Assessing the influence of graft loss on 4-year patient survival after simultaneous pancreas-kidney transplantation: Kaplan-Meier versus Competing Risk Analysis model.

BACKGROUND: Graft loss increases the risk of patient death after simultaneous pancreas-kidney (SPK) transplantation. The relative risk of each graft failure is complex due to the influence of several competing events. METHODS: This retrospective, single-center study compared 4-year patient survival according to the graft status using Kaplan-Meier (KM) and Competing Risk Analysis (CRA). Patient survival was also assessed according to five eras (Era 1: 2001-2003; Era 2: 2004-2006; Era 3: 2007-2009; Era 4: 2010-2012; Era 5: 2012-2015). RESULTS: Between 2000 and 2015, 432 SPK transplants were performed. Using KM, patient survival was 86.5% for patients without graft loss (n = 333), 93.4% for patients with pancreas graft loss (n = 46), 43.7% for patients with kidney graft loss (n = 16), and 25.4% for patients with pancreas and kidney graft loss (n = 37). Patient survival was underestimated using KM versus CRA methods in patients with pancreas and kidney graft losses (25.4% vs. 36.2%), respectively. Induction with lymphocyte depleting antibodies was associated with 81% reduced risk (HR.19, 95% CI.38-.98, p = .0048), while delayed kidney function (HR 2.94, 95% CI 1.09-7.95, p = .033) and surgical complications (HR 2.94, 95% CI 1.22-7.08, p = .016) were associated with higher risk of death. Four-year patient survival increased from Era 1 to Era 5 (79% vs. 87.9%, p = .047). CONCLUSION: In this cohort of patients, kidney graft loss, with or without pancreas graft loss, was associated with higher mortality after SPK transplantation. Compared to CRA, the KM model underestimated survival only among patients with pancreas and kidney graft losses. Patient survival increased over time.

Efficacy and safety of single-dose anti-thymocyte globulin versus basiliximab induction therapy in pediatric kidney transplant recipients: A retrospective comparative cohort study.

BACKGROUND: This study aimed to compare the efficacy and safety of basiliximab (BAS) versus a single dose of anti-thymocyte globulin (r-ATG) induction therapy in pediatric kidney transplant recipients (KTRs). METHODS: This single-center retrospective comparative cohort study included all pediatric KTRs from May 2013 to April 2018 and followed up to 12 months. In the first period, all recipients received BAS, while from May 2016, a single 3 mg/kg dose of r-ATG was instituted. Maintenance therapy consisted of a calcineurin inhibitor plus prednisone plus azathioprine or mycophenolate. RESULTS: A total of 227 patients were included (BAS, n = 113; r-ATG, n = 114). The main combination of immunosuppressive drugs was tacrolimus, prednisone, and azathioprine in both groups (87% vs. 88%, p = .718). Patients receiving r-ATG showed superior survival-free of the composite endpoint (acute rejection, graft loss, or death; 76% vs. 61%, p = .003; HR 2.08, 1.29-3.34, p = .003) and lower incidence of biopsy-proven acute rejection (10% vs. 21%, p = .015). There was no difference in the overall incidence of CMV infection (33% vs. 37%, p = .457), PTLD (1% vs. 3%, p = .309), 30-day hospital readmissions (24% vs. 23%, p = .847), and kidney function at 12 months (86 ± 29 vs. 84 ± 30 mL/min/1.73m2, p = .614). CONCLUSIONS: These data suggest that induction therapy with a single 3 mg/kg dose of r-ATG is associated with higher efficacy for preventing acute rejection and similar safety profile compared to BAS.

Urological Complications Associated With Pyeloureterostomy Without Ipsilateral Nephrectomy in Renal Transplant Recipients.

Background: The implications of ligating the native ureter without ipsilateral nephrectomy after primary kidney transplant pyeloureterostomy (PU) have been described previously. Methods: This single-center retrospective cohort study including 4,215 kidney transplants performed between February 2010 and December 2014, analyzed urological complications following primary (P-PU) and secondary (S-PU) pyeloureterostomy used to treat urological leaks (UL-PU) and ureteral stenosis (US-PU) without concomitant ipsilateral nephrectomy, in a large cohort of patients. Results: There were 495 (11.7%) pyeloureterostomy with native ureter ligation without nephrectomy, 409 P-PU (82.6%) and 86 S-PU (17.4%), of which 76 were UL-PU and 10 were US-PU. The median follow-up was 33.8 months. The incidence of native ipsilateral kidney complications requiring nephrectomy was 2.02% (n = 10). Urinary leak was diagnosed in 3.6% of patients after P-UP and 9.2% after UL-PU. Ureteral stenosis was diagnosed in 1.7% of patients after P-UP, 3.9% after UL-PU and 10% after US-PU. Conclusion: This cohort analysis suggests that native ureter ligation during pyeloureterostomy without native nephrectomy is associated with low incidence of clinically indicated ipsilateral native nephrectomy. Caution and awareness should be emphasized in patients with history of ADPKD and neurogenic augmented bladders.

Lower seroprevalence for SARS-CoV-2-specific antibodies among kidney transplant recipients compared to the general population in the city of Sao Paulo, Brazil.

BACKGROUND: Kidney transplant recipients have higher COVID-19 associated mortality compared to the general population. However, as only symptomatic patients seek medical attention, the current level of exposure, the main sources of acquisition, and the behavior of humoral immunity over time are poorly understood. METHODS: This cross-sectional prospective single-center study recruited kidney transplant recipients of any age living in Sao Paulo. A sample size of 401 patients was calculated considering the 17.2% seroprevalence in the municipality population from a published survey, a 95% confidence interval and an absolute error of 2%. RESULTS: Of the 2636 eligible patients, 416 were included. The seroprevalence for IgG anti-SARS-CoV-2 was 8.2%. Seroconversion rate decreased with increasing age, from 15.7% (18-35 years) to 8.3% (36-60 years) and 4.2% (>60 years, p = 0.042). Seropositivity among previously confirmed COVID-19 patients was 68.4%, followed by 9.4% in those with flu-like symptoms and only 4.6% among asymptomatic patients (p < 0.0001). Seroprevalence was significantly higher among patients reporting household contact (p = 0.018). Twenty-seven from the 34 IgG+ patients had a second test after 59 (IQR 50-63) days, and, in 33%, the IgG index became below the positivity threshold. CONCLUSIONS: In this cohort of kidney transplant recipients, the seroprevalence for IgG anti-SARS-CoV-2 was lower than that of the general population, decreased with ageing, and was associated with household contacts. In a considerable proportion of the patients, there was a significant decay in the IgG levels in a short period of time. Therefore, preventive strategies, such as prioritization for vaccination, should be urgently considered.

Kidney transplantation in the time of COVID-19: Dilemmas, experiences, and perspectives.

INTRODUCTION: Hospital do Rim is a high-volume kidney transplant (KT) center located in São Paulo, a city with 12.2 million inhabitants. Over the last 18 years, we performed 11 436 KT, 70% of which from deceased donors. To mitigate the effects of reduction in the number of transplants on the waiting list, sequential measures were implemented when COVID-19 was declared pandemic. METHODS: The first step was to provide SARS-COV-2 RT-PCR testing for all symptomatic employees and patients and the compulsory use of personal protective equipment in the hospital facilities. Living donor KT were postponed, and all deceased donors and recipients were tested before the transplantation. The immunosuppressive protocols were maintained, and telehealth strategies were developed. RESULTS: Among the 1013 employees, there were 214 cases of COVID-19, nine required ward hospitalization, and no deaths occurred. In 26%, the probable source of contamination was occupational. From the first patient diagnosed with COVID-19 in 03/20/2020 till 10/21/2020, 523 deceased KT were performed, a 21% increase compared with 2019, with no confirmed donor-derived SARS-CoV-2 infection. Four patients were transplanted with a positive pretransplant SARS-CoV-2 test, but none of them developed the disease. Overall, of 11 875 KT followed in our center, 674 developed COVID-19. Among the hospitalized, 53% required mechanical ventilation, and 45% required hemodialysis. Their overall mortality rate was 27.5%. CONCLUSION: This experience shows the challenges that transplant centers faced as the pandemic unfolded and illustrates the effectiveness of the sequential measures implemented to provide a safe environment for transplantation.

Budd-Chiari Syndrome after Bilateral Nephrectomy for Polycystic Kidney Disease in a Kidney Transplant Recipient.

We report a rare case of Budd-Chiari syndrome (BCS) as a postoperative complication after bilateral nephrectomy in a kidney transplant recipient with polycystic liver and kidneys. Contrast-enhanced computed tomography of the abdomen showed a narrowed inferior vena cava, compressed by the polycystic liver that moved downwards after nephrectomy. A stenting angioplasty was performed, resulting in remarkable clinical improvement. This case highlights the need for careful evaluation of polycystic kidneys and their anatomic relationship with the liver before nephrectomy, as well as for considering BCS as a differential diagnosis in similar cases.

Impact of Dialysis Time on Long-term Outcomes in HLA-identical Living Donor Kidney Transplant Recipients.

Background: Dialysis vintage is associated with worse outcomes after kidney transplantation. The reasons behind this observation include immunological and nonimmunological risk factors. To mitigate the influence of immunological factors, we examined the association between time on dialysis and clinical outcomes in a cohort of HLA-identical kidney transplant recipients. Methods: This retrospective study included 13 321 kidney transplant recipients between 1999 and 2016, of whom 589 were HLA identical followed for at least 5 y. Patient and graft survivals were compared according to dialysis time (<12 or >12 mo) using the log-rank test and Cox regression analysis. We compared surgical complications, cytomegalovirus infection, acute rejection, disease recurrence, and the trajectories of estimated glomerular filtration rate (eGFR). Results: Median time on dialysis was 15 mo; 9.2% of patients received preemptive transplants, and 55.3% of patients were on dialysis for >12 mo. After a median follow-up time of 154 mo, there were no differences in unadjusted and adjusted patient and graft survivals (1, 5, 10, and 15 y) between the 2 groups. There were no differences in the incidence of surgical complications (6.2% versus 3.1%), acute rejection (6.1% versus 7.7%), cytomegalovirus infection (7.6% versus 4.0%), and disease recurrence (4.2% versus 4.0%), respectively. There were no differences in mean eGFR during 5 y or in the proportion of patients with an eGFR <30 mL/min at 5 y (9.9% versus 9.2%). Conclusions: In this low immunological risk cohort of HLA-identical kidney transplant recipients, we did not observe any association between dialysis vintage on patient survival and graft survival.

Age and Epstein-Barr viral load at diagnosis of post-transplant lymphoproliferative disease are associated with patient survival in kidney transplant recipients.

INTRODUCTION: This study investigated variables associated with mortality in kidney transplant recipients (KTRs) diagnosed with post-transplant lymphoproliferative disease (PTLD) and a simultaneous Epstein-Barr virus (EBV) viremia. METHODS: This was a retrospective cohort study enrolling KTRs diagnosed with PTLD between 2018 and 2020. Outcome: death within two years after diagnosis. RESULTS: Among 1,625 KTRs who collected EBV viremia (by PCR, 2018-2020) for any reason, 238 (14.6%) had a positive viral load and 41 (17.2%) simultaneous PTLD. These 41 patients were 40.1 years old at diagnosis and 8.6 years after transplantation; 26.8% were induced with rATG and 92.7% were maintained on tacrolimus and azathioprine (TAC/AZA) as immunosuppressive regimen. Lymph nodes (75.6%) was the most common site of PTLD, followed by the gastrointestinal tract (48.8%), with 61.0% at Lugano stage IV and 80.5% monomorphic PTLD. The mean EBV viral load was 12,198 IU/mL. One- and two-year patient survival post-diagnosis was 60.4% and 46.8%, respectively. In the Cox regression analysis, age at PTLD diagnosis (HR for each year = 1.039; p < 0.001) and EBV viral load (HR for each log = 1.695; p = 0.026) were associated with risk of death. CONCLUSION: This study suggests that in patients predominantly on TAC/AZA, PTLD with simultaneous EBV positive viral load is a late event, and worse survival is associated with older age and EBV viral load at diagnosis.

A Head-to-head Comparison of De Novo Sirolimus or Everolimus Plus Reduced-dose Tacrolimus in Kidney Transplant Recipients: A Prospective and Randomized Trial.

BACKGROUND: Mammalian target of rapamycin inhibitors (mTORi), sirolimus (SRL) and everolimus (EVR), have distinct pharmacokinetic/pharmacodynamics properties. There are no studies comparing the efficacy and safety of de novo use of SRL versus EVR in combination with reduced-dose calcineurin inhibitor. METHODS: This single-center prospective, randomized study included first kidney transplant recipients receiving a single 3 mg/kg antithymocyte globulin dose, tacrolimus, and prednisone, without cytomegalovirus (CMV) pharmacological prophylaxis. Patients were randomized into 3 groups: SRL, EVR, or mycophenolate sodium (MPS). Doses of SRL and EVR were adjusted to maintain whole blood concentrations between 4 and 8 ng/mL. The primary endpoint was the 12-mo incidence of the first CMV infection/disease. RESULTS: There were 266 patients (SRL, n = 86; EVR, n = 90; MPS, n = 90). The incidence of the first CMV event was lower in the mTORi versus MPS groups (10.5% versus 7.8% versus 43.3%, P < 0.0001). There were no differences in the incidence of BK polyomavirus viremia (8.2% versus 10.1% versus 15.1%, P = 0.360). There were no differences in survival-free from treatment failure (87.8% versus 88.8% versus 93.3%, P = 0.421) and incidence of donor-specific antibodies. At 12 mo, there were no differences in kidney function (75 ± 23 versus 78 ± 24 versus 77 ± 24 mL/min/1.73 m 2 , P = 0.736), proteinuria, and histology in protocol biopsies. Treatment discontinuation was higher among patients receiving SRL or EVR (18.6% versus 15.6% versus 6.7%, P = 0.054). CONCLUSIONS: De novo use of SRL or EVR, targeting similar therapeutic blood concentrations, shows comparable efficacy and safety. The reduced incidence of CMV infection/disease and distinct safety profile of mTORi versus mycophenolate were confirmed in this study.

Long-term Kidney Transplant Survival Across the Globe.

BACKGROUND: The outcomes after kidney transplantation (KT), including access, wait time, and other issues around the globe, have been studied. However, issues do vary from one country to another. METHODS: We obtained data from several countries from North America, South America, Europe, Asia, and Australia, including the number of patients awaiting KT from 2015, transplant rate per million population (pmp), proportion of living donor and deceased donor (LD/DD) KT, and posttransplant survival. We also sought opinions on key difficulties faced by each of these countries with respect to KT and long-term survival. RESULTS: Variation in access to KT across the globe was noted. Countries with the highest rates of KT pmp included the United States (79%) and Spain (71%). A higher proportion of LD transplants was noted in Japan (93%), India (85%), Singapore (63%), and South Korea (63%). A higher proportion of DD KTs was noted in Spain (90%), Brazil (90%), France (85%), Italy (85%), Finland (85%), Australia-New Zealand (80%), and the United States (77%). The 5-y graft survival for LD was highest in South Korea (95%), Singapore (94%), Italy (93%), Finland (93%), and Japan (93%), whereas for DD, it was South Korea (93%), Italy (88%), Japan (86%), and Singapore (86%). The common issues surrounding KTs are access and a limited number of LDs and DDs. Key issues identified for long-term survival were increasing age of donors and recipients, higher recipient comorbidity, and posttransplant events, such as alloimmune injury to the kidney, infection, cancer, and suboptimal adherence to therapy. CONCLUSIONS: A unified approach is necessary to improve issues surrounding KT as the demand continues to increase.

Use of Machine Perfusion to Increase the Number of Expanded Criteria Deceased Donor Kidney Transplants: A Pharmacoeconomic Analysis.

Background: The discard of expanded criteria donor (ECD) kidneys is unacceptably high, considering the growing demand for transplantation. Using machine perfusion may reduce the discard rate, increase the number of transplants, and reduce mortality on the waiting list. Methods: We developed a 5-y Markov model to simulate incorporating the pulsatile perfusion machine into the current government-funded healthcare system. The model compared the universal use of static cold storage for all kidneys with the selective use of machine perfusion for ECD kidneys. Real-life data were used to compose the cohort characteristics in this model. This pharmacoeconomic analysis aimed to determine the cost-effectiveness and budgetary impact of using machine perfusion to preserve ECD kidneys. Results: Compared with the universal use of static cold storage, the use of machine perfusion for ECD kidneys was associated with an increase in the number of kidney transplants (n = 1123), a decrease in the number of patients on the waiting list (n = 815), and decrease in mortality (n = 120), with a cost difference of US dollar 4 486 009 in the period. The budget impact analysis revealed an additional cost of US dollar 4 453 749 >5 y. The budget impact analysis demonstrated a progressive reduction in costs, becoming cost-saving during the last year of the analysis. Conclusions: This stochastic model showed that incorporating machine perfusion for ECD kidneys is most often a dominant or cost-effective technology associated with an increase in the number of transplants and a reduction in the number of patients on the waiting list, reducing mortality on the waiting list.

Two-Hit Kidney Allograft Injury by SARS-CoV-2.

Coronavirus disease 2019 (COVID-19) has been associated with acute kidney injury in kidney transplant recipients by several mechanisms. The authors report a case of acute kidney allograft dysfunction in a 48-year-old patient who presented in the emergency room with anasarca and nephrotic syndrome close after mild COVID-19 and no other clinical condition. Histopathology of the allograft biopsy revealed two distinct and simultaneous kidney lesions, collapsing glomerulopathy and thrombotic microangiopathy. Renal function persistently deteriorated, and definitive dialysis was initiated. After excluding other plausible causes for the findings, this case strengthens the hypothesis that the kidney allograft is also a target of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Challenges of Multidrug-resistant New Delhi Metallo-beta-Lactamase (NDM-1)-producing Enterobacteriaceae in Kidney Transplant Patients.

BACKGROUND: The emergence of multidrug-resistant NDM-1-producing enterobacteriaceae strains has become a threat to inpatients, especially to immunosuppressed ones, such as kidney transplant recipients. NDM-1 is a carbapenemase that makes gram-negative bacteria resistant to many types of antibiotics. The incidence of carbapenemase-producing enterobacteria infection in solid organ transplant recipients is around 3 to 10%, with a mortality rate of up to 30%. METHODS: We present a case series of 4 patients with NDM-1-producing enterobacteria isolated in urine cultures or rectal swabs. We also conducted a cross-sectional study 30 days after patient identification, collecting surveillance cultures (rectal swab) from all inpatients to assess the extent of spread of this resistance mechanism; a total of 101 patients were included. RESULTS: Two patients were adequately treated with negative control cultures. The other two patients were not treated because they were asymptomatic and had subsequent negative urine cultures. No new colonization was identified in the cross-sectional screening, and no new cases of urinary NDM-1 infection were recorded after a 4-year follow-up. CONCLUSION: Surveillance for infections caused by multidrug-resistant strains in hospitals treating immunosuppressed patients should be continued and prompt action should be taken in cases of outbreaks of multidrug-resistant infections.

The Association Between Kidney Donor Profile Index and 1-y Graft Function.

The association between Kidney Donor Profile Index (KDPI) and 1-y estimated glomerular filtration rate (eGFR) with long-term kidney graft survival is well known. Yet, the association between KDPI and 1-y eGFR remains uncertain considering the several concurrent competing risk factors. Methods: This single-center, retrospective cohort study analyzed data from 3059 consecutive deceased donor kidney transplant recipients with a 1-y follow-up from January 2013 to December 2017. The aim was to determine the association between the KDPI strata (0%-35%, 36%-50%, 51%-85%, 86%-100%) and 1-y eGFR estimated by the CKD-EPI equation. Results: The incidence of delayed graft function (50.6% versus 59.3% versus 62.7% versus 62.0%; P < 0.001) and cytomegalovirus infection (36.7% versus 36.6% versus 43.3% versus 57.8%; P < 0.001) increased with increasing KDPI strata but not biopsy-proven acute rejection (9.1% versus 9.8% versus 8.4% versus 9.1%; P = 0.736). The median 1-y eGFR decreased with increasing KDPI strata (64.8 versus 53.5 versus 46.9 versus 39.1 mL/min/1.73 m2; P < 0.001). In the Cox regression, the higher the KDPI was, the lower the probability of a lower 1-y eGFR was. Assuming the 0%-35% strata as the reference, the likelihood of eGFR <50 mL/min/1.73 m2 was increased by 76.6% (hazard ratio [HR] = 1.767, 95% confidence interval [CI] = 1.406-2.220), 2.24- and 2.87-fold higher for KDPI higher >35%-50% (HR = 2.239, 95% CI = 1.862-2.691), and >51%-85% (HR = 2.871, 95% CI = 2.361-3.491), respectively. Other variables associated with a lower graft function were donor sex (HR male versus female = 0.896, 95% CI = 0.813-0.989) and cold ischemia time (HR for each hour = 1.011, 95% CI = 1.004-1.019). This association was sustained after the Poisson mediation analysis, including delayed graft function, cytomegalovirus, and acute rejection as mediators. Conclusions: In this cohort of deceased donor kidney recipients, KDPI, and cold ischemia time were the major independent risk factors associated with lower 1-y kidney function.

Paired kidney donation: are we going beyond reasonable limits in living-donor transplantation?

The growing demand for transplant kidneys requires strategies to increase organ supply and avoid long waiting periods on the list. The increase in the number of transplants from living donors involves the growth in the use of unrelated donors and paired kidney donation. Most of these transplants are performed in the USA, where they already represent, respectively, 34% and 16% of total transplants from living donors. In Latin America, and especially in Brazil, there is no collective enthusiasm for these modalities, either at the request of transplanters or that of the community, with the region's priority being to increase transplants from deceased donors, which growth can be up to three-fold. Concerning transplants from matched donors, the possible conflicting results between donors can generate public challenges and they risk compromise the concepts of equal opportunities for transplant candidates, with the possibility of generating resistance to organ donation, especially in regions with socioeconomic limitations and disparities in access to qualified health care and education. This donation model involves challenging ethical and logistical issues, which are subject to questionings, starting with an act of exchange between two pairs until reaching embarrassing proposals, which can compromise the altruistic character of organ donation, and thus not be universally incorporated.

Presumed cytomegalovirus retinitis late after kidney transplant.

Cytomegalovirus (CMV) retinitis is a rare manifestation of CMV invasive disease and potentially threatening to vision in immunocompromised individuals. Clinical suspicion is fundamental since it is an unusual entity with a progressive and often asymptomatic installation over a long period. The authors report a 70-year-old man with diabetic nephropathy who underwent a kidney transplant (KT) in August 2014 with good clinical evolution. No previous CMV infection or episodes of acute rejection were reported. Five years after transplant, he was admitted due to a reduced visual acuity of the left eye with seven days of evolution with associated hyperemia, without exudate. The ophthalmologic evaluation was compatible with acute necrosis of the retina and presumed associated with CMV infection. He had a progressive improvement after ganciclovir initiation. CMV retinitis is one of the most serious ocular complications in immune-suppressed individuals and can lead to irreversible blindness, and because of that, early diagnosis and treatment remains crucial in obtaining the best visual prognosis in affected patients. Secondary prophylaxis with ganciclovir is not consensual, neither is the safety of reintroducing the antimetabolite in these cases.

Inactivated Whole-virus Vaccine Triggers Low Response Against SARS-CoV-2 Infection Among Renal Transplant Patients: Prospective Phase 4 Study Results.

BACKGROUND: Anti-severe acute respiratory syndrome coronavirus 2 mRNA vaccines elicit lower humoral responses in solid-organ transplant recipients. This is the first prospective trial investigating the effect of an inactivated whole-virion vaccine in kidney transplant recipients. METHODS: Prospective, single-center, phase 4, interventional study. Kidney transplant recipients aged 30-69 y with >30 d of transplantation received two 3 µg intramuscular doses of CoronaVac 28 d apart and are being followed for 6 mo. Primary outcomes: (1) reactogenicity after first dose; (2) antibody responses 28 d after each dose; and (3) incidence/severity of confirmed coronavirus disease 2019 (COVID-19) and 28-d lethality rate. For this analysis, clinical effectiveness was assessed for 3 mo, starting 15 d after the second dose, and compared with 3-mo period before vaccination. RESULTS: Of the 3371 individuals who received the first dose, 99% completed vaccination schedule. Mild/local adverse reactions were reported by 33% of the patients. In the immunogenicity cohort (n = 942), the proportion of patients with IgG antibodies to severe acute respiratory syndrome coronavirus 2 increased from 15.2% after first dose to 43% after second dose. Increase in antibody values after second dose was associated with higher proportion of patients with detected neutralizing antibodies. A significant reduction in the incidence of COVID-19 was observed (6.4% versus 4.2%; P < 0.0001), although the 28-d lethality rate remained unchanged (25% versus 22%; P = 0.534). In 45 patients from the immunogenicity cohort who developed COVID-19, all the 6 deaths occurred among those without antibody response (n = 22; 49%). CONCLUSIONS: CoronaVac vaccine was associated with low reactogenicity, low immunogenicity but reduced incidence of COVID-19 among kidney transplant recipients. The lack of reduction in lethality rates is perhaps associated with the low percentage of patients developing humoral response after the second dose.

Immunogenicity After a Heterologous BNT262b2 Versus Homologous Booster in Kidney Transplant Recipients Receiving 2 Doses of CoronaVac Vaccine: A Prospective Cohort Study.

BACKGROUND: Comparative studies of third heterologous doses following the CoronaVac vaccine against coronavirus disease 2019 (COVID-19) in kidney transplant recipients are lacking. METHODS: This prospective, single-center cohort study included kidney transplant recipients without previous COVID-19. Patients received a third heterologous (BNT162b2 mRNA) or homologous dose at least 4 wk after 2 doses of the CoronaVac vaccine. Immunoglobulin G antibody response and seroprevalence for neutralizing anti-severe acute respiratory syndrome coronavirus 2 antibodies immediately before and 28 d after third doses were compared between the groups. RESULTS: There were 307 patients in the heterologous group and 777 in the homologous group. Patients in the heterologous group were older (54 versus 50 y; P < 0.0001), with a longer time since transplant (11 versus 6 y; P < 0.0001). Immediately before the third dose, immunoglobulin G seroprevalence (36% versus 34%; P = 0.597) and antibody titers (246 versus 268 AU/mL; P = 0.279) were similar. After booster, seroconversion was higher in the heterologous group (49% versus 32%; P < 0.0001), resulting in a higher seroprevalence (67% versus 55%; P = 0.0003); however, 42% of all patients remained seronegative. Antibody titers after booster in seropositive patients were higher in the heterologous group (7771 versus 599 AU/mL; P < 0.0001). These results persisted after adjusting for confounding variables. Lastly, a similar proportion of patients became seropositive for neutralizing antibodies (98% versus 94%; P = 0.098). CONCLUSIONS: In kidney transplant recipients fully vaccinated with CoronaVac, a third dose with an mRNA vaccine produced a higher seroconversion rate and antibody titers than a third homologous dose. However, both boosters achieved equivalent seroprevalence for neutralizing antibodies. The high proportion of still seronegative patients indicates the need for alternative strategies of protection.

Risk factors of transplant renal artery stenosis in kidney transplant recipients.

BACKGROUND: Transplant Renal Artery Stenosis (TRAS) is a recognized vascular complication after kidney transplantation. The overall risk predictors of TRAS are poorly understood. METHODS: Retrospective analysis of patients with suspected TRAS (Doppler ultrasound PSV > 200 cm/s) who underwent angiographic study in a single center between 2007 and 2014. All patients with stenosis > 50% were considered with TRAS. Stenosis restricted in the body of the artery was also analyzed in a subgroup. RESULTS: 274 patients were submitted to a renal angiography and 166 confirmed TRAS. TRAS group featured an older population (46.3 ± 11.0 vs. 40.9 ±14.2 years; p = 0.001), more frequent hypertensive nephropathy (30.1% vs. 15.7%; p = 0.01), higher incidence of Delayed Graft Function (DGF) (52.0% vs. 25.6%; p < 0.001) and longer Cold Ischemia Time (CIT) (21.5 ± 10.6 vs. 15.7 ± 12.9h; p < 0.001). In multivariable analyses, DGF (OR = 3.31; 95% CI 1.78‒6.30; p < 0.0001) was independent risk factors for TRAS. DM and CIT showed a tendency towards TRAS. The compound discriminatory capacity of the multivariable model (AUC = 0.775; 95% CI 0.718‒0.831) is significantly higher than systolic blood pressure and creatinine alone (AUC = 0.62; 95% CI 0.558-0.661). In body artery stenosis subgroup, DGF (OR = 1.86; 95% CI 1.04‒3.36; p = 0.03) and Diabetes Mellitus (DM) (OR = 2.44; 95% CI 1.31‒4.60; p = 0.005) were independent risk factors for TRAS. CONCLUSION: In our transplant population, DGF increased more than 3-fold the risk of TRAS. In the subgroup analysis, both DGF and DM increases the risk of body artery stenosis. The addition of other factors to hypertension and renal dysfunction may increase diagnostic accuracy. TRAS TRIAL REGISTRED: clinicaltrials.gov (n° NCT04225338).