pg/ml [5.6, 53.1] vs 59.1 pg/ml [39.2, 119.4]; p = .003), IL-15 (12.0 pg/ml [12.0, 12.0] vs 12.0 pg/ml [12.0, 126.7]; p = .03), and IFN-α (5.1 pg/mL [5.1, 5.1] vs 5.1 pg/ml [5.1, 26.3]; p = .04). Regulated upon Activation, Normal T Cell Expressed and Secreted (RANTES) was higher in transplant SAB vs nontransplant SAB (mean [SD]: 750.2 pg/ml [194.6] vs 656.5 pg/ml [147.6]; p = .046).     

Successful treatment of severe COVID‐19 pneumonia in a liver transplant recipient

Coronavirus disease 2019 (COVID‐19) pandemic spreads rapidly and may be an increasing challenge for transplant community. Clinical data on COVID‐19 infection in transplant population is very limited. Herein we presented the clinical course and outcome of a 50‐year‐old male post liver transplantation who contracted COVID‐19, with subsequent infection of his wife. The process of illness was representative. A therapeutic regime with temporary immunosuppression withdrawal and systemic low‐dose corticosteroid as principle was involved in the management of the patient which made him recover from severe COVID‐19 pneumonia.     

Reduced humoral response to mRNA SARS-CoV-2 BNT162b2 vaccine in kidney transplant recipients without prior exposure to the virus

COVID-19 is associated with increased morbidity and mortality in transplant recipients. There are no efficacy data available regarding these patients with any of the available SARS-CoV-2 vaccines. We analyzed the humoral response following full vaccination with the BNT162b2 (Pfizer-BioNTech) in 136 kidney transplant recipients, and compared it to 25 controls. In order to exclude prior exposure to the virus, only participants with negative serology to SARS-CoV-2 nucleocapsid protein were included. All controls developed a positive response to spike protein, while only 51 of 136 transplant recipients (37.5%) had positive serology (p < .001). Mean IgG anti-spike level was higher in the controls (31.05 [41.8] vs. 200.5 [65.1] AU/mL, study vs. control, respectively, p < .001). Variables associated with null humoral response were older age (odds ratio 1.66 [95% confidence interval 1.17–2.69]), high-dose corticosteroids in the last 12 months (1.3 [1.09–1.86]), maintenance with triple immunosuppression (1.43 [1.06–2.15]), and regimen that includes mycophenolate (1.47 [1.26–2.27]). There was a similar rate of side effects between controls and recipients, and no correlation was found between the presence of symptoms and seroconversion. Our findings suggest that most kidney transplant recipients remain at high risk for COVID-19 despite vaccination. Further studies regarding possible measures to increase recipient's response to vaccination are required.     

Humoral response to SARS-CoV-2 is well preserved and symptom dependent in kidney transplant recipients

Data on the immune response to SARS-CoV-2 in kidney transplant recipients are scarce. Thus, we conducted a single-center observational study to assess the anti-SARS-CoV-2 IgG seroprevalence in outpatient kidney transplant recipients (KTR; n = 1037) and healthcare workers (HCW; n = 512) during the second wave of the COVID-19 pandemic in fall 2020 and evaluated the clinical variables affecting antibody levels. Antibodies against S1 and S2 subunit of SARS-CoV-2 were evaluated using immunochemiluminescent assay (cut off 9.5 AU/ml, sensitivity of 91.2% and specificity of 90.2%). Anti-SARS-CoV-2 IgG seroprevalence was lower in KTR than in HCW (7% vs. 11.9%, p = .001). Kidney transplant recipients with SARS-CoV-2 infection were younger (p = .001) and received CNI-based immunosuppression more frequently (p = .029) than seronegative KTR. Anti-SARS-CoV-2 IgG positive symptomatic KTR had a higher BMI (p = .04) than asymptomatic KTR. Interestingly, anti-SARS-CoV-2 IgG levels were higher in KTR than in HCW (median 31 AU/ml, IQR 17–84 vs. median 15 AU/ml, IQR 11–39, p < .001). The presence of moderate to severe symptoms in KTR was found to be the only independent factor affecting IgG levels (Beta coefficient = 41.99, 95% CI 9.92–74.06, p = .011) in the multivariable model. In conclusion, KTR exhibit a well-preserved symptom-dependent humoral response to SARS-CoV-2 infection.     

COVID‐19 pneumonia in lung transplant recipients: Report of 2 cases

Coronavirus disease 2019 (COVID‐19) has been declared pandemic since March 2020. In Europe, Italy was the first nation affected by this infection. We report anamnestic data, clinical features, and therapeutic management of 2 lung transplant recipients with confirmed COVID‐19 pneumonia. Both patients were in good clinical condition before the infection and were receiving immunosuppression with calcineurin inhibitors (CNI), mycophenolate mofetil, and corticosteroids. Whereas mycophenolate mofetil was withdrawn in both cases, CNI were suspended only in the second patient. The first patient always maintained excellent oxygen saturation throughout hospitalization with no need for additional oxygen therapy. He was discharged with a satisfactory pulmonary function and a complete resolution of radiological and clinical findings. However, at discharge SARS‐CoV‐2 RNA could still be detected in the nasopharyngeal swab and in the stools. The second patient required mechanical ventilation, had a progressive deterioration of his clinical conditions, and had a fatal outcome. Further insight into SARS‐CoV‐2 infection is eagerly awaited to improve the outcome of transplant recipients affected by COVID‐19 pneumonia.     

Humoral and cellular immune response and safety of two-dose SARS-CoV-2 mRNA-1273 vaccine in solid organ transplant recipients

Solid organ transplant recipients are at high risk of severe disease from COVID-19. We assessed the immunogenicity of mRNA-1273 vaccine using a combination of antibody testing, surrogate neutralization assays, and T cell assays. Patients were immunized with two doses of vaccine and immunogenicity assessed after each dose using the above tests. CD4+ and CD8+ T cell responses were assessed in a subset using flow-cytometry. A total of 127 patients were enrolled of which 110 provided serum at all time points. A positive anti-RBD antibody was seen in 5.0% after one dose and 34.5% after two doses. Neutralizing antibody was present in 26.9%. Of note, 28.5% of patients with anti-RBD did not have neutralizing antibody. T cell responses in a sub-cohort of 48 patients showed a positive CD4+ T cell response in 47.9%. Of note, in this sub-cohort, 46.2% of patients with a negative anti-RBD, still had a positive CD4+ T cell response. The vaccine was safe and well-tolerated. In summary, immunogenicity of mRNA-1273 COVID-19 vaccine was modest, but a subset of patients still develop neutralizing antibody and CD4+T- cell responses. Importantly polyfunctional CD4+T cell responses were observed in a significant portion who were antibody negative, further highlighting the importance of vaccination in this patient population. IRB Statement: This study was approved by the University Health Network Research Ethics Board (CAPCR ID 20–6069).     

Dynamics of virus‐specific T cell immunity in pediatric liver transplant recipients

Immunosuppression following solid organ transplantation (SOT) has a deleterious effect on cellular immunity leading to frequent and prolonged viral infections. To better understand the relationship between posttransplant immunosuppression and circulating virus‐specific T cells, we prospectively monitored the frequency and function of T cells directed to a range of latent (CMV, EBV, HHV6, BK) and lytic (AdV) viruses in 16 children undergoing liver transplantation for up to 1 year posttransplant. Following transplant, there was an immediate decline in circulating virus‐specific T cells, which recovered posttransplant, coincident with the introduction and subsequent routine tapering of immunosuppression. Furthermore, 12 of 14 infections/reactivations that occurred posttransplant were successfully controlled with immunosuppression reduction (and/or antiviral use) and in all cases we detected a temporal increase in the circulating frequency of virus‐specific T cells directed against the infecting virus, which was absent in 2 cases where infections remained uncontrolled by the end of follow‐up. Our study illustrates the dynamic changes in virus‐specific T cells that occur in children following liver transplantation, driven both by active viral replication and modulation of immunosuppression.     

Burkholderia multivorans septicemia in a pediatric liver transplant patient

“Cepacia syndrome”, caused by Burkholderia cepacia complex and often associated with cystic fibrosis, carries a high mortality rate. It is rare for Burkholderia multivorans, a species within the B. cepacia complex, to cause cepacia syndrome even among patients with cystic fibrosis. This is the first reported fatal case of cepacia syndrome caused by B. multivorans occurring in a pediatric liver transplant recipient who does not have cystic fibrosis. We describe the unique characteristics of this pathogen among the non–cystic fibrosis population and the importance of early recognition and treatment.     

Immune‐mediated graft dysfunction in liver transplant recipients with hepatitis C virus treated with direct‐acting antiviral therapy

Interferon treatment of hepatitis C virus (HCV) infection after liver transplantation (LT) can result in immune‐mediated graft dysfunction (IGD). The occurrence of, risk factors for, and outcomes of IGD with direct‐acting antiviral (DAA) therapy have not been reported. We conducted a multicenter study of HCV+LT recipients who did or did not develop DAA‐IGD (1 case: 2 controls—33 vs 66). Among all treated between 2014 and 2016, DAA‐IGD occurred in 3.4% (33/978). IGD occurred only after treatment completion (76.0 [IQR, 47.0;176]). Among those treated, 48% had plasma cell hepatitis, 36% acute cellular rejection, 6% chronic rejection, and 9% combined findings. Median time to liver enzyme resolution was 77.5 days (IQR, 31.5;126). After diagnosis, hospitalizations, steroid‐induced hyperglycemia, and infection occurred in a higher percentage of cases vs controls (33% vs 7.5%, 21% vs 1.5%, 9% vs 0%; all P < .05). Only one IGD patient died and none required retransplant. A multivariate regression analysis found that liver enzyme elevations during and soon after DAA therapy completion correlated with subsequent IGD. In conclusion, while DAA‐IGD is uncommon, liver enzyme elevations during or after DAA therapy may be a sign of impending IGD. These indicators should guide clinicians to diagnose and treat IGD early before the more deleterious later clinical presentation.     

Assessment of tacrolimus intrapatient variability in stable adherent transplant recipients: Establishing baseline values

The purpose of this study was to determine the intrapatient (within the same patient) variability of tacrolimus in adherent patients. Daily tacrolimus trough levels were obtained at home using dried blood spot technology in kidney and liver transplant recipients. Patients were randomized to receive 3 formulations of tacrolimus, each for two 1‐week periods. Adherence was monitored by patient diary, pill counts, and use of the Medication Event Monitoring System (MEMS). Variability was quantified as the coefficient of variation (CV). Comparison of CV between groups was by independent t test or one‐way ANOVA as appropriate. The population was found to be adherent with a rate of 99.9% with a mean interval between the evening and morning dose of tacrolimus of 11.86 hours. The median CV for the entire population was 15.2% (range 4.8%‐110%). There were no differences in CV by allograft type or tacrolimus formulation. The multivariate analysis did not identify any demographic characteristics associated with a CV > 30%. In a highly adherent population, tacrolimus did not display high intrapatient variability. Given the association between IPV and poor allograft outcomes, future studies are needed to quantitate the influence of adherence and establish target IPV goals.