Elevated tacrolimus levels among COVID-19 kidney transplant recipients are associated with worse disease severity and clinical outcomes.

BACKGROUND: The therapeutic effects of immunosuppressive drugs against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections causing coronavirus disease 2019 (COVID-19) are being actively investigated. However, COVID-19's potential effects on serum calcineurin inhibitor levels have only been described recently. This study aimed to evaluate COVID-19's effect on tacrolimus levels in renal transplant recipients with moderate to severe symptoms and to assess their potential correlation with disease severity. MATERIALS AND METHODS: We retrospectively investigated 50 kidney transplant recipients with moderate to severe COVID-19. Their tacrolimus trough level on admission was compared to baseline levels, and their laboratory measurements and clinical course were reviewed on days 1 (admission), 7, 14, and 28. RESULTS: We found that 90% of patients had admission tacrolimus trough levels above baseline, with a mean increase of 176%. In addition, 71% had tacrolimus trough levels ≥ 50% above baseline, and 40% had supra-therapeutic trough levels of > 15 ng/mL. Supra-therapeutic trough levels were associated with greater hypoxemic respiratory failure, acute kidney injury, and increased 30-day mortality. CONCLUSION: Elevated tacrolimus levels occur in many renal transplant recipients with moderate to severe COVID-19 and are associated with worse clinical outcomes. Close drug monitoring is crucial to avoid toxicities and minimize over-immunosuppression complications.

Weight-based vs fixed dosing of darbepoetin alfa for anemia following kidney transplantation.

PURPOSE: Post-transplantation anemia (PTA) is common in kidney transplant recipients, with patients frequently treated with erythropoietin-stimulating agents such as darbepoetin alfa. The optimal dosing for darbepoetin alfa remains controversial. METHODS: This retrospective cohort study involved kidney transplant recipients who received darbepoetin alfa at 2 clinics. Patients were stratified into 2 groups: those who received a fixed dose of 200 µg and those who received a weight-based dose of 0.45 µg/kg. The dosing interval varied depending on clinical response, clinic visit timing, and frequency allowed by insurance. The primary outcome was achieving a hemoglobin concentration of at least 10 g/dL without blood transfusion by 12 weeks after darbepoetin alfa initiation. RESULTS: Of the 110 patients in the study, 45% received weight-based dosing and 55% received fixed dosing. Darbepoetin alfa was initiated significantly earlier after transplantation in the fixed-dose group (median of 14 vs 20 days; P = 0.003). The weight-based group received more doses of darbepoetin alfa (median of 4 vs 2 doses; P = 0.002) and had a significantly lower cumulative exposure to darbepoetin alfa (125 vs 590 µg; P < 0.001). The median time between doses was 9 days (interquartile range, 7-14 days) in the weight-based group and 12 days (7-32 days) in the fixed-dose group (P = 0.04). Patients in the weight-based group more frequently achieved the primary outcome (67.3% vs 47.5%; P = 0.059). There was no significant difference in secondary or safety outcomes between the groups. CONCLUSION: Weight-based and fixed dosing approaches for darbepoetin alfa were not different in the achievement of a hemoglobin concentration of at least 10 g/dL without blood transfusion at 12 weeks after darbepoetin alfa initiation, with significantly lower cumulative darbepoetin alfa utilization in the weight-based group. Weight-based dosing of darbepoetin alfa in PTA appears to be safe and effective, with the potential for significant patient and health-system cost savings.

Therapeutic considerations for prevention and treatment of thrombotic events in COVID-19.

Thrombosis is a known complication of SARS-CoV-2 infection, particularly within a severely symptomatic subset of patients with COVID-19 disease, in whom an aggressive host immune response leads to cytokine storm syndrome (CSS). The incidence of thrombotic events coinciding with CSS may contribute to the severe morbidity and mortality observed in association with COVID-19. This review provides an overview of pharmacologic approaches based upon an emerging understanding of the mechanisms responsible for thrombosis across a spectrum of COVID-19 disease involving an interplay between immunologic and pro-thrombotic events, including endothelial injury, platelet activation, altered coagulation pathways, and impaired fibrinolysis.

Minimal change disease and COVID-19 vaccination: Four cases and review of literature.

There have been multiple reports of the development of de novo or relapse of glomerular diseases after SARS-CoV-2 vaccination. While most of them have occurred with the mRNA vaccines (Pfizer/BioNTech and Moderna/NIAID), there also have been reports associated with the vector vaccines (AstraZeneca/ChAdOx1-S) vaccine and the inactivated vaccines. Minimal change disease (MCD) is one of the more common glomerular diseases noted to have been associated with the COVID-19 vaccination. We report here 4 more cases of MCD occurring in association with the COVID-19 vaccine, 3 were de novo cases, and 1 case had a relapse of MCD. We also review all the 41 cases described thus far in the literature and review potential common pathways activated by the vaccination that play a role in the pathogenesis of MCD.

Early outcomes of kidney transplant recipients from donors with severe SARS-CoV-2 pneumonia: A report of 5 cases.

BACKGROUND: Transplanting kidneys from donors with a recent history of severe SARS-CoV-2 pneumonia is uncommon due to concerns about the risk of viral transmission and the quality of kidneys from these donors. To date, there are no conclusive data on viral transmission from extrapulmonary solid organ transplants. Given the prevalence of SARS-CoV-2 infections in potential donors, shortage of kidneys available for transplantation, and low risk of viral transmission, we developed a clinical protocol for accepting kidneys from donors with recent severe SARS-CoV-2 pneumonia who demonstrate preserved kidney function. MATERIALS AND METHODS: We collected data on early outcomes of 5 kidney transplant recipients from 4 deceased donors hospitalized for severe SARS-CoV-2 infection. RESULTS: Donor creatinine ranged from 0.51 to 0.60 mg/dL and kidney donor profile index (KDPI) from 14 to 52%. Three of the five kidneys were from donation after circulatory death. All recipients were fully vaccinated, and 4/5 received post-exposure prophylactic monoclonal antibody treatment. While 3 recipients had delayed graft function, all had excellent graft function at 3 or 4 weeks post-operatively. None of the recipients displayed signs or symptoms of SARS-CoV-2 infection post-transplant. CONCLUSION: Our findings suggest that kidney grafts from donors with a recent history of severe SARS-CoV-2 infection but with preserved kidney function can be safely used and have good early outcomes.

The mechanistic basis linking cytokine storm to thrombosis in COVID-19.

It is now well established that infection with SARS-CoV-2 resulting in COVID-19 disease includes a severely symptomatic subset of patients in whom an aggressive and/or dysregulated host immune response leads to cytokine storm syndrome (CSS) that may be further complicated by thrombotic events, contributing to the severe morbidity and mortality observed in COVID-19. This review provides a brief overview of cytokine storm in COVID-19, and then presents a mechanistic discussion of how cytokine storm affects integrated pathways in thrombosis involving the endothelium, platelets, the coagulation cascade, eicosanoids, auto-antibody mediated thrombosis, and the fibrinolytic system.

Serum sickness induced by alemtuzumab in a kidney-pancreas transplant recipient.

Serum sickness is an immune-complex-mediated hypersensitivity reaction that was first noted in the early 1900s in patients receiving heterologous antisera, such as horse antitetanus or antidiphtheria serum. This condition is primarily self-limited; however, in its acute state, it can cause severe symptoms of fever, rash, polyarthritis, or polyarthralgias. In solid organ transplantation, this condition is frequently reported in association with the use of rabbit anti-thymocyte globulin and chimeric murine monoclonal antibodies such as rituximab. Alemtuzumab, designed as a humanized monoclonal antibody against CD52, is expected to be less immunogenic. Here, we report a case of serum sickness associated with alemtuzumab induction therapy in a kidney-pancreas dual-organ recipient.

Treatment of recurrent, post-kidney transplant membranoproliferative glomerulonephritis with plasmapheresis and rituximab: A case report and literature review
.

Membranoproliferative glomerulonephritis is known to recur after kidney transplantation and may lead to allograft loss. Although an optimal treatment has not been determined, B-cell targeted therapies are now increasingly used as first-line agents, based on growing data showing antibodies as key players in the pathogenesis of membranoproliferative glomerulonephritis. Here, we report a case of recurrent immune complex-mediated membranoproliferative glomerulonephritis 3 years after a living-donor kidney transplant. Treatment with plasmapheresis and rituximab resulted in immediate and sustained improvement in allograft function.
.

Routine ultrasonography surveillance of native kidneys for renal cell carcinoma in kidney transplant candidates.

Renal cell carcinoma (RCC) has a high incidence in the kidney transplant population and annual surveillance detects these tumors early in their natural history. Minimal guidelines exist regarding RCC surveillance in ESRD patients awaiting transplant. A retrospective review of our kidney transplant database examined the outcomes of annual ultrasonographic surveillance during initial kidney transplant evaluation and upon annual reassessment. Of 2642 patients listed for transplant, 145 patients were found to have masses during initial kidney transplant evaluation or annual imaging consistent with new complex cystic disease or RCC. A total of 71 patients had RCC identified, with 52 found on initial kidney transplant evaluation and 19 identified on annual surveillance. Male gender and African-American race were independently associated with RCC (P<.05). RCC was detected a median of 2.0 years after listing (two annual ultrasonography studies). Patients with complex cysts were more likely to undergo transplantation (48.7%) compared to patients with RCC (21.1%; P<.001). There was no significant difference in survival between RCC patients and those found to have complex cystic disease, suggesting incidental RCC can be diagnosed early in the natural history and at a curable stage through implementation of a biennial surveillance program.

Late presentation of adenovirus-induced hemorrhagic cystitis and ureteral obstruction in a kidney-pancreas transplant recipient.

We report a late presentation of adenovirus-induced renal allograft and bladder infection causing azotemia and hemorrhagic cystitis in a patient 5 years after simultaneous kidney-pancreas transplantation. Adenovirus has been increasingly recognized as a cause of morbidity and mortality in both solid organ and stem cell transplant recipients. We wish to emphasize the importance of early detection, as treatment options involve reduction of immunosuppression, followed by the addition of antiviral agents and supportive care.

West Nile virus infection in kidney and pancreas transplant recipients in the Dallas-Fort Worth Metroplex during the 2012 Texas epidemic.

BACKGROUND: In 2012, the United States experienced one of its worst West Nile virus (WNV) epidemics, reporting 5,387 human cases and final death toll of 243. Texas was at the epicenter of the outbreak, with 1,875 reported cases and 89 deaths that year. The Texas outbreak centered mainly in the Dallas-Fort Worth area where 30 deaths were reported. We report three cases of severe WNV infection complicated by meningoencephalitis in our organ transplant population. METHODS: Clinical data were collected from chart review. Therapy and outcomes on three identified patients were reviewed and compared with previously reported cases of WNV infection in kidney/pancreas transplant recipients and the general population. RESULTS: Two recipients of kidney and one recipient of a combined kidney and pancreas transplant were treated at our center for WNV infection. All three patients presented with a rapid decline in mental status within 24 hours of admission consistent with meningoencephalitis. Diagnosis was made based on detection of WNV IgM in the serum. All patients received intravenous immunoglobulin (IVIG) therapy at 400 mg/kg × 3 to 4 doses. As a result, two patients had a full recovery, and one patient died. CONCLUSION: Transplant recipients have a higher risk of neurologic complications from WNV infection. In areas where WNV is endemic, clinicians must have a high index of suspicion when treating patients presenting with fever, headache, and confusion. Full recovery in two of three patients suggests a potential role of IVIG therapy in controlling active WNV infection, particularly in immunosuppressed patients.

Use of an immune function assay to monitor immunosuppression for treatment of post-transplant lymphoproliferative disorder.

The first-line treatment for PTLD is reduction in immunosuppression, allowing partial reconstitution of cell-mediated immunity. However, there is a risk of inducing acute allograft rejection during clinical resolution of PTLD. A recently available assay, Immuknow, measures the cell-mediated immune response and could be used to monitor reduction of immunosuppression. We report a case of PTLD occurring in a pediatric kidney transplant recipient where the reduction in immunosuppression was serially followed using this assay and quantitative EBV-PCR. A rapid reduction to minimal immunosuppression was followed by resolution of PTLD. Later, when the cell-mediated immune response increased, with negative viral load, immunosuppression was gradually increased utilizing the assay to adjust dosing. Presently, there are no signs of PTLD and renal function remains normal.

Renal transplantation: older recipients and donors.

The majority of patients receiving a renal allograft, including a kidney from an older donor, do well. Renal transplantation from a living donor is associated with distinct advantages, including prolonged allograft survival. When live donors are not available, however, deceased donor kidneys provide suitable renal function that frequently lasts the lifetime of elderly recipients. Elderly patients who receive a kidney transplant enjoy improved survival, better quality of life, and lower medical costs than those who remain on dialysis.

Hepatocyte growth factor induces an endothelin-mediated decline in glomerular filtration rate.

Hepatocyte growth factor (HGF) is a multifunctional cytokine that plays a crucial role in renal development, injury, and repair. HGF also serves a protective role in chronic renal disease by preventing tissue fibrosis. Endothelin-1 (ET-1), produced primarily by endothelial cells, is a potent vasoconstrictor that also acts as a proinflammatory peptide, promoting vascular injury and renal damage. In addition to mediating a variety of epithelial cell responses, HGF also induces hemodynamic changes that are poorly understood. The aim of the present study was to study the acute and chronic effects of HGF on ET-1 production in the kidney. We hypothesized that hemodynamic changes upon HGF treatment are likely mediated by immediate ET-1 release, whereas protection from renal fibrosis in rats chronically treated with HGF is likely due to suppression of ET-1 production. Acute HGF infusion into rats caused a decline in blood pressure that was enhanced by pretreatment with bosentan (an endothelin A and B receptor antagonist). HGF infusion also resulted in a decline in glomerular filtration rate (GFR) that could be entirely prevented by bosentan, suggesting that HGF acutely increases production and/or release of ET-1, which then mediates the observed decline in GFR. In cultured glomerular endothelial cells, HGF induced ET-1 production in a dose-dependent manner. Moreover, although there was an initial increase in ET-1 production upon HGF treatment, longer administration suppressed ET-1 production. This finding was consistent with the observation in vivo of a decrease in ET-1 production in renal parenchyma of rats chronically treated with HGF. Our data suggest both a hemodynamic and biological role for HGF-mediated ET-1 regulation.

Renal transplant survival from older donors: a single center experience.

HYPOTHESIS: Despite the observation that kidney transplantations from older donors have an increased risk of failure, the percentage of kidney donors 55 years and older has increased. We explored the risk of allograft failure in a single transplantation center with older (55-79 years) vs younger (18-54 years) donors. DESIGN: Retrospective cohort review with a mean follow-up of 32 months. SETTING: Academic transplant center. PATIENTS: Consecutive recipients (n = 324) of renal transplants from adult donors. INTERVENTIONS: Patients were divided into 4 groups based on donor status (living or deceased) and donor age (< or =54 or > or =55 years). MAIN OUTCOME MEASURES: Allograft survival and function, incidence of acute rejection. RESULTS: Recipients of older donor kidneys were significantly older (53.6 vs 43.6 years, P<.001). Seven allografts (12.7%) failed from 55 transplants from donors 55 years and older, compared with 41 allografts (15.2%) from 269 younger donors (P =.63). Renal function was superior following renal transplantation using younger donors (P =.004). However, renal function was acceptable in all groups, with a mean +/- SD serum creatinine level of 1.7 +/- 0.4 mg/dL (150 +/- 35 micro mol/L) among recipients of older donor kidneys. Allograft survival at 1, 2, and 3 years, censored for death with allograft function, did not differ when comparing older vs younger donors. CONCLUSIONS: Most patients receiving allografts from older donors do well. Older donor kidneys provide suitable renal function for many patients on dialysis awaiting transplantation.

Comparative study of prophylactic oral ganciclovir and valacyclovir in high-risk kidney transplant recipients.

BACKGROUND: Cytomegalovirus (CMV) is a major pathogen in renal transplant patients causing significant post-transplant morbidity and mortality. Prophylactic antiviral therapy, currently implemented in most kidney transplant centres, has significantly reduced the incidence of CMV infection after transplantation. Oral ganciclovir has been shown to be an effective prophylactic agent in preventing CMV disease and infection with a demonstrated superior efficacy over oral acyclovir. Valacyclovir, a prodrug of acyclovir with a higher level of bioavailability than acyclovir, has also been shown to be effective in preventing CMV disease when given as prophylactic treatment. METHODS: In a retrospective analysis of 150 renal transplant recipients in our centre, we compared the efficacy of oral ganciclovir with valacyclovir in preventing CMV infection. Seventy-seven consecutive renal transplant recipients prophylactically treated with oral ganciclovir for 12 weeks after transplant were compared with 73 consecutive recipients treated with oral valacylovir for an equal length of time. RESULTS: No difference was noted in the incidence of CMV infection between the two treatment groups (5.1 vs 5.4%) after a 6 month follow-up. Likewise, the incidence of acute rejection was similar in both groups (11.6 vs 6.8%). All cases of CMV infection occurred in high-risk patients (donor positive/recipient negative). CONCLUSION: The prophylactic use of oral valacylovir is as effective as oral ganciclovir in reducing CMV infection and disease after kidney transplantation.

Management of thrombophilia in renal transplant patients.

Renal allograft recipients with thrombophilia (a hypercoagulable state) are at higher risk for early allograft loss. Following an episode of allograft renal vein thrombosis in a patient subsequently diagnosed with protein C deficiency, we adopted universal screening for hypercoagulable risk factors. Patients with a history of a thromboembolic event underwent laboratory screening for thrombophilia. Eight patients with a defined hypercoagulable disorder or a strong clinical history of thrombosis even in the absence of hematologic abnormalities were treated with anticoagulation following renal transplantation. We reviewed the outcomes of these eight patients and all renal transplant recipients at our center who developed thrombotic complications after renal transplantation. Since the introduction of universal screening for hypercoagulable risk factors, 235 consecutive transplants were performed without allograft thrombosis. Eight patients with evidence of thrombophilia, recognized before renal transplantation, received perioperative heparin and postoperative oral anticoagulation. Two of these eight patients developed perinephric hematomas requiring evacuation, blood transfusion, and temporary withholding of anticoagulation. Of interest, two of the remaining 227 patients, not identified with thrombophilia before surgery, developed thrombotic complications after renal transplantation. A hypercoagulable disorder was subsequently documented in each. Identifying patients with thrombophilia before transplantation and defining their management presents many challenges. The risk of allograft thrombosis must be weighed against the risk of perioperative bleeding and the need for long-term anticoagulation. Recommendations for managing thrombophilia in renal transplant recipients are suggested based on our experience and review of the literature.