Assessing the Utility of a Genotype-Guided Tacrolimus Equation in African American Kidney Transplant Recipients: A Single Institution Retrospective Study.

Tacrolimus metabolism is heavily influenced by the CYP3A5 genotype, which varies widely among African Americans (AA). We aimed to assess the performance of a published genotype-informed tacrolimus dosing model in an independent set of adult AA kidney transplant (KTx) recipients. CYP3A5 genotypes were obtained for all AA KTx recipients (n = 232) from 2010 to 2019 who met inclusion criteria at a single transplant center in Philadelphia, Pennsylvania, USA. Medical record data were used to calculate predicted tacrolimus clearance using the published AA KTx dosing equation and two modified iterations. Observed and model-predicted trough levels were compared at 3 days, 3 months, and 6 months post-transplant. The mean prediction error at day 3 post-transplant was 3.05 ng/mL, indicating that the model tended to overpredict the tacrolimus trough. This bias improved over time to 1.36 and 0.78 ng/mL at 3 and 6 months post-transplant, respectively. Mean absolute prediction error-a marker of model precision-improved with time to 2.33 ng/mL at 6 months. Limiting genotype data in the model decreased bias and improved precision. The bias and precision of the published model improved over time and were comparable to studies in previous cohorts. The overprediction observed by the published model may represent overfitting to the initial cohort, possibly limiting generalizability.

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.

COVID-19 infection and vaccination rarely impact HLA antibody profile in waitlisted renal transplant candidates- a multicenter cohort.

Although rare, infection and vaccination can result in antibodies to human leukocyte antigens (HLA). We analyzed the effect of SARS-CoV-2 infection or vaccination on HLA antibodies in waitlisted renal transplant candidates. Specificities were collected and adjudicated if the calculated panel reactive antibodies (cPRA) changed after exposure. Of 409 patients, 285 (69.7 %) had an initial cPRA of 0 %, and 56 (13.7 %) had an initial cPRA > 80 %. The cPRA changed in 26 patients (6.4 %), 16 (3.9 %) increased, and 10 (2.4 %) decreased. Based on cPRA adjudication, cPRA differences generally resulted from a small number of specificities with subtle fluctuations around the borderline of the participating centers' cutoff for unacceptable antigen listing. All five COVID recovered patients with an increased cPRA were female (p = 0.02). In summary, exposure to this virus or vaccine does not increase HLA antibody specificities and their MFI in approximately 99 % of cases and 97 % of sensitized patients. These results have implications for virtual crossmatching at the time of organ offer after SARS-CoV-2 infection or vaccination, and these events of unclear clinical significance should not influence vaccination programs.

A survey of solid organ transplant recipient attitudes and concerns regarding contraception and pregnancy.

INTRODUCTION: Many women who are solid organ transplant (SOT) recipients wish to have children after transplantation. Contraception is an important component of post-transplant planning and care, given the increased risk associated with post-transplant pregnancies. We sought to understand patient attitudes and concerns about post-transplant contraception and pregnancy. METHODS: Following a comprehensive literature review, our team developed a survey that was administered to female SOT recipients of childbearing age. We used descriptive and inferential statistics to characterize participant views RESULTS: A total of 243 transplant recipients completed the survey (80.7% response rate). The mean age of respondents was 37.5 years (±8.1 years), 66.7% were kidney recipients, and 40.7% were within the first year after transplant. The most common concerns among respondents included fetal and maternal health complications. Participants generally did not agree that transplant recipients should be advised to avoid pregnancy. There was strong support for shared decision-making about pregnancy after transplantation CONCLUSION: Understanding patient perspectives can help transplant providers make better care recommendations and support patient autonomy in reproductive decisions post-transplant. Given that there are some differences in views by transplant type, individualized conversations between patients and providers are needed.

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.

Tolerability of mycophenolate mofetil in elderly kidney transplant recipients: A retrospective cohort study.

BACKGROUND: Optimal immunosuppression in elderly kidney transplant recipients (KTRs) is not well defined, with mycophenolate mofetil (MMF) being poorly tolerated. Study aim was to compare MMF dose reduction incidence and reason(s) in elderly vs. nonelderly KTRs in the 1st year after transplant with a protocol dose of 1 g/day. METHODS: In this single-center retrospective study, first or repeat KTRs receiving rabbit antithymocyte globulin (rATG), MMF 1 g/day, tacrolimus, and prednisone, were stratified by age [≥60 (elderly) or <60 years (nonelderly)]. Primary outcome was MMF dose reduction incidence in the first year. Secondary outcomes included dose reduction rationale, 1-year patient and graft survival, graft function, rejection, infection, hospital presentation, and time to dose reduction. Of 335 KTRs, dose reduction incidence was significantly greater in the elderly group (66% and 54%, p = 0.04), though this did not remain significant when adjusted for sex, race, and valganciclovir use. Most common rationale was leukopenia in the elderly group and CMV in the nonelderly group. There were no significant differences in secondary outcomes. CONCLUSIONS: Mycophenolate mofetil 1 g/day was poorly tolerated in both elderly and nonelderly KTRs receiving lymphocyte-depleting induction with a high incidence of dose reductions; however, no short-term adverse graft outcomes were identified.

Germinal center responses to SARS-CoV-2 mRNA vaccines in healthy and immunocompromised individuals.

Vaccine-mediated immunity often relies on the generation of protective antibodies and memory B cells, which commonly stem from germinal center (GC) reactions. An in-depth comparison of the GC responses elicited by SARS-CoV-2 mRNA vaccines in healthy and immunocompromised individuals has not yet been performed due to the challenge of directly probing human lymph nodes. Herein, through a fine-needle aspiration-based approach, we profiled the immune responses to SARS-CoV-2 mRNA vaccines in lymph nodes of healthy individuals and kidney transplant recipients (KTXs). We found that, unlike healthy subjects, KTXs presented deeply blunted SARS-CoV-2-specific GC B cell responses coupled with severely hindered T follicular helper cell, SARS-CoV-2 receptor binding domain-specific memory B cell, and neutralizing antibody responses. KTXs also displayed reduced SARS-CoV-2-specific CD4 and CD8 T cell frequencies. Broadly, these data indicate impaired GC-derived immunity in immunocompromised individuals and suggest a GC origin for certain humoral and memory B cell responses following mRNA vaccination.

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.

BLyS neutralization results in selective anti-HLA alloantibody depletion without successful desensitization.

Pre-existing anti-HLA allo-antibodies (allo-Abs) are a major barrier to successful kidney transplantation, resulting in an elevated risk for antibody-mediated rejection (AMR) and eventual graft loss. The cytokine B lymphocyte stimulator (BLyS) promotes B cell maturation and plasma cell survival; consequently, anti-BLyS therapy represents a potential therapeutic opportunity in diminishing pre-existing allo-Abs. Here we report that in our 1-year pilot trial, BLyS neutralization failed to reduce total anti-HLA allo-Ab levels in highly sensitized candidates awaiting kidney transplant in a clinically meaningful way. Additionally, we performed a post hoc analysis using sera from trial candidates which revealed selective depletion of anti-HLA class I and class II Abs in response to belimumab treatment, restricted to certain allele specificities and IgG subclasses. Altogether, we observed that BLyS blockade only results in selective depletion of anti-HLA Abs recognizing a few discrete HLA allele specificities.

Use of Dietary Supplements in Living Kidney Donors: A Critical Review.

Dietary supplement use is high among US adults, with the intention by users to promote overall health and wellness. Kidney donors, who are selected based on their overall good health and wellness, can have high utilization rates of dietary supplements. We provide a framework for the evaluation of living kidney donors and use of dietary supplements. In this review, dietary supplements will include any orally administered dietary or complementary nutritional products, but excluding micronutrients (vitamins and minerals), food, and cannabis. Use of dietary supplements can influence metabolic parameters that mask future risk for chronic illness such as diabetes and hypertension. Dietary supplements can also alter bleeding risk, anesthesia and analgesic efficacy, and safety in a perioperative period. Finally, postdonation monitoring of kidney function and risk for supplement-related nephrotoxicity should be part of a kidney donor educational process. For practitioners evaluating a potential kidney donor, we provide a list of the most commonly used herbal supplements and the effects on evaluation in a predonation, perioperative donation, and postoperative donation phase. Finally, we provide recommendations for best practices for integration into a comprehensive care plan for kidney donors during all stages of evaluation. We recommend avoidance of dietary supplements in a kidney donor population, although there is a paucity of data that identifies true harm. Rather, associations, known mechanisms of action, and common sense suggest that we avoid use in this population.

Kidney transplantation and donation in the transgender population: A single-institution case series.

The medical needs of the transgender population are increasingly recognized within the US health care system. Hormone therapy and gender-affirming surgery present distinct anatomic, hormonal, infectious, and psychosocial issues among transgender kidney transplant donors and recipients. We present the first reported experience with kidney transplantation and donation in transgender patients. A single-center case series (January 2014-December 2018) comprising 4 transgender kidney transplant recipients and 2 transgender living donors was constructed and analyzed. Experts in transplant surgery, transplant psychiatry, transplant infectious disease, pharmacy, and endocrinology were consulted to discuss aspects of care for these patients. Four transgender patients identified as male-to-female and 2 as female-to-male. Three of 6 had gender-affirming surgeries prior to transplant surgery, 1 of whom had further procedures posttransplant. Additionally, 4 patients were on hormone therapy. All 6 had psychiatric comorbidities. The 4 grafts have done well, with an average serum creatinine of 1.45 mg/dL at 2 years (range 1.01-1.85 mg/dL). However, patients encountered various postoperative complications, 1 of which was attributable to modified anatomy. Thus, transgender kidney transplant patients can present novel challenges in regard to surgical considerations as well as pre- and posttransplant care. Dedicated expertise is needed to optimize outcomes for this population.

Chronopharmacokinetics and Food Effects of Single-Dose LCP-Tacrolimus in Healthy Volunteers.

BACKGROUND: A modified-release version of tacrolimus, LCP-tacrolimus (LCPT; Envarsus XR, Veloxis Pharmaceuticals, Cary, NC), has been licensed in the United States for prophylaxis of organ rejection in de novo kidney transplant patients. As tacrolimus has a narrow therapeutic window, the impact of circadian patterns on LCPT drug exposure, including food and chronopharmacokinetic effects, needs to be elucidated to optimize dosing. METHODS: Two randomized, crossover, phase 1 studies were conducted in healthy volunteers. The first assessed the effect of morning versus evening dosing on the pharmacokinetic profile of LCPT 2 mg; the second assessed the effect of food on the pharmacokinetic profile of LCPT 5 mg. In both, blood samples were drawn from participants for up to 144 hours after administration of a single LCPT dose. RESULTS: No significant differences were observed between evening and morning dosing in peak blood concentration (4.4 versus 4.0 ng/mL; P = 0.27), area under the time-concentration curve (AUC) from time 0 to time of the last concentration (89.1 versus 102.6 ng/mL; P = 0.20), AUC from time 0 to infinity (99.7 versus 114.3 ng·h/mL; P = 0.18), AUC from 0 to 24 hours post-dose (AUC0-24; 49.4 versus 51.6 ng·h/mL; P = 0.56), time to reach maximum blood concentration (median, 6.0 versus 6.0 hours; P = 0.91), total clearance (arithmetic mean = 21.5 versus 19.5 L/h; P = 0.50), or terminal half-life (arithmetic mean = 26.8 versus 28.1 hours; P = 0.26). After a high-calorie meal in the morning, the AUC0-24 reduced by 54% (ratio of geometric means = 45.6%; P < 0.0001) and peak blood concentration reduced by 22% (ratio of geometric means = 78.4%; P = 0.0006). However, the terminal half-life did not differ between fasted and fed states (33.3 versus 34.8 hours; P = 0.16), implying that these differences occurred because of altered bioavailability rather than modified clearance. CONCLUSIONS: For LCPT, no chronopharmacokinetic effects were observed, whereas food significantly reduced the 24-h exposure and the peak blood concentration.

Class and Kinetics of Weakly Reactive Pretransplant Donor-specific HLA Antibodies Predict Rejection in Kidney Transplant Recipients.

BACKGROUND: The clinical impact of weakly reactive pretransplant donor-specific antibody (DSA) in kidney transplantation is controversial. While some evidence suggests that weakly reactive DSA can lead to rejection, it is unclear which patients are at risk for rejection and whether posttransplant changes in weakly reactive DSA are clinically meaningful. METHODS: We retrospectively studied 80 kidney transplant recipients with weakly reactive pretransplant DSA between 2007 and 2014. We performed a multivariate Cox regression analysis to identify immunologic factors most associated with risk of biopsy-proven rejection. RESULTS: Biopsy-proven rejection occurred in 13 of 80 (16%) patients. The presence of both class I and II DSA before transplant (hazards ratio 17.4, P < 0.01) and any posttransplant increase in DSA reactivity above a mean fluorescence intensity of 3000 (hazards ratio 7.8, P < 0.01) were each significantly associated with an increased risk of rejection, which primarily occurred within the first 18 months. CONCLUSIONS: Pretransplant DSA class and DSA kinetics after transplantation are useful prognostic indicators in patients with weak DSA reactivity. These results identify a small, high-risk patient group that warrants aggressive posttransplant DSA monitoring and may benefit from alternative donor selection.

Bariatric surgery before and after kidney transplantation: long-term weight loss and allograft outcomes.

BACKGROUND: Severe obesity is frequently a barrier to kidney transplantation, and kidney transplant recipients often have significant weight gain following transplantation. OBJECTIVES: The goals of this study were to evaluate the long-term risks and benefits of bariatric surgery before and after kidney transplantation. SETTING: University Hospital, United States. METHODS: We performed a retrospective cohort study of 43 patients who had pretransplantation bariatric surgery and 21 patients who had posttransplantation bariatric surgery from 1994 to 2017 with propensity-score matching to identify matched controls using national registry data. RESULTS: Body mass index at the time of transplantation was similar in patients who underwent bariatric surgery before versus after transplantation (32 versus 34 kg/m2, P = .172). There was no significant difference in body mass index in the 5 years after bariatric surgery among patients who underwent bariatric surgery before versus after kidney transplantation (36 versus 32 kg/m2, P = 0.814). Compared with matched controls, bariatric surgery before (n = 38) and after (n = 18) kidney transplantation was associated with a decreased risk of allograft failure (hazard ratio .31 [95% confidence interval .29-0.33] and .85 [95% confidence interval .85-.86] for pre- and posttransplant, respectively) and mortality (hazard ratio .57 [95% confidence interval .53-.61] and .80 [95% confidence interval .79-.82] for pre- and posttransplant, respectively). CONCLUSIONS: Bariatric surgery before and after kidney transplantation results in similar maintenance of weight loss and improved long-term allograft survival compared with matched controls. Bariatric surgery appears to be a safe and reasonable approach to weight loss both before and after transplantation.

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.

Native kidney BK virus nephropathy, a systematic review.

BACKGROUND: There is a growing base of literature describing BK nephropathy (BKVN) in patients outside of the setting of kidney transplant. Previous systematic reviews of the literature have been limited by methodology or by the scope of patients included. STUDY DESIGN AND METHODS: Systematic Review (Prospero # CRD42018088524). SETTING & POPULATION: Patients without kidney transplant who had biopsy-proven BKVN. SELECTION CRITERIA FOR STUDIES: Full-text articles that describe native BKVN patient cases. ANALYTICAL APPROACH: Descriptive synthesis. RESULTS: The search identified 630 unique articles of which 51 were included in the final review. Sixty-five cases (including two new cases presented in this review) were identified, all but one occurred in the setting of known immunosuppression. LIMITATIONS: The primary limitation was the exclusion of studies that did not fulfill the stringent review criteria. We excluded reports with only a clinical diagnosis of BKVN, such as those with viruria and/or viremia without biopsy. CONCLUSIONS: As of May 2018, there are 65 reported cases of BKVN in native kidneys. This represents the most comprehensive description of biopsy-proven BKVN in native kidneys to date. Evaluation for BK nephropathy should be considered in immunocompromised patients who exhibit unexplained renal failure.