Background and Rationale: Early life stress (ELS) includes emotional abuse, physical trauma, poverty, household dysfunction, and other forms of childhood adversity that occur prior to 18 years of age. ELS has generally been associated with increased cardiovascular disease (CVD) risk and other poor health outcomes in adulthood but affects males and females differently in both humans and animal models. The type, degree, and timing of ELS exposure can be quantified using a variety of validated instruments: Adverse Childhood Experiences (ACE), Children’s Report of Exposure to Violence (CREV), Adolescent Discrimination Distress Index (ADDI), Adolescent Life Change Event Scale (ALCES), and the Childhood Trauma Questionnaire (CTQ). However, few studies have profiled multiple forms of ELS within an adolescent cohort to determine the sex-specific differential impacts on surrogates for future CVD risk. Therefore, in this study we hypothesized that males would have increased exposure to violence, females would have increased exposure to emotional/physical abuse, and both relationships would be associated with worse surrogates for future CVD risk. Methods: We tested this hypothesis in an interim analysis of an ongoing prospective cohort study of ELS in healthy adolescents. Each participant completed a single study visit with a blood draw followed by ACE, CREV, ADDI, ALCES, and CTQ questionnaires to quantify ELS exposure. We measured creatinine-based estimated GFR (eGFR) and plasma uric acid (pro-inflammatory and pro-oxidant molecule) as CVD risk factors and our primary outcomes. We tested associations between each ELS exposure and eGFR/uric acid in the overall population as well as in male and female subgroups to identify sex differences in ELS exposures and CVD risk surrogates. We used Student’s t test to compare means and Pearson’s correlation to analyze linear relationships between continuous variables. Results: We analyzed 163 adolescents enrolled to date. The cohort included 52% males and 48% females and the median (min, max) age was 15 (13-18) years; other demographic features of the cohort were consistent with our local population. We detected sex-specific differences in some ELS exposures, as ALCES scores were significantly higher in females (17.73 ± 6.62 vs. 12.25 ± 6.51; P = .017) while CREV scores were significantly higher in males (1.39 ± 2.26 vs. 0.81 ± 1,24; P = .046); the other ELS exposures were equally distributed between sexes. Only in males, we found trends for positive correlations between ACE scores (r2= 0.203, P = 0.062) and CTQ emotional neglect scores (r2 = 0.199, P = 0.062) with uric acid levels but found no associations between ELS exposures and eGFR. There were no relationships between ELS exposures and either eGFR or uric acid in the female subgroup. Conclusions: We found important sex-specific differences in ELS in adolescents, with greater exposure to violence in males and greater exposure to personal, social, and family changes in females. Males with certain forms of ELS exposure could be at risk for higher uric acid levels, which if validated in our final cohort would provide one mechanistic link between ELS exposure and future cardiovascular disease in adulthood. We speculate that even if ELS exposure in adolescents is unable to be “cured” per se, identifying treatable ELS-mediated mechanisms of future CVD risk is of paramount importance. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

e12621 Background: In October 2023, intraoperative frozen section (IOFS) was restricted to breast cancer patients after neoadjuvant chemotherapy (NACT) only due to shortage of pathologists at the largest tertiary center in Austria. Here, we investigate the impact of the omission of IOFS on positive margins in the final pathology report. Methods: In this retrospective analysis, breast cancer patients undergoing breast conserving surgery at the University Hospital of Vienna between April 2020 and October 2024 were included. Patients after NACT, those who underwent mastectomy, had skin and/or muscle infiltration or other locally advanced disease were excluded from this analysis. Results: A total of 697 patients, 382 with IOFS before October 2023 and 315 without IOFS thereafter, with a median age of 63 years have been included in this analysis. No differences between IOFS and no-IOFS group were seen regarding median BMI (25.3 vs 25.6 kg/m 2 ), median tumor size (12mm vs 13mm; 1 to 75mm), multifocal disease (39pts (10.2%) vs 34pts (10.8%)), receptor status and grading as well as use of sentinel node removal (340pts (89%) vs 271 (86%)). Intraoperative re-excisions due to frozen resection result or gut feeling of the surgeon differed significantly (145 (38%) in the IOFS vs 41 (13%) in the no-IOFS, p < 0.001) with no difference regarding detection of residual cancer in those specimens (65 (44.8%) vs 16 (39%),p = 0.66). The final pathology result reported a significantly higher rate of positive margins in the no-IOFS group versus the IOFS group (94pts (29.8%) vs 82pts (21.5%), p = 0.011). This could be confirmed in the univariate logistic regression model (OR 1.56, CI1.11-2.2, p = 0.011) and was even more pronounced in the full multivariable logistic regression model (OR 2.06, CI1.36-3.14, p < 0.001) as well as in the final model after backward stepwise model selection based on AIC (OR 2.05, CI1.38-3.09, p < 0.001). Other factors that significantly impacted positive margins in the multivariate regression model were the presence of additional DCIS (OR 2.27, CI1.42-3.67, p < 0.001), lobular cancer (OR 3.29, CI1.56-6.85, p < 0.001) and multifocal disease (OR 3.22, CI1.86-5.58, p < 0.001). Of 610 patients, who underwent sentinel node removal 55pts (16.2%) had a positive SLN in the IOFS and 36pts (13.3%) in the no-IOFS group, respectively (p = 0.2). Conclusions: The cut down on intraoperative frozen section in a tertiary center led to a significant short-term increase in positive margins resulting in 30% of patients in the final pathology report with a doubling in the likelihood when compared to the use of IOFS. This may result in major increase in direct as well as indirect re-operation costs and psychological distress of the patients. Further follow-up is needed to analyze long-term effects of omitting IOFS on oncological outcomes.

BACKGROUND:Alemtuzumab is an induction immunosuppressive agent effective in preventing hyperacute rejection; however, it can result in prolonged lymphocyte depletion. Here we assessed the dosing, tolerability, and outcomes with alemtuzumab induction via IV vs. SQ route in pediatric kidney transplantation. METHODS:A multicenter analysis of 119 patients < 21 years old who received alemtuzumab induction immunosuppression. Total dose (mg) and dose by body weight (mg/kg) were assessed. Tolerability was defined by the development of leukopenia (WBC < 3.0 × 103/uL) or neutropenia (ANC < 1.5 × 103/uL). Outcomes in the first year post-transplant were defined by eGFR, hospitalizations, infections, development of de novo DSA, and rejection. RESULTS:A total of 83 and 36 recipients received alemtuzumab IV and SQ, respectively. SQ group was slightly older, 14.0 y. (SD 5.5) vs. 11.9 y. (SD 6.1) (p = 0.07), and had more highly sensitized recipients, 14 (38.9%) vs. 10 (12.1%) (p = 0.002). Total dose and dose by weight were higher in the SQ group, 22.3 mg (SD 8.9) vs. 14.9 mg (SD 9.5), and 0.57 mg/kg (SD 0.21) vs. 0.36 mg/kg (SD 0.18 mg), respectively (p = 0.0001 and p < 0.0001). SQ group experienced more leukopenia and resultant medication dose reduction; however, there were no differences between the groups in eGFR, infections, hospitalizations, and rejection in the year following transplant. CONCLUSION:Despite the higher dose of alemtuzumab and rates of leukopenia in the SQ group, there were no other differences in tolerability and outcomes compared to IV alemtuzumab. Overall, alemtuzumab is well tolerated during the first year post-transplant as an induction immunosuppression agent in the pediatric population.

Background: The synthetic lipopeptide tecemotide (liposomal BLP25, Stimuvax®) is an investigational cancer vaccine designed to induce a cellular immune response to cancer cells that express the glycoprotein MUC1. Aberrant MUC1 is widely over-expressed in malignancies such as lung, breast, and colorectal cancer. The aim of the prospective randomized two-arm multicenter phase-II ABCSG 34 trial was to investigate the efficacy and safety of tecemotide in 400 patients with early BC when given concomitantly with neoadjuvant systemic Standard-of-Care (SoC) chemotherapy or neo-endocrine therapy. The study was accompanied by an extensive translational program which included immune response parameters such as MUC1 and PD-L1 expression, TILs, monocyte and ctDNA. Patients and Methods: 400 patients with HER2- early BC were randomized 1:1 to receive neo-adjuvant SoC systemic therapy with or without 12 concomitant tecemotide vaccinations. Postmenopausal women with luminal A tumors received letrozole 2.5mg od for 24 weeks as SoC. TNBC patients and patients with luminal B tumors, in whom chemotherapy was considered to be SoC, received 4 x epirubicin/cyclophosphamide and 4 x docetaxel q3w. MUC1 protein expression on tumor cells was analyzed by immunohistochemistry. Invasive disease-free survival (IDFS), distant recurrence free survival (DRFS) and overall survival (OS) were analyzed with Cox regression models. Results: Seven years after surgery, follow-up (FU) data were collected retrospectively and available for 289 women. Of these, 236 had received chemotherapy, while 53 had received neo-endocrine letrozole. 141 had been randomized to receive concomitant tecemotide, while 148 had been randomized to SoC only. Patient and tumor characteristics in the FU group were highly representative of the overall study population, and clinical-pathological characteristics in the two randomization arms were well balanced. After a 7 year FU, patients who had received SoC + tecemotide had an IDFS of 69.1% vs 60.5% in the SoC alone group (HR 0.75, 95% CI 0.51–1.10, p=0.141). DRFS of patients who had received SoC + tecemotide was 80.8% vs 64.7% (HR 0.53, 95% CI 0.34-0.83, p=0.005); OS in the SoC + tecemotide was 83.0% vs 68.2% (HR for OS 0.53, 95% CI 0.33-0.85, p=0.008). Participants who had received chemotherapy + tecemotide had a particularly favorable outcome with an IDFS of 71.3% vs 59.8% (HR 0.69, 95% CI 0.45–1.05, p=0.084), a DRFS of 81.9% vs 65.0% (HR 0.50, 95% CI 0.31–0.83, p=0.007), and an OS of 83.6% vs 67.8% (HR 0.51, 95% CI 0.30–0.88, p=0.016). Sensitivity analysis adjusting for T-stage, Nodal status, KI67, cancer type, and age at randomization were consistent with the primary results and confirmed the robustness of the analysis. MUC1 protein data were available for 278 pts at baseline and 199 pts at surgery. MUC1 was expressed in 97.9% of baseline samples and in 98.5% of the surgical samples in which pCR was not achieved. Expression was high (i.e. detected in >80% of tumor cells) in 72.1% and 74.5%, respectively. While MUC1 expression levels were neither prognostic nor associated with pCR, tecemotide-treated patients with high MUC1 protein expression in their surgical sample showed a particularly good outcome with an improved IDFS (HR 0.57, 95% CI 0.34–0.98), DRFS (HR 0.38, 95% CI 0.20-0.72), and OS (HR 0.35, 0.17–0.71), when compared to SoC alone. Subgroup analysis and additional biomarker analyses will be presented at the meeting. Conclusions: Tecemotide, when given concomitantly with neoadjuvant SoC systemic therapy, profoundly improved IDFS, DRFS and OS in a follow-up analysis of this prospective Phase II trial. The improved long-term outcome was particularly evident in patients whose tumors expressed high levels of MUC1. While long-term outcome is an exploratory objective, this is the first study in which a therapeutic cancer vaccine has resulted in a statistically significant and substantial long-term survival benefit in breast cancer patients. Citation Format: Christian F. Singer, Dominik Hlauschek, Georg Pfeiler, Daniel Egle, Rupert Bartsch, Christoph Suppan, Angelika Pichler, Edgar Petru, Richard Greil, Margaretha Rudas, Michael Seifert, Gregor Huber, Andreas Petzer, Florian Fitzal, Zsuzsanna Bago-Horvath, Martin Filipits, Lidija Soelkner, Christian Fesl, Michael Gnant. Vaccination with MUC-1-targeting tecemotide improves Survival of patients receiving neo-adjuvant chemotherapy for early breast cancer: Results from the Prospective Randomized ABCSG 34 Trial [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr PS3-03.

510 Background: Carboplatin-based regimen are effective in patients (pts) with eTNBC, and olaparib improves the outcome of pts with BRCA1/2 pathogenic variants (PV), but the safety / efficacy of OC co-treatment in HRD-positive TNBC is unknown. ABCSG 45 (EU CT 2024-512821-10) is a prospective multicenter phase II study investigating the efficacy and tolerability of OC compared to conventional chemotherapy in HRD-positive eTNBC. Methods: Pts with HRD (Myriad genetics)-positive eTNBC were randomized to 6 cycles of olaparib (100 mg bid, days 4-16) / carboplatin (AUC 5) q3w, or 6 cycles of docetaxel/epirubicin/cyclophosphamide (75/50/500) q3w (TAC). In an initial dose-finding phase, 100 mg bid was identified as olaparib combination dose. Stratification factors were tumoral BRCA1/2 and menopausal status. Primary endpoint was centrally assessed residual cancer burden (RCB), pCR and QoL were secondary endpoints. Planned sample size was 90 pts, randomized 1:1 to achieve 80% power (two-sided alpha=0.05) to detect a RCB 0/I difference of 31%. Differences between treatment arms were assessed with a two-sided Cochran Mantel-Haenszel test using stratification factors. Pre-defined subgroup analysis was performed with logistic regression. Results: A total of 90 pts (OC: n=46; TAC: n=44), of whom 42 (47%) were BRCA1/2 PV carriers, were randomized between November 2019 and December 2023. Median age was 50.5 years (range 27.0-80.0). 40% had cT1, 55.6% cT2, and 4.4% cT3/4 tumors, and 60% of pts were clinically N0. 94.4% of tumors were G3, and Ki67 was >60% in 71.1%. Overall, the RCB0/I rate with OC was 52.2% vs. 70.5% with TAC (stratified risk difference = -18.8% (95%CI: -39.6% to 2.0%); p=0.068). In pts with BRCA1/2 PV, RCB0/I rates were comparable: 77.3% (OC) vs. 65.0% (TAC), while in 47 pts with BRCA1/2 wild type (WT), OC was significantly less effective: RCB0/I of 29.2% vs 73.9% in TAC (interaction p=0.008). pCR was achieved in 47.8% (OC) vs 59.1% (TAC; p=0.231). In pts with a BRCA1/2 PV, OC resulted in 77.3% pCR rate, vs. TAC 65.0%, in BRCA1/2 WT pts pCR was achieved by 20.8% (OC) vs. 56.5% (TAC) (interaction p=0.021). OC treatment resulted in more ≥ grade 3 hematologic toxicities with 30% vs 3% thrombocytopenia and 43% vs 18% neutropenia but caused fewer non-hematological toxicities. Conclusions: In this prospective randomized study in HRD-positive TNBC, 6 cycles of TAC resulted in strikingly high RCB0/I and pCR rates, independent of BRCA1/2 status. 6 cycles of OC achieved a pCR rate of >77% in BRCA1/2 PV but were less effective in pts with BRCA1/2 WT disease. These results may help to optimize neoadjuvant treatment strategies in TNBC. This research was conducted with support from AstraZeneca Austria GmbH. Clinical trial information: 2024-512821-10 .

Introduction: Early life stress (ELS), including child abuse and neglect, household dysfunction, poverty, or exposure to violence or trauma, has been associated with increased risk of hypertension and cardiovascular disease in adulthood. However, the impact of ELS on cardiovascular outcomes, particularly vascular dysfunction and hypertension, remains understudied in adolescence – a key age window near the time of ELS exposure that is usually free of comorbidities. Hypothesis: We tested the hypothesis that ELS is associated with surrogates of future cardiovascular disease in adolescents: vascular dysfunction and abnormal ambulatory blood pressure (BP). Methods: This was an interim analysis of a prospective cross-sectional study in 141 adolescents (ages 13–18) recruited from outpatient clinics at Children’s of Alabama. ELS was assessed using the Adverse Childhood Experiences (ACEs) survey and categorized as ACE = 0 or ACE ≥ 1. The primary outcome was vascular stiffness, assessed by aortic augmentation index. Secondary outcomes were carotid-femoral pulse wave velocity and analysis, clinic BP, and ambulatory BP patterns. Group differences were analyzed using independent t-tests or Mann-Whitney U tests, based on non-normal distribution of the outcomes. Results: Adolescents with ACE ≥1 displayed a trend toward higher central diastolic BP (74 ± 11 vs. 70 ± 8 mmHg; p=0.07), daytime diastolic BP (73 mmHg ± 8 vs. 70 ± 6; p =0.06), and 24-hour mean diastolic BP (68 ± 8 vs. 66 ± 5 mmHg; p=0.07). Nighttime diastolic BP was significantly higher in the ACE ≥1 group (61 ± 8 vs. 57 ± 6 mmHg; p < 0.05). No significant differences were observed in vascular stiffness or other ambulatory BP patterns. Conclusions: ELS was associated with elevated diastolic BP in adolescents, indicating a potential long-term impact on cardiovascular health during critical developmental years. Future research should investigate the mechanisms through which ELS influences BP regulation. Additionally, studies should identify potential mediators that could help mitigate its effects during adolescence, a critical age window for preventive measures to reduce future cardiovascular risk.

Introduction: Neoadjuvant chemotherapy (NACT) is an established form of therapy for early breast cancer (BC). The aim of our study was to analyze histopathological parameters before and after receiving NACT and to determine the influence of these changes on prognosis of BC patients. Material and methods: We retrospectively analyzed data of patients with primary early BC, diagnosed between January 2012 and December 2019, and NACT, followed by primary surgery. Patients achieving pathological complete response (pCR) were excluded. For the outcome analysis, disease-free survival (DFS) and overall survival (OS) were defined. Results: A total of 237 tumors were analyzed in the study. The conversion rates of tumor grade, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), Ki67 status, and BC subtype were 34.6 %, 3.4 %, 14.3 %, 4.6 %, 30.0 %, and 28.7 %, respectively. After a median follow-up of 58.03 months, we found an association between consistently negative ER/PR with the worst prognosis (DFS and OS) (ER p < 0.0001 for both; PR p = 0.0003, p = 0.0004, respectively). The conversion from Ki67 ≥14 % to <14 % led to an improved outcome compared to a constant Ki67 ≥14 % (DFS p = 0.003, OS p = 0.001). Tumor residuals with a non-triple-negative (nTN) subtype (TN → nTN) showed a better prognosis than those with TN subtype (nTN → TN) (DFS and OS p < 0.0001). Conclusions: After NACT, tumor grade and Ki67 showed the highest conversion rates between primary biopsy and tumor residual. Depending on changes in ER, PR, Ki67, and subtype, we found significant differences in the prognosis of the patients.

1502 Background: Genetic counseling is an essential part of germline genetic testing, which is reccomended for use of PARP inhibitors in breast cancer treatment. Despite its importance, only about 40-60% of breast cancer patients receive genetic counseling. A video tool has been developed to provide genetic counseling, aiming to reduce the physician's workload and improve the patient's understanding. Methods: Advice seekers at increased risk for hereditary breast and ovarian cancer as well as breast and ovarian cancer patients were included in the trial. They were randomly assigned 1:1 to either standard of care (physician only, PO) or video based followed by physician genetic counseling (VPO). A 15-minute video tool was created for VPO participants, who watched it on an iPad and answered 6 comprehension questions online. The physician then clarified any misunderstood topics. In both groups, counseling time was measured from conversation start to blood donation. Afterwards, participants completed a questionnaire with 9 comprehension questions (16 points total). Data analysis included Bernard’s and Pearson’s tests for categorical data, Kendall’s test for correlations, and ordinal logistic regression for multivariable analysis. Results: A total of 110 participants with a median age of 47 years were randomized into two groups: PO counseling (55 participants, 50%) and VPO counseling (55 participants, 50%). Among them, 29% (32 participants) received therapeutic counseling for breast/ovarian cancer, while 71% (78 participants) received predictive counseling with no cancer diagnosis. Participant characteristics were well balanced between groups, with no significant differences in age, indication for counseling, sex (90% female), level of education, or German-speaking proficiency. Participants reported their sources of genetics knowledge as previous knowledge (30%) and physician counseling (70%) in the PO group, and as previous knowledge (20%), physician counseling (30%), and the video tool (45%) in the VPO group. The video significantly improved comprehension scores from 62.5% (10 points, PO group) to 81.3% (13 points,VPO group) (p < 0.0001). Additionally, the video tool significantly reduced the time physicians spent on counseling from 6.6 minutes to 2.4 minutes (p < 0.0001). According to the logistic regression model, both the level of education (estimate -1.34, p = 0.002) and German language comprehension level (estimate 1.62, p = 0.001) significantly influenced the genetic counseling comprehension score. Conclusions: In this prospective randomized trial, video genetic counseling improved comprehension and reduced physician counseling time. The genetic video tool, which can be translated into various languages, facilitates genetic counseling by decreasing the workload for physicians, which may increase the genetic counseling rate in the clinic.

Early life stress (ELS) is a widespread but understudied risk factor for cardiovascular disease. ELS is defined as adverse experiences occurring before age 18, such as exposure to family poverty, neighborhood disadvantage, and violence. Low socioeconomic status and parent education are known to be associated with reduced nighttime blood pressure dipping; a natural decrease in blood pressure that occurs during sleep, and a known risk factor for cardiovascular disease. However, less is known about ELS more broadly defined in relation to ambulatory and nighttime blood pressure. In the current study, it is hypothesized that higher early life stress is associated with reduced nighttime blood pressure dipping in adulthood. We utilized the Healthy Passages cohort to understand the relationships between ELS and nighttime blood pressure. A composite ELS score was created by summing the following childhood conditions: neighborhood poverty > 1 standard deviation at age 11 (0-1), number of time points when family income fell below federal poverty level at ages 11, 13, and 16 (0-3), number of time points youth reported witnessing violence at ages 11, 13, 16, and 19 (0-4), and number of time points youth reported any victimization by violence at ages 11, 13, 16, and 19 (0-4). Participants returned to complete ambulatory blood pressure monitoring (ABPM) as young adults (n=401; M age 29; range = 27-34 years). The mean composite ELS score was 3.7 (SD=2.8). After controlling for sociodemographics and body mass index, linear regressions revealed that greater composite ELS was linked to lower nighttime dipping in diastolic blood pressure (b = -0.58; SE = 0.25; p = .02) and lower mean arterial pressure (b = -0.65; SE = 0.28; p = .02) but not systolic blood pressure. There were no significant effects of composite ELS on the overall mean arterial pressure, systolic blood pressure, or diastolic blood pressure. While further research is needed, these results have important implications for clinical settings, where healthcare providers should prioritize comprehensive care for adults with a history of early life stress, ensuring regular monitoring and tailored interventions to mitigate cardiovascular risks.

Background Recent studies indicate that up to 36% of pediatric and adult kidney transplant recipients with stable serum creatinine levels will have acute rejection detected on surveillance biopsy. The purpose of this study was to develop and validate a risk algorithm for identifying low- and high-risk patients using a novel automated platform that simultaneously measures urinary C-C motif ligand 2 (CCL2), CXC-motif chemokine 9 (CXCL9), CXC-motif chemokine 10 (CXCL10), and vascular endothelial growth factor A (VEGF-A) with high precision. Methods We designed a multicenter observational study to evaluate the performance of urinary CCL2, CXCL9, CXCL10, and VEGF-A in a training set of 517 banked samples collected at the time of surveillance or indication kidney biopsies from both adult and pediatric recipients. Risk algorithms combining all four analytes were developed in the training set and subsequently validated in three laboratory sites in two additional pediatric cohorts (N=174). Results The automated platform had remarkably high throughput, generating reproducible results in 60-70 minutes. Analysis was initially performed in the training set (N=517), which included biopsies read as normal (N=330), acute rejection (N=92), or borderline rejection (N=95). We found that each biomarker independently discriminated normal biopsies versus those with acute rejection (P < 10-5). A risk algorithm using all four biomarkers (score4) had excellent diagnostic performance for acute rejection in both for-cause and surveillance biopsies performed on patients with stable GFRs, outperforming any individual biomarker as well as estimated GFR assessments. Validation assays performed in the two additional pediatric cohorts in three laboratory sites demonstrated a robust correlation of results; score4 retained excellent diagnostic performance (75% specificity and 92% negative predictive value). Conclusions Automated measurements of urine CCL2, CXCL9, CXCL10, and VEGF-A can distinguish kidney transplant recipients at low versus high risk of rejection. We suggest that this assay can advantage clinical decision making in routine post-transplant monitoring because of its low cost, rapid throughput, and operator independence.

BACKGROUND Incomplete resolution of T cell-mediated rejection (TCMR) after treatment may not be detected with serum creatinine monitoring and is associated with donor-specific antibodies and chronic rejection. We evaluate the utility of follow-up biopsies (FUB) to identify and characterize rates of persistent TCMR after treatment in pediatric kidney transplant patients. METHODS Patients from two pediatric transplant centers performing standard of care FUB at 1.5-2 months after treatment for TCMR were included. FUB were evaluated for extent of rejection resolution (complete vs. incomplete) and grade. Clinical data at time of FUB and later were reported, where available. RESULTS Fifty-eight patients underwent FUB, at mean of 1.7 months (SD 0.7) post-index biopsy. Rejection grade on index biopsy was Banff borderline (≥i1t1 and <i2t2) in 59% and Banff ≥1A (≥i2t2) in 41%. Acute rejection was persistent in 32 (55%) of FUB. Borderline rejection had higher rates of complete resolution of rejection compared to grade ≥1A (53% vs. 33%, p = .033). Incomplete resolution of rejection on FUB was re-treated in 25 (78%) of cases. Change in eGFR from index to FUB did not differ between those with complete and incomplete resolution (5.7 ± 32.2 vs. 13.1 ± 51.3, p = .28) and was not a sensitive marker of identifying persistent rejection. CONCLUSIONS FUB were effective at detecting persistent rejection, which was common among pediatric transplant patients after standard TCMR treatment. Until more effective rejection treatments or sensitive biomarkers are available, FUB may be effectively utilized to identify patients with ongoing rejection who would benefit from further treatment.

BACKGROUND:BK polyomavirus (BKV) can cause permanent loss of allograft function due to BKV-associated nephropathy (BKVN) in kidney transplant recipients. Besides immunosuppression reduction, there are no consistently effective interventions for BKV infection. Study purpose was to define natural history of BKV infection, identify risk factors for BKV reactivation and BKVN in kidney transplant recipients, and inform the design/conduct of future clinical trials of BKV-targeted therapeutics. METHODS:We conducted a multicenter prospective observational study of incident kidney transplant recipients at six U.S. transplant centers. Participants were monitored every 4 weeks for BKV reactivation and followed for up to 24 months post-transplant. We used regression models (logistic, survival, mixed models) to study relationships between BK viremia/BKVN, clinical characteristics, and allograft function. RESULTS:We enrolled 335 participants. Fifty-eight (17%) developed BK viremia, 6 (2%) developed biopsy-proven BKVN, and 29 (9%) developed suspected/presumed BKVN (defined as BKV viral load > 10,000 copies/mL without biopsy). Male donor sex was associated with lower odds for BK viremia, whereas recipient Black race was associated with two-fold increased odds for BK viremia. Recipient female sex was associated with more rapid clearance of BK viremia. Persistent BK viremia/BKVN was associated with poorer allograft function by 24 months post-transplant. CONCLUSIONS:We identified multiple donor and recipient demographic factors associated with risk for BKV infection and poorer allograft function by 24 months post-transplant. This may help design future clinical trials of therapies to prevent or mitigate the deleterious impact of BKV reactivation on kidney transplant outcomes.

INTRODUCTION:The successes in the field of pediatric kidney transplantation over the past 60 years have been extraordinary. Year over year, there have been significant improvements in short-term graft survival. However, improvements in longer-term outcomes have been much less apparent. One important contributor has been the phenomenon of low-level rejection in the absence of clinical manifestations-so-called subclinical rejection (SCR). METHODS:Traditionally, rejection has been diagnosed by changes in clinical parameters, including but not limited to serum creatinine and proteinuria. This review examines the shortcomings of this approach, the effects of SCR on kidney allograft outcome, the benefits and drawbacks of surveillance biopsies to identify SCR, and new urine and blood biomarkers that define the presence or absence of SCR. RESULTS:Serum creatinine is an unreliable index of SCR. Surveillance biopsies are the method most utilized to detect SCR. However, these have significant drawbacks. New biomarkers show promise. These biomarkers include blood gene expression profiles and donor derived-cell free DNA; urine gene expression profiles; urinary cytokines, chemokines, and metabolomics; and other promising blood and urine tests. CONCLUSION:Specific emphasis is placed on studies carried out in pediatric kidney transplant recipients. TRIAL REGISTRATION:ClinicalTrials.gov: NCT03719339.

Background:Focal segmental glomerulosclerosis (FSGS) is a common cause of end-stage kidney disease requiring kidney transplantation and can recur in the allograft in 30-80% of recipients resulting in reduced graft survival. Plasmapheresis has shown efficacy in treating some cases of recurrent FSGS but isolated plasmapheresis has not demonstrated efficacy in preventing recurrent FSGS. Rituximab has had anecdotal success in preventing recurrence in a single center study but has not been studied in combination with plasmapheresis for preventing FSGS recurrence.Methods:We are conducting a randomized, controlled, multicenter clinical trial of adult and pediatric kidney transplant recipients with primary FSGS to assess whether plasmapheresis in combination with rituximab prevents recurrent disease post-transplantation.Discussion:Rituximab combined with plasmapheresis is a promising, novel therapy to prevent recurrent FSGS, a disease with limited therapeutic options and no consensus guidelines for prevention or treatment.Clinical trial registration:https://clinicaltrials.gov/ct2/show/NCT03763643, identifier NCT03763643.

Predicting long-term kidney allograft failure is an unmet need for clinical care and clinical trial optimization in children. We aimed to validate a kidney allograft failure risk prediction system in a large international cohort of pediatric kidney transplant recipients. Patients from 20 centers in Europe and the United States, transplanted between 2004 and 2017, were included. Allograft assessment included estimated glomerular filtration rate, urine protein-to-creatinine ratio, circulating antihuman leukocyte antigen donor-specific antibody, and kidney allograft histology. Individual predictions of allograft failure were calculated using the integrative box (iBox) system. Prediction performances were assessed using discrimination and calibration. The allograft evaluations were performed in 706 kidney transplant recipients at a median time of 9.1 (interquartile range, 3.3-19.2) months posttransplant; mean estimated glomerular filtration rate was 68.7 ± 28.1 mL/min/1.73 m2, and median urine protein-to-creatinine ratio was 0.1 (0.0-0.4) g/g, and 134 (19.0%) patients had antihuman leukocyte antigen donor-specific antibodies. The iBox exhibited accurate calibration and discrimination for predicting the outcomes up to 10 years after evaluation, with a C-index of 0.81 (95% confidence interval, 0.75-0.87). This study confirms the generalizability of the iBox to predict long-term kidney allograft failure in children, with performances similar to those reported in adults. These results support the use of the iBox to improve patient monitoring and facilitate clinical trials in children.