Search

B cells play crucial roles in cell-mediated alloimmune responses. In vitro, B cells can support or regulate indirect T-cell alloreactivity in response to donor antigens on ELISpot and these patterns associate with clinical outcome. Previous reports of associations between B-cell phenotype and function have examined global phenotypes and responses to polyclonal stimuli. We hypothesized that studying antigen-specific B cells, using samples from sensitized patients, would inform further study to identify novel targets for intervention. Using biotinylated HLA proteins, which bind HLA-specific B cells via the B-cell receptor in a dose-dependent fashion, we report the specific phenotype of HLA-binding B cells and define how they associated with patterns of anti-HLA response in interferon-γ ELISpot. HLA-binding class-switched and IgM

This study was aimed to examine the clinical utility and impact of the 2016 Banff criteria for acute antibody-mediated rejection (acute AMR) in patients with liver transplantation. Among adult patients with donor-specific antibody (DSA) assays performed between 2015 and 2020, cases with proved DSA (mean fluorescent index2000) and matched liver biopsy available were reviewed. Among 55 patients identified, 28 (51%) had class I DSA, 45 (82%) had class II DSA and 18 (33%) had both. Mild, moderate and severe microvasculitis were observed in 11 (20%), 2 (4%) and 1 (2%) case, respectively. Diffuse immunoreactivity to C4d on portal microvascular endothelia was confirmed in 5 cases (9%), which met the criteria of definite (n = 2) or suspicious for acute AMR (n = 3). Cases of acute AMR more commonly had class I DSA (100% vs. 46%; p = 0.027) or both class I and II DSA (80% vs. 28%; p = 0.018) than cases of non-acute AMR. One case of pure acute AMR with veno-occlusion was successfully treated with plasma exchange. The remaining 4 cases had features of combined acute AMR/T cell-mediated rejection (TCMR), and two progressed to ductopenic rejection within 3 weeks. In conclusion, only 9% of DSA-positive patients met the Banff criteria for acute AMR, necessitating careful morphological and immunohistochemical assessments of the allograft biopsies according to the proposed standards. Combined acute AMR/TCMR was more common than isolated acute AMR, and additional AMR in TCMR cases may be associated with rapid progression to ductopenic rejection.

Urbanization involves numerous environmental changes that may affect the timing of plant reproduction and foliar damage by pathogens, herbivores, and human activities. Yet such relationships have not been examined simultaneously in plant populations across levels of urbanization.We conducted monthly surveys of 22 populations of Plantago lanceolata and P. rugelii in parks spanning an urbanization gradient. We quantified plant reproductive development and prevalence of powdery mildew infection, insect herbivory, and mowing damage. Additionally, we placed potted “sentinel” plants into field populations to directly measure infection and herbivory rates.Urbanization was associated with earlier flowering and more seed production for P. rugelii, but less seed maturation for P. lanceolata. Mildew epidemics on P. rugelii started earlier and achieved greater prevalence in more urban sites. Correspondingly, sentinels only became infected in suburban and urban sites. There was less infection on P. lanceolata, including sentinels, suggesting low availability of pathogen genotypes able to infect this species. Early-summer herbivory on both plant species was accelerated in urban sites.Urbanization has species-specific associations with reproductive phenology and is associated with increased early-summer herbivory, larger epidemics of a foliar pathogen, and more mowing damage on two weedy herbs

Anti-HLA-antibody characteristics aid to risk-stratify patients and improve long-term renal graft outcomes. Complement activation by donor-specific antibody (DSA) is an important characteristic that may determine renal allograft outcome. There is heterogeneity in graft outcomes within the moderate to high immunological risk cases (cross-match-positive). We explored the role of C3d-positive DSAs in sub-stratification of cross-match-positive cases and relate to the graft outcomes. We investigated 139 cross-match-positive living-donor renal transplant recipients from four transplant centres in the United Kingdom. C3d assay was performed on serum samples obtained at pretreatment (predesensitization) and Day 14 post-transplant. C3d-positive DSAs were found in 52 (37%) patients at pretreatment and in 37 (27%) patients at Day 14 post-transplant. Median follow-up of patients was 48 months (IQR 20.47–77.57). In the multivariable analysis, pretreatment C3d-positive DSA was independently associated with reduced overall graft survival, the hazard ratio of 3.29 (95% CI 1.37–7.86). The relative risk of death-censored five-year graft failure was 2.83 (95% CI 1.56–5.13). Patients with both pretreatment and Day 14 C3d-positive DSAs had the worst five-year graft survival at 45.5% compared with 87.2% in both pretreatment and Day 14 C3d-negative DSA patients with the relative risk of death-censored five-year graft failure was 4.26 (95% CI 1.79, 10.09). In this multicentre study, we have demonstrated for the first time the utility of C3d analysis as a distinctive biomarker to sub-stratify the risk of poor graft outcome in cross-match-positive living-donor renal transplantation.

All UK H&I laboratories and transplant units operate under a single national kidney offering policy, but there have been variations in approach regarding when to undertake the pre-transplant crossmatch test. In order to minimize cold ischaemia times for deceased donor kidney transplantation we sought to find ways to be able to report a crossmatch result as early as possible in the donation process. A panel of experts in transplant surgery, nephrology, specialist nursing in organ donation and H&I (all relevant UK laboratories represented) assessed evidence and opinion concerning five factors that relate to the effectiveness of the crossmatch process, as follows: when the result should be ready for reporting; what level of donor HLA typing is needed; crossmatch sample type and availability; fairness and equity; risks and patient safety. Guidelines aimed at improving practice based on these issues are presented, and we expect that following these will allow H&I laboratories to contribute to reducing CIT in deceased donor kidney transplantation.

After the major changes with regard to acute and chronic ABMR in the Banff classification initiated in 2013, there has been an improvement in diagnosing antibody-mediated rejection (ABMR) in adult studies but no data have been published in the paediatric population. We assessed 56 paediatric kidney transplant biopsies due to kidney dysfunction in patients with donor-specific antibodies (DSA) in a retrospective single-centre study between January 2006 and March 2012. The results were compared with 2003/2007 Banff classification noting the subsequent 2017 and 2019 modifications do not change the 2013 Banff classification with regard to acute antibody-mediated rejection (apart from the addition of gene transcripts/classifiers that do not affect our analysis). Following the 2013 Banff classification, there were seven cases (12.5%) diagnosed with ABMR that would have been misclassified when applying the 2003/2007 classification. Evaluating the histological features of all ABMR-related cases, we report the importance of v− (intimal arteritis) and t− (tubulitis) lesions: absence of v− and t− lesions in the biopsy is related to significantly higher kidney allograft survival (OR 7.3, 95%CI 1.1–48.8, p = 0.03 and OR 5.3, 95%CI 1.2–25.5, p = 0.04 respectively). Moreover, absence of t− lesions was associated with significantly fewer rejection episodes the year after the initial biopsy (OR 5.1, 95%CI 1.4–19.8, p = 0.01). Our study supports that the updated 2013 Banff classification shows superior clinicopathological correlation in identifying ABMR in paediatric kidney transplant recipients. Our results can be extrapolated to the recently updated 2019 Banff classification.

Chronic rejection is the single biggest cause of premature kidney graft failure. HLA antibodies (Ab) are an established prognostic biomarker for premature graft failure so there is a need to test whether treatment decisions based on the presence of the biomarker can alter prognosis. The Optimised TacrolimuS and MMF for HLA Antibodies after Renal Transplantation (OuTSMART) trial combines two elements. Firstly, testing whether a routine screening programme for HLA Ab in all kidney transplant recipients is useful by comparing blinding versus unblinding of HLA Ab status. Secondly, for those found to be HLA Ab+, testing whether the introduction of a standard optimisation treatment protocol can reduce graft failure rates. OuTSMART is a prospective, open-labelled, randomised biomarker-based strategy (hybrid) trial, with two arms stratified by biomarker (HLA Ab) status. The primary outcome was amended from graft failure rates at 3 years to time to graft failure to increase power and require fewer participants to be recruited. Length of follow-up subsequently is variable, with all participants followed up for at least 43 months up to a maximum of 89 months. The primary outcome will be analysed using Cox regression adjusting for stratification factors. Analyses will be according to the intention-to-treat using all participants as randomised. Outcomes will be analysed comparing standard care versus biomarker-led care groups within the HLA Ab+ participants (including those who become HLA Ab+ through re-screening) as well as between HLA-Ab-unblinded and HLA-Ab-blinded groups using all participants. Changes to the primary outcome permit recruitment of fewer participants to achieve the same statistical power. Pre-stating the statistical analysis plan guards against changes to the analysis methods at the point of analysis that might otherwise introduce bias through knowledge of the data. Any deviations from the analysis plan will be justified in the final report. ISRCTN registry, ID: ISRCTN46157828 . Registered on 26 March 2013; EudraCT 2012–004308-36 . Registered on 10 December 2012.

Blood group O or B recipients wait longer for a kidney transplant. We studied the distribution of anti-ABO blood group antibody titres in patients awaiting a kidney transplant, and modelled the effect of altering the UK National Kidney Allocation Scheme to allow for patients with 'LOW' titres (≤1:8, ≤3 dilutions) to receive a deceased donor ABOi (ddABOi) transplant. In a prospective study of 239 adult patients on the waiting list for a transplant in 2 UK centres, ABO-antibody titres (anti-A and anti-B) were measured. Based on the proportions of 'LOW' anti-A or anti-B antibodies, four simulations were performed to model the current allocation rules compared with variations allowing ddABOi allocation under various conditions of blood group, HLA matching, and waiting time. The simulations permitting ddABOi resulted in more blood group B recipients being transplanted, with median waiting time reduced for this group of recipients, and more equitable waiting times across blood groups. Additionally, permitting ddABOi resulted in greater numbers of 000MM allocations overall in compatible transplants under modelled conditions. Changing allocation in the UK to permit ddABOi in patients with 'LOW' titres would not change the total number of transplants, but redistributes allocation more equitably amongst blood groups, altering waiting times accordingly.

Background Donor-specific antibodies are reported to increase the risk of rejection and reduce allograft survival following simultaneous liver-kidney transplantation. Optimal immunosuppression regimens to reduce this risk and to treat rejection episodes are underinvestigated. Methods Cohort analysis of the first 27 simultaneous liver-kidney transplant recipients, between 2014 and 2018 at our unit, is performed under a new risk stratification policy. Those with donor-specific antibodies to class II HLA with a mean fluorescence intensity >10 000 are considered high risk for antibody-mediated rejection (AMR). These patients received immunosuppression, which consisted of induction therapy, tacrolimus, mycophenolate mofetil, and prednisolone. All other patients are considered low risk and received tacrolimus and prednisolone alone. Results Three patients were high risk for rejection, and 2 of these patients developed AMR, which was treated with plasma exchange and intravenous immunoglobulin. At 1 y, their estimated glomerular filtration rate (eGFR) were 50 and 59 mL/min. Two other patients developed AMR, which was similarly treated, and their 1-y eGFR was 31 and 50 mL/min. The overall histologically proven acute rejection rate within the first year was 33%, and median eGFR, for the 27 patients, at 1 y was 52 mL/min and at 2 y was 49 mL/min. Conclusions This study confirms that there is a risk of AMR following simultaneous liver-kidney transplantation despite increased immunosuppression. This can be effectively treated with plasma exchange and intravenous immunoglobulin.

RituxiCAN-C4 combined an open-labeled randomized controlled trial (RCT) in 7 UK centers to assess whether rituximab could stabilize kidney function in patients with chronic rejection, with an exploratory analysis of how B cell-depletion influenced T cell anti-donor responses relative to outcome. Between January 2007 and March 2015, 59 recruits were enrolled after screening, 23 of whom consented to the embedded RCT. Recruitment was halted when in a pre-specified per protocol interim analysis, the RCT was discovered to be significantly underpowered. This report therefore focuses on the exploratory analysis, in which we confirmed that when B cells promoted CD4+ anti-donor IFNγ production assessed by ELISPOT, this associated with inferior clinical outcome; these patterns were inhibited by optimized immunosuppression but not rituximab. B cell suppression of IFNγ production, which associated with number of transitional B cells and correlated with slower declines in kidney function was abolished by rituximab, which depleted transitional B cells for prolonged periods. We conclude that in this patient population, optimized immunosuppression but not rituximab promotes anti-donor alloresponses associated with favorable outcomes. Clinical Trial Registration: Registered with EudraCT (2006-002330-38) and www.ClinicalTrials.gov, identifier: NCT00476164.

Background: More than 40% of patients awaiting a kidney transplant in the UK are sensitised with human leucocyte antigen (HLA) antibodies. Median time to transplantation for such patients is double that of unsensitised patients at about 74 months. Removing antibody to perform an HLA-incompatible (HLAi) living donor transplantation is perceived to be high risk, although patient survival data are limited. We compared survival of patients opting for an HLAi kidney transplant with that of similarly sensitised patients awaiting a compatible organ. Methods: From the UK adult kidney transplant waiting list, we selected crossmatch positive living donor HLAi kidney transplant recipients who received their transplant between Jan 1, 2007, and Dec 31, 2013, and were followed up to Dec 31, 2014 (end of study). These patients were matched in a 1:4 ratio with similarly sensitised patients cases listed for a deceased-donor transplant during that period. Data were censored both at the time of transplantation (listed only), and at the end of the study period (listed or transplant). We used Kaplan-Meier curves to compare patient survival between HLAi and the matched cohort. Findings: Of 25 518 patient listings, 213 (1%) underwent HLAi transplantation during the study period. 852 matched controls were identified, of whom 41% (95% CI 32-50) remained without a transplant at 58 months after matching. We noted no difference in survival between patients who were in the HLAi group compared with the listed only group (log rank p=0·446), or listed or transplant group (log rank p=0·984). Interpretation: Survival of sensitised patients undergoing HLAi in the UK is comparable with those on dialysis awaiting a compatible organ, many of whom are unlikely to be have a transplant. Choosing a direct HLAi transplant has no detrimental effect on survival, but offers no survival benefit, by contrast with similar patients studied in a North American multicentre cohort. Funding: UK National Health Service Blood & Transplant and Guy's & St Thomas' National Institute for Health Research Biomedical Research Centre.

Background Renal transplantation improves quality of life (QoL) and survival in children requiring renal replacement therapy (RRT). Sensitization with development of a broad-spectrum of anti-HLA antibodies as a result of previous transplantation or after receiving blood products is an increasing problem. There are no published reports of desensitization protocols in children allowing renal transplantation from HLA-antibody-incompatible living donors. Methods We adopted our well-established adult desensitization protocol for this purpose and undertook HLA antibody-incompatible living donor renal transplants in two children: a 14-year-old girl and a 13-year-old boy. Results After 2 and 1.5 years of follow-up, respectively, both patients have stable renal allograft function despite a rise in donor-specific antibodies in one case. Conclusions HLA-incompatible transplantation should be considered in selected cases for sensitized children.

Background: An increasing number of patients are requiring multiple retransplants. We assessed outcomes of third and fourth kidney transplants, to aid decision making on the most suitable donor type. Methods: Data were collected retrospectively for 2561 transplants, including 69 third and 8 fourth, performed from 2000 to 2017. Demographics and outcomes for the combined third/fourth group were compared to first and second transplants. Within the third/fourth kidney transplant group, comparisons were made between deceased donors (n = 39), live donor HLA-compatible (n = 23) and -incompatible (n = 13) transplants, as well as between standard (n = 25) and extended-criteria (n = 14) deceased donor transplants. Results: Patient survival did not differ significantly by transplant number (P = 0.532), whereas death-censored graft survival declined progressively, from 89% at 5 years in first, 85% in second and 74% in the third/fourth transplant group (P < 0.001). Within the combined third/fourth transplant subgroup, 5-year graft survival was found to be 100% in recipients of HLA-compatible live donors, compared to 75% in deceased donors and 53% in HLA-incompatible live donors, although this difference did not reach statistical significance (P = 0.083). No significant difference in patient survival (P = 0.356) or complication rates (P = 0.757) were detected between these groups. For recipients of deceased donors in the third/fourth transplant group, there were no significant differences between standard versus extended-criteria donors for any of the outcomes considered. Conclusions: Despite variable functional outcomes, third and fourth kidney transplant recipients experience comparable patient survival rates to first and second transplants, regardless of the donor type. In selected patients, HLA-incompatible live donors and extended-criteria deceased donors should be considered.

Background Lack of blood group compatible donors and sensitisation resulting in development of broad spectrum anti-HLA antibodies, is an increasing problem making it difficult for some children with renal disease to undergo transplantation. We have set up the first antibody incompatible transplant programme for children in the UK. Methods We describe 11 patients who underwent blood group incompatible (ABOi) and 2 who had HLA antibody-incompatible kidney transplantation (referred from other transplant centers). Our well established adult desensitisation protocols were adopted. Results For 11 ABOi transplants, we used the following protocol: rituximab for titres 1:8 or more; with addition of double plasmapheresis for titres 1:16-1:32 and immunoabsorption if titers >1:64. Death-censored graft survival was 100% and this was comparable with blood group compatible transplants (98%)

Background. ABO and HLA antibody incompatible (HLAi) renal transplants (AIT) now comprise around 10% of living donor kidney transplants. However, the relationship between pretransplant factors and medium-term outcomes are not fully understood, especially in relation to factors that may vary between centers. Methods. The comprehensive national registry of AIT in the United Kingdom was investigated to describe the donor, recipient and transplant characteristics of AIT. Kaplan-Meier analysis was used to compare survival of AIT to all other compatible kidney transplants performed in the United Kingdom. Cox proportional hazards regression modeling was used to determine which pretransplant factors were associated with transplant survival in HLAi and ABOi separately. The primary outcome was transplant survival, taking account of death and graft failure. Results. For 522 HLAi and 357 ABO incompatible (ABOi) transplants, 5-year transplant survival rates were 71% (95% confidence interval [CI], 66-75%) for HLAi and 83% (95% CI, 78-87%) for ABOi, compared with 88% (95% CI, 87-89%) for 7290 standard living donor transplants, and 78% (95% CI, 77-79%) for 15 322 standard deceased donor transplants (P < 0.0001). Increased chance of transplant loss in HLAi was associated with increasing number of donor specific HLA antibodies, center performing the transplant, antibody level at the time of transplant, and an interaction between donor age and dialysis status. In ABOi, transplant loss was associated with no use of IVIg, cytomegalovirus seronegative recipient, 000 HLA donor-recipient mismatch; and increasing recipient age. Conclusions. Results of AIT were acceptable, certainly in the context of a choice between living donor AIT and an antibody compatible deceased donor transplant. Several factors were associated with increased chance of transplant loss, and these can lead to testable hypotheses for further improving therapy.

Introduction We have previously shown that children who developed de novo donor-specific human leukocyte antigen (HLA) antibodies (DSA) had greater decline in allograft function. We hypothesised that patients with complement-activating DSA would have poorer renal allograft outcomes. Methods A total of 75 children developed DSA in the original study. The first positive DSA sample was subsequently tested for C1q and C3d fixing. The primary event was defined as 50% reduction from baseline estimated glomerular filtration rate and was analysed using the Kaplan–Meier estimator. Results Of 65 patients tested, 32 (49%) and 23 (35%) tested positive for C1q and C3d fixing, respectively. Of the 32 C1q-positive (c1q+) patients, 13 (41%) did not show concomitant C3d fixing. The mean fluorescence intensity values of the original immunoglobulin G DSA correlated poorly with complement-fixing positivity (C1q: adjusted R 2 0.072; C3d: adjusted R 2 0.11; p

Intimal vascular lesions are considered features of acute T-cell-mediated rejection yet can occur in the absence of tubulointerstitial inflammation, termed isolated 'v' lesions. The clinical significance of these lesions is unclear. The diagnosis requires a biopsy with the presence of arteries. The frequency of adequate biopsies was analysed in 89 renal transplant biopsies from 57 paediatric renal allograft recipients, and the incidence of isolated endarteritis was determined. 60 (67%) biopsies contained an artery and of these, isolated 'v' lesions occurred in 6 (10%). 5 (83%) biopsies with isolated 'v' lesions were associated with positive DSA, suggesting that these lesions may represent acute antibody-mediated rejection. Patients with vessel-negative biopsies had an increased decline in eGFR (median -20.5, IQR -24.4 to 1.2 ml/min/1.73 m(2) vs. -9.6, IQR -78.7 to -6.8 ml/min/1.73 m(2) ; P = 0.01). Patients with vessel-negative biopsies were more likely to have repeat biopsy for ongoing allograft dysfunction, (25.0% vs. 2.4%; P < 0.01). The data suggest that isolated 'v' lesions are more common than previously thought. A significant proportion of biopsies classified as 'normal' or 'borderline change' in the absence of a large vessel may represent undiagnosed acute rejection. This may result in suboptimal therapy with possible adverse effects on renal outcome.

BACKGROUND: The last Banff 2013 report recognizes acute/active antibody-mediated rejection (ABMR) and C4d staining without evidence of rejection. The goal of our study was to analyze the incidence of C4d deposition after ABO-incompatible transplantation and assess outcomes in patients with ABMR, C4d staining without evidence of rejection (all acute Banff scores = 0), and C4d staining with tubulointerstitial inflammation (i > 0 with or without tubulitis). METHODS: Three-months 'For cause' or protocol biopsies in 50 ABO-incompatible patients were rescored and were correlated with clinical outcomes and antibody titres. RESULTS: Active/acute ABMR was found in 23 patients (46%), C4d staining without evidence of rejection in 7 patients (14%), C4d staining with tubulointerstitial inflammation in 6 patients (12%), tubulointerstitial inflammation in 6 patients (12%), and no evidence of rejection in 8 patients (16%). Patients with active/acute ABMR had a 3-month estimated glomerular filtration rate (median,: 43 mL/min) lower than patients with no evidence of rejection (median, 61 mL/min; P = 0.01). However, after 3 months, a progressively declining estimated glomerular filtration rate was observed more frequently in patients with C4d staining and tubulointerstitial inflammation when compared to patients with no evidence of rejection (100% vs 25%, P = 0.03). Finally, independently of C4d status, interstitial inflammation occurred more frequently in patients with a pretransplant ABO antibody titre higher than 16 and/or posttransplant ABO antibody increase. CONCLUSIONS: Whereas isolated C4d deposition and isolated interstitial inflammation appear to be benign lesions, C4d deposition in association with interstitial inflammation is the biopsy finding most strongly associated with the development of chronic graft dysfunction.

Graft survival seems to be worse in positive cross-match (HLAi) than in ABO-incompatible (ABOi) transplantation. However, it is not entirely clear why these differences exist. Sixty-nine ABOi, 27 HLAi and 10 combined ABOi+HLAi patients were included in this retrospective study, to determine whether the frequency, severity and the outcome of active antibody-mediated rejection (AMR) were different. Five-year death-censored graft survival was better in ABOi than in HLAi and ABOi+HLAi patients (99%, 69% and 64%, respectively, P = 0.0002). Features of AMR were found in 38%, 95% and 100% of ABOi, HLAi and ABOi+HLAi patients that had a biopsy, respectively (P = 0.0001 and P = 0.001). After active AMR, a declining eGFR and graft loss were observed more frequently in HLAi and HLAi+ABOi than in ABOi patients. The poorer prognosis after AMR in HLAi and ABOi+HLAi transplantations was not explained by a higher severity of histological lesions or by a less aggressive treatment. In conclusion, ABOi transplantation offers better results than HLAi transplantation, partly because AMR occurs less frequently but also because outcome after AMR is distinctly better. HLAi and combined ABOi+HLAi transplantations appear to have the same outcome, suggesting there is no synergistic effect between anti-A/B and anti-HLA antibodies.

This paper provides information about the prevalence and topography of self-injurious behavior in children and adults with autism spectrum disorder and intellectual disability. Dominant models regarding the etiology of self-injury in this population are reviewed, with a focus on the role of reactivity to pain and sensory input. Neuroimaging studies are presented and suggestions are offered for future research.

Standard leucodepleted blood transfusions can induce the production of human leukocyte antigen (HLA)-specific antibodies, which are associated with longer transplant waiting times and poorer graft outcomes. We hypothesized that additional washing of leucodepleted red cells might reduce antigenic stimulus by removal of residual leukocytes and soluble HLA.A retrospective review of HLA antibodies in children with chronic kidney disease stage 4-5 who had ≥ two HLA antibody screens between 2000 and 2009, pre- and post-transfusion, and were HLA antibody-negative at first testing. Patients were divided according to whether they received standard leucodepleted blood or "washed cells". To assess the efficacy of washing methods, total leukocytes were enumerated pre- and post- manual and automated washing of standard leucodepleted red cells that had been supplemented with whole blood to achieve measurable leukocyte levels pre-washing.A total of 106 children were included: 23 received no blood transfusions (group 1), six had washed cells only (group 2), 59 had standard transfusions only (group 3), and 18 had both standard and washed cells (group 4). Sensitization rates were 26, 17, 44, and 44 % in groups 1-4 (p = 0.32). Patients in groups 3 and 4 had more transfusions with red cells, platelets, and plasma products. There was no difference in HLA sensitization risk with washed or standard red cells on analysis of co-variance controlling for platelets and plasma transfusions. The red cell washing study showed no significant reduction in leukocytes using manual methods. Although there was a statistically significant reduction (33 %) from baseline pre-washing using the automated method, from 6.54 ± 0.84 × 10(6) to 4.36 ± 0.67 × 10(6) leukocytes per unit, the majority of leukocytes still remained.There was no evidence that using washed leucodepleted red cells reduced patient HLA sensitization rates. Washing leucodepleted red cells is unlikely to reduce the risk of HLA sensitization due to the limited effect on residual leukocytes.

HLA-specific antibodies bind discrete clusters of amino acids called epitopes, but serological assignment of antibody specificities makes no reference to this. As HLA typing for solid organ transplantation is provided at only medium (serologically equivalent) resolution, this means that recipient HLA antibodies to donor HLA epitopes may not be identified. We have designed a novel and rapid HLA-A epitope typing method (epityping) using a two-stage PCR-SSP-based method to detect the HLA-A locus epitopes described by El Awar et al. 2007, Transplantation, 84, 532. The initial PCR step utilizes HLA-A locus-specific primers; the product is cleaned using the QIAquick Spin Purification procedure. The purified product is tested using our in-house epitope-specific primer panel, the results being visualized using gel electrophoresis. Twenty two UCLA DNA Exchange samples were epityped, blinded to the HLA type. Of the 75 primer pairs, the mean correlation coefficient was 0.95 with each sample giving 67 or more correct primer results. In all cases, it was possible to derive the first field classic HLA type from the epityping results. These results indicate that a method for identification of HLA epitopes which is comparable in time, cost and technical expertise to current HLA typing methods is achievable. Redesigning HLA typing to correlate with what the antibody binds should minimize inappropriate organ allocation. We suggest that epityping provides a more effective method than standard HLA typing for solid organ transplantation.

Aims To report the successful outcome of HLA incompatible renal transplantation using plasmapheresis and intravenous immunoglobulin (on day –1) and quadruple immunosuppression with anti–thymocyte globulin (1.5 mg/kg day 1–4), corticosteroids, mycophenolate mofetil and tacrolimus (from day -7). Methods Six month follow–up data of 14–year old young lady who underwent living related ABO compatible (O into B) and HLA incompatible renal transplantation from her father (mismatch 0,1,1) for end-stage kidney disease on peritoneal dialysis secondary to congenital abnormalities of the kidney and urinary tract with bilateral renal dysplasia, recurrent urinary tract infections, bilateral vesico–ureteric reflux after left ureteric reimplantation and right nephrectomy. She had a previous failed renal transplantation at 11 years of age with primary non–function due to intra-renal thrombosis (no acute rejection or TMA) requiring transplant nephrectomy the day after transplantation with 95–100% calculated reaction frequency due to HLA antibodies, specific for mismatches HLA B7 and DQ8 against father with B cell positive (T cell negative) crossmatch which was reduced to negative with test plasma exchange and reduction in MFI from 16,200 to 6,480 and from 11,602 to 4,625 on the day prior to transplantation. She had no offers from the deceased donor waiting list or via the paired exchange scheme (NLDKSS). Results Successful renal transplant without further antibody removal or surgical complications with six month follow–up data with stable renal allograft function with eGFR of 60–96 mls/min/1.73m 2 , 12-hour trough tacrolimus and mycophenolate levels of 7.3 mcg/l and 3.0 mg/l respectively, controlled hypertension on one anti-hypertensive agent with minimal albuminuria (17.4 mg/mmol). Her DSA reduced to 4,691on day 2 but increased further to 23,772 to 38,630 during weeks 1 to 3 and have stabilised out at 21,246 to 22,168 (B7 and DQ8 of 8,407 and 13,761 respectively). She has had three percutaneous renal transplant biopsies at weeks 2, 7 and 11 without acute rejection or IFTA but moderate concentric fibrous intimal thickening of large muscular arteries and C4d deposition in peritubular capillaries and glomeruli. Conclusions This is the first paediatric HLA incompatible renal transplantation in UK and highlights that clinicians must consider this option in ESKD patients whose living donors have been excluded due to HLA incompatibility.

Background. Because of the presence of confounding antigens, the assignment of HLA antibody specificity is difficult in highly sensitized patients, and the definition of an acceptable HLA mismatch requires a significant workload per patient. We describe a new ELISA method, monoLISA, for detection of immunoglobulin (Ig)G HLA antibody using single recombinant HLA class I monomers bound to microtiter plates. Methods. HLA-A2 and -B8 monomers were synthesized and used as screening targets for 85 sera from renal patients. The sera contained various IgG and IgM HLA-specific antibodies, including anti-A2 and anti-B8,defined in a conventional complement-dependent cytotoxicity test (CDC). Investigations were performed to determine possible effects on antibody binding of differential monomer peptide presentation as well as lack of glycosylation. Results. A good correlation was found between CDC-defined specificities and the reactivity observed with HLA monomers. MonoLISA attained means of 100% sensitivity and 92.5% specificity compared with CDC. Neither the presence of different peptides, nor the absence of glycosylation of the monomer affected the ability of monoLISA to detect antibody. Conclusion. This study demonstrates that the monoLISA method for HLA antibody detection is valid. Because this has the potential to reduce the work involved in screening sensitized patients awaiting transplantation for HLA antibodies, resources aimed at increasing the number of constructed monomers would be well targeted.

Address: 1Mucosal Immunology Unit, Kings College London, London, UK, 2Immunodex, Copenhagen, Denmark, 3National Institute of Health, Bethesda, MD, USA, 4Lionex Diagnostics & Therapeutics, Braunschweig, Germany, 5Academic Medical Center, Amsterdam, Netherlands, 6Chinese Centre for Disease Control and Prevention, Beijing, PR China and 7Swedish Institute for Infectious Disease Control, Stockholm, Sweden * Corresponding author