Conversion to mTOR-inhibitors with calcineurin inhibitor elimination or minimization reduces urinary polyomavirus BK load in kidney transplant recipients

The case for the therapeutic use of mechanistic/mammalian target of rapamycin (mTOR) inhibitors in xenotransplantation

The mechanistic/mammalian target of rapamycin (mTOR) is one of the systems that are necessary to maintain cell homeostasis, such as survival, proliferation, and differentiation. mTOR inhibitors (mTOR-Is) are utilized as immunosuppressants and anti-cancer drugs. In organ allotransplantation, current regimens infrequently include an mTOR-I, which are positioned more commonly as alternative immunosuppressants. In clinical allotransplantation, long-term efficacy has been established, but there is a significant incidence of adverse events, for example, inhibition of wound healing, buccal ulceration, anemia, hyperglycemia, dyslipidemia, and thrombocytopenia, some of which are dose-dependent. mTOR-Is have properties that may be especially beneficial in xenotransplantation. These include suppression of T cell proliferation, increases in the number of T regulatory cells, inhibition of pig graft growth, and anti-inflammatory, anti-viral, and anti-cancer effects. We here review the potential benefits and risks of mTOR-Is in xenotransplantation and suggest that the benefits exceed the adverse effects.

Stepwise Reduction of Mycophenolate Mofetil with Conversion to Everolimus for the Treatment of Active BKV in Kidney Transplant Recipients: A Single-Center Experience in Vietnam

Background: No specific antiviral drug can effectively treat BKV reactivation after kidney transplantation. Thus, we evaluated stepwise-reduced immunosuppression to treat BKV reactivation. Methods: 341 kidney-transplant recipients were monitored for BKV infection (BKV-viremia, BKV-viruria). Positive samples with a significant virus load were nested PCR-genotyped in the VP1 region. In 97/211 patients presenting BKV viremia ≥104 copies/mL and/or BKV viruria ≥107 copies/mL, or BKV-nephropathy immunosuppression (i.e., mycophenolate mofetil [MMF]) was reduced by 50%. If viral load did not decrease within 28 days, MMF dose was further reduced by 25%, although calcineurin-inhibitor (CNI) therapy remained unchanged. If BKV viral load did not decrease within another 28 days, MMF was withdrawn and replaced by everolimus combined with reduced CNIs. Results: Only 41/97 BKV (+) cases completed the 6-month follow-up. Among these, 29 (71%) were in the BKV-I group and 12 (29%) were in BKV-IV. BKV viruria and BKV viremia were significantly decreased from 9.32 to 6.09 log10 copies/mL, and from 3.59 to 2.45 log10 copies/mL (p < 0.001 and p = 0.024, respectively). 11/32 (34.4%) patients were cleared of BKV viremia; 2/32 (6.3%) patients were cleared of BKV in both serum and urine, and 9/9 (100%) only had BKV viruria but did not develop BKV viremia. eGFR remained stable. No patient with BKV-related nephropathy had graft loss. There was a significant inverse relationship between changes in eGFR and serum BKV load (r = −0.314, p = 0.04). Conclusions: This stepwise immunosuppressive strategy proved effective at reducing BKV viral load in kidney transplant recipients that had high BKV loads in serum and/or urine. Renal function remained stable without rejection.

Polyoma BK Virus in Kidney Transplant Recipients: Screening, Monitoring, and Management

Polyomavirus BK virus (BKPyV) infection is an important complication of kidney transplantation and allograft failure. The prevalence of viremia is 10%-15%, compared with BK-associated nephropathy (BKPyVAN) at 3%-5%. Given that there are no effective antiviral prophylaxis or treatment strategies for BKPyVAN, active screening to detect BKPyV viremia is recommended, particularly during the early posttransplant period. Immunosuppression reduction to allow viral clearance may avoid progression to severe and irreversible allograft damage. The frequency and duration of screening are highly variable between transplant centers because the evidence is reliant largely on observational data. While the primary treatment goals center on achieving viral clearance through immunosuppression reduction, prevention of subsequent acute rejection, premature graft loss, and return to dialysis remain as major challenges. Treatment strategies for BKPyV infection should be individualized to the recipient's underlying immunological risk and severity of the allograft infection. Efficacy data for adjuvant therapies including intravenous immunoglobulin and cidofovir are sparse. Future well-powered and high-quality randomized controlled trials are needed to inform evidence-based clinical practice for the management of BKPy infection.

High Incidence and Early Onset of Urinary Tract Cancers in Patients with BK Polyomavirus Associated Nephropathy

Over-immunosuppressed kidney transplant recipients are susceptible to malignancies and BK polyomavirus (BKPyV)-associated nephropathy (BKPyVAN). This study aimed to verify the association between BKPyV infection and urinary tract cancers (UTC). A total of 244 kidney transplant recipients were enrolled at Chang Gung Memorial Hospital from June 2000 to February 2020. Biopsy-proven BKPyVAN patients (n = 17) had worse kidney function (eGFR: 26 ± 13.7 vs. 47.8 ± 31.0 mL/min/1.73 m²). The 5-year allograft survival rates for patients with and without BKPyVAN were 67% and 93%, respectively (p = 0.0002), while the 10-year patient survival was not different between the two groups. BKPyVAN patients had a significantly higher incidence of UTC compared to the non-BKPyVAN group (29.4% vs. 6.6%). Kaplan-Meier analysis showed that the UTC-free survival rate was significantly lower in BKPyVAN patients, and the onset of UTC was significantly shorter in BKPyVAN patients (53.4 vs. 108.9 months). The multivariate logistic regression analysis demonstrated that age (RR = 1.062) and BKVAN (RR = 6.459) were the most significant risk factors for the development of UTC. Our study demonstrates that BKPyVAN patients have greater allograft losses, higher incidence, a lower cancer-free survival rate, and an earlier onset with a higher relative risk of developing UTC compared to non-BKPyVAN patients.

Polyomavirus BK, BKV microRNA, and urinary neutrophil gelatinase-associated lipocalin can be used as potential biomarkers of lupus nephritis

Objective

Lupus nephritis (LN) frequently progresses to end-stage renal disease. Finding a biomarker for LN and a predictor for the development of chronic kidney disease (CKD) is important for patients with systemic lupus erythematosus (SLE).

Methods

Ninety patients with SLE were divided into biopsy-proven LN (n = 54) and no kidney involvement (non-LN) (n = 36) groups and followed up for 54 months.

Results

Of 36 patients with LN, 3 (5.6%) had class II disease, 3 (5.6%) had class III, 35 (64.8%) had class IV, 10 (18.5%) had class V, and 3 (5.6%) had class VI (advanced sclerosis). Compared to the non-LN group, patients in the LN group had higher autoimmunity evidenced by a higher proportion of low C3 and C4 levels, positive anti-double-stranded DNA antibody levels, and lower estimated glomerular filtration rates (eGFR). Urinary neutrophil gelatinase-associated lipocalin (uNGAL) levels were significantly higher in the LN group (LN vs non-LN, 670 vs 33 ng/mL, respectively). The patients with LN had a higher urinary polyomavirus BK (BKV) load (3.6 vs 3.0 log copies/mL) and a lower urinary BKV miRNA (miR-B1) 5p level (0.29 vs 0.55 log copies/mL, p = 0.025), while there was no significant difference in the level of miR-B1-3p. Urinary miR-B1-5p level but not urinary BKV load was negatively correlated with uNGAL level (r = -0.22, p = 0.004). At the cutoff value of 80 ng/mL, the receiver operating characteristic curve analysis showed that uNGAL level as a predictor of the presence of LN had a high sensitivity (98%) and specificity (100%) (area under the curve [AUC], 0.997; p < 0.001). During the 54-month follow-up period, 14 (7%) patients with LN and none of the non-LN patients developed CKD. Multivariate Cox regression analysis revealed that baseline uNGAL level was the only predictive factor for CKD development, while baseline serum creatinine level and eGFR were not.

Conclusion

An elevated urinary BKV viral load with a decreased level of miR-B1 implies the presence of LN. In addition, an increased uNGAL level is a good biomarker not only in predicting the presence of LN but also for prediction of CKD development in patients with SLE.

Effect of mechanistic target of rapamycin inhibitors on postrenal transplantation malignancy: A nationwide cohort study

BACKGROUND

Post-transplantation malignancy influenced graft survival and overall survival in the patients receiving renal transplantation. Immunosuppressants influenced the immune surveillance, but whether immunosuppressive agents have impact for incidence of post-transplantation malignancy is still elusive in Taiwan.

METHOD

We conducted a nationwide population-based study. Patients who did not have malignancy history and received kidney transplantation between 2000 and 2010 were enrolled. Specific immunosuppressive users are defined as sustained use (more than 12 months) after renal transplantation. The primary outcome is the development of cancer after kidney transplantation. A Cox proportional hazards model was used to determine the risk of cancer development.

RESULT

Among 4438 recipients, 559 of them were diagnosed with malignancy after 1 year of transplantation. A total of 742 of recipients were as user of mechanistic target of rapamycin (mTOR) inhibitors. The mTOR users had higher rate of receiving pulse therapy. The hazard ratios (HR) for mTOR inhibitor users with exposure more than 5 years for overall malignancy and urothelial malignancy were 0.68 (95% CI: 0.48-0.95, P = 0.02) and 0.60 (95% CI: 0.36-0.99, P = 0.02), respectively. For the overall mortality and reentry of dialysis, the probability of both groups was similar (overall mortality: P = 0.53; reentry of dialysis: P = 0.77).

CONCLUSION

Among the recipients of renal transplantation in Taiwan, mTOR inhibitors with exposure more than 5 years provided a protective role in reducing the risk of overall neoplasm and urothelial malignancy. The probability of reentry of dialysis and overall mortality was similar between the mTORi users and nonusers.

Everolimus with Reduced Calcineurin Inhibitor Exposure in Renal Transplantation

Background Everolimus permits reduced calcineurin inhibitor (CNI) exposure, but the efficacy and safety outcomes of this treatment after kidney transplant require confirmation.Methods In a multicenter noninferiority trial, we randomized 2037 de novo kidney transplant recipients to receive, in combination with induction therapy and corticosteroids, everolimus with reduced-exposure CNI (everolimus arm) or mycophenolic acid (MPA) with standard-exposure CNI (MPA arm). The primary end point was treated biopsy-proven acute rejection or eGFR<50 ml/min per 1.73 m² at post-transplant month 12 using a 10% noninferiority margin.Results In the intent-to-treat population (everolimus n=1022, MPA n=1015), the primary end point incidence was 48.2% (493) with everolimus and 45.1% (457) with MPA (difference 3.2%; 95% confidence interval, -1.3% to 7.6%). Similar between-treatment differences in incidence were observed in the subgroups of patients who received tacrolimus or cyclosporine. Treated biopsy-proven acute rejection, graft loss, or death at post-transplant month 12 occurred in 14.9% and 12.5% of patients treated with everolimus and MPA, respectively (difference 2.3%; 95% confidence interval, -1.7% to 6.4%). De novo donor-specific antibody incidence at 12 months and antibody-mediated rejection rate did not differ between arms. Cytomegalovirus (3.6% versus 13.3%) and BK virus infections (4.3% versus 8.0%) were less frequent in the everolimus arm than in the MPA arm. Overall, 23.0% and 11.9% of patients treated with everolimus and MPA, respectively, discontinued the study drug because of adverse events.Conclusions In kidney transplant recipients at mild-to-moderate immunologic risk, everolimus was noninferior to MPA for a binary composite end point assessing immunosuppressive efficacy and preservation of graft function.

Human polyomavirus-7-associated eruption successfully treated with acitretin

Advances in molecular technologies have led to the discovery of several novel human polyomaviruses (HPyVs), including human polyomavirus-7 (HPyV-7). Although low levels of HPyV-7 are shed from apparently normal skin, recent reports have described clinically significant cutaneous infection in immunocompromised patients that manifests as generalized pruritic plaques. The pruritus can be severe, and treatment options have not been described. Herein we report HPyV-7 cutaneous infection in a heart transplant patient who experienced temporary improvement with intravenous cidofovir, and complete remission with acitretin. We report a case of HPyV-7 cutaneous infection demonstrating a good response to treatment.

Human Polyomavirus Is Associated With Earlier Onset of Upper Urinary Tract Urothelial Carcinoma in Patients After Kidney Transplantation

OBJECTIVES

Polyomavirus has been reported to be oncogenic due to viral integration into the human genome. A relatively high prevalence of upper urinary tract urothelial carcinoma (UTUC) was noted after kidney transplantation (KT) in Taiwan. However, little was known about the impact of polyomavirus on the urothelial cancer behavior. Therefore, the aim of this study is to analyze the characteristics of polyomavirus-related UTUC after KT.

METHODS

From 2005 to 2014, 27 patients were found to have UTUCs after KT. All the patients underwent standard nephroureterectomy. Detailed perioperative parameters were obtained from chart records. A qualified pathologist who is blinded to the clinical outcome examined large T antigen expression and pathological features. All the patients were divided into two groups according to positive or negative expression of large T antigen.

RESULTS

In the patient demography, a significantly younger median age was found in patients with large T antigen-positive UTUCs compared with the negative control group (48.1 ± 8.3 years versus 54.6 ± 4.1 years, respectively, P = .013). As for the pathological features and oncologic outcome, there were no obvious differences between these two groups. Non-organ-confined status and positive lymphovascular invasion are prognostic factors associated with systemic disease recurrence (P = .017 and .001, respectively).

CONCLUSIONS

Although UTUC commonly develops in the elderly, earlier onset of post-KT UTUCs was observed especially in patients with positive large T antigen expression in our cohort. This preliminary result provides valuable experience suggesting more frequent upper urinary tract screening for polyomavirus infected patients after KT in Taiwan.