Vascular Rejection Research Articles

NK Cells: Not Just Followers But Also Initiators of Chronic Vascular Rejection.

Chronic graft rejection represents a significant threat to long-term graft survival. Early diagnosis, understanding of the immunological mechanisms and appropriate therapeutic management are essential to improve graft survival and quality of life for transplant patients. Knowing which immune cells are responsible for chronic vascular rejection would allow us to provide effective and appropriate treatment for these patients. It is now widely accepted that natural killer (NK) cells play an important role in chronic vascular rejection. They can either initiate chronic vascular rejection by recognizing missing self on the graft or be recruited by donor-specific antibodies to destroy the graft during antibody-mediated rejection. Whatever the mechanisms of activation of NK cells, they need to be primed to become fully activated and damaging to the graft. A better understanding of the signaling pathways involved in NK cell priming and activation would pave the way for the development of new therapeutic strategies to cure chronic vascular rejection. This review examines the critical role of NK cells in the complex context of chronic vascular rejection.

226.3: Irradiated apoptotic peripheral blood mononuclear secretome (APOSEC) attenuates complement activation and decreases acute vascular rejection in an in vitro xenotransplantation model.

226.3: Irradiated apoptotic peripheral blood mononuclear secretome (APOSEC) attenuates complement activation and decreases acute vascular rejection in an in vitro xenotransplantation model.

Treatments for pathogen infection rescued 2 patients with renal artery rupture after kidney transplantation: A case report.

Renal artery rupture due to allograft infection, especially by fungi, is a serious clinical complication that can occur after kidney transplantation, and may lead to graft loss and death. Two kidney recipients from China who developed renal artery rupture at our hospital on 5 days (47-year-old female) and 45 days (39-year-old male) after surgery. The male had immunoglobulin A nephropathy as a primary disease, and experienced a postoperative attack of vascular rejection and mixed infection by Mucor and bacteria. The female had chronic glomerulonephritis as a primary disease, and experienced renal artery rupture near the anastomosis site with infection by fungi and other pathogens. The male received resection of the implanted kidney and antibiotic therapy with intravenous vancomycin (0.5 g, 2 days) and amphotericin B (530 mg in 33 days). The female received replacing the segment of renal arterial and internal iliac artery by saphenous vein, as well as antibiotic therapy with amphotericin B (320 mg in 8 days). The male was recovered and received a second transplantation, while the female was discharged on postoperative day 19. In both patients, prompt surgery and aggressive treatment with an antifungal drug (amphotericin B) and antidrugs led to successful rescue.

Comprehensive review of imaging in pancreas transplantation: a primer for radiologists.

Pancreas transplantation is a complex surgical procedure performed to restore normoglycemia in patients with type 1 diabetes and includes whole/segmental organ transplant and islet cell transplantation (ICT). In the United States, simultaneous pancreas-kidney transplant (SPK) is most commonly performed due to the higher occurrence of end-stage renal disease in diabetic patients. Understanding the surgical technique and postoperative anatomy is imperative for effective and accurate surveillance following transplantation. Imaging plays an essential role in patients with pancreatic transplants and is often used to evaluate viability, vascular and parenchymal anatomy, and identify potential complications. Imaging techniques such as ultrasound, color and spectral Doppler, computed tomography (CT), magnetic resonance imaging (MRI), and angiography have a complementary role in the postoperative evaluation following a pancreas transplant. The common complications after a whole organ pancreas transplant include vascular thrombosis, graft rejection, pancreatitis, and infections. Complications can be classified into vascular (partial or complete venous thrombosis, arterial thrombosis, stenosis or pseudoaneurysm), parenchymal (pancreatitis, graft rejection), and bowel-related or miscellaneous causes (bowel obstruction, anastomotic leak, and peripancreatic fluid collections). Islet cell transplantation is an innovative therapy for patients with type 1 diabetes. It involves isolating insulin-producing islet cells from donor pancreas and transplanting into recipients, to provide long-term insulin independence or significantly reduce insulin requirements. In recent years, isolation techniques, immunosuppressive regimens, and post-transplant monitoring advancements have propelled ICT as a viable therapeutic option. This comprehensive review aims to provide insights into the current state-of-the-art imaging techniques discussing both normal and abnormal features following pancreas transplantation.

The Endothelial Glycocalyx in Pig-to-Baboon Cardiac Xenotransplantation-First Insights.

Cardiac xenotransplantation has seen remarkable success in recent years and is emerging as the most promising alternative to human cardiac allotransplantation. Despite these achievements, acute vascular rejection still presents a challenge for long-term xenograft acceptance and new insights into innate and adaptive immune responses as well as detailed characterizations of signaling pathways are necessary. In allotransplantation, endothelial cells and their sugar-rich surface-the endothelial glycocalyx-are known to influence organ rejection. In xenotransplantation, however, only in vitro data exist on the role of the endothelial glycocalyx so far. Thus, in the current study, we analyzed the changes of the endothelial glycocalyx components hyaluronan, heparan sulfate and syndecan-1 after pig-to-baboon cardiac xenotransplantations in the perioperative (n = 4) and postoperative (n = 5) periods. These analyses provide first insights into changes of the endothelial glycocalyx after pig-to-baboon cardiac xenotransplantation and show that damage to the endothelial glycocalyx seems to be comparable or even less pronounced than in similar human settings when current strategies of cardiac xenotransplantation are applied. At the same time, data from the experiments where current strategies, like non-ischemic preservation, growth inhibition or porcine cytomegalovirus (a porcine roseolovirus (PCMV/PRV)) elimination could not be applied indicate that damage of the endothelial glycocalyx also plays an important role in cardiac xenotransplantation.

Factor V Leiden Heterozygous Mutation and Hyperhomocysteinemia Presenting with Vascular Rejection and Renal Allograft Infarction

Factor V Leiden Heterozygous Mutation and Hyperhomocysteinemia Presenting with Vascular Rejection and Renal Allograft Infarction

A Mouse Aortic Interposition Model to Study Alloimmune-Induced Vascular Rejection

A Mouse Aortic Interposition Model to Study Alloimmune-Induced Vascular Rejection

Long-term outcomes of pediatric liver transplantation in acute liver failure vs end-stage chronic liver disease: A retrospective observational study.

Children with acute liver failure (ALF) who meet the criteria are eligible for super-urgent transplantation, whereas children with end-stage chronic liver disease (ESCLD) are usually transplanted electively. Pediatric liver trans plantation (PLT) in ALF and ESCLD settings has been well described in the literature, but there are no studies comparing the outcomes in these two groups. To determine if there is a difference in post-operative complications and survival outcomes between ALF and ESCLD in PLT. This was a retrospective observational study of all primary PLTs performed at a single center between 2000 and 2019. ALF and ESCLD groups were compared for pretransplant recipient, donor and operative parameters, and post-operative outcomes including graft and patient survival. Over a 20-year study period, 232 primary PLTs were performed at our center; 195 were transplanted for ESCLD and 37 were transplanted for ALF. The ALF recipients were significantly older (median 8 years vs 5.4 years; P = 0.031) and heavier (31 kg vs 21 kg; P = 0.011). Living donor grafts were used more in the ESCLD group (34 vs 0; P = 0.006). There was no difference between the two groups concerning vascular complications and rejection, but there were more bile leaks in the ESCLD group. Post-transplant patient survival was significantly higher in the ESCLD group: 1-, 5-, and 10-year survival rates were 97.9%, 93.9%, and 89.4%, respectively, compared to 78.3%, 78.3%, and 78.3% in the ALF group (P = 0.007). However, there was no difference in 1-, 5-, and 10-year graft survival between the ESCLD and ALF groups (90.7%, 82.9%, 77.3% vs 75.6%, 72.4%, and 66.9%; P = 0.119). Patient survival is inferior in ALF compared to ESCLD recipients; the main reason is death in the 1st year post-PLT in ALF group. Once the ALF children overcome the 1st year after transplant, their survival stabilizes, and they have good long-term outcomes.

RE: Imlifidase-generated Single-cleaved IgG: Implications for Transplantation.

With great interest, we read the article by Bockermann et al1 on crossmatch assays after the administration of the novel desensitization drug Imlifidase. Proteolysis by Imlifidase generates single-cleaved immunoglobulin G (IgG) in a rapid first reaction and subsequently 2 F(ab’)2 fragments and a fully separated Fc fragment in a longer second reaction.2 Bockermann et al1 demonstrated that Luminex single antigen bead (SAB) testing, and crossmatching with both flowcytometry (FCXM) and the anti-human IgG-amplified complement-dependent cytotoxicity crossmatch (CDCXM) do not fully distinguish single-cleaved IgG from intact IgG. Bockermann et al1 suggest that the nonamplified CDCXM is best capable of demonstrating relevant residual intact IgG. Our center performed the first Imlifidase reimbursed HLA-incompatible kidney transplantation in March 2022. Contrary to Bockermann et al,1 we had difficulties in the interpretation of nonamplified CDCXM after Imlifidase treatment. A 29-y-old female with 6-y dialysis vintage after 2 failed kidney transplants was running out of vascular access. Despite high-urgency status and priority allocation via the Eurotransplant Acceptable Mismatch program, she remained without kidney offers. This was caused by her virtual panel-reactive antibody status of 100%. Her historical SAB mean fluorescence intensity (MFI) levels were high with broad reactivity in B-cell memory, with current MFI levels in the lower ranges. To enable for a timely HLA-incompatible kidney transplant, we delisted all unacceptable antigens with corresponding MFI levels of <3000, provided that CDC screening was negative. By this delisting, we increased her donor frequency of 0.000%–3.95%. Eight days later, this resulted in an HLA 1-2-2 mismatched kidney offer, with 2 “delisted DR-unacceptables.” Imlifidase was administered based on a virtual crossmatch. Serum was sampled 2 and 4 h after Imlifidase administration. Nonamplified CDCXMs with donor spleen cells were performed with preblood simultaneously tested with post 2-h and post 4-h sampling. Pre-CDCXM without dithiothreitol (DTT) treatment (which dissolves the disulfide bridges of IgM tetramers) was positive, indicating autoreactivity. DTT treatment revealed a negative pre-Imlifidase CDCXM. To our surprise, both the 2- and 4-h Imlifidase CDCXMs with DTT were positive (value 35 of 100). We had to decide whether or not to proceed with transplantation based on the nonamplified CDCXMs alone, as additional FCXM and SAB testing were scheduled for the next day. Because our patient had not recently received blood transfusions, was without infectious episodes, and had a negative pre-Imlifidase CDCXM, we expected assay interference by Imlifidase and decided to proceed with transplantation. The retrospectively performed pre-Imlifidase FCXM was negative for T cells and was 1.94 MCS for B cells. Luminex SAB was positive on 2 donor DR loci with 2500 and 2200, and became negative after Imlifidase. We investigated CDCXM on frozen donor spleen cells retrospectively and noticed CDC-positivity 2 and 4 h after Imlifidase, with negative CDCXMs on day 3. The patient did experience a vascular rejection after 1 wk, without signs of AMR. SAB testing revealed HLA antibody rebound from day 4 onward; however, DSA remained negative until current follow-up of 4 mo. This case demonstrates that even in nonamplified CDCXM, an interference by Imlifidase may occur. We advise to combine different assays when interpreting desensitization results after Imlifidase treatment.

Co-inhibition of immunoproteasome subunits LMP2 and LMP7 enables prevention of transplant arteriosclerosis.

The loss of vascular wall cells in allotransplanted arteries is the initial event leading to transplant arteriosclerosis (TA) and ensuing loss of allograft function. Pharmacological agents able to prevent TA are currently lacking. We previously showed that selective inhibition of the immunoproteasome prevented the chronic rejection of renal allografts. However, the role and mechanisms of selective inhibition of a single immunoproteasome subunit to prevent immune-mediated vascular allograft rejection and TA is not clear. The effect and potential mechanism of combined or individual inhibition of peptidolytically active immunoproteasome LMP7 (β5i) and LMP2 (β1i) subunits on immune rejection-mediated TA was investigated using the epoxyketone inhibitor ONX 0914, and the recently developed LMP7-selective inhibitor KZR-329 and LMP2-selective inhibitor KZR-504 in a rat aorta transplantation model. We find that co-inhibition of LMP7 and LMP2 in allogeneic recipients significantly suppressed T-cell activation and function by expressing inhibitory surface markers and then activating inhibitory signals. Moreover, co-inhibition of LMP7 and LMP2 substantially reduced the number of immunoglobulin G-secreting cells and plasma cells and production of alloantibodies through activating the unfolded protein response and incapacitating the survival niche of plasma cells in the bone marrow. Consequentially, the accumulation of inflammatory cytokines, complement, and antibodies is reduced and the apoptosis of vascular wall cells decreased in aortic allografts via LMP7 and LMP2 co-inhibition with ONX 0914 treatment or combined KZR-329 and KZR-504 treatment. However, neither individual inhibition of LMP7 by KZR-329 nor individual inhibition of LMP2 by KZR-504 showed suppression of immune rejection and TA. We define a critical role of LMP7 and LMP2 in TA and strongly propose co-inhibition of both immunoproteasome subunits as promising therapeutic approach to suppress TA and allograft rejection.

Potential Utility of Neutrophil-to-Lymphocyte, Platelet-to-Lymphocyte, and Neutrophil, Lymphocyte, and Platelet Ratios in Differential Diagnosis of Kidney Transplant Acute Rejection: A Retrospective, Propensity Score Matched Analysis.

BACKGROUND Acute kidney transplant rejection can negatively affect long-term graft function. The neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio have been proposed as non-invasive predictors of acute rejection in stable kidney transplant recipients. The aim of this study was to validate the predictive value of these ratios, as well as neutrophil, lymphocyte, and platelet ratios in the diagnosis of acute rejection during the early post-transplant period. MATERIAL AND METHODS After propensity score matching, we compared 71 kidney recipients with biopsy-proven acute rejection with 71 patients without rejection and also subjects with different histologic types of rejection. All 3 types of blood cell count-derived ratios were calculated 6 and 3 days prior to biopsy and on the day of biopsy. RESULTS There were 15 patients with T cell-mediated rejection, 33 with vascular rejection, and 23 with antibody-mediated rejection. The values of all examined ratios did not differ between subgroups with and without rejection. However, at all post-transplant study time-points, patients with antibody-mediated rejection had significantly higher values of all analyzed ratios than subjects with other types of rejection. In multivariate regression models, higher values of blood cell count-derived ratios were independently associated with the occurrence of antibody-mediated rejection. CONCLUSIONS In the early post-transplant period, the values of neutrophil-to-lymphocyte, platelet-to-lymphocyte, and neutrophil, lymphocyte, and platelet ratios were similar in patients with and without an acute rejection episode, but significantly higher values were found in subjects with antibody-mediated rejection as compared with other types of rejection and those without rejection. High values of analyzed ratios in patients with satisfactory early kidney graft function may be helpful in selecting subjects with increased risk of subclinical antibody-mediated rejection.

IL-18BP Improves Early Graft Function and Survival in Lewis-Brown Norway Rat Orthotopic Liver Transplantation Model.

Interleukin-18 (IL-18) can effectively activate natural killer (NK) cells and induce large concentrations of interferon-γ (IFN-γ). In healthy humans, IL-18 binding protein (IL-18BP) can inhibit the binding of IL-18 to IL-18R and counteract the biological action of IL-18 due to its high concentration and high affinity, thus preventing the production of IFN-γ and inhibiting NK-cell activation. Through previous studies and the phenomena observed by our group in pig-non-human primates (NHPs) liver transplantation experiments, we proposed that the imbalance in IL-18/IL-18BP expression upon transplantation encourages the activation, proliferation, and cytotoxic effects of NK cells, ultimately causing acute vascular rejection of the graft. In this research, we used Lewis-Brown Norway rat orthotopic liver transplantation (OLTx) as a model of acute vascular rejection. AAV8-Il18bp viral vectors as gene delivery vehicles were constructed for gene therapy to overexpress IL-18BP and alleviate NK-cell rejection of the graft after transplantation. The results showed that livers overexpressing IL-18BP had reduced damage and could function longer after transplantation, effectively improving the survival time of the recipients.

P8.109: Simultaneous Vascular and Antibody-Mediated Rejection (AMR) in Pediatric Patients Caused Poor Prognosis in Renal Allograft

Introduction: The prognostic significance of simultaneous vascular rejection (VR) and AMR on graft survival is not clear enough, especially in the pediatric population. Accordingly, this study aims to determine the impact of simultaneous VR and AMR on the development of transplant glomerulopathy (TG) and interstitial fibrosis (IF) with the resulting graft survival. Methods: Forty-five recipients younger than 18 were separated into Group 1 patients (n:25) with pure AMR and Group 2 patients (n:20) with simultaneous VR+AMR. Tubular expression of TNF-α, TGF-β, and HLA-DR was evaluated. Peritubular capillary (PTC) and interstitial leukocytes were highlighted with TNF-α, HLA-DR, and CD68. The loss of HLA-DR expression on PTCs was studied to determine the PTC destruction. Diffuse IF and TG development were analyzed in the follow-up biopsies. Results: The response of Group 2 patients to rejection therapy was lower than Group 1 (p<0.001). PTC C4d expression was found higher in Group 2 than Group 1 (P<0.001). Group 2 showed a higher PTC destruction, IF, and TG incidence than Group 1(P<0.01). The development of IF and TG increases with the increasing degree of glomerulitis, C4d expression, and PTC destruction (p<0.01). Tubular and interstitial TNF-α, TGF-β, and HLA-DR expressions were found higher in Group 2 compared to Group 1 (p<0.01). The degree of PTC destruction and C4d expression increased with increasing leukocyte and macrophage infiltration in PTCs and interstitium (p<0.001). The development time of IF and TG decreased with increasing intensity of PTC and interstitial infiltration, glomerulitis, PTC destruction, and C4d expression (p<0.01). Also, the development of IF and TG shortened with increasing HLA-DR, TNF-α expression in inflammatory cells and increasing TNF-α, TGF-β, HLA-DR expression in tubular cells (P<0.01). Overall, the 1-, 3- and 5-year graft survival was 96%, 92%, and 79%, respectively, for Group 1 patients, while 95%, 40%, and 10% respectively for Group 2 recipients (p<0.001). Conclusion: The prognosis and course of antibody-mediated vascular rejection are noticeably different from pure AMR, with antibody-mediated vascular rejection having the poorest outcome through leading the early development of IF and TG via augmenting inflammatory and fibrotic pathways. Thus, developing new treatment strategies for antibody-mediated vascular rejection could salvage many kidney allografts.

332.4: Microvascular Injury With Macrophage, Neutrophil, And Hla-dr Positive Inflammatory Infiltrate, either in dsa Positive or Negative abmr, Determines the Prognosis in Renal Allografts

Introduction: Antibody-mediated rejection (ABMR) has well-defined histomorphological lesions, like linear C4d staining or microvascular inflammation [(g + ptc) ≥ 2] in peritubular capillaries (PTCs). Although these histologic features of ABMR (ABMRh) are usually compatible with donor-specific antibodies (DSA), it is demonstrated that recipients can develop ABMRh in the absence of DSAs. Indeed, DSA can not be found in 40-60% of patients with marked microvascular inflammation (MVI). We aimed to investigate the relationship between PTC macrophage (M), neutrophil, and HLA-DR positive cell infiltration with variable clinical presentations of ABMR. Methods: A total of 125 patients with acute ABMR were categorized into four groups; Group 1: DSA (+) ABMR, Group 2: DSA (-) ABMR, Group 3: DSA (+) mixed rejection (ABMR+vascular rejection), and Group 4: DSA (-) mixed rejection. The degree of the glomerular and PTC macrophage (CD68+), neutrophil, and HLA-DR positive cells was graded. The loss of HLA-DR expression in PTC endothelium was accepted as PTC destruction. The follow-up biopsies were evaluated for the development of diffuse interstitial fibrosis (IF) and transplant glomerulopathy (TG). Results: The type of ABMR showed a significant correlation with PTC C4d expression, the presence of TMA, PTC destruction, microvascular (PTC and glomerular) macrophage, neutrophil, and DR+ cell infiltration (p<0.01 for all). Group 3 showed the highest microvascular inflammation, PTC destruction, C4d expression, and TMA. Groups 4, 1, and 2 followed Group 3, respectively, and Group 2 showed the best outcome. Also, patients in Group 3 developed the highest and earliest IF and TG development during follow-up (p<0.01). Similarly, Groups 4, 1, and 2 followed Group 3 regarding the development of IF and TG development. PTC C4d staining intensity significantly correlated with PTC destruction and DSA positivity (p<0.001). Overall 5-year graft survival was 86%, 51%, 45%, and 26% for Groups 2, 1, 4, and 3, respectively (p<0.001). Overall 5-year graft survival was 87%, 54%, and 20% for patients with grades 1, 2, and 3 PTC destruction, respectively (p<0.001). Additionally, overall 5-year survival was 100%, 81%, and 21% for grades 1, 2, and 3 C4d depositions in PTCs, respectively (P<0.001). Conclusion: ABMRh comprising characteristic histologic findings without detectable DSA represent a distinct phenotype with superior renal allograft survival than ABMRh with positive DSA. Additionally, PTC C4d deposition and the resulting PTC destruction were shown to significantly indicate graft failure and poor prognosis independent of the DSA positivity. Therefore, we concluded that ABMR should be divided into different subgroups for treatment, considering the presence of DSA and vascular rejection.

P8.057: Cannabidiol (CBD) Oil and Tacrolimus: The Unexpected High in Renal Transplant Recipients – Case Series and Review

Introduction: Calcineurin inhibitor (CNI) based regimens afford the greatest protection against acute rejection and are used in > 90% of kidney transplant recipients. Cannabidiol (CBD) has been advertised as a natural remedy to treat several disorders. Information on the concurrent use of CBD and tacrolimus is limited. Herein we describe four cases of patients reporting CBD use post kidney transplant, and the effects on tacrolimus drug levels. Results: □Case 1: 38-year-old male with chronic kidney disease secondary to polycystic kidney disease (PKD) received a living unrelated kidney transplant from his spouse.His course was uncomplicated until 3 months post-transplant when he started using CBD oil for sleep. One week after starting CBD oil he presented for follow up and was noted to have a tacrolimus level of 40.1 ng/mL. His tacrolimus level returned at 20 ng/mL after stopping CBD oil. □Case2: A 55-year-old male with chronic kidney disease secondary to lithium toxicity received a living unrelated kidney transplant. He self-started CBD oil three weeks post-transplant and was noted to have an increase in tacrolimus level to 16.1 ng/mLHe elected to stop his CBD oil because he thought it may be interfering with his medications and four days later his tacrolimus levels decreased to 8.8 ng/mL. □Case3: 46 year old male with ESRD ascribed to diabetes mellitus received a deceased donor kidney transplant.One year later he presented for a routine follow up with a serum creatinine of 3.7 mg/dL with a tacrolimus level of 2.4 ng/mLHe reported taking CBD oil for the past 6 weeks for anxiety.His tacrolimus was increased, and he underwent a kidney transplant biopsy which showed acute cell mediated and vascular rejection with chronic active antibody mediated rejection. HLA testing showed de novo HLA antibodies to DQ7 and DQA1*05. □Case 4: 64 yr old female received her pancreas transplant in 2005.14 years later patient presented for a routine follow up and was noticed to have a tacrolimus level of 12.1 while on a steady dose of 1 mg BID. She endorsed starting CBD oil a month prior for relief of her neuropathy symptoms.Her tacrolimus was adjusted down to 0.5 mg BID with improvement inher level to 7. Discussion: Cannabidiol (CBD) is a non-psychogenic cannabinoid found in the Cannibis sativa plant. The Agriculture Improvement Act of 2018 legalized production of industrial hemp plants, so long as it contained no more than 0.3% of delta-9-tetrahydrocannabinol (THC).Interestingly, amongst our cases 3 resulted in an increase in tacrolimus levels and another resulted in a marked decrease in tacrolimus levels which precipitated allograft rejection. all cases of increased levels occurred without a change in tacrolimus dosing and relative stable levels prior to known administration. Tacrolimus levels improved after stopping CBD oil supplements. The solitary case of reduced tacrolimus levels following CBD oil exposure i may have been related to another compound within the CBD oil labelled product.

Ocular adverse effects of COVID-19 vaccines: A systematic review.

The COVID-19 pandemic has led to the development and rollout of several vaccines worldwide at unprecedented pace. This systematic review of published literature has been undertaken to spread awareness among general physicians and ophthalmologists about the various reported adverse effects in the eye following COVID-19 vaccination. A systematic search was performed on 25 January 2022 through PuBMed, Medline and Google scholar for publications on ocular adverse effects after COVID-19 vaccination. One brief communication, four retrospective case series, sixteen case reports, and five letters to editors were included. Ocular manifestations most commonly appear in the uvea and retina. Other manifestations are seen on the eyelid, cornea and ocular surface, and in cranial nerves innervating the eye. The incidence rate of these manifestations is quite low after COVID-19 vaccinations. Our systematic review meticulously enumerates various adverse effects of COVID -19 vaccine on the eye. Most of these adverse effects are transient and observed to resolve without any sequelae except for cases of retinal and ophthalmic vascular occlusions and corneal graft rejections. An emphasis on close follow-up and a need to delay vaccination and modified therapy to control flare up of signs and symptoms in certain sub-populations, Graves' disease (autoimmune etiology), pre-existing uveal inflammation and corneal graft cases are warranted. We need long-term, larger, multicentric studies to substantiate our findings and establish the causal relationship with certainty. Mass vaccinations to curb this pandemic after outweighing the ocular risks associated with it is warranted.

P8.045: Modern Medicine Needs Modern Technology Tools

Introduction: Early detection of subclinical rejection is critical to prevent the allograft loss. Currently used methods to detect subclinical rejection include surveillance biopsy protocol, serum creatinine level, eGFR or DSA; however, these methods have limited sensitivity and specificity to accurately detect subclinical rejection. Donor derived cell-free DNA (dd cf-DNA) is a non-invasive biomarker for allograft injury and has been shown to predict allograft rejection with higher sensitivity to detect subclinical rejection compare to some methods (1,2). Here, we show the value of dd cf-DNA in detecting early allograft rejection by presenting two cases where dd cf-DNA assay, AlloSure (CareDx) detected subclinical rejection while other indicators showed stable allograft function. Methods: Ochsner uses AlloSure (CareDx) for a surveillance for the high-risk patients. Results: Thirty-two years old Caucasian female with end stage kidney disease secondary to HIV infection underwent deceased-donor renal transplant in 2018 with KDPI 19% and cPRA 84%. Serum creatinine level had been stable at 1.1mg/dL to 1.2mg/dL post-transplant. This patient was monitored using AlloSure (CareDx) for 1-,2-,3-,4-,6- and 9-month post-transplant. AlloSure values for month 1 to 6 were <0.21, which indicates stable allograft function. However, at 9-month post-transplant, AlloSure value went up to 4.5%, which indicates possible allograft injury, while serum creatinine level remained stable at 1.2 mg/dL with low level of class 2 DSA (DR-1573). Despite stable creatinine level and low level DSA, we initiated biopsy because of sharp increase in AlloSure value. Biopsy revealed acute T-cell mediated rejection and acute vascular rejection. The second case is a 33 years-old Caucasian female with history of previous renal transplant. The first allograft failed in 2018 due to renal artery and vein thrombosis. The patient underwent deceased donor kidney transplant in 2019. Serum creatinine level was stable at 1.0 – 1.3 mg/dL and sharp increase in respectively. At month 3, AlloSure value went up to 0.78% but DSA was negative. We initiated biopsy based on increase in AlloSure value and it revealed acute antibody mediated rejection (ABMR) (Figure 1). The third case is a 56 years-old male with history of end-stage renal disease secondary to hypertension. The patient received deceased donor kidney transplant in 2017. He developed acute renal failure (Cr went up from 1.2 mg/dl to 1.7 mg/dL) few months after kidney transplant and his kidney biopsy showed acute antibody mediated rejection and T-cell mediated rejection which were treated. At 1-year post-transplant, serum creatinine level remained 1.2 mg/dL to 1.3 mg/dL. He was place on monthly Allosure surveillance. The first value was 1.9%, which indicate possible allograft injury. Monthly monitoring showed increase trend in AlloSure value up to 4.1% while Cr remained stable at 1.2 mg/dL-1.3 mg/dL. At that point, biopsy was performed, and it revealed acute antibody mediated rejection and chronic active antibody rejection. Patient was treated with for ABMR. In addition, monthly Tocilizumab was considered for chronic active antibody mediated rejection for 6 months. AlloSure values reflected the early detection of rejection in a patient with stable Cr as well as the efficacy of treatment with down trending values (Figure 2). Conclusion: For all 3 cases, biopsy would not have been initiated most likely due to stable creatinine level and weak or negative DSA. If this had gone untreated for long period of time, this would have led to significant decrease in graft survival. These cases demonstrate that normal serum creatinine does not mean patient has no active inflammatory process. When other indicators are normal/stable, AlloSure was able to detect early rejection. All three cases demonstrated the value of AlloSure as a monitoring tool for detection of early allograft rejection.

The number of donor HLA-derived T cell epitopes available for indirect antigen presentation determines the risk for vascular rejection after kidney transplantation.

The role of the indirect T-cell recognition pathway of allorecognition in acute T cell-mediated rejection (aTCMR) is not well defined. The amount of theoretical T-cell epitopes available for indirect allorecognition can be quantified for donor-recipient combinations by the Predicted Indirectly ReCognizable HLA Epitopes algorithm (PIRCHE-II). The PIRCHE-II score was calculated for 688 donor kidney-recipient combinations and associated with the incidence of first-time diagnosed cases of TCMR. A diagnosis of TCMR was made in 182 cases; 121 cases of tubulo-interstitial rejection cases (79 cases of borderline TCMR, 42 cases of TCMR IA-B) and 61 cases of vascular TCMR (TCMR II-III). The PIRCHE-II score for donor HLA-DR/DQ (PIRCHE-II DR/DQ) was highly associated with vascular rejection. At one year after transplantation, the cumulative percentage of recipients with a vascular rejection was 12.7%, 8.6% and 2.1% within respectively the high, medium and low tertile of the PIRCHE-II DR/DQ score (p<0.001). In a multivariate regression analysis this association remained significant (p<0.001 for PIRCHE-II DR/DQ tertiles). The impact of a high PIRCHE-II DR/DQ score was mitigated by older recipient age and a living donor kidney. In conclusion, indirect antigen presentation of donor HLA-peptides may significantly contribute to the risk for acute vascular rejection.

The Clinical and Pathologic Phenotype of Antibody-Mediated Vascular Rejection Diagnosed Using Arterial C4d Immunoperoxidase

IntroductionThe diagnosis of antibody-mediated vascular rejection (AM-VR) should be reliable and accurate. We hypothesized that arterial C4d (C4dart) immunoperoxidase deposition represents endothelial interaction with antibody.MethodsFrom 3309 consecutive, kidney transplant biopsies from a single center, 100 vascular rejection (VR) cases were compared against rejection without arteritis (n = 540) and normal controls (n = 1108). The clinical utility of C4dart for diagnosis and classification of AM-VR was evaluated against an independent reference test.ResultsC4dart occurred in 20.4% of acute, 11.0% of subclinical, and 46% of VR episodes. Semiquantitative C4dart score significantly correlated with immunodominant donor-specific antibodies (DSAs) (rho = 0.500, P < 0.001), peritubular capillary C4d (C4dptc), microvascular inflammation, and Banff v scores. Banff v3 arteritis suggested AM-VR. Addition of C4dart to Banff antibody-mediated rejection (AMR) schema increased diagnostic sensitivity for AM-VR from 57.9% to 93.0%, accuracy 74.0% to 92.0%, and specificity 95.4% to 90.2% versus Banff 2019 (using C4dptc). Death-censored graft failure was associated with C4dart AM-VR criteria using Cox regression (adjusted hazard ratio [HR] 4.310, 95% CI 1.322–14.052, P = 0.015). VR was then etiologically classified into AM-VR (n = 57, including 36 mixed VR) or “pure” (TCM-VR, n = 43). AM-VR occurred within all post-transplant periods, characterized by greater total, interstitial, and microvascular inflammation, arterial and peritubular C4d, DSA levels, and graft failure rates compared with TCM-VR. Mixed VR kidneys had the greatest inflammatory burden and graft loss (P < 0.001).ConclusionC4dart is a suggestive biomarker of the humoral alloresponse toward muscular arteries. Inclusion of C4dart into the Banff schema improved its diagnostic performance for detection of AM-VR and etiologic classification of arteritis.

Validation of Systematic Histologic Reporting of Transbronchial Biopsy Eosinophils for Sensitivity of Detection and Associations with Early Outcomes After Lung Transplant

<h3>Purpose</h3> Eosinophils are reported in 8% of transbronchial biopsies (TBBx) and their presence is associated with an increased risk of CLAD and death. We aimed to validate a systematic reporting scheme for the presence, gradation, and pattern of TBBx eosinophils. <h3>Methods</h3> A prospective reporting scheme for TBBx eosinophils was introduced at St Vincent's Sydney in Jan-20. All TBBx were reported by blinded pathologists for the presence of eosinophils, histologic pattern (peribronchial, interstitial, perivascular) and count/high power field (HPF). Standardised reporting was compared with a historic TBBx cohort from Jan-Dec 2019. TBBx were classified for cellular rejection as per ISHLT guidelines and positive bronchoalveolar lavage (BAL) microbiology/eosinophils and blood eosinophil count was recorded. Multivariable logistic regression measured associations with an increased risk of TBBx eosinophils. <h3>Results</h3> A total of 213 TBBx from 93 lung transplant recipients were systematically reviewed, with 61.5% as surveillance procedures. The mean (SD) recipient age was 52 (13), with 96 (45%) males, at median (IQR) 85 (475) days after transplant. TBBx eosinophils were detected in greater proportions with systematic (27.7%) compared to historic reporting (5.6%) p<0.001. When present, eosinophils were detected in median (IQR) 18.0% (19) biopsy specimens with median (IQR) 2 (5) cell/HPF. TBBx eosinophil patterns were reported in the following proportions; Interstitial 64%, perivascular 7%, peribronchial 25%. In univariable analysis, A grade (OR 3.11 p<0.01), blood eosinophils (OR 13.28 p=0.04) and BAL microbiology (OR 2.15 p=0.02) were associated with increased risk of TBBx eosinophils, however BAL eosinophils (OR 1.75 p=0.31) were not. In multivariable analysis, A grade (OR 2.93 95%CI 1.65-5.20) and positive BAL microbiology (OR 2.18 95%CI 1.10-4.31) were associated with an increased risk of TBBx eosinophils. <h3>Conclusion</h3> Systematic reporting of TBBx eosinophils improves sensitivity for detection compared with historic reporting. Acute vascular rejection grades and positive BAL microbiology were independently associated with an increased risk of TBBx eosinophils after adjustment for blood eosinophil count. Systematic reporting of TBBx eosinophils may identify patients at risk of poor outcomes.