Donor specific HLA antibodies and renal transplant outcomes

Despite the use of potent modern immunosuppressive agents chronic rejection remains the leading cause of allograft failure after renal transplant. Historically T cells were considered to be the main pivot of rejection mechanisms; however, over the past decade the key role of B cells in allograft rejection has been much more fully described. Antibody mediated rejection [AMR] was first classified as a distinct entity in the Banff histological classification of allograft pathology as late as 2001. This was a consequence of the demonstration of the complement split product C4d in renal allografts giving indirect evidence of humoral injury, along with the development of newer assays to detect circulating HLA donor specific antibodies [DSAs]; both of which were subsequently shown to be associated with reduced allograft survival. The development of solid phase technologies, in particular single antigen beads has introduced a readily available assay which can detect HLA DSA with high sensitivity and specificity. The benefit of routine application of such assays in renal transplantation is not known and is the principal question of this thesis; that is to establish if the detection of HLA DSAs will help in predicting rejection and allograft loss. Patients transplanted at Imperial College Renal and Transplant Centre were recruited into the studies. The underlying hypothesis is that donor specific antibodies identified by the more recently developed techniques are associated with inferior allograft survival, addressed in several related studies as follows: 1. Is C4d staining with no morphological features of rejection associated with risk of subsequent AMR and allograft loss? 2. Are preformed DSA detected by single antigen beads in the setting of a negative crossmatch associated with inferior allograft survival? 3. What is the relevance of de novo DSAs after renal transplantation? 4. What is the clinical significance of DQ DSA and should consideration be given to DQ mismatching in deceased organ allocation? 5. Do outcomes in patients with ACR with a humoral component differ when compared to those with pure ACR when treated in a uniform manner? A summary of the results is as follows: 1. C4d in the absence of histological features is not associated with AMR. However, patients with acute tubular injury who have DSA are at risk of subsequent AMR. 2. Patients with preformed DSA are at significant risk of AMR and allograft loss and as such antibodies detected by single antigen beads alone pre-transplant should be considered a relative contraindication to transplantation. 3. Patients who develop de novo DSA are at risk of AMR, transplant glomerulopathy [TG] and allograft failure. Routine testing for the detection of DSA may allow the potential to augment immunosuppression in order to improve outcomes. 4. DQ DSA are the most common DSA detected after transplant and are associated with inferior allograft outcomes. Patients mismatched at both DR and DQ alleles are at risk of developing DQ DSA. Algorithms incorporating the level of DQ mismatch might reduce DQ DSA formation and therefore improve long term allograft survival. 5. Patients with ACR with a humoral element are at risk of subsequent AMR, TG and graft failure. Such patients might benefit from more aggressive therapies than those targeted at ACR alone

Frailty and the psychosocial components of the edmonton frail scale are most associated with patient experience in older kidney transplant candidates – a secondary analysis within the kidney transplantation in older people (KTOP) study

© 2023 Thind, Levy, Wellsted, Willicombe and Brown. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). https://creativecommons.org/licenses/by/4.0/Background: Older people with end-stage kidney disease (ESKD) are vulnerable to frailty, which impacts on clinical and experiential outcomes. With kidney transplantation in older people increasing, a better understanding of patient experiences is necessary for guiding decision making. The Kidney Transplantation in Older People (KTOP):impact of frailty on outcomes study aims to explore this. We present a secondary analysis of the Edmonton Frail Scale (EFS) and its relationship with patient experience scores. Methods: The KTOP study is a single centre, prospective study, which began in October 2019. All ESKD patients aged ≥60 considered for transplantation at Imperial College Renal and Transplant Centre were eligible. Frailty was assessed using the EFS and 5 questionnaires assessed patient experience and quality of life (QoL) (Short Form-12(v2), Palliative Care Outcome Scale–Symptoms Renal, Depression Patient Health Questionnaire-9, Illness Intrusiveness Ratings Scale, Renal Treatment Satisfaction Questionnaire). The EFS was divided into 4 subdomains (psychosocial, physical function, medical status, and general health) and then compared with the questionnaire scores. Results: 210 patients have been recruited (aged 60-78), 186 of whom completed EFS assessments. 118 (63.4%) participants were not frail, 36 (19.4%) vulnerable, and 32 (17.2%) were frail. Worse frailty scores were associated with poorer patient experience and QoL scores across all questionnaires. Severe deficits in the EFS psychosocial subdomain showed a statistically significant association with higher depression screen scores (coefficient 4.9, 95% CI 3.22 to 6.59), lower physical (coefficient -4.35, 95% CI -7.59 to -1.12) and mental function scores (coefficient -8.33, 95% CI -11.77 to -4.88) from the Short Form-12(v2), and lower renal treatment satisfaction scores (coefficient -5.54, 95% CI -10.70 to -0.37). Deficits in the physical function and medical status EFS subdomians showed some association with patient experience scores. Conclusion: In the KTOP study cohort at recruitment vulnerable and frail candidates reported worse QoL and patient experiences. Severe deficits in the psychosocial subdomains of the EFS showed a strong association with patient experience and QoL, whilst physical function and medical status deficits showed a lesser association. This has highlighted specific EFS domains that may be suitable for targeted interventions to improve experiences and optimise outcomes.Peer reviewe

Frailty and the psychosocial components of the edmonton frail scale are most associated with patient experience in older kidney transplant candidates – a secondary analysis within the kidney transplantation in older people (KTOP) study

BackgroundOlder people with end-stage kidney disease (ESKD) are vulnerable to frailty, which impacts on clinical and experiential outcomes. With kidney transplantation in older people increasing, a better understanding of patient experiences is necessary for guiding decision making. The Kidney Transplantation in Older People (KTOP):impact of frailty on outcomes study aims to explore this. We present a secondary analysis of the Edmonton Frail Scale (EFS) and its relationship with patient experience scores.MethodsThe KTOP study is a single centre, prospective study, which began in October 2019. All ESKD patients aged ≥60 considered for transplantation at Imperial College Renal and Transplant Centre were eligible. Frailty was assessed using the EFS and 5 questionnaires assessed patient experience and quality of life (QoL) (Short Form-12(v2), Palliative Care Outcome Scale–Symptoms Renal, Depression Patient Health Questionnaire-9, Illness Intrusiveness Ratings Scale, Renal Treatment Satisfaction Questionnaire). The EFS was divided into 4 subdomains (psychosocial, physical function, medical status, and general health) and then compared with the questionnaire scores.Results210 patients have been recruited (aged 60-78), 186 of whom completed EFS assessments. 118 (63.4%) participants were not frail, 36 (19.4%) vulnerable, and 32 (17.2%) were frail. Worse frailty scores were associated with poorer patient experience and QoL scores across all questionnaires. Severe deficits in the EFS psychosocial subdomain showed a statistically significant association with higher depression screen scores (coefficient 4.9, 95% CI 3.22 to 6.59), lower physical (coefficient -4.35, 95% CI -7.59 to -1.12) and mental function scores (coefficient -8.33, 95% CI -11.77 to -4.88) from the Short Form-12(v2), and lower renal treatment satisfaction scores (coefficient -5.54, 95% CI -10.70 to -0.37). Deficits in the physical function and medical status EFS subdomians showed some association with patient experience scores.ConclusionIn the KTOP study cohort at recruitment vulnerable and frail candidates reported worse QoL and patient experiences. Severe deficits in the psychosocial subdomains of the EFS showed a strong association with patient experience and QoL, whilst physical function and medical status deficits showed a lesser association. This has highlighted specific EFS domains that may be suitable for targeted interventions to improve experiences and optimise outcomes

Clinical impact of early post-transplant red cell transfusions in kidney transplantation: a systematic review and meta-analysis

Introduction: Red blood cell transfusions (RBCT) represent a potentially modifiable risk factor for HLA sensitisation and adverse outcomes post transplantation. Evidence of the clinical impact of post-transplant RBCT has been infrequently reported. Herein, we performed a systematic review of available literature to assess the prevalence of RBCT post kidney transplant, and the effect of transfusion on transplant outcomes. Methods: We included studies from 2000 to July 2022, published on Medline, Embase and the Transplant Library. Results: Ten studies were analysed which included a total of 32,817 kidney transplant recipients, with a median transfusion prevalence of 40% (range 18-64%). There was significant heterogeneity between studies in terms of patient and allograft characteristics, immunological risk, and immunosuppression protocols. Analysis of unadjusted outcomes showed that post-transplant RBCTs are associated with inferior patient survival, allograft loss, rejection and donor specific antibodies. Adjusted outcomes were described where available, and supported the adverse associations seen in the unadjusted models in many studies. Discussion: This review demonstrates that RBCT post-transplant are common and maybe associated with inferior outcomes, highlighting the urgent need for high quality prospective evidence of the effect of RBCTs on transplant outcomes. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier, CRD42022348763767

Severe COVID-19 is associated with endothelial activation and abnormal glycosylation of von Willebrand factor in patients undergoing hemodialysis

Background: A major clinical feature of severe coronavirus diease 2019 (COVID-19) is microvascular thrombosis linked to endothelial cell activation. Consistent with this, a number of studies have shown that patients with severe COVID-19 have highly elevated plasma levels of von Willebrand Factor (VWF) that may contribute to the prothrombotic phenotype. In the current study, we investigated the extent of endothelial activation in patients receiving hemodialysis who had either mild or severe COVID-19. Methods: Plasma VWF, ADAMTS-13, angiopoietin-2 (Ang2), and syndecan-1 levels were determined by ELISA. The sialic acid content of VWF was investigated using a modified ELISA to measure elderberry bark lectin, specific for sialic acid residues, binding to VWF. Results: Patients receiving hemodialysis with severe COVID-19 had significantly higher plasma levels of VWF and lower ADAMTS-13. VWF levels peaked and were sustained during the first 10 days after positive confirmation of infection. While Ang2 trended toward being higher in severely ill patients, this did not reach significance; however, severely ill patients had significantly higher soluble syndecan-1 levels, with high levels related to risk of death. Finally, higher VWF levels in severely ill patients were correlated with lower VWF sialic acid content. Conclusions: Severe COVID-19 in patients undergoing hemodialysis is associated with both acute and sustained activation of the endothelium, leading to alteration of the VWF/ADAMTS-13 axis. Lower VWF sialic acid content represents altered VWF processing and further confirms the disturbance caused to the endothelium in COVID-19

Progressive IgA Nephropathy Is Associated With Low Circulating Mannan-Binding Lectin-Associated Serine Protease-3 (MASP-3) and Increased Glomerular Factor H-Related Protein-5 (FHR5) Deposition

Introduction IgA nephropathy (IgAN) is characterized by glomerular deposition of galactose-deficient IgA1 and complement proteins and leads to renal impairment. Complement deposition through the alternative and lectin activation pathways is associated with renal injury. Methods To elucidate the contribution of the lectin pathway to IgAN, we measured the 11 plasma lectin pathway components in a well-characterized cohort of patients with IgAN. Results M-ficolin, L-ficolin, mannan-binding lectin (MBL)–associated serine protease (MASP)-1 and MBL-associated protein (MAp) 19 were increased, whereas plasma MASP-3 levels were decreased in patients with IgAN compared with healthy controls. Progressive disease was associated with low plasma MASP-3 levels and increased glomerular staining for C3b/iC3b/C3c, C3d, C4d, C5b-9, and factor H–related protein 5 (FHR5). Glomerular FHR5 deposition positively correlated with glomerular C3b/iC3b/C3c, C3d, and C5b-9 deposition, but not with glomerular C4d. These observations, together with the finding that glomerular factor H (fH) deposition was reduced in progressive disease, are consistent with a role for fH deregulation by FHR5 in renal injury in IgAN. Conclusion Our data indicate that circulating MASP-3 levels could be used as a biomarker of disease severity in IgAN and that glomerular staining for FHR5 could both indicate alternative complement pathway activation and be a tissue marker of disease severity

Blood transfusions post kidney transplantation are associated with inferior allograft and patient survival—it is time for rigorous patient blood management

Background: Patient Blood Management (PBM), endorsed by the World Health Organisation is an evidence-based, multi-disciplinary approach to minimise inappropriate blood product transfusions. Kidney transplantation presents a particular challenge to PBM, as comprehensive evidence of the risk of transfusion is lacking. The aim of this study is to investigate the prevalence of post-transplant blood transfusions across multiple centres, to analyse risk factors for transfusion and to compare transplant outcomes by transfusion status. Methods: This analysis was co-ordinated via the UK Transplant Registry within NHS Blood and Transplant (NHSBT), and was performed across 4 centres. Patients who had received a kidney transplant over a 1-year period, had their transfusion status identified and linked to data held within the national registry. Results: Of 720 patients, 221(30.7%) were transfused, with 214(29.7%) receiving a red blood cell (RBC) transfusion. The proportion of patients transfused at each centre ranged from 20% to 35%, with a median time to transfusion of 4 (IQR:0-12) days post-transplant. On multivariate analysis, age [OR: 1.02(1.01-1.03), p=0.001], gender [OR: 2.11(1.50-2.98), p<0.0001], ethnicity [OR: 1.28(1.28-2.60), p=0.0008], and dialysis dependence pre-transplant [OR: 1.67(1.08-2.68), p=0.02], were associated with transfusion. A risk-adjusted Cox proportional hazards model showed transfusion was associated with inferior 1-year patient survival [HR 7.94(2.08-30.27), p=0.002] and allograft survival [HR: 3.33(1.65-6.71), p=0.0008], and inferior allograft function. Conclusion: RBC transfusions are common and are independently associated with inferior transplant outcomes. We urge that further research is needed to understand the mechanisms behind the outcomes, to support the urgent development of transplant-specific anaemia guidelines

Lack of seroresponse to SARS-CoV-2 booster vaccines given early post-transplant in patients primed pre-transplantation

SARS-CoV-2 vaccines are recommended pre-transplantation, however, waning immunity and evolving variants mandate booster doses. Currently there no data to inform the optimal timing of booster doses post-transplant, in patients primed pre-transplant. We investigated serial serological samples in 204 transplant recipients who received 2 or 3 SARS-CoV-2 vaccines pre-transplant. Spike protein antibody concentrations, [anti-S], were measured on the day of transplantation and following booster doses post-transplant. In infection-naïve patients, post-booster [anti-S] did not change when V3 (1st booster) was given at 116(78-150) days post-transplant, falling from 122(32-574) to 111(34-682) BAU/ml, p=0.78. Similarly, in infection-experienced patients, [anti-S] on Day-0 and post-V3 were 1090(133-3667) and 2207(650-5618) BAU/ml respectively, p=0.26. In patients remaining infection-naïve, [anti-S] increased post-V4 (as 2nd booster) when given at 226(208-295) days post-transplant, rising from 97(34-1074) to 5134(229-5680) BAU/ml, p=0.0016. Whilst in patients who had 3 vaccines pre-transplant, who received V4 (as 1st booster) at 82(49-101) days post-transplant, [anti-S] did not change, falling from 981(396-2666) to 871(242-2092) BAU/ml, p=0.62. Overall, infection pre-transplant and [anti-S] at the time of transplantation predicted post-transplant infection risk. As [Anti-S] fail to respond to SARS-CoV-2 booster vaccines given early post-transplant, passive immunity may be beneficial to protect patients during this period