Outcomes in kidney transplant recipients treated with immediate-release tacrolimus capsules versus extended-release tacrolimus capsules: A cohort study.

INTRODUCTION: Prior randomized trials and observational studies have generally reported similar outcomes in kidney transplant recipients (KTRs) treated with immediate-release tacrolimus (IR-TAC) versus extended-release tacrolimus (ER-TAC). However, many of these previous studies focused on patients with low immunological risks, had small sample sizes and brief follow-up periods, and excluded outcomes associated with graft loss, such as chronic rejection. METHODS: To address these limitations, we conducted a cohort study of 848 KTRs at a single transplantation center who had generally high immunological risks and were treated with either IR-TAC capsules (589 patients, 65.9%) or ER-TAC capsules (289 patients, 34.1%). All patients received their designated maintenance immunosuppressive regimen for at least 3 months post-transplantation. Afterwards, tacrolimus formulation was at the discretion of each patient's transplant nephrologist. For the two treatment groups, we compared the hazards of experiencing a composite outcome of acute or chronic antibody-mediated rejection (AMR), acute or chronic T-cell-mediated rejection, de novo DSA, and/or graft loss over a 3-year period starting at 3 months post-transplantation. RESULTS: In a multivariable Cox proportional hazards regression model, KTRs treated with IR-TAC capsules had an increased hazard of experiencing the composite outcome when compared to patients treated with ER-TAC capsules; however, this result was not significant (adj HR 1.24, 95% CI .92-1.68, p = .163). Similar results were obtained with inverse probability of treatment weighting (IPTW) using a propensity score (adj HR 1.25, 95% CI .93-1.68, p = .146). CONCLUSION: These findings suggest that when compared to IR-TAC capsules, ER-TAC capsules do not reduce the hazard of poor outcomes in KTRs with generally high immunological risks.

How to maximize graft survival.

PURPOSE OF REVIEW: Kidney transplant failure results in significant patient morbidity and mortality, increased financial burden and exacerbates the organ shortage faced by kidney transplant candidates. The different strategies to maximize graft survival in kidney transplant recipients is presented in this review. RECENT FINDINGS: Maximizing kidney graft survival requires optimizing immunosuppression, preventing and managing recurrent disease and using general chronic kidney disease strategies to slow allograft injury. Herein, we review: 1) strategies to tailor immunosuppression to the individual patient to avoid over and underimmunosuppression, and avoid immunosuppression-related drug toxicities, 2) latest findings in the following recurrent diseases: focal segmental glomerulosclerosis, membranous nephropathy, complement-mediated kidney disease and monoclonal gammopathy of renal significance, and, 3) approaches to slow allograft injury including BP control, and the use of antiproteinuric agents and SGLT-2 inhibitors. SUMMARY: The last two decades has seen significant improvement in allograft outcomes resulting from advances in immunosuppression. With the federal government's renewed focus on kidney disease and transplantation, and recent advances in biomarkers, genetic testing, big data analytics and machine learning, we hope to see further outcome improvements in the next decade.

Association of donor hepatitis C virus infection status and risk of BK polyomavirus viremia after kidney transplantation.

Kidney transplantation (KT) from deceased donors with hepatitis C virus (HCV) into HCV-negative recipients has become more common. However, the risk of complications such as BK polyomavirus (BKPyV) remains unknown. We assembled a retrospective cohort at four centers. We matched recipients of HCV-viremic kidneys to highly similar recipients of HCV-aviremic kidneys on established risk factors for BKPyV. To limit bias, matches were within the same center. The primary outcome was BKPyV viremia ≥1000 copies/ml or biopsy-proven BKPyV nephropathy; a secondary outcome was BKPyV viremia ≥10 000 copies/ml or nephropathy. Outcomes were analyzed using weighted and stratified Cox regression. The median days to peak BKPyV viremia level was 119 (IQR 87-182). HCV-viremic KT was not associated with increased risk of the primary BKPyV outcome (HR 1.26, p = .22), but was significantly associated with the secondary outcome of BKPyV ≥10 000 copies/ml (HR 1.69, p = .03). One-year eGFR was similar between the matched groups. Only one HCV-viremic kidney recipient had primary graft loss. In summary, HCV-viremic KT was not significantly associated with the primary outcome of BKPyV viremia, but the data suggested that donor HCV might elevate the risk of more severe BKPyV viremia ≥10 000 copies/ml. Nonetheless, one-year graft function for HCV-viremic recipients was reassuring.

Association between dd-cfDNA levels, de novo donor specific antibodies, and eGFR decline: An analysis of the DART cohort.

BACKGROUND: Donor-derived cell-free DNA (dd-cfDNA) is a marker of allograft injury in transplant recipients; however, the relationship between dd-cfDNA and other clinical parameters associated with adverse allograft outcomes is not well-characterized. METHODS: We performed a retrospective analysis of kidney transplant recipients from the DART cohort (ClinicalTrials.gov Identifier: NCT02424227) to evaluate the associations between eGFR decline, de novo donor-specific antibodies (dnDSA), and dd-cfDNA. RESULTS: Both elevated dd-cfDNA (≥1%) and dd-cfDNA variability (≥.34%) in the first post-transplant year were associated with decline in eGFR ≥25% in the second year (21.4% vs. 4.1%, P = .005; 25% vs. 3.6%, P = .002, respectively). Compared to samples from DSA negative patients, samples from patients with concurrent de novo HLA DSAs had higher dd-cfDNA levels (P < .0001). DISCUSSION: Abnormalities in dd-cfDNA levels are associated with clinical parameters commonly used as surrogate endpoints for adverse allograft outcomes, raising the possibility that molecular injury as characterized by dd-cfDNA could help identify patients at risk of these outcomes.

A pragmatic outreach pilot to understand and overcome barriers to COVID-19 vaccination in abdominal organ transplant.

BACKGROUND: Solid organ transplant recipients (SOTRs) are at increased risk for adverse outcomes with coronavirus disease 19 (COVID-19). Early data show a lower severe acute respiratory syndrome virus 2 (SARS-CoV-2) spike antibody immune response among SOTRs leading to patient concerns about vaccine efficacy. Public health messaging has largely left out immunocompromized individuals leading to a higher risk of vaccine misinformation. The American Society of Transplantation recommends COVID-19 vaccination for all SOTRs; however, patient concerns and beliefs about vaccination are largely unknown. METHODS: We conducted a transplant-center-based, pragmatic pilot trial to encourage COVID-19 vaccination among 103 unvaccinated SOTRs. We assessed vaccine concerns, barriers to vaccination, answered questions about efficacy, side effects, and clinical recommendations. RESULTS: A total of 24% (n = 25) of SOTRs reported that they will schedule COVID-19 vaccination after the study call, 46% reported that they will consider vaccination in the future, and 30% said they will not consider vaccination. Older age and White race were associated with lower willingness to schedule the vaccine, whereas Black race and longer time from transplant were associated with higher willingness. Common vaccine concerns included lack of long-term data, inconsistent messaging from providers, scheduling inconvenience, and insufficient resources. Follow-up approximately 1 month after the initial outreach found 52% (n = 13) of liver transplant recipients, and 10% (n = 3) of kidney transplant recipients subsequently received COVID-19 vaccines for a vaccination rate of 29% among respondents. CONCLUSION: Transplant center-based vaccine outreach efforts can decrease misinformation and increase vaccination uptake; however, vaccine-related mistrust remains high.

Phenome-wide association analysis suggests the APOL1 linked disease spectrum primarily drives kidney-specific pathways.

The relationship between commonly occurring genetic variants (G1 and G2) in the APOL1 gene in African Americans and different disease traits, such as kidney disease, cardiovascular disease, and pre-eclampsia, remains the subject of controversy. Here we took a genotype-first approach, a phenome-wide association study, to define the spectrum of phenotypes associated with APOL1 high-risk variants in 1,837 African American participants of Penn Medicine Biobank and 4,742 African American participants of Vanderbilt BioVU. In the Penn Medicine Biobank, outpatient creatinine measurement-based estimated glomerular filtration rate and multivariable regression models were used to evaluate the association between high-risk APOL1 status and renal outcomes. In meta-analysis of both cohorts, the strongest phenome-wide association study associations were for the high-risk APOL1 variants and diagnoses codes were highly significant for "kidney dialysis" (odds ratio 3.75) and "end stage kidney disease" (odds ratio 3.42). A number of phenotypes were associated with APOL1 high-risk genotypes in an analysis adjusted only for demographic variables. However, no associations were detected with non-renal phenotypes after controlling for chronic/end stage kidney disease status. Using calculated estimated glomerular filtration rate -based phenotype analysis in the Penn Medicine Biobank, APOL1 high-risk status was associated with prevalent chronic/end stage kidney disease /kidney transplant (odds ratio 2.27, 95% confidence interval 1.67-3.08). In high-risk participants, the estimated glomerular filtration rate was 15.4 mL/min/1.73m2; significantly lower than in low-risk participants. Thus, although APOL1 high-risk variants are associated with a range of phenotypes, the risks for other associated phenotypes appear much lower and in our dataset are driven by a primary effect on renal disease.

Peritransplant eculizumab does not prevent delayed graft function in deceased donor kidney transplant recipients: Results of two randomized controlled pilot trials.

Animal models and observational human data indicate that complement, including C5a, pathogenically participates in ischemia reperfusion (IR) injury that manifests as delayed graft function (DGF) following deceased donor kidney transplantation. We report on the safety/efficacy of anti-C5 monoclonal antibody eculizumab (Ecu) administered in the operating room prior to reperfusion, to prevent DGF in recipients of deceased donor kidney transplants in two related, investigator-sponsored, randomized controlled trials. Eight recipients from a single center were enrolled in a pilot study that led to a 19-subject multicenter trial. Together, 27 deceased donor kidney transplant recipients, 16 Ecu-treated and 11 controls, were treated with rabbit antithymocyte globulin, tacrolimus, mycophenolate mofetil with or without glucocorticoids, and followed for 6 months. Data analysis showed no epidemiological or transplant-related differences between study arms. Ecu was well tolerated with a similar severe adverse event incidence between groups. The DGF rate did not differ between Ecu-treated (44%) and control (45%, P = 1.0) subjects. Serum creatinine reduction in the first week after transplantation, and graft function up to 180-days post-transplant, were also similar. Ecu administration was safe but did not reduce the rate of DGF in a high-risk population of deceased donor recipients.

KDOQI US Commentary on the 2018 KDIGO Clinical Practice Guideline for the Prevention, Diagnosis, Evaluation, and Treatment of Hepatitis C.

The first KDIGO (Kidney Disease: Improving Global Outcomes) guideline for the prevention, diagnosis, evaluation, and treatment of hepatitis C virus (HCV) infection was published in 2008. The ensuing decade bore witness to remarkable advances in the treatment of HCV infection following the approval of direct-acting antiviral (DAA) agents that deliver cure rates routinely >95%. In this context, the KDIGO organization correctly recognized the need for an updated HCV guideline that would be relevant to the treatment of HCV-infected patients with kidney disease in the DAA era. The current NKF-KDOQI (National Kidney Foundation-Kidney Disease Outcomes Quality Initiative) commentary provides an in-depth review and perspective on the 2018 KDIGO guideline. Of note, the KDIGO work group made significant updates to guideline chapters 2 and 4 as a direct result of the availability of DAAs. The intent of this commentary is to provide useful interpretation for nephrologists and other practitioners caring for HCV-infected patients with chronic kidney disease, including dialysis patients and kidney transplant recipients. The availability of DAA agents that are safe and highly effective has created new opportunities, such as the transplantation of kidneys from HCV-infected kidney donors. The ability to treat HCV infection in patients with kidney disease will have a significant impact on the care of our patients and should favorably influence long-term outcomes as well.

National Trends in Utilization and 1-Year Outcomes with Transplantation of HCV-Viremic Kidneys.

BACKGROUND: Recent pilot trials have demonstrated the safety of transplanting HCV-viremic kidneys into HCV-seronegative recipients. However, it remains unclear if allograft function is impacted by donor HCV-viremia or recipient HCV-serostatus. METHODS: We used national United States registry data to examine trends in HCV-viremic kidney use between 4/1/2015 and 3/31/2019. We applied advanced matching methods to compare eGFR for similar kidneys transplanted into highly similar recipients of kidney transplants. RESULTS: Over time, HCV-seronegative recipients received a rising proportion of HCV-viremic kidneys. During the first quarter of 2019, 200 HCV-viremic kidneys were transplanted into HCV-seronegative recipients, versus 69 into HCV-seropositive recipients, while 105 HCV-viremic kidneys were discarded. The probability of HCV-viremic kidney discard has declined over time. Kidney transplant candidates willing to accept a HCV-seropositive kidney increased from 2936 to 16,809 from during this time period. When transplanted into HCV-seronegative recipients, HCV-viremic kidneys matched to HCV-non-viremic kidneys on predictors of organ quality, except HCV, had similar 1-year eGFR (66.3 versus 67.1 ml/min per 1.73 m2, P=0.86). This was despite the much worse kidney donor profile index scores assigned to the HCV-viremic kidneys. Recipient HCV-serostatus was not associated with a clinically meaningful difference in 1-year eGFR (66.5 versus 71.1 ml/min per 1.73 m2, P=0.056) after transplantation of HCV-viremic kidneys. CONCLUSIONS: By 2019, HCV-seronegative patients received the majority of kidneys transplanted from HCV-viremic donors. Widely used organ quality scores underestimated the quality of HCV-viremic kidneys based on 1-year allograft function. Recipient HCV-serostatus was also not associated with worse short-term allograft function using HCV-viremic kidneys.

Early emergence of anti-HCV antibody implicates donor origin in recipients of an HCV-infected organ.

Hepatitis C virus (HCV) seroconversion among HCV-uninfected transplant recipients from HCV-infected (NAT+/Antibody+) or HCV-exposed (NAT-/Antibody+) donors has been reported. However, the origin of anti-HCV antibody and the implications of seroconversion remain unknown. We longitudinally tested plasma from HCV-uninfected kidney (n = 31) or heart transplant recipients (n = 9) of an HCV NAT+ organ for anti-HCV antibody (both IgG and IgM isotypes). Almost half of all participants had detectable anti-HCV antibody at any point during follow-up. The majority of antibody-positive individuals became positive within 1-3 days of transplantation, and 6 recipients had detectable antibody on the first day posttransplant. Notably, all anti-HCV antibody was IgG, even in samples collected posttransplant day 1. Late seroconversion was uncommon (≈20%-25% of antibody+ recipients). Early antibody persisted over 30 days in kidney recipients, whereas early antibody dropped below detection in 50% of heart recipients within 2 weeks after transplant. Anti-HCV antibody is common in HCV-uninfected recipients of an HCV NAT+ organ. The IgG isotype of this antibody and the kinetics of its appearance and durability suggest that anti-HCV antibody is donor derived and is likely produced by a cellular source. Our data suggest that transfer of donor humoral immunity to a recipient may be much more common than previously appreciated.

Transplanting hepatitis C virus-infected hearts into uninfected recipients: A single-arm trial.

The advent of direct-acting antiviral therapy for hepatitis C virus (HCV) has generated tremendous interest in transplanting organs from HCV-infected donors. We conducted a single-arm trial of orthotopic heart transplantation (OHT) from HCV-infected donors into uninfected recipients, followed by elbasvir/grazoprevir treatment after recipient HCV was first detected (NCT03146741; sponsor: Merck). We enrolled OHT candidates aged 40-65 years; left ventricular assist device (LVAD) support and liver disease were exclusions. We accepted hearts from HCV-genotype 1 donors. From May 16, 2017 to May 10, 2018, 20 patients consented for screening and enrolled, and 10 (median age 52.5 years; 80% male) underwent OHT. The median wait from UNOS opt-in for HCV nucleic-acid-test (NAT)+ donor offers to OHT was 39 days (interquartile range [IQR] 17-57). The median donor age was 34 years (IQR 31-37). Initial recipient HCV RNA levels ranged from 25 IU/mL to 40 million IU/mL, but all 10 patients had rapid decline in HCV NAT after elbasvir/grazoprevir treatment. Nine recipients achieved sustained virologic response at 12 weeks (SVR-12). The 10th recipient had a positive cross-match, experienced antibody-mediated rejection and multi-organ failure, and died on day 79. No serious adverse events occurred from HCV transmission or treatment. These short-term results suggest that HCV-negative candidates transplanted with HCV-infected hearts have acceptable outcomes.

Mortality and Kidney Transplantation Outcomes Among Hepatitis C Virus-Seropositive Maintenance Dialysis Patients: A Retrospective Cohort Study.

RATIONALE & OBJECTIVE: Hepatitis C virus (HCV) infection is common among maintenance dialysis patients. Few studies have examined both dialysis survival and transplantation outcomes for HCV-seropositive patients because registry data sets lack information for HCV serostatus. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Adult long-term dialysis patients treated by a US national dialysis provider between January 1, 2004, and December 31, 2014. EXPOSURE: HCV antibody serostatus obtained as part of clinical data from a national dialysis provider. OUTCOMES: Mortality on dialysis therapy, entry onto the kidney transplant waiting list, kidney transplantation, and estimated survival benefit from kidney transplantation versus remaining on the waitlist. ANALYTICAL APPROACH: After linking clinical data with data from the Organ Procurement and Transplantation Network, Cox and cause-specific hazards regression were implemented to estimate the associations between HCV seropositivity and mortality, as well as entry onto the kidney transplant waitlist. Cox regression was also used to estimate the survival benefit from transplantation versus dialysis among HCV-seropositive individuals. RESULTS: Among 442,171 dialysis patients, 31,624 (7.2%) were HCV seropositive. HCV seropositivity was associated with a small elevation in the rate of death (adjusted HR [aHR], 1.09; 95% CI, 1.07-1.11) and a substantially lower rate of entry onto the kidney transplant waitlist (subdistribution HR [sHR], 0.67; 95% CI, 0.61-0.74). Once wait-listed, the kidney transplantation rate was not different for HCV-seropositive (sHR 1.10; 95% CI, 0.96-1.27) versus HCV-seronegative patients. HCV-seropositive patients lived longer with transplantation (aHR at 3 years, 0.42; 95% CI, 0.27-0.63). Receiving an HCV-seropositive donor kidney provided a survival advantage at the 2-year posttransplantation time point compared to remaining on dialysis therapy waiting for an HCV-negative kidney. LIMITATIONS: No data for HCV viral load or liver biopsy. CONCLUSIONS: HCV-seropositive patients experience reduced access to the kidney transplantation waitlist despite deriving a substantial survival benefit from transplantation. HCV-seropositive patients should consider foregoing HCV treatment while accepting kidneys from HCV-infected donors to facilitate transplantation and prolong survival.

Single-center, real-world experience with granulocyte colony-stimulating factor for management of leukopenia following kidney transplantation.

BACKGROUND: Leukopenia is a frequent complication following kidney transplantation. Granulocyte colony-stimulating factor (G-CSF) has been used to accelerate white blood cell (WBC) count recovery; however, published experience in kidney transplantation is limited. METHODS: We retrospectively reviewed our kidney transplant recipients from January 2012 to September 2016 with a G-CSF order to evaluate leukopenia management (defined as WBC <3000 cells/µL). RESULTS: Thirty-six recipients were included. On average, G-CSF treatment began at 98 ± 38 days. At G-CSF initiation, mean WBC count was 1240 ± 420 cells/µL and absolute neutrophil count (ANC) was 653 ± 368 cells/µL. Mean G-CSF dose was 4.6 ± 1.2 mcg/kg/dose (total 11.8 ± 9.0 mcg/kg), 77.8% of recipients were prescribed G-CSF as outpatients, and overall, median time to WBC count recovery was 9 (IQR 4-14) days. Changes in immunosuppression and prophylaxis regimens for leukopenia were also common. Within 1 month following leukopenia onset, no patients experienced acute rejection and 5 (14%) developed infection requiring hospitalization or opportunistic infection. CONCLUSION: In kidney recipients with leukopenia, G-CSF may be helpful to achieve WBC count recovery in addition to changes in immunosuppression and prophylaxis medications. Prospective, randomized data are still needed to determine optimal G-CSF dosing in this population.

Management and treatment of the HCV-infected kidney transplant patient.

The prevalence of hepatitis C virus infection is increased in patients with end stage kidney disease compared to the general population and is an adverse outcome determinant. Direct-acting antiviral therapy for hepatitis C virus is changing the management paradigm of infected kidney transplant candidates and recipients, with potential to reduce patient morbidity and mortality. This review describes the hepatic and nonhepatic manifestations of hepatitis C virus in kidney transplant patients as well as management and treatment strategies to optimize transplant outcomes, highlighting the importance of direct-acting antivirals in this population.

The effect of transfer to adult transplant care on kidney function and immunosuppressant drug level variability in pediatric kidney transplant recipients.

Adolescent age at time of transplant has been recognized as a risk factor for renal allograft loss. Increased risk for graft failure may persist from adolescence to young adulthood. Transfer of care is hypothesized as a risk factor for non-adherence and graft loss. We explored whether kidney allograft function declined at an accelerated rate after transfer of care to adult transplant centers and whether coefficient of variation of tacrolimus (CV TAC) trough levels predicted allograft loss. Single-center, retrospective chart review was performed for pediatric kidney transplant recipients who received transplants between 1999 and 2011. Change in eGFR pre- and post-transfer was performed via a linear mixed-effects model. CV TAC was calculated in transplant recipients with TAC data pre- and post-transfer. t test was performed to determine the difference between means of CV TAC in subjects with and without allograft loss following transfer of care. Of the 138 subjects who transferred to adult care, 47 subjects with data pre- and post-transfer demonstrated a decrease in the rate of eGFR decline post-transfer from 8.0 mL/min/1.73 m2 per year to 2.1 mL/min/1.73 m2 per year, an ~80% decrease in eGFR decline post-transfer (P = 0.01). Twenty-four subjects had CV TAC data pre- and post-transfer of care. Pretransfer CV TAC for subjects with allograft loss post-transfer was significantly higher than in subjects without allograft loss (49% vs 26%, P < 0.05). Transfer of care was not independently associated with acceleration in eGFR decline. CV TAC may aid in identifying patients at risk for allograft loss post-transfer.

Twelve-Month Outcomes After Transplant of Hepatitis C-Infected Kidneys Into Uninfected Recipients: A Single-Group Trial.

Background: Organs from hepatitis C virus (HCV)-infected deceased donors are often discarded. Preliminary data from 2 small trials, including THINKER-1 (Transplanting Hepatitis C kidneys Into Negative KidnEy Recipients), suggested that HCV-infected kidneys could be safely transplanted into HCV-negative patients. However, intermediate-term data on quality of life and renal function are needed to counsel patients about risk. Objective: To describe 12-month HCV treatment outcomes, estimated glomerular filtration rate (eGFR), and quality of life for the 10 kidney recipients in THINKER-1 and 6-month data on 10 additional recipients. Design: Open-label, nonrandomized trial. (ClinicalTrials.gov: NCT02743897). Setting: Single center. Participants: 20 HCV-negative transplant candidates. Intervention: Participants underwent transplant with kidneys infected with genotype 1 HCV and received elbasvir-grazoprevir on posttransplant day 3. Measurements: The primary outcome was HCV cure. Exploratory outcomes included 1) RAND-36 Physical Component Summary (PCS) and Mental Component Summary (MCS) quality-of-life scores at enrollment and after transplant, and 2) posttransplant renal function, which was compared in a 1:5 matched sample with recipients of HCV-negative kidneys. Results: The mean age of THINKER participants was 56.3 years (SD, 6.7), 70% were male, and 40% were black. All 20 participants achieved HCV cure. Hepatic and renal complications were transient or were successfully managed. Mean PCS and MCS quality-of-life scores decreased at 4 weeks; PCS scores then increased above pretransplant values, whereas MCS scores returned to baseline values. Estimated GFRs were similar between THINKER participants and matched recipients of HCV-negative kidneys at 6 months (median, 67.5 vs. 66.2 mL/min/1.73 m2; 95% CI for between-group difference, -4.2 to 7.5 mL/min/1.73 m2) and 12 months (median, 72.8 vs. 67.2 mL/min/1.73 m2; CI for between-group difference, -7.2 to 9.8 mL/min/1.73 m2). Limitation: Small trial. Conclusion: Twenty HCV-negative recipients of HCV-infected kidneys experienced HCV cure, good quality of life, and excellent renal function. Kidneys from HCV-infected donors may be a valuable transplant resource. Primary Funding Source: Merck.

Treating hepatitis C infection in patients with advanced CKD in the real world: time to refocus on what our real treatment goals should be.

In this issue, Alric and colleagues demonstrate through real-world experience that grazoprevir-elbasvir is safe and effective for treating hepatitis C in advanced kidney disease patients with higher comorbidity burdens. This commentary highlights that this and similar studies have primarily focused on treatment safety and efficacy, rather than the clinical impact of viral eradication. Critical knowledge gaps including which patients to treat, and when, as well as potential management strategies that may improve outcomes, are discussed.

A clone-directed approach may improve diagnosis and treatment of proliferative glomerulonephritis with monoclonal immunoglobulin deposits.

The optimal treatment for the monoclonal gammopathies of renal significance is not known, but there is consensus among experts that treatment should be specific for the underlying clone. The majority of patients with proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) do not have an identifiable clone, and prior studies have found poor renal outcomes for patients with PGNMID treated with a variety of regimens. Here we present a retrospective case series of 19 patients with PGNMID with a more uniform, clone-directed approach. A circulating paraprotein was detected in 37% of patients, and the overall clone detection rate was 32%. Treatment was directed at the underlying clone or, for patients without a detectable clone, empirically prescribed to target the hypothesized underlying clone. Of the 16 patients who underwent treatment, the overall renal response rate was 88%, and 38% of patients experienced complete renal response (proteinuria reduction to under 0.5 gm/24 hours) with initial treatment. All patients were End Stage Renal Disease-free at last follow-up (median 693 days after diagnosis), and treatment was well tolerated. Thus, a clone-directed approach may lead to novel, targeted treatment strategies that could significantly improve outcomes for patients with PGNMID.