KDIGO clinical practice guideline for the care of kidney transplant recipients

Posttransplantation proteinuria: an approach to diagnosis and management

Proteinuria is a common problem encountered in the treatment of renal transplant recipients, occurring in up to 45% of patients. Proteinuria from native kidneys falls rapidly after renal transplantation, and persistent or worsening proteinuria is usually indicative of allograft pathology. Biopsy studies of transplant patients with proteinuria have confirmed that transplant-specific diagnoses (transplant glomerulopathy, interstitial fibrosis and tubular atrophy, and acute rejection) are more commonly found than other proteinuric conditions, such as glomerulonephritis. As in the nontransplant setting, proteinuria is associated with worse clinical outcomes, including an increased risk for death, cardiovascular events, and graft loss. Blockade of the renin-angiotensin-aldosterone system with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers will reduce proteinuria, but the long-term effect of these medications on patient and graft survival remains unknown.

Monitoring and managing graft health in the kidney transplant recipient

Ongoing monitoring of kidney transplants is a widely accepted and practiced part of posttransplantation management. One reason to monitor is to evaluate whether the transplant is stable. The transplant community evaluates stability by checking kidney function. Despite problems with sensitivity and specificity, obtaining serial serum creatinine levels is the most common approach to assessing kidney function. Some programs supplement serial serum creatinine levels with surveillance kidney biopsies. Although not uniformly accepted as beneficial, surveillance biopsies are useful in select subsets of patients such as highly sensitized recipients. Recent biopsy studies shed light on which histopathology findings portend poor prognoses. The Long-Term Deterioration of Kidney Allograft Function Study (DeKAF) and similar studies that will prospectively evaluate therapeutic interventions should help the transplant community better define how to monitor and manage the kidney transplant optimally. In the meantime, Kidney Diseases: Improving Global Outcomes (KDIGO) provides an evidence-based approach toward monitoring and managing the kidney transplant.

The BK virus in renal transplant recipients-review of pathogenesis, diagnosis, and treatment

The BK virus, a DNA virus from the Polyomavirus group, represents an opportunistic infection of immunosuppressed transplant recipients. Though the virus was discovered approximately 40 years ago, the emergence of BK virus nephropathy since 1995 onwards, with associated high graft loss rates, has revolutionized renal transplantation medicine. Kidney transplant professionals realized that the consequences of over-immunosuppression were as severe as the consequences of under-immunosuppression and we entered the era of immunosuppressive minimization. Despite this recognition, the optimal testing type for BK virus infections and frequency of testing are hotly debated. Similarly, optimal treatment strategies remain sources of intense controversy. The authors review the current strategies of screening, diagnosis, and possible treatment, and also review the amount and quality of evidence in favor or against. Similarities and differences between cytomegalovirus, Epstein-Barr virus, and BV virus, the three major viral infections in kidney transplantation, are highlighted.

[Mineral and bone disorders associated with chronic kidney disease]

Chronic renal failure (CRF) is frequent in patients with osteoporosis and the rheumatologist should be familiarized with basic diagnostic and treatment guidelines for bone mineral disease associated to this process. In patients with osteoporosis and stage I and II CRF, diagnosis and treatment does not vary from that in patients with normal RF. In stage III CRF, the focus will depend on the result of testing. In advanced stage CRF the approach should be coordinated with a nephrologist. In these cases it is possible to use antiresorptive agents although in well-selected and studied patients. The present review analyzes recent advances in this field with a focus on daily clinical practice.

Early monitoring of the human polyomavirus BK replication and sequencing analysis in a cohort of adult kidney transplant patients treated with basiliximab

Background

Nowadays, better immunosuppressors have decreased the rates of acute rejection in kidney transplantation, but have also led to the emergence of BKV-associated nephropathy (BKVAN). Therefore, we prospectively investigated BKV load in plasma and urine samples in a cohort of kidney transplants, receiving basiliximab combined with a mycophenolate mofetil-based triple immunotherapy, to evaluate the difference between BKV replication during the first 3 months post-transplantation, characterized by the non-depleting action of basiliximab, versus the second 3 months, in which the maintenance therapy acts alone. We also performed sequencing analysis to assess whether a particular BKV subtype/subgroup or transcriptional control region (TCR) variants were present.

Methods

We monitored BK viruria and viremia by quantitative polymerase chain reaction (Q-PCR) at 12 hours (Tx), 1 (T1), 3 (T2) and 6 (T3) months post-transplantation among 60 kidney transplant patients. Sequencing analysis was performed by nested-PCR with specific primers for TCR and VP1 regions. Data were statistically analyzed using χ² test and Student's t-test.

Results

BKV was detected at Tx in 4/60 urine and in 16/60 plasma, with median viral loads of 3,70 log GEq/mL and 3,79 log GEq/mL, respectively, followed by a significant increase of both BKV-positive transplants (32/60) and median values of viruria (5,78 log GEq/mL) and viremia (4,52 log GEq/mL) at T2. Conversely, a significantly decrease of patients with viruria and viremia (17/60) was observed at T3, together with a reduction of the median urinary and plasma viral loads (4,09 log GEq/mL and 4,00 log GEq/mL, respectively). BKV TCR sequence analysis always showed the presence of archetypal sequences, with a few single-nucleotide substitutions and one nucleotide insertion that, interestingly, were all representative of the particular subtypes/subgroups we identified by VP1 sequencing analysis: I/b-2 and IV/c-2.

Conclusions

Our results confirm previous studies indicating that BKV replication may occur during the early hours after kidney transplantation, reaches the highest incidence in the third post-transplantation month and then decreases within the sixth month, maybe due to induction therapy. Moreover, it might become clinically useful whether specific BKV subtypes or rearrangements could be linked to a particular disease state in order to detect them before BKVAN onset.

Induction antibody therapy in renal transplantation using early steroid withdrawal: long-term results comparing anti-IL2 receptor and anti-thymocyte globulin

BACKGROUND

The present study intends to investigate the effects of anti-IL2 receptors (anti-IL2R) vs. lymphocyte-depleting agents in the early steroid withdrawal (ESW) scheme.

METHODS

This is a retrospective cohort of 167 consecutive adult renal transplant recipients. Immunosuppression was based on tacrolimus and mycophenolate mofetil. Antibody induction therapy was carried out with lymphocyte-depleting agent (thymoglobulin) or anti-IL2R (Basiliximab or Daclizumab). ESW protocol was performed by administering intravenous methlyprednisolone as follows: 500 mg on day 0, 250 mg on day 1, 125 mg on day 2, 60 mg on day 3, and then stopped.

RESULTS

Among the 167 studied patients, 79 (47.3%) received anti-IL2R and 88 (52.7%) received thymoglobulin induction. Significantly fewer episodes of acute rejection were seen at one year in patients treated with thymoglobulin as compared to anti-IL2R (25.6% vs. 11.4%, p=0.01). At five years, a significant difference in graft survival was observed in anti-IL2R-treated patients compared with thymoglobulin (83.5% vs. 95.5%, p=0.01). Multivariate analysis disclosed that female sex, antibody induction therapy using thymoglobulin and a trough tacrolimus level higher than 10 were protective factors against acute rejection, while there was a trend to increased risk of acute rejection at first year post-transplantation in patients presenting delayed graft function (DGF). Antibody induction was independently associated with patient and graft survival at five years (OR 0.213, 95% CI 0.046-0.991, p=0.04).

CONCLUSION

ESW scheme seems to be safe and its use is beneficial since there are fewer adverse effects. Thymoglobulin induction therapy is associated with fewer rejection episodes. Induction therapy with thymoglobulin is associated with higher patient and allograft survival when comparing with anti-IL2R.

BK polyomavirus infection and nephropathy: the virus-immune system interplay

Reactivation of latent BK polyomavirus (BKV) infection continues to be a major challenge in renal graft recipients. Progression of BKV infection to BKV-associated nephropathy (BKVAN) leads to graft loss in up to 60% of affected patients. Interestingly, although >80% of healthy adults are seropositive for BKV, BKVAN occurs almost exclusively in transplanted kidneys, which raises questions about its underlying pathogenetic mechanisms. Intragraft inflammation and an insufficient antiviral immune response seem to be the most important risk factors. Early studies revealed an association between the rate of recovery of BKV-specific cellular immunity (which shows high interindividual variation) and BK viral clearance, which determines the clinical course of BKV infection. In patients with prompt recovery of BKV-specific T cells, BKV infection can be controlled at the early reactivation stage and does not progress to BKVAN. By contrast, in patients with persistent BKV reactivation caused by insufficient BKV-specific immunity, continued viral replication and inflammation ultimately lead to graft injury and/or BKVAN. As the chronic course of BKV infection can be prevented in most patients by prompt restoration of BKV-specific immunity, frequent monitoring of BK viral load and targeted, timely modification or reduction of immunosuppression is strongly recommended for affected patients.

Malignancy after renal transplantation: the role of immunosuppression

Outcomes of kidney transplantation, in terms of graft and patient survival, have improved over the past few decades, partly as a result of the introduction of new immunosuppressive drugs. Many immunosuppressive agents are associated with an increased risk of cardiovascular events and an increased risk of cancer, however, which can compromise patient survival. Cancer is more common among solid-organ transplant recipients than it is in the general population or in patients on dialysis. In fact, malignancy is the third most common cause of death in renal transplant recipients. Immunosuppressive treatments used in renal transplant recipients can cause malignancy by supporting oncogenesis caused by certain viruses or by impairing immune surveillance thereby enabling faster tumor growth. In this Review, we describe the epidemiological and clinical characteristics of common tumor types occurring after kidney transplantation, and the etiopathogenetic factors that lead to their appearance, with a particular focus on the relationship between immunosuppressive treatment and malignancy. Immunosuppressive drugs associated with an increased risk of malignancy after transplantation are also discussed, as are immunosuppressive drugs that seem to have antioncogenic properties.

Reevaluating and optimizing polyomavirus BK and JC real-time PCR assays to detect rare sequence polymorphisms

PCR-based molecular assays have a central role in polyomavirus diagnostics. To assure optimal performance, target sequences should be regularly updated according to newly available sequences. The aim of this study was to review our in-house polyomavirus BK (BKV) and JC (JCV) real-time PCR assays. Database analysis revealed variations in the BKV target region which might affect the assay performance, while no significant changes were found in the JCV target region. We compared two degenerate versions of our BKV primers which accommodated at least 95% of all published genetic variants. Dilutions of cloned viral genomic DNA and probit analysis indicated an analytical sensitivity of the updated BKV assay of 4.15 copies/reaction and that of the JCV assay was 3.37 copies/reaction. The specificity was assessed by testing JCV- and BKV-positive samples that showed no cross-reactivity. The performance of the original and updated BKV assay was compared in 101 urine and 200 plasma samples submitted to our routine diagnostic laboratory revealed similar quantitative results. We conclude that our JCV and updated BKV real-time PCR assays are robust and detect rare variants possibly encountered in the clinical routine.

New-onset diabetes after transplantation: risk factors and clinical impact

With improvements in patient and graft survival, increasing attention has been placed on complications that contribute to long-term patient morbidity and mortality. New-onset diabetes after transplantation (NODAT) is a common complication of solid-organ transplantation, and is a strong predictor of graft failure and cardiovascular mortality in the transplant population. Risk factors for NODAT in transplant recipients are similar to those in non-transplant patients, but transplant-specific risk factors such as hepatitis C (HCV) infection, corticosteroids and calcineurin inhibitors play a dominant role in NODAT pathogenesis. Management of NODAT is similar to type 2 diabetes management in the general population. However, adjusting the immunosuppressant regimen to improve glucose tolerance must be weighed against the risk of allograft rejection. Lifestyle modification is currently the strategy with the least risk and the most benefit.

Chronic viral hepatitis in kidney transplantation

Chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection in potential kidney transplant candidates-once considered absolute contraindications to kidney transplantation-no longer creates overt barriers to transplantation. Advances in the medical management of HBV and HCV infection have created opportunities for a substantial number of patients to be effectively treated with antiviral therapy before transplantation. For HBV infection, a number of new drugs enable clearance of the virus with minimal adverse effects and drug resistance. Pretransplantation antiviral therapy is advisable for patients with HCV infection, but adverse effects are common and viral eradication remains challenging. Regardless of viral clearance, pretransplant patients without bridging fibrosis (as confirmed by liver biopsy) or clinical stigmata of cirrhosis should be considered for kidney transplantation as survival is superior when compared to treatment with dialysis, and progression of liver disease is unlikely. For patients with advanced liver disease, simultaneous liver-kidney transplantation is an important consideration. These treatment advances further increase the burden of organ donor shortage; however, organs from deceased donors with chronic HBV or HCV infection could be efficiently allocated to certain individuals with a viral infection of the same type to increase the pool of available transplant organs.

Single-nucleotide polymorphisms, acute rejection, and severity of tubulitis in kidney transplantation, accounting for center-to-center variation

BACKGROUND

Acute rejection (AR) is associated with worse renal allograft outcomes. Therefore, this study investigated single-nucleotide polymorphisms (SNPs) to identify genetic variants associated with AR, accounting for center variation, in a multicenter, prospective, observation study.

METHODS

We enrolled patients from six transplant centers, five in the United States and one in Canada. A total of 2724 SNPs were genotyped. We accounted for center variation in AR rates by stratifying by transplant center and using novel knowledge discovery methods.

RESULTS

There was significant center variation in AR rates across the six transplant sites (P<0.0001). Accounting for this difference and clinical factors independently associated with AR, we identified 15 novel SNPs associated with AR with stratification by transplant center (P<0.05). We also identified 15 novel SNPs associated with severity of tubulitis scores, after adjusting for transplant center and other clinical factors independently associated with severity of tubulitis (P<0.05). There was some overlap with one SNP associated with AR and also associated with severity of tubulitis, among the top 15 SNPs.

CONCLUSION

Center-to-center variation is a major challenge to genomic studies focused on AR. The SNPs associated with AR and severity of tubulitis in this study will need to be validated in independent cohort of kidney transplant recipients.

Hypertension following kidney transplantation

The majority of patients become hypertensive following kidney transplantation. Its occurrence is associated not only with increased fatal and nonfatal cardiovascular events but also with decreased allograft survival. This review summarizes the current knowledge of the epidemiology, etiology, pathophysiology, and management of post-transplant hypertension.

Changing attitudes toward influenza vaccination in U.S. Kidney transplant programs over the past decade

BACKGROUND AND OBJECTIVES

Influenza infection in transplant recipients is often associated with significant morbidity. Surveys were conducted in 1999 and 2009 to find out if the influenza vaccination practices in the U.S. transplant programs had changed over the past 10 years.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In 1999, a survey of the 217 United Network for Organ Sharing-certified kidney and kidney-pancreas transplant centers in the U.S. was conducted regarding their influenza vaccination practice patterns. A decade later, a second similar survey of 239 transplant programs was carried out.

RESULTS

The 2009 respondents, compared with 1999, were more likely to recommend vaccination for kidney (94.5% versus 84.4%, P = 0.02) and kidney-pancreas recipients (76.8% versus 48.5%, P < 0.001), family members of transplant recipients (52.5% versus 21.0%, P < 0.001), and medical staff caring for transplant patients (79.6% versus 40.7%, P < 0.001). Physicians and other members of the transplant team were more likely to have been vaccinated in 2009 compared with 1999 (84.2% versus 62.3% of physicians, P < 0.001 and 91.2% versus 50.3% of nonphysicians, P < 0.001).

CONCLUSIONS

Our study suggests a greater adoption of the Centers for Disease Control and Prevention influenza vaccination guidelines by U.S. transplant programs in vaccinating solid-organ transplant recipients, close family contacts, and healthcare workers.

Cost-efficient screening for BK virus in pediatric kidney transplantation: a single-center experience and review of the literature

BKVNP is an increasingly recognized cause of graft dysfunction and loss in kidney transplant recipients. Protocols for BKV screening and for the diagnosis of BKVNP are still evolving. PCR-based BKV detection became available at our institution in 2007, when we began using it according to published guidelines. We subsequently reviewed our experience with urine and plasma BKV PCR testing in our pediatric kidney transplant recipient population. We found rates of viruria, viremia, and BKVNP that were similar to the published literature. We also conducted a cost analysis suggesting that urine PCR testing, as used by us, is not cost efficient in the detection of BKV. We conclude that plasma only-based PCR testing for BKV may be sufficient in most clinical settings.

Primary care of the renal transplant patient

There has been a remarkable rise in the number of kidney transplant recipients (KTR) in the US over the last decade. Increasing use of potent immunosuppressants, which are also potentially diabetogenic and atherogenic, can result in worsening of pre-existing medical conditions as well as development of post-transplant disease. This, coupled with improving long-term survival, is putting tremendous pressure on transplant centers that were not designed to deliver primary care to KTR. Thus, increasing numbers of KTR will present to their primary care physicians (PCP) post-transplant for routine medical care. Similar to native chronic kidney disease patients, KTRs are vulnerable to cardiovascular disease as well as a host of other problems including bone disease, infections and malignancies. Deaths related to complications of cardiovascular disease and malignancies account for 60-65% of long-term mortality among KTRs. Guidelines from the National Kidney Foundation and the European Best Practice Guidelines Expert Group on the management of hypertension, dyslipidemia, smoking, diabetes and bone disease should be incorporated into the long-term care plan of the KTR to improve outcomes. A number of transplant centers do not supply PCPs with protocols and guidelines, making the task of the PCP more difficult. Despite this, PCPs are expected to continue to provide general preventive medicine, vaccinations and management of chronic medical problems. In this narrative review, we examine the common medical problems seen in KTR from the PCP's perspective. Medical management issues related to immunosuppressive medications are also briefly discussed.

Using Epstein-Barr viral load assays to diagnose, monitor, and prevent posttransplant lymphoproliferative disorder

Epstein-Barr virus (EBV) DNA measurement is being incorporated into routine medical practice to help diagnose, monitor, and predict posttransplant lymphoproliferative disorder (PTLD) in immunocompromised graft recipients. PTLD is an aggressive neoplasm that almost always harbors EBV DNA within the neoplastic lymphocytes, and it is often fatal if not recognized and treated promptly. Validated protocols, commercial reagents, and automated instruments facilitate implementation of EBV load assays by real-time PCR. When applied to either whole blood or plasma, EBV DNA levels reflect clinical status with respect to EBV-related neoplasia. While many healthy transplant recipients have low viral loads, high EBV loads are strongly associated with current or impending PTLD. Complementary laboratory assays as well as histopathologic examination of lesional tissue help in interpreting modest elevations in viral load. Circulating EBV levels in serial samples reflect changes in tumor burden and represent an effective, noninvasive tool for monitoring the efficacy of therapy. In high-risk patients, serial testing permits early clinical intervention to prevent progression toward frank PTLD. Restoring T cell immunity against EBV is a major strategy for overcoming PTLD, and novel EBV-directed therapies are being explored to thwart virus-driven neoplasia.

Adverse effects of immunosuppression in pediatric solid organ transplantation

Solid organ transplantation is a life-saving treatment for end-stage organ failure in children. Immunosuppressant medications are used to prevent rejection of the organ transplant. However, these medications are associated with significant adverse effects that impact growth and development, quality of life (QOL), and sometimes long-term survival after transplantation. Adverse effects can differ between the immunosuppressants, but many result from the overall state of immunosuppression. Strategies to manage immunosuppressant adverse effects often involve minimizing exposure to the drugs while balancing the risk for rejection. Early recognition of immunosuppressant adverse effects may help to reduce morbidities associated with solid organ transplantation, improve QOL, and possibly increase overall patient survival.

Kidney disease: improving global outcomes

Kidney Disease: Improving Global Outcomes (KDIGO) is an independent organization with the mission to improve care and outcomes of patients with kidney disease worldwide through the development and coordination of clinical practice guidelines. KDIGO has established firm links with other organizations that have previously produced clinical practice guidelines in the field of kidney disease. The first three KDIGO guidelines--treatment of hepatitis C, management of bone and mineral disease, and care of kidney transplant recipients--have been finalized and the next three--acute kidney injury, management of glomerulonephritis, and management of blood pressure in chronic kidney disease--are under development. The ultimate goal is to cover most major aspects of care for patients with kidney disease. Corner stones of KDIGO's guideline development process are independent, multidisciplinary, international work groups, close collaboration with professional methodology experts who perform systematic evidence reviews, and open public review of each guideline. Grades of Recommendation Assessment, Development, and Evaluation (GRADE) methodology is applied for grading the quality of evidence and strength of recommendations. International conferences organized by KDIGO support the coordination of guideline development, assess the suitability of guideline topics and help to establish global consensus on definitions and policies.