De Novo Donor-Specific Anti-HLA Antibodies Research Articles

HLA-DR/DQ Single Molecule Eplet Mismatch and Formation of De Novo Donor-Specific Anti-HLA Antibodies After Kidney Transplantation in Children

HLA-DR/DQ Single Molecule Eplet Mismatch and Formation of De Novo Donor-Specific Anti-HLA Antibodies After Kidney Transplantation in Children

Clinical Significance of Shared T Cell Epitope Analysis in Early De Novo Donor-Specific Anti-HLA Antibody Production After Kidney Transplantation and Comparison With Shared B cell Epitope Analysis

In pre-sensitizing events, immunological memory is mainly created via indirect allorecognition where CD4+ T cells recognize foreign peptides in the context of self-HLA class II (pHLA) presented on antigen-presenting cells. This recognition makes it possible for naive CD4+ T-helper cells to differentiate into memory cells, resulting in the creation of further antibody memory. These responses contribute to effective secretion of donor-specific anti-HLA antibodies (DSA) after second encounters with the same peptide. Preformed donor-reactive CD4+ memory T cells may induce early immune responses after transplantation; however, the tools to evaluate them are limited. This study evaluated shared T cell epitopes (TEs) between the pre-sensitizing and donor HLA using an in silico assay, an alternative to estimate donor-reactive CD4+ memory T cells before transplantation. In 578 living donor kidney transplants without preformed DSA, 69 patients had anti-HLA antibodies before transplantation. Of them, 40 had shared TEs and were estimated to have donor-reactive CD4+ memory T cells. De novo DSA formation in the early phase was significantly higher in the shared TE-positive group than in the anti-HLA antibody- and shared TE-negative groups (p=0.001 and p=0.02, respectively). In conclusion, evaluation of shared TEs for estimating preformed donor-reactive CD4+ memory T cells may help predict the risk of early de novo DSA formation after kidney transplantation.

Non-adherence assessment to immunosuppressant therapy with a self-report questionnaire and intra-patient variability in renal transplantation: risk factors and clinical correlations.

Non-adherence (NA) to immunosuppressive drugs is to date considered a crucial issue in kidney transplanted patients (KTRs), leading to de-novo donor-specific anti-HLA antibodies (dnDSA) development, acute and chronic rejection, and at least graft loss. However, NA assessment is challenging, often leading to underestimation in real-life settings. NA evaluation in all KTRs referred to our post-transplantation clinic in the period between 01/01-15/07/2018 with self-report questionnaire combined to intra-patient variability (IPV) of the pivotal immunosuppressive drug (based on trough levels of tacrolimus/mTOR inhibitor). Based on both questionnaire and IPV, 86 out of the 504 tested KTRs (17%) were classified as NA. Male gender (OR, 2.0; 95% confidence interval [CI], 1.2 to 3.4), high educational level (OR for KTRs with a degree, 1.8 [95% CI, 1.0 to 3.1]), employment (OR, 2.0 [95% CI, 1.2 to 3.3]), young age at transplantation (P=0.017), longer time on the waiting list and after transplantation (P=0.027 and 0.049 respectively) were all associated with NA. High IPV was mostly documented in KTRs treated with the twice-daily formulation of the immunosuppressive drug (OR, 1.5 [95% CI, 1.0 to 2.1]) and better associated with dnDSA appearance (OR, 2.1 [95% CI, 1.1 to 3.9]). NA is a significant problem, difficult to assess, and can lead to dnDSA development also in our population. Identifying risk factors for NA might be an underestimated tool to improve graft and patient outcome in KTRs.

Comparison of Characteristics of De Novo Donor-Specific Anti-HLA Antibodies (dnDSAs) in Living-Donor Lobar Lung Transplantation and Deceased-Donor Lung Transplantation

The impact of de novo donor-specific anti-HLA antibodies (dnDSAs) on patients after lung transplantation remains controversial. We investigated various characteristics of dnDSAs such as timing of initial dnDSA detection and type of HLA classes and compared them between living-donor lobar lung transplants (LDLLTs) and deceased-donor lung transplants (DDLTs) at a single institution in Japan. We performed 92 LDLLTs and 129 DDLTs between 2008 and 2019. Patients, in whom anti-HLA antibodies were measured both pre- and post-operatively, were included in this study. Patients who had pre-formed DSA and patients undergoing re-transplantation were excluded. This retrospective study included 79 recipients undergoing LDLLT and 109 recipients undergoing DDLT. In total, 29 patients (15.8%) had dnDSAs. They consisted of 6 LDLLT recipients and 23 DDLT recipients. In LDLLT, cumulative incidence of dnDSA detection was 4.2%, 4.2% and 6.3% at 1, 3 and 5 years, respectively. On the other hand, in DDLT, cumulative incidence of dnDSA detection was 18.1%, 21.6% and 23.7% at 1, 3 and 5 years, respectively (p=0.002, Figure 1). Class I dnDSAs were more frequently detected in DDLT recipients (10.1%) than in LDLLT recipients (1.3%, p=0.015), while the incidence of class II dnDSAs were comparable between two groups (12.8% in DDLT and 7.6% in LDLLT, p=0.34). We found that dnDSAs were significantly more frequently detected in DDLT than in LDLLT. Types of dnDSA seemed different between LDLLT and DDLT.

Comparison of De Novo Donor-Specific Anti-HLA Antibodies (DSAs) between Living-Donor Lobar Lung Transplantation and Cadaveric Lung Transplantation

Comparison of De Novo Donor-Specific Anti-HLA Antibodies (DSAs) between Living-Donor Lobar Lung Transplantation and Cadaveric Lung Transplantation

Characteristics of De Novo Donor-specific Anti-HLA Antibodies (DSAs) in Living-donor Lobar and Cadaveric Lung Transplantation

The impact of de novo donor-specific anti-HLA antibodies (DSA) on patients after lung transplantation remains controversial. We investigated various characteristics of de novo DSAs, such as timing of initial de novo DSA detection, treatment, and prognosis in living-donor lobar lung transplantation (LDLLT) and cadaveric lung transplantation (CLT) at a single institution in Japan.

Characteristics and Clinical Significance of De Novo Donor-Specific Anti-HLA Antibodies after Kidney Transplantation.

BackgroundThe association of de novo donor-specific anti-human leukocyte antigens (HLA) antibodies (DSA) and development of antibody-mediated rejection (AMR) in kidney transplant recipients (KTRs) is still undetermined.MethodsWe prospectively screened de novo DSA in 167 KTRs during 32 months after kidney transplantation (KT). Timing of DSA detection was at 3, 6, and 12 months post-transplant and annually thereafter and when clinically indicated. DSA levels were determined by Luminex assays and expressed as mean fluorescence intensity (MFI). We evaluated the incidence, characteristics of DSA, and association between DSA and tacrolimus trough levels or AMR.ResultsDe novo DSA developed in 16 KTRs (9.6%) and acute AMR occurred more commonly in KTRs with de novo DSA compared to KTRs without de novo DSA (18.8% vs. 0%, P < 0.001). All de novo DSA were against class II antigens. The mean number of DSA was 1.8 ± 1.2 and the average MFI of DSA was 7,399 ± 5,470. Tacrolimus trough level during the first 0–2 months after KT was an independent predictor of DSA development (hazard ratio, 0.70; 95% confidence interval, 0.50–0.99; P = 0.043). No differences were found in the number of DSA, average MFI of DSA, and tacrolimus levels during the first year between de novo DSA-positive KTRs with AMR and those without AMR.ConclusionThe results of our study suggest that monitoring of DSA and maintaining proper tacrolimus levels are essential to prevent AMR during the initial period after KT.

De-novo donor-specific anti-HLA antibodies 30 days after lung transplantation are associated with a worse outcome

The impact of de-novo donor-specific anti-HLA antibodies (DSA) on patient and graft survival after lung transplantation remains controversial. We analyzed DSA that developed at Day 7 and Month (M) 1, M3, M6 and M12 after lung transplantation and evaluated their impact on chronic lung allograft dysfunction (CLAD) development and survival. One hundred thirty-four patients who underwent lung transplantation at our institution between November 2007 and August 2013 were included in this study. During the first post-transplant year, 82 (61%) patients developed de novo DSA and 52 (39%) patients did not. Three mean fluorescence intensity (MFI) intervals were used to define scores of anti-HLA antibody positivity: score 4 if MFI was 500 to 1,000; score 6 if MFI was 1,000 to 3,000; and score 8 if MFI was ≥3,000. Patients' records were retrospectively reviewed. DSA with MFI scores of ≥4 (hazard ratio [HR] 2.21, 95% confidence interval [CI] 1.08 to 4.54, p = 0.03), 6 (HR 2.63, 95% CI 1.27 to 5.20, p < 0.01) and 8 (HR 2.83, 95% CI 1.42 to 5.67, p < 0.01) at M1; female gender (HR 0.49, 95% CI 0.28 to 0.87, P = 0.01); and with post-operative extracorporeal membrane oxygenation (HR 0.09, 95% CI 0.01 to 0.28, p = 0.02) were significantly associated with CLAD. Multivariate analysis identified score 8 at M1 (HR 2.71, 95% CI 1.34 to 5.47, p < 0.01) as an independent risk factor for mortality. Overall, 1-, 3- and 5-year survival rates were 76%, 52% and 41% compared with 84%, 74% and 70% for patients with or without de-novo DSA at M1, respectively (p = 0.02). Early de-novo DSA may significantly impact long-term outcomes after lung transplantation and should therefore prompt regular screening.

(557) - Clinical Implication of Non-Complement-Binding De Novo Donor-Specific Anti-HLA Antibodies in Heart Transplant Recipients: Do We Really Have to Care All the DSA Positive Patients?

(557) - Clinical Implication of Non-Complement-Binding De Novo Donor-Specific Anti-HLA Antibodies in Heart Transplant Recipients: Do We Really Have to Care All the DSA Positive Patients?

Non-Complement-Binding De Novo Donor-Specific Anti-HLA Antibodies and Kidney Allograft Survival.

C1q-binding ability may indicate the clinical relevance of de novo donor-specific anti-HLA antibodies (DSA). This study investigated the incidence and risk factors for the appearance of C1q-binding de novo DSA and their long-term impact. Using Luminex Single Antigen Flow Bead assays, 346 pretransplant nonsensitized kidney recipients were screened at 2 and 5 years after transplantation for de novo DSA, which was followed when positive by a C1q Luminex assay. At 2 and 5 years, 12 (3.5%) and eight (2.5%) patients, respectively, had C1q-binding de novo DSA. De novo DSA mean fluorescence intensity >6237 and >10,000 at 2 and 5 years, respectively, predicted C1q binding. HLA mismatches and cyclosporine A were independently associated with increased risk of C1q-binding de novo DSA. When de novo DSA were analyzed at 2 years, the 5-year death-censored graft survival was similar between patients with C1q-nonbinding de novo DSA and those without de novo DSA, but was lower for patients with C1q-binding de novo DSA (P=0.003). When de novo DSA were analyzed at 2 and 5 years, the 10-year death-censored graft survival was lower for patients with C1q-nonbinding de novo DSA detected at both 2 and 5 years (P<0.001) and for patients with C1q-binding de novo DSA (P=0.002) than for patients without de novo DSA. These results were partially confirmed in two validation cohorts. In conclusion, C1q-binding de novo DSA are associated with graft loss occurring quickly after their appearance. However, the long-term persistence of C1q-nonbinding de novo DSA could lead to lower graft survival.

(307) - Human Intravenous Immunoglobulins With Rituximab vs. Therapeutic Plasma Exchange With Rituximab for Pre-Emptive Treatment of Early Donors Specific Antibodies After Lung Transplantation: Preliminary Result

At our Institution, patients developing de-novo donor specific anti-HLA antibodies (DSA) early after lung transplantation were treated preemptively with therapeutic plasma exchange (tPE) and Rituximab until April 2013 and, since May 2013, with human intravenous immunoglobulins (IVIG) and Rituximab. Aim of this study was to evaluate the efficacy of IVIG vs. tPE protocols. Records of patients transplanted between January 2009 and September 2014 were retrospectively reviewed. Patients treated with tPE underwent sessions of 3 or 5 tPE only during initial hospitalization after lung transplantation. Patients treated with IVIG initially received 1g/kg body weight IVIG loading-dose, followed by additional courses of 0.5g/kg IVIG every four weeks until DSA clearance or to a maximum of 6 months. Patients received a single dose of Rituximab (375mg/m2) at the end of the first tPE session or IVIG loading-dose. DSA treatment was performed preemptively before appearance of graft-dysfunction. Among 694 transplanted patients, 57 (8%) patients (Group A) and 43 (6%) patients (Group B) underwent DSA treatment with tPE or IVIG, respectively. There was no difference among groups regarding preoperative characteristics. Postoperatively, more Group B than A patients developed class II DSA (91%vs.68%, p=0.008). Forty-nine (86%) Group A and 39 (91%) Group B patients received only one tPE session and one dose of IVIG, respectively. At discharge, more Group B than A patients showed DSA (71%vs.50%, p=0.05). At follow-up, no Group A patients underwent additional tPE. Instead, 34 Group B patients underwent 3±2 additional IVIG courses. At last DSA control, after having censored Group B patients (n=9) who have still not completed the IVIG protocol, 13 (27%) Group A and 4 (12%) Group B showed DSA (p=0.10). At 1-year follow-up, there was no difference among groups regarding freedom from steroid-pulsed therapy (p=0.1) and biopsy-proven rejection (p=0.78). Overall survival was significantly better in Group B patients (p=0.01). The IVIG protocol achieved satisfactory DSA clearance after repeated therapy courses. A combination of the two protocols may further improve DSA clearance. Further studies are warranted.

(704) - Characteristics of De Novo Donor-Specific Anti-HLA Antibodies (DSAs) in Living-Donor Lobar Lung Transplantation Might Be Different From Those in Cadaveric Lung Transplantation

(704) - Characteristics of De Novo Donor-Specific Anti-HLA Antibodies (DSAs) in Living-Donor Lobar Lung Transplantation Might Be Different From Those in Cadaveric Lung Transplantation

De Novo Donor-Specific Anti-HLA Antibodies Are a Risk Factor for the Development of Biliary Strictures After DBD Liver Transplantation.

De Novo Donor-Specific Anti-HLA Antibodies Are a Risk Factor for the Development of Biliary Strictures After DBD Liver Transplantation.

(474) - Late Antibody-Mediated Rejection Due To De-Novo Donor-Specific Anti-HLA Antibodies in Heart Transplant Recipients: A Cohort of 20 Consecutive Patients

PurposeWhereas early antibody-mediated rejections (AMR) in sensitized patients are well described, data are scarce concerning late AMR due to de novo donor-specific anti-HLA antibodies (DSA) in heart transplant recipients.MethodsWe performed a retrospective observational cohort study in a high volume heart transplantation center. We included all patients treated for late symptomatic AMR due to de novo DSA from November 2006 to February 2013. We realized retrospective blinded reinterpretation of EMB (including EMB before and after treated AMR).ResultsLate AMR due to de novo DSA was diagnosed in 20 patients. Prevalence was estimated to 2 %. All patients but one had evidence of allograft dysfunction (cardiogenic shocks: n = 6). De novo DSA were identified in all patients (MFI range: 312 to 49395). Typical histological patterns of AMR were found in 18 patients (90 %). Despite aggressive immunosuppressive therapies (IV methylprednisolone: 100 % of patients, IVIg: 90 %, plasmapheresis: 85 %, Rituximab: 45 %), the prognosis remained poor: survival was 80 % at 1 month, 60 % at 3 months and 50 % at 1 year (see figure). Median survival was 0.96 years. Among patients alive at 3 months (n = 12), one third had evidence of histological AMR relapse during follow-up. Two patients developed fulminant cardiac allograft vasculopathy (CAV) in the month following AMR. Interestingly, signs of microvascular inflammation were observed on previous BEM for 13 patients (65%).Conclusion PurposeWhereas early antibody-mediated rejections (AMR) in sensitized patients are well described, data are scarce concerning late AMR due to de novo donor-specific anti-HLA antibodies (DSA) in heart transplant recipients. Whereas early antibody-mediated rejections (AMR) in sensitized patients are well described, data are scarce concerning late AMR due to de novo donor-specific anti-HLA antibodies (DSA) in heart transplant recipients. MethodsWe performed a retrospective observational cohort study in a high volume heart transplantation center. We included all patients treated for late symptomatic AMR due to de novo DSA from November 2006 to February 2013. We realized retrospective blinded reinterpretation of EMB (including EMB before and after treated AMR). We performed a retrospective observational cohort study in a high volume heart transplantation center. We included all patients treated for late symptomatic AMR due to de novo DSA from November 2006 to February 2013. We realized retrospective blinded reinterpretation of EMB (including EMB before and after treated AMR). ResultsLate AMR due to de novo DSA was diagnosed in 20 patients. Prevalence was estimated to 2 %. All patients but one had evidence of allograft dysfunction (cardiogenic shocks: n = 6). De novo DSA were identified in all patients (MFI range: 312 to 49395). Typical histological patterns of AMR were found in 18 patients (90 %). Despite aggressive immunosuppressive therapies (IV methylprednisolone: 100 % of patients, IVIg: 90 %, plasmapheresis: 85 %, Rituximab: 45 %), the prognosis remained poor: survival was 80 % at 1 month, 60 % at 3 months and 50 % at 1 year (see figure). Median survival was 0.96 years. Among patients alive at 3 months (n = 12), one third had evidence of histological AMR relapse during follow-up. Two patients developed fulminant cardiac allograft vasculopathy (CAV) in the month following AMR. Interestingly, signs of microvascular inflammation were observed on previous BEM for 13 patients (65%). Late AMR due to de novo DSA was diagnosed in 20 patients. Prevalence was estimated to 2 %. All patients but one had evidence of allograft dysfunction (cardiogenic shocks: n = 6). De novo DSA were identified in all patients (MFI range: 312 to 49395). Typical histological patterns of AMR were found in 18 patients (90 %). Despite aggressive immunosuppressive therapies (IV methylprednisolone: 100 % of patients, IVIg: 90 %, plasmapheresis: 85 %, Rituximab: 45 %), the prognosis remained poor: survival was 80 % at 1 month, 60 % at 3 months and 50 % at 1 year (see figure). Median survival was 0.96 years. Among patients alive at 3 months (n = 12), one third had evidence of histological AMR relapse during follow-up. Two patients developed fulminant cardiac allograft vasculopathy (CAV) in the month following AMR. Interestingly, signs of microvascular inflammation were observed on previous BEM for 13 patients (65%). Conclusion