BK Virus Infection in Pediatric Renal Transplantation

The Second International Consensus Guidelines on the Management of BK Polyomavirus in Kidney Transplantation

BK polyomavirus (BKPyV) remains a significant challenge after kidney transplantation. International experts reviewed current evidence and updated recommendations according to Grading of Recommendations, Assessment, Development, and Evaluations (GRADE). Risk factors for BKPyV-DNAemia and biopsy-proven BKPyV-nephropathy include recipient older age, male sex, donor BKPyV-viruria, BKPyV-seropositive donor/-seronegative recipient, tacrolimus, acute rejection, and higher steroid exposure. To facilitate early intervention with limited allograft damage, all kidney transplant recipients should be screened monthly for plasma BKPyV-DNAemia loads until month 9, then every 3 mo until 2 y posttransplant (3 y for children). In resource-limited settings, urine cytology screening at similar time points can exclude BKPyV-nephropathy, and testing for plasma BKPyV-DNAemia when decoy cells are detectable. For patients with BKPyV-DNAemia loads persisting >1000 copies/mL, or exceeding 10 000 copies/mL (or equivalent), or with biopsy-proven BKPyV-nephropathy, immunosuppression should be reduced according to predefined steps targeting antiproliferative drugs, calcineurin inhibitors, or both. In adults without graft dysfunction, kidney allograft biopsy is not required unless the immunological risk is high. For children with persisting BKPyV-DNAemia, allograft biopsy may be considered even without graft dysfunction. Allograft biopsies should be interpreted in the context of all clinical and laboratory findings, including plasma BKPyV-DNAemia. Immunohistochemistry is preferred for diagnosing biopsy-proven BKPyV-nephropathy. Routine screening using the proposed strategies is cost-effective, improves clinical outcomes and quality of life. Kidney retransplantation subsequent to BKPyV-nephropathy is feasible in otherwise eligible recipients if BKPyV-DNAemia is undetectable; routine graft nephrectomy is not recommended. Current studies do not support the usage of leflunomide, cidofovir, quinolones, or IVIGs. Patients considered for experimental treatments (antivirals, vaccines, neutralizing antibodies, and adoptive T cells) should be enrolled in clinical trials.

Effect of Leflunomide on Treatment of Pediatric Renal Transplant Recipients With BK Virus Infection

OBJECTIVES

Infection with the BK virus is a significant complication after renal transplant and can progress to BK virus nephropathy and graft dysfunction. There is no consensus on the management of BK virus infection in pediatric renal transplant recipients. The most common therapeutic option is immunosuppression reduction, which can increase rejection risk. We aimed to examine the effect of leflunomide, an agent with antiviral and immunosuppressive actions, in a case series of pediatric renal transplant recipients with BK virus infection.

MATERIALS AND METHODS

Routine screening with blood BK virus DNA polymerase chain reaction was performed regularly in all of our renal transplant patients. When BK virus was detected, we reduced tacrolimus levels, discontinued mycophenolate mofetil, and started active treatment with leflunomide. Treatment with leflunomide was continued until BK virus was undetectable by polymerase chain reaction in at least 2 blood samples 2 weeks apart.

RESULTS

All pediatric patients developed BK virus infection in a mean period of 3.9 months after transplant. Graft dysfunction was evident in all patients with 20% to 100% elevation of creatinine from baseline. Afterleflunomide initiation, all patients had undetectable levels of BK virus by plasma polymerase chain reaction in at least 2 different samples within a mean period of 3.4 months, and renal function had normalized back to the baseline. None of our patients had evidence of hepatotoxicity or anemia on regular monitoring, with no other adverse events. Renal function remained stable in the follow-up period with no reoccurrence of BK viremia up to the date of this writing.

CONCLUSIONS

Treatment with leflunomide resulted in rapid BK virus clearance and preservation of renal function with no adverse effects.

BK Viremia and Changes in Estimated Glomerular Filtration Rate in Children and Young Adults after Hematopoietic Cell Transplantation

Kidney disease in allogeneic hematopoietic cell transplantation (HCT) recipients is associated with increased mortality rates. BK virus (BKV) viremia has been associated with kidney dysfunction in pediatric HCT recipients; however, few studies have investigated longer-term kidney outcomes in association with BKV in this population. Here we assessed the relationship between BK viremia and changes in estimated glomerular filtration rate (eGFR) in children in the first year post-HCT. We selected 136 patients age ≤26 years who underwent HCT in 2007 to 2018 at a single center and had plasma BK viral load data available at 2 time points, weeks 4 to 7 post-HCT and weeks 10 to 13 post-HCT from prospectively collected stored plasma samples. A total of 272 samples were analyzed for BKV using quantitative PCR. We used multivariate linear models to determine the association of BK viremia and change in eGFR by 1 year post-HCT. Forty percent of the patients (54 of 136) had BKV detection in weeks 4 to 7, 13% of whom (7 of 54) had a BK viral load of ≥10,000 copies/mL, and 46% (62 of 136) had BKV detected in weeks 10 to 13, 34% (21 of 62) of whom had a BK viral load of ≥10,000 copies/mL. The mean decline in eGFR was 25.73 mL/min/1.73 m² by 1 year post-HCT. In multivariate models, a BK viral load of ≥10,000 copies/mL during weeks 4 to 7 was associated with a mean decline in eGFR of 30.6 mL/min/1.73 m² (95% confidence interval, -55.94 to -5.17; P = .019) compared with a BK viral load <10,000 copies/mL. In adjusted analyses, a high BK viral load in the blood (≥10,000 copies/mL) was associated with a significant decline in eGFR by 1 year post-HCT.

Treatment of BK virus with a stepwise immunosuppression reduction and intravenous immunoglobulin in pediatric kidney transplant

BACKGROUND

BKV and BKVN are common in pediatric kidney transplant, but there is limited data on treatment approaches. Our objective was to study the prevalence of BKV and BKVN utilizing only plasma qPCR and report treatment outcomes with stepwise IR and IVIG.

METHODS

A retrospective study of all pediatric kidney transplants from 2013 to 2020. Excluded patients >21 years at transplant and immediate graft failure. Surveillance was conducted using only plasma BK qPCR at 1, 3, 6, 9, 12, 18, and 24 months and annually. BKV defined as ≥250 copies/ml and resolution as <250 copies/ml. Presumed BKVN as >10 000 copies/ml despite IR; and BKVN if confirmed on histology.

RESULTS

Fifty-six patients were included in the study; 20 (35.7%) had BKV. BKV was associated with longer duration of stent, 40 vs. 33.5 days (p = .004). Two patients (3.5%) had confirmed, and 2(3.5%) had presumed BKVN. The first-line treatment was IR in 100% of patients. BKVN confirmed and presumed received IVIG every month for six doses. Viral resolution was achieved in 70%, and no difference was noted in estimated glomerular filtration rate between BKV and non-BKV group (p = .438). There were no rejection episodes, and graft survival was 100% over median follow-up of 3 years.

CONCLUSIONS

Plasma qPCR alone is adequate for screening and monitoring treatment of BKV and BKVN. A stepwise IR and IVIG resulted in BKV resolution in the majority of patients. Larger studies are required to study the role of IVIG in the treatment of BKVN.

BK Polyomavirus Infection and Risk Factors in Pediatric Patients Undergoing Kidney Transplant

OBJECTIVES

BK polyomavirus infection is a critical complication affecting graft survival after kidney transplant. We aimed to determine the frequency, the effect on graft function, and the risk factors of BK polyomavirus infection in pediatric kidney transplant patients.

MATERIALS AND METHODS

We retrospectively reviewed data of 144 pediatric patients (female/male: 67/77; 0-18 years of age) who received kidney transplants in the past 10 years at our center. Demographic/ laboratory data, kidney failure etiologies, donor types, and immunosuppressive treatments were recorded. Patients were grouped as those with and without BKV infection, with groups compared in terms of transplant age, sex, kidney failure etiology, donor type, immunosuppressive treatments, presence of ureteral stents, acute rejection episodes, accompanying viral infections, glomerular filtration rate, and graft loss rate.

RESULTS

Twelve patients (8.3%) had BK polyomavirus infection. All 12 patients had viruria (8.3%), 8 (5.5%) had viremia, and 4 (2.8%) had BK polyomavirus nephropathy. Two patients (1.4%) had graft loss because of BK polyomavirus nephropathy. When patients with and without infection were compared, no significant differences were found in terms of sex, transplant age, donor type, presence of a ureteral stent, acute rejection, graft loss, or immunosuppressive treatment (P > .05). Rates of congenital anomalies of the kidney and urinary tract were 30.3% and 66.6% in those without and with BK polyomavirus infection, respectively (P < .05). The group positive for BK polyomavirus had a significantly higher incidence of cytomegalovirus infection versus the group without infection (P < .05). Glomerular filtration rate values at years 1 and 3 were similar between groups (P > .05).

CONCLUSIONS

Frequency of BK polyomavirus nephropathy in pediatric patients undergoing kidney transplant in our center was consistent with data from other centers. Graft loss can be prevented by early detection and treatment through close periodic control and adequate evaluation of risk factors.

Novel coronavirus infection and acute kidney injury in two renal transplant recipients: a case report

BACKGROUND

The causative virus of coronavirus disease 2019 (COVID-19) may cause severe fatal pneumonia. The clinical presentation includes asymptomatic infection, severe pneumonia, and acute respiratory failure. Data pertaining to acute renal injury due to COVID-19 in patients who have undergone renal transplantation are scarce. We herein report two cases of COVID-19 along with acute kidney injury following kidney transplantation.Case presentation: Two patients with COVID-19 underwent renal transplantation and were subsequently diagnosed with acute kidney injury. The first patient presented with progressive respiratory symptoms and acute renal injury. He was treated with diuretics and suspension of immunosuppressive therapy; however, the patient died. The second patient presented with respiratory tract symptoms, hypoxemia, and progressive deterioration of renal function followed by improvement. Her mycophenolate mofetil was stopped after admission, and tacrolimus was discontinued 10 days later. Moxifloxacin and methylprednisolone were continued in combination with albumin and gamma globulin infusion. A diuretic was administered, and prednisone was gradually reduced along with tacrolimus. The patient exhibited a satisfactory clinical recovery.

CONCLUSION

Patients who develop COVID-19 after kidney transplantation are at risk of acute kidney injury, and their prednisone, immunosuppressant, and gamma globulin treatment must be adjusted according to their condition.

A case-control study to assess the role of polyomavirus in transplant complications: Where do we stand?

PURPOSE

The study's aim was to assess whether polyomavirus DNAemia screening was associated with different outcomes in patients with positive viremia compared with negative viremia.

METHODS

Case-control retrospective study of patients with polyomavirus DNAemia (viremia > 1000 copies/mL) matched 1:1 with controls. Control group consists of the patient who received a transplant immediately before or after each identified case and did have nil viremia.

FINDING

Ultimately, 120 cases of BK polyomavirus (BKPyV) were detected and matched with 130 controls. Of these, 54 were adult kidney transplant recipients (KTRs), 43 were pediatric KTRs, and 23 were undergoing hemato-oncologic therapy, of which 20 were undergoing hematopoietic stem cell transplantation. The odds ratio (OR) for overall risk of poorer outcomes in cases versus controls was 16.07 (95% CI: 5.55-46.54). The unfavorable outcome of switching the immunosuppressive drug (ISD) (14/40,35%) was no different from that of those treated with reduced ISD doses (31/71, 43.6%, P = .250). Acute rejection or graft-versus-host disease, previous transplant, and intensity of immunosuppression (4 ISDs plus induction or conditioning) were risk factors for BKPyV-DNAemia (OR: 13.96, 95% CI: 11.25-15.18, P < .001; OR: 6.14, 95% CI: 3.91-8.80, P < .001; OR: 5.53, 95% CI: 3.37-7.30, P < .001, respectively).

CONCLUSIONS

Despite viremia screening, dose reduction, and change in therapeutic protocol, patients with positive BKPyV-DNAemia present poorer outcomes and unfavorable results.

Clinical manifestations of BK virus infection in pediatric kidney transplant patients

Background

Polyomavirus BK (BKV) infection is an important cause of graft loss in kidney transplant patients.

Purpose

The purpose of this study was to evaluate clinical findings and risk factors for BKV in pediatric patients after kidney transplantation.

Methods

This retrospective single-center study included 31 pediatric kidney transplant recipients from January 2002 to December 2017. Two patients received 2 transplantations during the study period, and each transplant was analyzed independently. Total number of cases is 33 cases with 31 patients. BKV infection was confirmed from blood samples via periodic quantitative polymerase chain reaction.

Results

The mean age at kidney transplantation was 11.0±4.7 years, and the male-to-female ratio was 2.7:1. Three patients had a past medical history of high-dose chemotherapy and autologous stem-cell transplantation for solid tumors. Nine patients (27.3%) developed BKV infection. The median period from kidney transplantation to BKV detection in blood was 5.6 months. There was no statistically significant difference in estimated glomerular filtration rate between patients with and those without BKV infection. Among 9 patients with BKV viremia, 7 were treated by reducing their immunosuppressant dose, and BKV was cleared in 6 of these 7 patients. In the other 2 BKV-positive patients, viremia improved without immunosuppressant reduction.

Conclusion

BKV infection is common in children with kidney transplantation and might not have affected short-term renal function in our patient sample due to early immunosuppressant reduction at the time of BKV detection.

Risk factors for BK virus viremia and nephropathy after kidney transplantation: A systematic review

In the last 20 years, the management of BK polyomavirus (BKPyV) reactivation in kidney transplant patients has become a true challenge for the transplant community. The only treatment option is based on the early identification of at-risk patients. The number of reported risk factors for BKPyV reactivation has increased markedly in the literature last years, although they are sometimes in an unclear or contradictory manner. Our purpose is to provide a systematic review and meta-analysis of risk factors for BKPyV viremia and nephropathy described in multivariate analyses. The PubMed database was searched for prospective or prospectively-based observational studies on risk factors for BKPyV viremia and/or nephropathy. Our qualitative assessment of risk factors was based on the odds ratios and hazard ratios calculated in multivariate regression analyses. Of the 241 publications screened, 34 were included in the qualitative analysis. In all, 144 and 19 distinct factors were analyzed for BKPyV viremia and for BKPyV nephropathy, respectively. Our evaluation highlighted eight risk factors for BKPyV viremia: a tacrolimus regimen, a deceased donor, a male recipient, a history of previous transplant, age at transplantation, ureteral stent use, delayed graft function, and acute rejection episodes increased the risk of BKV viremia to varying extents. Tacrolimus and acute rejection episodes were also associated with a higher incidence of BKPyV nephropathy. BKPyV reactivation is a serious complication after renal transplantation. With a view to combating this problem, existing data should be published in full, and new prospective international multicenter studies should be performed.

Kidney transplant after hematopoietic cell transplant in pediatrics: Infectious and immunosuppressive considerations

Pediatric patients requiring kidney transplant after hematopoietic cell transplant receive multiple courses of immunosuppression placing them at risk for infection. To elucidate potential risk factors for infection, we compared the immunosuppressive regimens and infectious complications of pediatric kidney transplant recipients at a single institution who had previously undergone hematopoietic cell transplant from different donors to similar patients reported in the literature. Among the initial four post-hematopoietic cell transplant kidney transplant patients reviewed, viremia episodes were universal, including BK virus, Epstein-Barr virus, and human herpesvirus-6, with one death from presumed BK virus encephalitis. No viremia was reported in five similar cases in the literature. Risk factors for increased infection include use of lymphodepleting serotherapy in HCT conditioning, multiple HCTs, limited immune reconstitution time between transplants, increased pre-KTx viral burden, and use of T-cell-depleting versus -suppressive induction immunosuppression for KTx. These findings suggest that pediatric post-HCT KTx recipients are at increased risk for viral infections, likely benefitting from thorough pre-KTx evaluation of immune reconstitution and preferential use of non-T-cell-depleting induction therapy for KTx. We applied these recommendations to one subsequent post-HCT patient requiring KTx at our institution with excellent outcomes one year post-KTx.