Kidney retransplantation following graft loss to polyoma virus-associated nephropathy: an effective treatment option in simultaneous pancreas and kidney transplant recipients

Outcomes of repeat kidney transplantation following prior graft failure secondary to BK nephropathy: A single-center retrospective study

BACKGROUND

BK virus is associated with development of nephropathy (BKVN) that can lead to graft failure after renal transplantation. There are limited data on rates of recurrence and outcomes of repeat renal transplantation after prior graft loss caused by BKVN.

METHODS

After IRB approval, data on all patients who underwent a repeat renal transplantation after prior graft failure as a result of BKVN were identified. Data on management of patients prior to retransplantation, induction and maintenance immunosuppression, and key clinical and virologic outcomes were collected. Descriptive statistics were used for analysis.

RESULTS

Thirteen patients were identified over a 13-year period, and follow-up of these patients occurred for a median of 4.7 years. Most patients have previous renal transplants removed prior to (7/13, 53.8%) or at the time of retransplantation (3/13, 23.1%). Close virologic monitoring of serum and urine, coupled with early immunosuppression minimization, was associated with few patients developing BK viruria above 1 × 10⁷ c/mL (4/13, 30.8%), BK viremia above 10,000 c/mL (2/13, 15.4%), and biopsy-proven BKVN (1/12, 8.3%); most (8/13, 61.5%) developed BK viruria at any level. Renal function at 1 year post-retransplantation was generally excellent and only 1 patient developed graft failure caused by recurrent focal segmental glomerulosclerosis. In our review of the literature, 2 large observational studies of the UNOS database as well as our analysis of case reports showed excellent graft survival and very low rates of recurrent BKVN leading to graft loss.

CONCLUSIONS

Retransplantation after prior graft failure caused by BKVN generally has low rates of recurrence when coupled with close monitoring and early immunosuppression minimization. Removal of failed renal transplant may allow easier monitoring for recurrence.

BK polyomavirus-pathogen, paradigm and puzzle

BK virus is a polyomavirus with seroprevalence rates of 80% in adults. Infection is usually acquired during childhood, and the virus is benign or pathologic depending on immune status. The virus reactivates in immunodeficiency states, mostly among transplant (either kidney or bone marrow) recipients. There are approximately 15 000 renal transplants every year in the USA, of which 5-10% develop BK polyomavirus nephropathy; 50-80% of patients who develop nephropathy go on to develop graft failure. BK virus is associated with BK polyomavirus nephropathy, ureteral stenosis, late-onset hemorrhagic cystitis, bladder cancer and other nonlytic large T-expressing carcinomas. The renal spectrum begins with viruria and can end with graft failure. The clinical spectrum and outcomes vary among transplant patients. New noninvasive diagnostic methods, such as urinary polyomavirus Haufen detected by electron microscopy, are currently under study. Treatment is primarily directed at decreasing immunosuppression but may be associated with graft rejection. Repeat transplantation is encouraged as long as viral clearance in plasma prior to transplant is accomplished. There remain no definitive data regarding the utility of transplant nephrectomy.

BK polyomavirus in solid organ transplantation-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

The present AST-IDCOP guidelines update information on BK polyomavirus (BKPyV) infection, replication, and disease, which impact kidney transplantation (KT), but rarely non-kidney solid organ transplantation (SOT). As pretransplant risk factors in KT donors and recipients presently do not translate into clinically validated measures regarding organ allocation, antiviral prophylaxis, or screening, all KT recipients should be screened for BKPyV-DNAemia monthly until month 9, and then every 3 months until 2 years posttransplant. Extended screening after 2 years may be considered in pediatric KT. Stepwise immunosuppression reduction is recommended for KT patients with plasma BKPyV-DNAemia of >1000 copies/mL sustained for 3 weeks or increasing to >10 000 copies/mL reflecting probable and presumptive BKPyV-associated nephropathy, respectively. Reducing immunosuppression is also the primary intervention for biopsy-proven BKPyV-associated nephropathy. Hence, allograft biopsy is not required for treating BKPyV-DNAemic patients with baseline renal function. Despite virological rationales, proper randomized clinical trials are lacking to generally recommend treatment by switching from tacrolimus to cyclosporine-A, from mycophenolate to mTOR inhibitors or leflunomide or by the adjunct use of intravenous immunoglobulins, leflunomide, or cidofovir. Fluoroquinolones are not recommended for prophylaxis or therapy. Retransplantation after allograft loss due to BKPyV nephropathy can be successful if BKPyV-DNAemia is definitively cleared, independent of failed allograft nephrectomy.

BK virus as a mediator of graft dysfunction following kidney transplantation

PURPOSE OF REVIEW

BK virus is a significant risk factor for kidney allograft dysfunction and loss among renal transplant recipients. Currently, there is no proven effective treatment except for the reduction of immunosuppression. In this review, we discuss diagnostic challenges and current treatment options for BK in kidney transplant recipients.

RECENT FINDINGS

Antiviral and antibiotic therapies have been employed for BK viraemia with variable efficacy. In addition, novel therapeutic regimens such as adoptive transfer of targeted T cells have been described as possible treatment options for recipients with BK nephropathy. BK can also be seen in the native kidneys of pancreas, heart, lung and liver transplant recipients, suggesting that BK screening measures should be employed to other solid organ transplant recipients.

SUMMARY

Early screening for BK combined with reduction of immunosuppression remains the mainstay of treatment for BK viraemia. New therapeutic advances demonstrate promise in vitro; however, the in-vivo efficacy will be demonstrated by future studies.

Kidney retransplantation: removal or persistence of the previous failed allograft?

A significant percentage of patients with failed renal graft are candidates for retransplantation. The outcomes of retransplantation are poorer than those of primary transplantation and sensitization is documented to be a major reason. The management of a failed allograft that is not immediately symptomatic is still very controversial. The aim of this study was to determine the impact of the failed allograft nephrectomy on a subsequent transplantation and its importance in the sensitization. We performed a retrospective analysis of the local prospective transplantation registry of the outcome of 126 second kidney transplantations among 2438 transplantations performed in our unit between June 1980 and March 2013, comparing those who underwent allograft nephrectomy prior to retransplantation with those who retained the failed graft. Primary endpoints were graft and patient survival. The levels of panel-reactive antibodies (PRA) and rate of acute rejections on retransplantation outcomes were also studied. Among the 126 patients who underwent a second renal transplantation, 76 (60.3%) had a prior graft nephrectomy (Group A), whereas 50 (39.7%) kept their failed graft (Group B). Group A showed significantly more positive PRA levels when compared with the other group (38% vs 10%; P < .001), as measured before the most recent transplantation, and a higher rate of acute rejection (19% vs 5.6%; P = .016). There were 28 (36%) renal allograft losses for Group A and 18 (36%) for those who had not had transplantectomy (P = not significant [NS]). One-, 3-, and 5-year graft survival rates were 96.6%, 90.7%, and 83.4%, respectively, in Group A and 95%, 82%, and 68.4%, respectively, in Group B, with no statistical differences (P = .19). Five-year actuarial patient survival rates in the 2 groups was 89.3% and 82.8%, respectively (P = .55). Multivariate analysis showed that PRA level and delayed graft function (DGF) had a statistically significant influence on graft survival (P = .028; odds ratio [OR] = 1.029; and P = .024; OR = 8.6), irrespective of whether the patient had graft nephrectomy or not. The allosensitization indicated by PRA increases after transplantectomy and leads to a higher incidence of acute rejection after retransplantation. Nephrectomy of failed allograft does not seem to significantly influence the survival of a subsequent graft. The decision to remove or retain a failed graft in the context of retransplantation should thus be based on known clinical indications for the procedure.

Kidney retransplantation for BK virus nephropathy with active viremia without allograft nephrectomy

BK virus nephropathy is an important cause of kidney allograft failure. Retransplantation has been successfully performed for patients with previous allograft loss due to BK virus nephropathy; however, whether allograft nephrectomy and viral clearance are required prior to retransplantation is controversial. Some recent studies have suggested that retransplantion can be successfully achieved without allograft nephrectomy if viremia is cleared prior to retransplant. The only published experience of successful retransplantation in the presence of active viremia occurred in the presence of concomitant allograft nephrectomy of the failing kidney. In this report, we describe a case of successful repeat kidney transplant in a patient with high-grade BK viremia and fulminant hepatic failure without concomitant allograft nephrectomy performed under the setting of a simultaneous liver-kidney transplant.

BK polyomavirus in solid organ transplantation

The human BK polyomavirus (BKV) is the major cause of polyomavirus-associated nephropathy (PyVAN) putting 1-15% of kidney transplant patients at risk of premature allograft failure, but is less common in other solid organ transplants. Because effective antiviral therapies are lacking, screening kidney transplant patients for BKV replication in urine and blood has become the key recommendation to guide the reduction of immunosuppression in patients with BKV viremia. This intervention allows for expanding BKV-specific cellular immune responses, curtailing of BKV replication in the graft, and clearance of BKV viremia in 70-90% patients. Postintervention rejection episodes occur in 8-12%, most of which are corticosteroid responsive. Late diagnosis is faced with irreversible functional decline, poor treatment response, and graft loss. Adjunct therapies such as cidofovir, leflunomide and intravenous immunoglobulins have been used, but the benefit is not documented in trials. Retransplantation after PyVAN is largely successful, but requires close monitoring for recurrent BKV viremia.

Polyomavirus-associated nephropathy

Polyomaviruses BK and JC are ubiquitous viruses with high seroprevalence rates in general population. Following primary infection, polyomaviruses BK and JC persist latently in different sites, particularly in the reno-urinary tract. Reactivation from latency may occur in normal subjects with asymptomatic viruria, while it can be associated to nephropathy (PVAN) in kidney transplantat recipients. PVAN may occur in 1%-10% of renal transplant patients with loss of the transplanted organ in 30% up to 80% of the cases. Etiology of PVAN is mainly attributable to BK virus, although approximately 5% of the cases may be due to JC. Pathogenesis of PVAN is still unknown, although viral replication and the lack of immune control play a major role. Immunosuppression represents the condicio sine qua non for the development of PVAN and the modulation of anti-rejection treatment represents the first line of intervention, given the lack of specific antiviral agents. At moment, an appropriate immunemodulation can only be accomplished by early identification of viral reactivacation by evaluation of polyomavirus load on serum and/or urine specimens, particularly in the first year post-trasplantation. Viro-immunological monitoring of specific cellular immune response could be useful to identify patients unable to recover cellular immunity posttransplantation, that are at higher risk of viral reactivation with development of PVAN. Herein, the main features of polyomaviruses BK and JC, biological properties, clinical characteristics, etiopathogenesis, monitoring and diagnosing of PVAN will be described and discussed, with an extended citation of related relevant literature data.

Long-term pancreatic allograft survival after renal retransplantation in prior simultaneous pancreas-kidney recipients

Over a 23-year period, our center performed 82 renal retransplants in prior simultaneous pancreas-kidney recipients with functioning pancreatic allografts. All patients were insulin-independent at retransplantation. We aimed to quantify the risk of returning to insulin therapy and to identify factors that predispose patients to pancreatic allograft failure after renal retransplantation. Among these 82 patients, pancreatic allograft survival after renal retransplantation was 78%, 49% and 40% at 1, 5 and 10 years. When analyzing risk factors, we unexpectedly found no clear relationship between the cause of primary renal allograft failure, hemoglobin A1c (HbA1c) or fasting C-peptide level at retransplant and subsequent pancreatic allograft failure. An elevated HbA1c in the month after renal retransplant correlated with subsequent pancreatic graft loss and patients experiencing pancreatic graft loss were more likely to subsequently lose their renal retransplant. Although it is difficult to prospectively identify those patients who will return to insulin therapy after repeat renal transplantation, the relatively high frequency of this event mandates that this risk be conveyed to patients. Nonetheless, the survival benefit associated with renal retransplantation justifies pursuing retransplantation in this population.

Simultaneous pancreas and kidney (SPK) retransplantation in prior SPK recipients

INTRODUCTION

We have performed 113 renal and 28 isolated pancreas retransplants in our cohort of more than 1200 prior simultaneous pancreas and kidney (SPK) recipients. On the basis of these experiences, we began performing repeat SPK in prior SPK recipients (n = 9).

METHODS

This retrospective review summarizes our experience with repeat SPK transplantation in prior SPK recipients. Mean age at retransplant was 39 yr; mean interval to retransplant was 7.8 yr. Thirty-three percent were pre-dialysis. Eighty-nine percent of patients underwent transplant nephrectomy (five during the repeat SPK and three prior to it), and 78% underwent transplant pancreatectomy (four during the repeat SPK and three prior to it). Enteric drainage was performed in all repeat SPKs.

RESULTS

Median length of stay was 11 d. Perioperative complications included the following: renal artery thrombosis (1), pancreatic portal venous thrombosis (1), enteric leak (1), and hematoma (2). Overall pancreatic allograft survival was 78% at one yr and 67% at two yr. Overall renal allograft survival was 89% at one yr and 78% at two yr. Patient survival at one and three yr was 100%.

CONCLUSIONS

Survival of repeat SPK allografts is acceptable despite the increased technical and immunologic demands of retransplantation. Graftectomy prior to or at the time of retransplantation is often necessary.

BK virus nephropathy after simultaneous pancreas-kidney transplantation

BACKGROUND

BK virus nephropathy (BKVN) was reported in up to 7.5% of patients after simultaneous pancreas-kidney transplantation (SPK). Its management by reduction in immunosuppression might pre-dispose to pancreatic graft loss.

METHODS

A retrospective analysis of 178 SPK recipients was performed. All patients received thymoglobulin, daclizumab and a maintenance of low-dose steroids, tacrolimus, and either sirolimus or mycophenolate.

RESULTS

Two (1.1%) patients were identified with BKVN. Time of diagnosis was 22 and 45 months after transplant. Both patients had superimposed calcineurin toxicity in their graft biopsies. Immunosuppression was reduced in both patients, and leflunomide (LEF) was used in one patient. Concurrent kidney rejection episodes were treated with steroid pulses in both patients. One kidney graft improved with a last estimated glomerular filtration rate (GFR) of 43 mL/min, and another kidney graft showed limited improvement with a last GFR of 30 mL/min. Pancreatic graft function remained excellent in both patients as assessed by serum c-peptide, glycosylated hemoglobin, amylase-lipase, and urine amylase levels.

CONCLUSION

Low incidence of BKVN was observed in our SPK series. Reduction in immunosuppression and sometimes LEF can be effective. The underlying mechanism of stable pancreatic allograft function despite ongoing kidney rejection warrants further investigation.

Impact of failed allograft nephrectomy on initial function and graft survival after kidney retransplantation

The management of an asymptomatic failed renal graft remains controversial. The aim of our study was to explore the effect of failed allograft nephrectomy on kidney retransplantation by comparing the outcome of recipients who underwent graft nephrectomy prior to retransplantation with those who did not. Retrospective comparison of patients undergoing kidney retransplantation with (group A, n = 121) and without (group B, n = 45) preliminary nephrectomy was performed, including subgroup analysis with reference to patients with multiple (≥2) retransplantations and patients of the European Senior Program (ESP). Nephrectomy leads to increased panel reactive antibody (PRA) levels prior to retransplantation and is associated with significantly increased rates of primary nonfunction (PNF; P = 0.05) and acute rejection (P = 0.04). Overall graft survival after retransplantation was significantly worse in group A compared with group B (P = 0.03). Among the subgroups especially ESP patients showed a shorter graft survival after previous allograft nephrectomy. On the multivariate analysis, pretransplant graft nephrectomy and PRA >70% were independent and significant risk factors associated with graft loss after kidney retransplantation. Nephrectomy of the failed allograft was not beneficial for retransplant outcome in our series. Patients with failed graft nephrectomy tended to have a higher risk of PNF and acute rejection after retransplantation. The possibility that the graft nephrectomy has a negative impact on graft function and survival after retransplantation is worth studying further.

Retransplantation after BK virus nephropathy in prior kidney transplant: an OPTN database analysis

BK virus (BKV) has emerged as a major complication of kidney transplantation. Since June 30, 2004, the OPTN in the USA collects BKV as a primary or secondary cause of graft loss and also if treatment for BK virus (TBKV) is administered. In this study, we determined characteristics of those recipients of repeat kidney transplants from the OPTN database, where either (a) a graft loss occurred between June 30, 2004 and December 31, 2008 and database recorded prior TBKV in that allograft or (b) a graft loss between June 30, 2004 and December 31, 2008 was attributed primarily or secondarily due to BKV. In the study time period, 823 graft losses have occurred where TBKV or graft failure attributable to BKV was reported in prior transplant; of these, 126 have received a retransplant as of June 5, 2009. Induction and maintenance immunosuppression usage mirrored current trends. As of June 5, 2009, 118/126 grafts are still functioning, one graft failure attributed to BKV. TBKV was reported in 17.5% of the retransplants. In the retransplants performed through December 31, 2007, 1-year acute rejection rate was 7%, 1-year and 3-year Kaplan-Meier graft survival rates and median GFR were 98.5%, 93.6%, 65.5 and 68.4 mL/min, respectively. Retransplantation after BKV appears to be associated with good results.