Donor Workup Research Articles

How to do it: Living donor liver transplantation

Use of living donor has expanded the pool of potential transplant recipients. We have outlined here the indications, contraindications, donor workup and surgical technique of modified right liver graft retrieval, recipient hepatectomy, benching and recipient implantation in brief.

24: Deceased Donor Adipose Tissue: An Untapped Source of Mesenchymal Stem Cells

Purpose: Adipose tissue from living donors is a widely accepted source of mesenchymal stem cells. Adipose tissue can also be procured from deceased donors in high volumes and routinely during the deceased donor workup. Materials: Adipose tissue was excised from the abdomen of research-consented deceased donors. Sections of the adipose tissue were mechanically minced and washed with saline. The mixture was then filtered, centrifuged, and resuspended in wash buffer to represent the stromal vascular fraction (SVF). The SVF was tested for viability, total nucleated cell count (TNC), and the presence of mesenchymal stem cells (MSC). The functionality of the MSC was assessed by their growth potential and their capacity to differentiate using specific differentiation media. Results: We observed that the mean TNC/g of samples processed fell above the living donor value ranges. The mean %MSC/TNC value fell within the living donor value range (Table 1). Induction of adipocyte differentiation led to the morphological conversion of MSC to form lipid droplets, a characteristic of mature white adipocytes, accompanied by the expression of adipocyte differentiation genes. Similarly, differentiation of MSC into osteocytes and chondrocytes, when exposed to the respective differentiation media, was observed. Differentiation specific gene expression was also confirmed. In all cases, the undifferentiated cells did not exhibit any changes either at the morphological or gene expression level (Figure 1). Conclusion: The deceased donor stem cells can be routinely procured and potentially supplement the current available living donor stem cells sources. We have established that deceased donor adipose-derived MSC are similar to living donor adipose-derived MSC and can differentiate to adipocytes, osteocytes, and chondrocytes. Figure 1. Differentiation of MSC isolated from non-enzyme treated SVF. Light microscopic images are representative of three separate experiments. (A) Adipocyte differentiation. (C) Osteocyte differentiation. (E) Chondrocyte differentiation. (B,D,F) Semi-quantitative qRT-PCR analysis of lineage-specific gene expression.

Reliability of computed tomography-based renal cortex volume to determine split renal function in preoperative living kidney donors.

Objective:The purpose of this study was to assess the utility of CT-based renal cortex volume to estimate split renal function (SRF) in pre-transplant living kidney donors and to evaluate its reliability to predict graft function in the recipients.Methods:Our study recruited all adult potential donors who had both Tc-99m-diethylenetriamine pentacetate (DTPA) scintigraphy and CT angiography of the abdominal aorta done before donating their kidney. We compared the correlation between CT-based renal cortex volume combined with kidney function and DTPA scan as well as post-donation kidney function in the recipients.Results:The correlation between CT-based split cortex volume and DTPA-measured SRF before transplantation was strong (intraclass correlation coefficient = 0.954–0.968). The inter-rater reliability of two radiologists also showed substantial agreement (intraclass correlation coefficient = 0.97, p < 0.001). In contrast, the correlations between renal cortical volume of donated kidney adjusted to recipient body weight and recipient kidney function was poor at both 2 week and 2 year follow-up.Conclusion:CT-based renal cortex volume combined with pre-operative kidney function appears to be precise and reproducible to evaluate pre-transplant SRF. Nevertheless, the prediction of recipient graft function needs to be further investigated to ensure a good outcome.Advances in knowledge:This method is practicable for all potential donors who undergo kidney transplantation in terms of streamline donor workup without compromising information.

Why do not all living kidney donor candidates proceed to donation?

There are national and international guidelines for donor workup and acceptance criteria of potential living kidney donor candidates (LKDC), but there is significant variation in clinical practice. We examined our local practice in assessing potential LKDC against current guidelines; nearly all of our accepted donors met these guidelines. LKDC who did not proceed to donation had an identified health issue (60%), the presence of risk factors for long-term end-stage kidney disease (17%), social (13%) or immunological reasons (7%).

A Pilot Study: Identification and Reduction of Barriers for Unrelated Allogeneic Hematopoietic Stem Cell Transplantation in Patients with High-Risk Hematologic Malignancies

The timeliness to Hematopoietic Stem Cell Transplant (HSCT) as a potential curative treatment for patients with high-risk hematologic malignancies such as acute leukemias, refractory disease, progressive disease, or other poor prognostic disease specific indications has been well established [3]. Timing is crucial from date of diagnosis, initiation of induction therapy, donor identification and transplantation. Any delay can provoke unfavorable patient outcomes and reinforces the critical need to reduce barriers for timeline to transplant [1]. Unrelated allogeneic HSCT pose greater risks due to the complexity of donor barriers versus match/mismatched related donor transplants [1]. Key factors resulting in delayed unrelated donor transplantation include; poor donor match probabilities – lack of ethnic minority populations or patients with rare allelic haplotype associations, low resolution Human Leukocyte Antigen (HLA) typing in donor registry, limited donor availability, lack of donor health history information, unknown infectious disease markers results, etc. [4]. Other potential areas for significant delay include time requirements for allele level HLA resolution, final donor selection and donor workup process. Given the high-risk patient population, identified existing donor barriers and finite window of opportunity for favorable HSCT outcomes; our center proposed a pilot study in conjunction with the National Marrow Donor Program (NMDP) to reduce barriers for rapid donor identification, selection and workup. The main objective of the proposed study was to identify and select a workup ready unrelated donor within 14 days of search initiation. Selected high-risk patients were enrolled in the pilot program from September 2016 through March 2018 (N = 25). Throughout the pilot study our center was able to identify areas of process improvement within our collective transplant program. Process improvements were also established in collaboration with the NMDP and their respective donor centers and collection centers. Following the completion of the study, we retrospectively analyzed our center's transplant data from 2017 and compared the time to transplant for pilot study patients (n = 15) versus all primary unrelated donor transplants (n = 100) performed, with the exclusion of cord blood unit transplants. We were able to obtain donor confirmatory typing appointments with a median of 7 days from formal search initiation. We were also able to reduce the median days for formal search to workup for the pilot study donors to 28 days versus 56 days, and the median days for formal search to donor collection to 35 days versus 97 days. Although we did not meet our proposed primary objective of 14 days, our center was able to successfully reduce the time needed to identify, select, and collect an unrelated donor for transplantation using the expedited process.

Can Split Renal Volume Assessment by Computed Tomography Replace Nuclear Split Renal Function in Living Kidney Donor Evaluations? A Systematic Review and Meta-Analysis.

Background:As part of their living kidney donor assessment, all living donor candidates complete a computed tomography (CT) angiogram, but some also receive a nuclear renogram for split renal function (SRF%).Objective:We considered whether split renal volume (SRV%) assessed by CT can predict SRF%.Design:Systematic review and meta-analysis.Setting:Living donor candidates undergoing evaluation as potential living kidney donors.Patients:Living donor candidates who received both a nuclear renogram for split function and CT for SRV as part of their living donor work-up.Measurements:Split renal volume from CT scans and SRF from nuclear renography.Methods:We performed a systematic review and meta-analysis of the literature, abstracting data and digitizing plots where possible. We searched Medline, EMBASE, and the Cochrane Library. We added data from donor candidates assessed in London, Ontario from 2013 to 2016. We used fixed and random-effects models to pool Fisher’s z-transformed Pearson’s correlation coefficient (r). We conducted random-effects meta-regression on digitized and aggregate data. Studies were restricted to living kidney donors or living donor candidates.Results:After pooling 19 studies (n = 1479), we obtained a pooled correlation of r = 0.74 (95% confidence interval [CI] = 0.61-0.82). By linear regression using individual-level data, we observed a 0.76% (95% CI = 0.71-0.81) increase in SRF% for every 1% increase in SRV%. Split renal volume had a specificity of 88% for discriminating SRF at a threshold that could influence the decision of which kidney is to be removed (between-kidney difference ≥10%). Predonation SRV and SRF both moderately predicted kidney function 6 to 12 months after donation: r = 0.75 for SRV and r = 0.73 for SRF; Δr = 0.05 (–0.02, 0.13).Limitations:Most studies were retrospective and measured SRV and SRF only on selected living donor candidates. Efficiency gains in removing the SRF from the evaluation will depend on the transplant program.Conclusion:Split renal volume has the potential to replace SRF for some candidates. However, it is uncertain whether it can do so reliably and routinely across different transplant centers. The impact on clinical decision-making needs to be assessed in well-designed prospective studies.Trial registration:The digitized data are registered with Mendeley Data (doi10.17632/dyn2bfgxxj.2).

Visceral obesity in Asian living kidney donors significantly impacts early renal function after donor nephrectomy.

Obesity may be a risk factor for kidney donors to develop reduced renal function. The Framingham heart study suggested that visceral adipose tissue (VAT) confers a more adverse metabolic profile compared with subcutaneous adipose tissue (SAT). Asians tend to have a higher VAT composition and it is unclear if their kidney function is affected differently. We hypothesized that Asian living kidney donors who have visceral obesity are at a higher risk of renal function deterioration 1year after donation. Between 2011 and 2014, we retrospectively evaluated data from 73 consecutive patients (52% male; mean age 44.9 ± 11.7years) before they underwent donor nephrectomy and at their 1year routine follow-up. VAT and SAT were measured at the level of the umbilicus on pre-operative computerized tomography (CT). Visceral obesity (VO) was defined as a VAT > 100cm [2] and patients were then further divided and compared in two subgroups: VAT > 100 and < 100cm [2]. Estimated glomerular filtration rate (eGFR, mL/min per 1.73m [2]) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation pre-operatively and 1year post-operatively. Both subgroups had similar baseline kidney function (P = NS) pre-operatively. At the 1year follow-up, patients with VO experienced a more significant decline of renal function (109 ± 9 to 89 ± 8mL/min per 1.73m2), compared to those without VO (111 ± 12 to 96 ± 11mL/min per 1.73m2, P = 0.013). VO was associated with a body mass index (BMI) > 25kg/m2 (P < 0.001), male gender (P < 0.001) and older age at the time of donor nephrectomy (48.0 vs 39.5years, P = 0.01). The presence of hypertension or hyperlipidaemia pre-operatively, choice of surgical approach, and post-operative complication rates, did not differ significantly between the subgroups. Visceral obesity as defined by VAT > 100cm2 at the level of the umbilicus on cross-sectional imaging, may have a significant impact on early renal function after donor nephrectomy. Adiposity markers, as measured by cross-sectional CT imaging, may be incorporated into routine pre-operative kidney donor workup.

P099 Comparison of ssop versus ngs for typing of HLA-A, B, C, DRB1, DRB3/B4/B5, DQA1, DQB1, DPA1, DPB1: Toward single pass high resolution hla typing in support of solid organ and hematopoietic cell transplant programs

Aim Many laboratories use a 2-tier HLA typing process: a first pass intermediate resolution and then high resolution, when clinically necessary. SSP or qPCR provide rapid typing for deceased donor workup; SSOP is widely employed for higher volumes; and Sanger sequencing has been the gold standard for high resolution. However, SSOP and Sanger SBT often yield ambiguous results and resolution is expensive and time consuming. Next generation sequencing offers a single pass technology to achieve unambiguous HLA allele assignments. We compared commercial SSOP and NGS systems with respect to accuracy, turnaround time, effort and resolution level. Methods Five laboratories submitted coded, blinded samples, previously typed by SSOP at each institute, to a separate lab for NGS of HLA-A, B, C at exons 1–7, DRB1, DRB3/4/5, DQA1, DQB1, DPB1 at exons 1–4, and DPA1 at exons 2–4. For up to 24 samples by SSOP or up to 48 samples by NGS, benchwork is completed by one technologist on day 1 with results available for reporting on day 2. Results At the SSOP resolution level, results were concordant except for 11 SSOP assignments in 8 specimens due to false probe reactions at DRB1, DRB5, DQA1, DQB1, and DPB1. NGS identified 21 novel sequences: one with a multi-exon deletion and 20 with SNP polymorphisms in HLA-C, DPA1, DPB1, DQA1, DRB1, DRB3, DRB4, and DRB5 alleles. Across the highly polymorphic HLA-A, B, C, DRB1 loci, only 1% of intermediate resolution, IR, SSOP results were unambiguous. Even higher resolution, HR, SSOP by 1 lab gave only 17% specific allele assignments. In contrast, over 99% of NGS results were specific unambiguous genotypes. Across all loci, NGS typing was specific except for certain discrete diploid ambiguities, also found in SSOP. Conclusions This study provides a compelling rationale for implementing NGS for single pass HLA analysis with accurate, 2 day turnaround, which includes the high resolution, unambiguous genotyping critical for unrelated donor HCT and that may be required for sensitized patients with allele specific antibodies. A.G. Smith: 2. Consultant; Company/Organization; Scisco Genetics Inc. S.E. Pereira: 4. Scientific/Medical Advisor; Company/Organization; Scisco Genetics Inc. C. Pyo: 4. Scientific/Medical Advisor; Company/Organization; Scisco Genetics Inc. W. Nelson: 5. Employee; Company/Organization; Scisco Genetics Inc. M. Bettinotti: 3. Speaker’s Bureau; Company/Organization; One Lambda ThermoFisher. M.Z. Askar: 3. Speaker’s Bureau; Company/Organization; Immucor. 4. Scientific/Medical Advisor; Company/Organization; Illumina. D.E. Geraghty: 6. Stock Shareholder; Company/Organization; Scisco Genetics Inc. Download : Download high-res image (283KB) Download : Download full-size image

Effect of Donor Age and Donor Relatedness on Time to Allogeneic Hematopoietic Cell Transplantation in Acute Leukemia

Relapse after allogeneic hematopoietic cell transplantation (HCT) for acute leukemia can be reduced when pursued early after first complete remission. The impact of donor age and donor relatedness on the time from diagnosis to transplant in patients with acute leukemia was examined to clarify the design of future prospective studies that can address optimal donor choice. Files of 100 consecutive patients undergoing transplantation for leukemia were reviewed. Recipients of related donors (RDs) and unrelated donors (UDs) were not significantly different in terms of recipient gender, age, underlying diagnosis, disease risk index, graft source, or donor HLA match. UDs were significantly younger than RDs (median age, 29 versus 51, P < .001). Multivariate linear regression revealed that when controlling for age of donor and recipient, the time from diagnosis to transplant was 35% longer with UDs compared with RDs (P = .018). No significant correlation was observed between donor and recipient age on length of time to transplant (P = .134 and P = .850, respectively), when controlling for other variables. The steps in UD procurement that contribute most to the longer time to transplant relate to activating the donor workup and scheduling the donor workup before cell collection. Understanding sources of delay in the transplant process will help transplant centers and UD registries reduce the time to transplant for patients with acute leukemia and will provide necessary insight for the design of prospective controlled studies that can address optimal donor choice.

Barriers to Living Kidney Donation

Renal transplantation is the best therapy to extend life expectancy and quality of life for patients with end-stage renal disease. As the waiting time of wait-listed patients for deceased donor kidney transplantation continues to increase, the need for living donor kidney transplants become more important. Despite a growing interest in investigating barriers to living kidney donation, published literature is limited. We investigated barriers that may influence access to live donor for kidney transplantations. A total of 472 potential living kidney donors have been assessed between 2007 and 2017 at Seoul National University Hospital. We retrospectively reviewed 288 potential donors who underwent living donor workup and were excluded as donors. In initial screening, potential donors were interviewed and evaluated to screen for any contraindications to kidney donation, including renal function, cross-match test and a history of cancer, heart disease, diabetes, hypertension or hereditary disease. In second evaluation, potential donors were assessed for radiological and psychological evaluation to decide on the candidacy of potential donor. The mean age of potential donors were 46 years old, and 48% of candidates were female. Eighty-one candidates (31%) were spouses of the recipient. The number of siblings, relatives and other living unrelated candidates were 62_(24%), 13_(5%), and 18_(7%), respectively. The recipients who had more than two potential candidates be assessed were 38_ (15%). The causes of inappropriateness for kidney donation were as follows- ; 157 cases were due to medical conditions, and 81 cases were due to disagreement kidney donation. One hundred ninety-one candidates (73%) did not pass the initial health screen; 68 had a positive cross-match (19 had a positive response on flow cytometric test, and 49 had a positive response on complement-dependent cytotoxicity assay), 41 had health problems that were contraindications to kidney donation, 6 cases were cancelled due to recipients’ renal cell carcinoma, 22 had the disagreement of family members, and 38 changed their will to donate. Sixty-nine candidates (27%) did not pass the 2nd evaluation; 20 had underlying medical disease, 9 had nephrolithiasis with high likelihood of recurrence, 7 had the late refusal of family members, 4 had changed their will to donate in the second step, and 4 had low glomerular filtration rate. Despite failure of living donation, 13 recipients received deceased donor kidney transplantation, while 200 recipients have been still on the wait-list. Elucidation of specific barriers to living donation including health-related and familial factors could contribute to more efficient processing of living donor selection.

1. Improving patient safety by performing comprehensive noncontrast MR screening in prospective living donor liver transplant (LDLT) surgery donors- looking beyond MRCP

Background and Aims: In a conventional prospective LDLT donor workup process, a noncontrast CT scan is performed first to exclude any significant liver steatosis followed by contrast enhanced CT angiography for volumetric and vascular assessment. Subsequently, MRCP is performed to assess biliary anatomy. However, a significant proportion of donors are rejected on the basis of CT assessment. We tried to minimize this undue CT exposure to potential LDLT donors by identifying majority of the factors responsible for rejection by performing a comprehensive non contrast MR as the first examination, evaluating for liver steatosis, volumetry, venous and biliary anatomy and overall abdominal evaluation. We aim to assess feasibility and impact of using non contrast enhanced MRI and MRCP as a screening tool in prospective LDLT donors in minimizing donor rejection rate after performing contrast enhanced CT scan. Methods: Donor MRI screening included liver parenchymal assessment for steatosis, assessment of biliary anatomy, liver volumetric assessment for calculating GRWR and remnant volume, assessment of portal venous anatomy on bright blood sequence, assessment of hepatic venous anatomy and the counting the number of inferior accessory hepatic veins and screening for any apparent intrahepatic or extrahepatic abnormality in upper abdomen. Results: We could minimize the numbers of rejected donors after CECT evaluation, thereby saving undue exposure of radiation and CT contrast to donor. Besides identifying donors to be rejected, screening MR could also suggest some form of presurgical management in a small cohort of patients with intrahepatic or extrahepatic abdominal pathology eg. borderline high liver fat content, incidentally detected abdominal lymphadenopathy etc. Conclusions: This resulted in considerable cost saving by reducing the number of unnecessary CT scans as well as reduction in numbers of liver biopsies since MR fat quantification has been proved to be more robust technique compared to CT fat quantification. The authors have none to declare.

Hepatobiliary Scintigraphy in the Preoperative Evaluation of Potential Living Liver Donors

BackgroundGraft selection strategy in living donor liver transplantation (LDLT) is usually multifactorial, but special attention is paid to the determination of donor liver volumes to minimize any risk of posthepatectomy liver failure (PHLF). Hepatobiliary scintigraphy (HBS) with single-photon-emission computed tomography allows for the measurement of total and future liver remnant function (FLR-F) and has been shown to predict the risk of PHLF more accurately than liver volumetry. MethodsSince November 2016, HBS has been performed at our Institution in every candidate to major hepatectomy, including potential living liver donors. ResultsThirty-seven consecutive patients were submitted to HBS, of whom 7 were potential living liver donors. After completed hepatectomy (n = 27), the median FLR-F of patients who developed PHLF (n = 9) was 1.72%/min/m2 (range 1.40–2.78) compared to that of patients who did not (n = 18), which was 4.02%/min/m2 (range 1.15–12.08). Three donors underwent operations (1 right hepatectomy and 2 left hepatectomies). In the only donor who developed PHLF, the FLR accounted for the 37% of the total liver volume, whereas the FLR represented only the 31% of the total liver function (TL-F = 11.29%/min) with a resulting FLR-F of 2.05%/min/m2. ConclusionsThe present study suggests that a non-invasive low-cost exam such as HBS may be a promising tool to predict PHLF not only in neoplastic patients but also to evaluate potential living donors. Larger studies are needed to draw any conclusion regarding the benefits of HBS in the living liver donor workup.

Lung transplant: The Indian experience and suggested guidelines – Part 1 selection of the donor and recipient

Background: The selection of the correct donor lung is crucial for a successful lung transplant. Since the median survival after lung transplant is 5 years and the morbidity and mortality of lung transplant is higher than other transplants, it is crucial to preselect the correct recipient. Methodology: In India, Dr. P. Venugopal at the All India Institute of Medical Sciences, New Delhi, performed the first successful heart transplant, while Dr. K. M. Cherian performed the first heart–lung transplant at Chennai. At Apollo Hopsitals, Chennai, the first heart transplant was performed by Dr. M. R. Girinath. Subsequently, the Department of Heart and Lung Transplantation at Apollo Hospitals, Chennai, have performed a large number of heart and lung transplants and its experience is summarized. Results: The Department of Heart and Lung Transplantation at Apollo Hospitals, Chennai, has done 101 lung and 62 heart transplants as part of their lung and heart lung transplant program. There were 21 heart–lung transplants and 25 double lung transplants. The results are discussed and indications, contraindications for lung and heart–lung transplant as well as recipient and donor workup are discussed in this first part of a set of three articles. Conclusions: Careful selection of a recipient and donor leads to a successful lung and heart–lung transplant program.

Risk of Exposure to Zika Virus and Impact on Cord Blood Banking and Adult Unrelated Donors in Hematopoietic Cell Transplantation: The Canadian Blood Services Experience

Zika virus has emerged as a potential threat to the Canadian blood supply system. Stem cell donors within Canadian Blood Services' Cord Blood Bank (CBB) and OneMatch Stem Cell and Marrow Network (OM) now undergo screening measures designed to reduce the risk of Zika virus transmission. The impact these screening measures have on cord blood and unrelated adult stem cell donations is currently unknown. Among 146 donor workups initiated by OM between July 2016 and May 2017, 102 were completed and 44 workups were canceled. There were 17 potential donors (11.6%) with a risk of Zika virus exposure identified by the donor questionnaire (13 completed, 4 canceled workups). None of the workups involved a donor diagnosed with confirmed Zika virus within the past 6 months. Only 1 of the 44 canceled workups (and only 1 of 4 cases with a risk of Zika transmission) was canceled because of the risk of Zika transmission, and a backup donor was selected. Canadian Blood Services' CBB identified 25 of 875 cord blood units (2.9%) from women who donated their infants' cord blood and underwent screening that otherwise met the initial cell number thresholds for banking and had at least 1 risk factor for exposure to Zika virus. No women were diagnosed with Zika virus at any point of their pregnancy. All 25 units were discarded. Unrelated donors at OM have a higher incidence of a risk of exposure to Zika virus compared with cord blood donors. Only rarely did transplant centers cancel donor workups due to potential Zika virus exposure. The impact of screening for Zika virus exposure risk on cord blood banking was minor. Continued vigilance and surveillance is recommended.

P163 Antibody identification and detection assays {Lab Screen Mixed (LSM), flow PRA screen, and Single Antigen Beads (SAB)}: Which one to believe?

Aim Negative SAB results in the context of positive LSM prevent accurate prediction of virtual crossmatch (XM) in the absence of sensitization history. The issue is particularly problematic in the event of unpredictable positive XM during a deceased donor workup. Unmissed HLA-antibody has to be excluded with certainty by other test. With different assays it may be difficult to choose the best combination. Here we describe the results of correlation between two antibody screening; LAB Screen Mixed using Luminex & FlowPRA Screen on conventional flowcytometry & compare their performance with LAB Screen SAB & XM. Methods 60 samples were tested by the two screening methods according to manufacturer instructions (One Lambda) & tested by SAB for Class I/Class II simultaneously. Sera demonstrated reactivity were crosmatched with surrogate cells bearing the corresponding antigens. Discrepant result was verified by flow specific beads. Results Table 1 summarized the correlation of the results for the three assays. The overall concordance for both screening methods was 72.5% (61.7 for Class I & 83.3 for Class II). In the discrepant results the SAB correlate better with the flow PRA screening. False positive screening was reported only by LSM. Failure of identification of antibody by SAB in presence of positive both screening methods was found in one case (figure1), interestingly the flow PRA of this case was suspicious, DR7 reactivity was confirmed by flow specific bead & weakly positive B-FCXM. In the Four positive cases detected by LSM but not with flow PRA, SAB identify weak antibodies likely to be false positive. Conclusions Flow PRA gives extra evidences about doubtful antibody & provides a rapid risk assessment on the same crossmatch platform.

Challenges for the Travelling Donor: Variability Between Donor Workup and Donor Surgery in the Canadian Kidney Paired Exchange Program

BackgroundA primary obstacle to providing renal transplantation is limited access to donated kidneys. The living-donor pool for renal allografts was greatly expanded through implementation of a kidney paired donation program. Whereas some programs ship donor kidneys to the site of renal transplantation, others send the donor to the site of transplantation. Performing the nephrectomy and transplantation at the same location may optimize functional renal outcomes, but preferred surgical approaches may differ between surgical teams performing the donor workup and donor surgery. Our objective was to identify incongruence between the surgery planned by the team that performed the donor's workup, and the surgery that took place at the site of donation. MethodsA retrospective chart review was performed between the site of preoperative surgical planning, and the site of surgery for kidney donors in the Canadian kidney paired donation program. ResultsFifty-one donors were preoperatively prepared in any of six Canadian provinces, and then underwent surgery in a different province. The surgical procedure performed for 31% of the patients' nephrectomies differed from the procedure suggested by the surgical team who conducted the preoperative workup. Half of these differences were between left laparoscopic and left laparoscopic hand-assisted, but the remainder included more substantial changes of sides and/or laparoscopic versus open procedures. ConclusionOptimal patient care is challenged in a kidney paired donation program that uses the “traveling donor” approach due to differing surgical techniques selected by the surgeon at the site of donor workup and the surgeon at the site of donation.

It’s about time: The development and validation of a rapid optimized single antigen bead (ROB) assay protocol for LABScreen

The LABScreen single antigen bead assay (SAB) is a method widely used for the identification and monitoring of human leukocyte antigen (HLA) antibodies in patients pre-and post-transplant. While accurate testing of patient samples is key for optimal patient care, time can also be important, especially during deceased donor workups or post-transplant assessments. Here we describe the development and validation of the Rapid Optimized SAB (ROB) protocol, a modified version of the One Lambda LABScreen SAB (OLSAB) procedure, which reduces assay time from 85 to 25min (>70% reduction) without impacting assay quality or sensitivity. Optimization steps included shortened centrifugation cycles and reduced serum and secondary antibody incubation times in combination with increased secondary antibody concentration. Linear regression analysis of baseline median fluorescence intensity (MFI) values showed excellent correlation between the ROB and OLSAB protocols (r2>0.98) for both class I and class II antibodies in 58 sera tested in two HLA laboratories. Importantly, the ROB protocol demonstrated a trend towards improved inter-laboratory MFI concordance when compared to the OLSAB procedure (r2=0.9816 vs 0.9451), especially for HLA antibody specificities in the 500–2000 MFI range (r2=0.7824 vs 0.6313). Implementation of the ROB protocol will expedite HLA antibody testing and may improve reproducibility of the SAB assay.

Shear Wave Elastography of the Spleen in Healthy Subjects

To evaluate spleen stiffness (SS) value measured by shear wave elastography (SWE) in healthy population. Sixty-eight healthy subjects who underwent donor workup (US including SWE and CT) for adult-to-adult living donor liver transplantation were included in this study. SWE of liver and spleen was performed on a Toshiba Aplio 500 unit by board certified radiologists, through right/left intercostal examination. SWE values were obtained the three measurements and the average in each organ, and we also measured the distance from skin to organic capsule. To determine the normal range of SS and spleen/liver stiffness ratio (SLSR), 2.5∼97.5 percentile values as well as mean and standard deviation were obtained. CT volumetry was performed to assess the liver and spleen volumes and liver/spleen volume ratio (LSVR). We evaluated the relationship between SS or SLSR and spleen volume or LSVR. On SWE, technical failure or unacceptable variability (coefficient of variability=SD/Mean ≥ 0.3) occurred more commonly for SS (n=26, 89.7%) than liver stiffness (LS, n=9, 31.0%) measurement. There was a significant difference in distance of skin-to-capsule between technical success and failure groups (p< 0.05). Among 31 subjects in whom both SS and LS measurements were successful, mean, SD, 2.5 percentile, and 97.5 percentile values were 16.0, 3.6, 8.2, and 24.5 kPa for SS, 5.7, 1.1, 4.1, and 8.6 kPa for LS, and 2.9, 0.8, 1.3, and 4.0 for SLSR.The SS and SLSR correlated significantly with spleen volume and liver/spleen volume ratio (p< 0.05, respectively). SS and SLSR measured by SWE in healthy population ranged from 8.2 to 24.5 kPa and 1.3 to 4.0 (2.5∼97.5 percentiles), and may be associated with spleen volume and liver/spleen volume ratio.

CT volumetry is superior to nuclear renography for prediction of residual kidney function in living donors.

Living kidney donor evaluation commonly includes nuclear renography to assess split kidney function and computed tomography (CT) scan to evaluate anatomy. To streamline donor workup and minimize exposure to radioisotopes, we sought to assess the feasibility of using proportional kidney volume from CT volumetry in lieu of nuclear renography. We examined the correlation between techniques and assessed their ability to predict residual postoperative kidney function following live donor nephrectomy. In a cohort of 224 live kidney donors, we compared proportional kidney volume derived by CT volumetry with split kidney function derived from nuclear renography and found only modest correlation (left kidney R(2) =26.2%, right kidney R(2) =26.7%). In a subset of 88 live kidney donors with serum creatinine measured 6months postoperatively, we compared observed estimated glomerular filtration rate (eGFR) at 6months with predicted eGFR from preoperative imaging. Compared to nuclear renography, CT volumetry more closely approximated actual observed postoperative eGFR for Chronic Kidney Disease Epidemiology Collaboration (J-test: P=.02, Cox-Pesaran test: P=.01) and Mayo formulas (J-test: P=.004, Cox-Pesaran test: P<.001). These observations support the use of CT volumetry for estimation of split kidney function in healthy individuals with normal kidney function and morphology.

Introducing Genetic Tests With Uncertain Implications in Living Donor Kidney Transplantation: ApoL1 as a Case Study.

Genetic mutations in apolipoprotein L1 (ApoL1) are associated with kidney disease. Apolipoprotein L1 mutations are common in African Americans (∼39% and 12% have 1 and 2 high-risk alleles, respectively). Carrying 2 ApoL1 risk alleles may explain much of the excess rate of kidney failure in African Americans compared to European Americans. Apolipoprotein L1 also has implications for kidney transplantation. Kidney grafts from deceased donors with 2 ApoL1 risk alleles have worse graft survival, but outcomes appear unaffected by recipient ApoL1 status. Unknown is whether donation increases the risk of kidney failure in living donors with 2 ApoL1 risk alleles and whether their donated kidneys have worse graft survival. There are 4 options to consider: (1) remain silent about ApoL1 risk alleles and renal failure and wait for more data; (2) counsel about race, ApoL1, and subsequent renal failure abstractly but remain agnostic about donor testing until more data are available; (3) provide counseling and encourage genotyping of prospective living donors of African ancestry as part of the living donor workup; or (4) mandate testing of all prospective living donors. We support option 3, and recommend, with donor permission, to discuss the results with potential recipients to promote informed decision-making. We also argue for a voluntary donor registry that collects long-term follow-up information. We provide ethical arguments to support these recommendations.