non-HLA Antibodies Research Articles

Non-HLA antibodies targeting angiotensin II Type 1 receptor and endothelin-1 Type A receptors induce endothelial injury via β2-arrestin link to mTOR pathway

Functional non-HLA antibodies (antibodies to non-human leukocyte antigens) targeting the G protein-coupled receptors angiotensin II type 1 receptor (AT1R) and endothelin-1 type A receptor (ETAR) are implicated in the pathogenesis of transplant vasculopathy. While ERK signaling (a regulator of cell growth) may represent a general cellular response to agonist stimulation, the molecular link between receptor stimulation and development of vascular obliteration has not been fully established. Here we hypothesize involvement of the versatile adaptor proteins, β-arrestins, and the major regulator of cell growth, PI3K/mTOR signaling, in impaired endothelial repair. To test this, human microvascular endothelial cells were treated with AT1R/ETAR antibodies isolated from patients with kidney transplant vasculopathy. These antibodies activated both mTOR complexes via AT1R and ETAR in a PI3K-dependent and ERK-independent manner. The mTOR inhibitor, rapamycin, completely abolished activation of mTORC1 and mTORC2 after long-term treatment with receptor antibodies. Imaging studiesrevealed that β2- but not β1-arrestin was recruitedto ETAR in response to ET-1 and patient antibodies but not with antibodies isolated from healthy individuals. Silencing of β2-arrestin by siRNA transfection significantly reduced ERK1/2 and mTORC2 activation. Non-HLA antibodies impaired endothelial repair by AT1R- and ETAR-induced mTORC2 signaling. Thus, we provide evidence that functional AT1R/ETAR antibodies induce ERK1/2 and mTOR signaling involving β2-arrestin in humanmicrovascular endothelium. Hence, our datamayprovide a translational rationale for mTORinhibitorsincombination with receptor blockers inpatientswith non-HLA receptor recognizing antibodies.

Association of preoperative non-HLA antibodies with kidney allograft rejection

Association of preoperative non-HLA antibodies with kidney allograft rejection

Inflammatory Profile Associated with Non-HLA Antibodies to G-Protein Coupled Receptors in Pediatric Kidney Transplant Recipients

Inflammatory Profile Associated with Non-HLA Antibodies to G-Protein Coupled Receptors in Pediatric Kidney Transplant Recipients

A descriptive analysis of non-human leukocyte antigens present in renal transplant donor-recipient pairs

IntroductionEnd stage renal disease (ESRD) is the irreversible deterioration of renal function requiring renal replacement therapy by dialysis or transplant. Human leucocyte antigens (HLA) have been well examined however research still is required into the non-HLA antibodies. Antibody mediated rejection (AMR) can be seen in the absence of HLA antibodies on biopsies of patients who have received identical transplants; anti-endothelial cell antibodies may explain this. Investigation into endothelial cell antigens on donor and recipient endothelium may elucidate and stratify the degree of risk of any given transplant and may guide towards the best matched donor. MethodsProtein array analysis was carried out on 8 patient pairs using nitro-cellulose membranes and biotinylated detection antibodies. The fluorescence emitted was captured by X-Ray film and results were recorded with ImageJ software. A fold increase of more than 2 was considered to be positive. Results11 proteins identified had a fold increase of increase ≥2 and were present in ≥2 patient pairs which may point to potential clinical utility. Nectin2/CD112 may be measured in order analyse graft survival time in transplant recipients. Prognosticating renal failure has clinical importance and potential markers that have been identified to aid which include MEPE, CRELD2, and TIMP-4. Novel pharmacological therapies for specific biomarkers identified in this study include JAM-A, E-Selectin, CD147, Galectin-3, JAM-C, PAR-1, and TNFR2. ConclusionProtein analysis showed differences in expression of antigens between patients with and without Chronic Kidney Disease (CKD). This information could be used at the matching stage of renal transplantation and also in the treatment of rejection episodes. The results highlight biomarkers that potentially prognosticate and pharmacological therapies that may ameliorate kidney disease and rejection in ESRD and transplant recipients.

Increased Autoantibodies Against Ro/SS-A, CENP-B, and La/SS-B in Patients With Kidney Allograft Antibody-mediated Rejection.

We analyzed non-HLA antibodies in sera from 80 kidney transplant patients with AMR, mixed rejection, acute cellular rejection (ACR), or acute tubular necrosis. IgM and IgG antibodies against 134 non-HLA antigens were measured in serum samples collected pretransplant or at the time of diagnosis. Fifteen non-HLA antibodies were significantly increased (P < 0.05) in AMR and mixed rejection compared with ACR or acute tubular necrosis pretransplant, and 7 at diagnosis. AMR and mixed cases showed significantly increased pretransplant levels of IgG anti-Ro/Sjögren syndrome-antigen A (SS-A) and anti-major centromere autoantigen (CENP)-B, compared with ACR. Together with IgM anti-CENP-B and anti-La/SS-B, these antibodies were significantly increased in AMR/mixed rejection at diagnosis. Increased IgG anti-Ro/SS-A, IgG anti-CENP-B, and IgM anti-La/SS-B were associated with the presence of microvascular lesions and class-II donor-specific antibodies (P < 0.05). Significant increases in IgG anti-Ro/SS-A and IgM anti-CENP-B antibodies in AMR/mixed rejection compared with ACR were reproduced in an external cohort of 60 kidney transplant patients. This is the first study implicating autoantibodies anti-Ro/SS-A and anti-CENP-B in AMR. These antibodies may participate in the crosstalk between autoimmunity and alloimmunity in kidney AMR.

Current Desensitization Strategies in Heart Transplantation.

Heart transplant candidates sensitized to HLA antigens wait longer for transplant, are at increased risk of dying while waiting, and may not be listed at all. The increasing prevalence of HLA sensitization and limitations of current desensitization strategies underscore the urgent need for a more effective approach. In addition to pregnancy, prior transplant, and transfusions, patients with end-stage heart failure are burdened with unique factors placing them at risk for HLA sensitization. These include homograft material used for congenital heart disease repair and left ventricular assist devices (LVADs). Moreover, these risks are often stacked, forming a seemingly insurmountable barrier in some cases. While desensitization protocols are typically implemented uniformly, irrespective of the mode of sensitization, the heterogeneity in success and post-transplant outcomes argues for a more tailored approach. Achieving this will require progress in our understanding of the immunobiology underlying the innate and adaptive immune response to these varied allosensitizing exposures. Further attention to B cell activation, memory, and plasma cell differentiation is required to establish methods that durably abrogate the anti-HLA antibody response before and after transplant. The contribution of non-HLA antibodies to the net state of sensitization and the potential implications for graft longevity also remain to be comprehensively defined. The aim of this review is to first bring forth select issues unique to the sensitized heart transplant candidate. The current literature on desensitization in heart transplantation will then be summarized providing context within the immune response. Building on this, newer approaches with therapeutic potential will be discussed emphasizing the importance of not only addressing the short-term pathogenic consequences of circulating HLA antibodies, but also the need to modulate alloimmune memory.

Utility of Donor-Derived Cell-Free DNA in Detecting ABMR in Patients With AT1R Antibodies

It is increasingly acknowledged that antibodies against human leukocyte antigens (HLAs) are implicated in less than 50% of histological features indicative of antibody-mediated rejection (ABMR).1 During that past decade, non-HLA antibodies against angiotensin II type 1 receptor (AT1R) have been recognized to be associated with ABMR in the absence of donor-specific HLA antibodies (DSA).2 The presence of AT1R antibodies is independently associated with high risk of episodes of ABMR and decreased long-term allograft survival.

Murine Cytomegalovirus-induced Complement-fixing Antibodies Deposit in Murine Renal Allografts During Acute Rejection.

Human cytomegalovirus (CMV) infection is associated with renal allograft dysfunction and loss, particularly in combination with acute rejection. Emerging literature suggests that non-HLA antibodies may contribute to antibody-mediated rejection, but pathogen-induced antibodies have not been investigated in this context. This study examines the presence of CMV-induced antibodies in murine CMV (MCMV)-infected renal allografts during acute rejection. Intragraft immunoglobulin G (IgG) and complement C3 immunostaining were compared among allogeneic MCMV D-/R-, D+/R-, and D+/R+ renal transplants. Intragraft antibody deposition was examined in B cell-deficient recipients treated with MCMV immune sera. Antibody binding and complement-dependent cytotoxicity (CDC) of D-/R- and D+/R+ sera against infected renal tubular epithelial cells (TECs) were measured in vitro. IgG immunostaining was performed in D+/R+ allografts and native kidneys and in D+/R- allografts treated with ganciclovir to inhibit viral replication. D+/R- and D+/R+ transplants had more abundant IgG and C3 deposition compared with D-/R- recipients. Greater IgG deposition was associated with more severe allograft injury in B cell-deficient recipients treated with MCMV immune sera compared with nonimmune sera. D+/R+ sera induced greater CDC of infected TECs compared with D-/R- sera. Native kidneys had lower IgG deposition compared with allografts, despite similar organ viral loads. Ganciclovir-treated allografts had reduced IgG deposition compared with untreated allografts. In this murine model, complement-fixing antibodies can deposit into MCMV-infected renal allografts, are associated with allograft damage, and can induce CDC of MCMV-infected renal TECs. The allogeneic response and viral replication may also contribute to intragraft antibody deposition.

Causes of Positive Pretransplant Crossmatches in the Absence of Donor-Specific Anti-Human Leukocyte Antigen Antibodies: A Single-Center Experience.

Pretransplant crossmatch (XM) testing is widely used for detecting preformed donor-specific antibodies (DSAs) against human leukocyte antigen (HLA). However, in some cases, there is a positive XM result in the absence of HLA-DSAs, the cause of which was rarely identified. We reviewed the causes of sequential positive XM results at a single center and analyzed the presence of non-HLA antibodies in patients with an unexplained positive pretransplant XM result. Among 251 patients with T-cell/B-cell complement-dependent cytotoxicity (CDC) or flow cytometric crossmatch (FCXM) positivity, HLA-DSAs were confirmed in 88 (35.1%) by a single antigen bead (SAB) assay, 150 (59.8%) used rituximab (anti-CD20), and 13 (5.2%) had neither HLA-DSAs nor a desensitization history. Anti-angiotensin II type 1 receptor IgG and 33 non-HLA antibodies were tested in the 13 patients with an unexplained positive pretransplant XM result, and more than one non-HLA antibody were revealed in all these patients; 11 patients had non-HLA antibodies reported to be associated with graft rejection, and two patients experienced rejection episode after kidney transplantation. Our study suggests considering non-HLA antibodies testing when a CDC or FCXM test is positive without a definite cause. Assessing non-HLA antibodies might be useful for interpreting XM results and evaluating immunologic risk in transplant recipients.

FC 128NON-HLA ANTIBODIES AND EPLET MISMATCHES IN KIDNEY TRANSPLANT RECIPIENTS WITH A HISTOLOGICAL PICTURE OF ANTIBODY-MEDIATED REJECTION WITH AND WITHOUT HLA DONOR-SPECIFIC ANTIBODIES

Abstract Background and Aims Correlation between antibody-mediated rejection (ABMR) and HLA donor-specific antibodies (DSA) is strong but imperfect in kidney transplant (KT) recipients, raising the possibility of other detrimental antibodies contributing to ABMR. The role of non-HLA antibodies on outcomes is not well known. Method We retrospectively assessed KT biopsies scored according to Banff’15 classification. Pre- and post-KT serum samples were checked for HLA and non-HLA antibodies (MICA-Ab, angiotensin II type 1 receptor (AT1R)-Ab, endothelin-1 type A receptor (ETAR)-Ab and crossmatches with primary aortic endothelial cells (EC-XM)). We also analyzed HLA epitope mismatches between donors and recipients. Results One-hundred eighteen patients with normal (n=19), ABMR histology (n=52) or IFTA (n=47) in their biopsy were studied. Graft survival was worse in ABMR patients (p=0.003). Pre-KT HLA-DSA were more frequent in ABMR cases (p=0.006). At biopsy, 73% ABMR patients had HLA-DSA (p&amp;lt;0.001). Pre-KT AT1R-Ab were more frequent in ABMR compared with IFTA and normal cases (p=0.003), without differences in other non-HLA antibodies. Fourteen patients with histological ABMR (27%) had no detectable HLA-DSA post-KT and only 3 had non-HLA Ab. However, these ABMR-DSA- cases showed similar biopsy changes and graft survival compared with ABMR-DSA+. Pre- or post-KT non-HLA antibodies other than AT1R-Ab were detected similarly in ABMR and in normal or IFTA cases. Both total class II and DRB1 epitope mismatches were associated with postransplant DSA and ABMR-DSA+. Multivariate analysis showed that both pre-KT HLA-DSA and AT1R-Ab (DSA: OR: 3.39 [1.20-9.59], p=0.021; AT1R-Ab: OR: 5.31 [1.75-16.10], p=0.003) were strong independent predictors of postransplant ABMR-DSA+ (Table 1). Conclusion Despite highly prevalent HLA-DSA before and after transplantation in KT with histological ABMR, 27% of cases did not show circulating HLA-DSA. Pre-KT AT1R-Ab associated with ABMR-DSA+, but not MICA-Ab, ETAR-Ab or EC-XM+. Any of them associated significantly with ABMR-DSA-. Epitope mismatch predicted both postransplant DRB-DSA and ABMR-DSA+. Detection of pre-KT HLA-DSA and/or AT1R-Ab, together with HLA epitope mismatch assessment, are valuable tools for better DSA and ABMR prediction in KT patients.

Abrogating biologics interference in flow cytometric crossmatching

The flow cytometric crossmatch is currently the gold standard for evaluating donor and recipient histocompatibility. The assay however does have limitations and is sensitive to false positive reactions resulting from the presence of non-HLA antibodies or therapy related immune biologics. Such false positive reactions can lead to the inappropriate decline of an acceptable donor organ or unnecessary therapeutic intervention. Here we describe the successful validation of anti-idiotype blocking antibodies in prevention of false positive flow crossmatch results caused by biologic therapy. Blocking antibodies specific for the Fab portion of Rituximab and/or Alemtuzumab were incubated with biologic containing patient serum prior to use in flow cytometric crossmatching. Biologic blocking successfully negated false positive crossmatch results with Rituximab (B cell ave. % change = -97%) or Alemtuzumab (T cell ave. % change = -99%, B cell ave. % change = -95%) infused sera respectively. Simultaneous blocking of these biologics was also successful. A complex case is presented to demonstrate the application of this procedure.

Histologic Antibody-mediated Kidney Allograft Rejection in the Absence of Donor-specific HLA Antibodies.

Histologic antibody-mediated rejection (hAMR) is defined as a kidney allograft biopsy satisfying the first 2 Banff criteria for diagnosing AMR: tissue injury and evidence of current/recent antibody interaction with the endothelium. In approximately one-half of such cases, circulating human leukocyte antigen (HLA) donor-specific antibodies (DSA) are not detectable by current methodology at the time of biopsy. Some studies indicated a better prognosis for HLA-DSA-negative cases of hAMR compared to those with detectable HLA-DSA, whereas others found equally poor survival compared to hAMR-negative cases. We reviewed the literature regarding the pathophysiology of HLA-DSA-negative hAMR. We find 3 nonmutually exclusive possibilities: (1) HLA-DSA are involved, but just not detected; (2) non-HLA-DSA (allo or autoantibodies) are pathogenically involved; and/or (3) antibody-independent NK cell activation is mediating the process through "missing-self" or other activating mechanisms. These possibilities are discussed in detail. Recommendations regarding the approach to such patients are made. Clearly, more research is necessary regarding the measurement of non-HLA antibodies, recipient/donor NK cell genotyping, and the use of antibody reduction therapy or other immunosuppression in any subset of patients with HLA-DSA-negative hAMR.

Association of non-HLA antibodies against endothelial targets and donor-specific HLA antibodies with antibody-mediated rejection and graft function in pediatric kidney transplant recipients

BackgroundNon-HLA antibodies against endothelial targets have been implicated in the pathogenesis of antibody-mediated rejection (ABMR), but data in pediatric patients are scarce.MethodsWe retrospectively analyzed a carefully phenotyped single-center (University Children’s Hospital Heidelberg, Germany) cohort of 62 pediatric kidney transplant recipients (mean age at transplantation, 8.6 ± 5.0 years) at increased risk of graft function deterioration. Patients had received their transplant between January 1, 1999, and January 31, 2010. We examined at time of late index biopsies (more than 1-year post-transplant, occurring after January 2004) the association of antibodies against the angiotensin II type 1 receptor (AT1R), the endothelin type A receptor (ETAR), the MHC class I chain-like gene A (MICA), and vimentin in conjunction with overall and complement-binding donor-specific HLA antibodies (HLA-DSA) with graft histology and function.ResultsWe observed a high prevalence (62.9%) of non-HLA antibody positivity. Seventy-two percent of HLA-DSA positive patients showed additional positivity for at least one non-HLA antibody. Antibodies against AT1R, ETAR, and MICA were associated with the histological phenotype of ABMR. The cumulative load of HLA-DSA and non-HLA antibodies in circulation was related to the degree of microinflammation in peritubular capillaries. Non-HLA antibody positivity was an independent non-invasive risk factor for graft function deterioration (adjusted hazard ratio 6.38, 95% CI, 2.11–19.3).ConclusionsOur data indicate that the combined detection of antibodies to HLA and non-HLA targets may allow a more comprehensive assessment of the patients’ immune responses against the kidney allograft and facilitates immunological risk stratification.

Non HLA Antibodies in Serum Prior to the Onset of Chronic Lung Allograft Dysfunction

PurposeNon-human leukocyte antigen (HLA) antibodies have been associated with chronic lung allograft dysfunction (CLAD). Whether they predate CLAD is unclear. We hypothesized that patients destined to develop CLAD might develop non-HLA antibodies prior to CLAD onset.MethodsIn a single centre retrospective study, we examined 100 consecutive crossmatch negative recipients of a bilateral lung transplant between 1 January 2013 and 31 December 2014. Using a two-colour fluorescent antigen microarray with 152 unique antigens, we measured IgG and IgM autoantibodies in pre-transplant and six months post-transplant serum samples. Log2-transformed mean fluorescent intensities (MFIs) were determined for each antigen. CLAD was determined using published definitions. Significance analysis of microarrays (SAM) was used to analyze differences in antigen reactivity with a false discovery rate of 0.05. Paired and unpaired analyses were used to examine differences within and between recipients who developed CLAD within 5 years and recipients who remained CLAD free at 5 years post-transplant.ResultsSerum samples were available for 96 recipients - 35 (36.5%) developed CLAD and 61 remained CLAD-free within 5 years. Total IgM and IgG reactivity decreased in most patients post-transplant (Fig 1A), although IgM levels were stable in patients developing CLAD. Three IgM autoantibodies - including anti-club cell secretory protein (CCSP, Fig 1B) - increased in most patients post-transplant; this increase was of greater magnitude in patients later developing CLAD. Patients destined to develop CLAD also had an increase in IgG fluorescence directed at human core histones (Fig 1C).ConclusionOur results suggest that there may be important differences in non-HLA antibody reactivity that appear before the onset of CLAD. These observations, which require validation in further studies, may also indicate a specific role for non-HLA antibodies directed at club cell secretory protein and nuclear antigens in CLAD development. Non-human leukocyte antigen (HLA) antibodies have been associated with chronic lung allograft dysfunction (CLAD). Whether they predate CLAD is unclear. We hypothesized that patients destined to develop CLAD might develop non-HLA antibodies prior to CLAD onset. In a single centre retrospective study, we examined 100 consecutive crossmatch negative recipients of a bilateral lung transplant between 1 January 2013 and 31 December 2014. Using a two-colour fluorescent antigen microarray with 152 unique antigens, we measured IgG and IgM autoantibodies in pre-transplant and six months post-transplant serum samples. Log2-transformed mean fluorescent intensities (MFIs) were determined for each antigen. CLAD was determined using published definitions. Significance analysis of microarrays (SAM) was used to analyze differences in antigen reactivity with a false discovery rate of 0.05. Paired and unpaired analyses were used to examine differences within and between recipients who developed CLAD within 5 years and recipients who remained CLAD free at 5 years post-transplant. Serum samples were available for 96 recipients - 35 (36.5%) developed CLAD and 61 remained CLAD-free within 5 years. Total IgM and IgG reactivity decreased in most patients post-transplant (Fig 1A), although IgM levels were stable in patients developing CLAD. Three IgM autoantibodies - including anti-club cell secretory protein (CCSP, Fig 1B) - increased in most patients post-transplant; this increase was of greater magnitude in patients later developing CLAD. Patients destined to develop CLAD also had an increase in IgG fluorescence directed at human core histones (Fig 1C). Our results suggest that there may be important differences in non-HLA antibody reactivity that appear before the onset of CLAD. These observations, which require validation in further studies, may also indicate a specific role for non-HLA antibodies directed at club cell secretory protein and nuclear antigens in CLAD development.

Humoral Risk Factors Associated to Allograft Dysfunction after Lung Transplantation: The Alert of Non-HLA Auto Antibody and HLA-Donor Specific Antibody (DSA) with Non-DSA HLA Antibody

<h3>Purpose</h3> Growing evidence has indicated the negative impact of non-HLA auto antibody (NHAuAb) on organ transplantation. Donor specific antibody (DSA) after lung transplantation (LuT) has been observed frequently with de novo Non-DSA (dN-DSA) HLA antibody. This study investigates the deleterious role of post-LuT NHAuAb and dN-DSA synergism to DSA in allograft damage. <h3>Methods</h3> We retrospectively analyzed NHAuAb and de novo DSA (dDSA)/dN-DSA data collected from the recipients who underwent LuT during 2012-2016. NHAuAbs were detected using LABScreen™ Autoantibody (>95% non-sensitized subjects as cut-off). HLA antibody was tested by LABScreen™ SAB (MFI≥ 1000 as cut-off). Clinical Antibody Mediated Rejection (cAMR, with acute graft dysfunction) and Chronic Lung Allograft Dysfunction (CLAD) were assessed for LuT outcomes. <h3>Results</h3> CXCL9, AURKA, REG3A, IFNγ, FLRT2, GDNF, HNRNPK, CXCL10, PLA2R, and Collagen IV detected from 111 patients' sera drawn at DSA peak phase showed significant association to total AMR, but only FLRT2 (P<0.001), GDNF, and CXCL10 (P<0.05) were remarkably correlated to cAMR (Table 1a). Preformed & persistent LG3, PECR, PKC-Z (P<0.001) and de novo ENO1, GAPDH, Lamin-B, TubulinA1B (p<0.05) identified from 113 patients' sera drawn around CLAD time, demonstrated strong correlation to the occurrence of CLAD (Table 1b). Patients with dDSA & dN-DSA had significantly higher incidence of cAMR than the patients with only dDSA (p<0.001, Table 1c). <h3>Conclusion</h3> Distinct clinical phases presented specific NHAuAb profiles. Multiple NHAuAbs, especially LG3, PKC-Z, and PECR which were preformed & persistent, promoted chronic graft dysfunction. HLA-dDSA augmented by dN-DSA (most likely through shared targeting epitopes) and NHAuAbs of FLRT2, GDNF, and CXCL10 were related to acute graft injury. These HLA and non-HLA humoral risk factors warrant timely enhanced immune therapy to prevent final allograft failure.

Early Antibody-Mediated Rejection in Non-Pre-Sensitized Heart Transplant Recipient

Introduction Antibody-mediated rejection (AMR) is an important cause of allograft dysfunction. It usually occurs after the first month of heart transplant (HT), but an early presentation is possible. We present an unusual case of a female HT recipient who had early AMR with no evidence of pre-sensitization to the donor. Case Report A woman, 45 years old, idiopathic dilated cardiomyopathy, two kids, with previous negative panel reactive antibody (PRA) was submitted to HT with success. The prospective crossmatch was negative and she did not receive blood cells during the surgery. The donor was a woman, 47 years old, who had a hemorrhagic stroke. After the procedure, she needed low doses of vasoactive drugs, received immunosuppression therapy according to institutional protocol and maintained normal ventricular function. On the 5th day, she developed biventricular graft dysfunction (left ventricular ejection fraction of 40%) requiring inotropes. The PRA revealed a donor specific antibody (DSA) not previously detected and the result of endomyocardial biopsy (EMB) confirmed acute AMR (pAMR2). Patient was successfully treated with methylprednisolone, plasmapheresis, immunoglobulin and rituximab. Biventricular function recovered; no DSA was detected and new EMB showed no rejection findings. Summary AMR results from recipient antibodies against donor-HLA antigens, causing complement activation, inflammation and injury to the allograft endothelium. In general, it occurs in the first two months after HT due to a rise in DSA by the contact with donor-HLA antigens. Early AMR, that occurs in the first week, is related to pre-sensitization to donor HLA antigens and associated with graft dysfunction. In this case report, no previous antibody had been detected. Two possibilities could explain such findings: the presence of non-HLA antibodies or the presence of memory B cells with levels of DSA too low to be detected on PRA. This case highlights the importance of monitoring antibodies in HT recipients with early allograft dysfunction even with previous negative PRA.

A 2020 Banff Antibody‐mediatedInjury Working Group examination of international practices for diagnosing antibody‐mediated rejection in kidney transplantation – a cohort study

The Banff antibody-mediated rejection (ABMR) classification is vulnerable to misinterpretation, but the reasons are unclear. To better understand this vulnerability, we evaluated how ABMR is diagnosed in practice. To do this, the Banff Antibody-Mediated Injury Workgroup electronically surveyed an international cohort of nephrologists/surgeons (n=133) and renal pathologists (n=99). Most providers (97%) responded that they use the Banff ABMR classification at least sometimes, but DSA information is often not readily available. Only 41.1% (55/133) of nephrologists/surgeons and 19.2% (19/99) of pathologists reported that they always have DSA results when the biopsy is available. Additionally, only 19.6% (26/133) of nephrologists/surgeons responded that non-HLA antibody or molecular transcripts are obtained when ABMR histologic features are present but DSA is undetected. Several respondents agreed that histologic features concerning for ABMR in the absence of DSA and/or C4d are not well accounted for in the current classification [31.3% (31/99) pathologists and 37.6% (50/133) nephrologist/surgeons]. The Banff ABMR classification appears widely accepted, but efforts to improve the accessibility of DSA information for the multidisciplinary care team are needed. Further clarity is also needed in Banff ABMR nomenclature to account for the spectrum of ABMR and for histologic features suspicious for ABMR when DSA is absent.

Emerging monitoring technologies in kidney transplantation.

Non-invasive technologies to monitor kidney allograft health utilizing high-throughput assays of blood and urine specimens are emerging out of the research realm and slowly becoming part of everyday clinical practice. HLA epitope analysis and eplet mismatch score determination promise a more refined approach to the pre-transplant recipient-donor HLA matching that may lead to reduced rejection risk. High-resolution HLA typing and multiplex single antigen bead assays are identifying potential new offending HLA antibody subtypes. There is increasing recognition of the deleterious role non-HLA antibodies play in post-transplant outcomes. Donor-derived cell-free DNA detected by next-generation sequencing is a promising biomarker for kidney transplant rejection. Multi-omics techniques are shedding light on discrete genomic, transcriptomic, proteomic, and metabolomic signatures that correlate with and predict allograft outcomes. Over the next decade, a comprehensive approach to optimize kidney matching and monitor transplant recipients for acute and chronic graft dysfunction will likely involve a combination of those emerging technologies summarized in this review.

Kidney Pancreas Transplant, a Brief Comprehension to Care

Surgical treatments for Insulin Dependent Diabetes Mellitus (IDDM) complicated with Advanced Chronic Kidney Disease (CKD) have emerged with the hope of providing a better sustainable quality of life. This article aims to highlight the utility of kidney and pancreas transplant in the management of IDDM with renal failure. There are different surgical methodologies, of which Simultaneous Pancreas And Kidney Transplantation (SPK) has been the most promising; in terms of graft survival and decreasing the need for a second surgical intervention in terms of kidney transplant. However, long waiting lists to find matching donors and post-operative complications are the most challenging obstacles. All recipients shall be screened for anti-HLA antibodies, non-HLA antibodies and Coronary Heart Disease (CHD). The presence of CHD poses a mortality risk post-surgery. Recipient selection requires a meticulous insight based on the insulin requirements, with the fact that not all will achieve insulin independence. A donor’s risk factors must be estimated by the Pancreas Donor Risk Index (PDRI), the higher the score lower the chances of graft survival. Pancreatic graft failure has no unanimously agreed definition of rejection and is dependent on a variety of donor and recipient factors. Close follow up and a high index of suspicion for any unexplained signs or symptoms is required to detect early allograft rejection, and the consideration of other surgical and medical etiologies is also required. This mini review will discuss various options for the management of insulin dependent diabetics whose diabetes remain uncontrolled with maximal efforts and have developed advanced chronic kidney disease pending renal replacement.

The Multifaceted Role of Non-human Leukocyte Antigens' Immune Response in Renal Allograft Rejection.

In renal transplantation (RT), human leukocyte antigens (HLA) expressed on donor cells are the principal targets of the recipient's immune system. In addition to classical HLA-alloantibodies, the importance of non-HLA antibodies (Abs) in RT is being increasingly recognized. The majority of non-HLA Abs are considered as autoantibodies as they are directed against cryptic autoantigens of vascular endothelium, which express following tissue (graft) injury. The mechanisms by which these Abs are produced and induce rejection are not fully understood. This review discusses the spectrum of non-HLA Abs, their putative pathogenetic mechanisms, clinical relevance, and their relationship with graft survival and rejection in RT.