Assessment of Tocilizumab (Anti–Interleukin‐6 Receptor Monoclonal) as a Potential Treatment for Chronic Antibody‐Mediated Rejection and Transplant Glomerulopathy in HLA‐Sensitized Renal Allograft Recipients

Extending the functional integrity of renal allografts is the primary goal of transplant medicine. The development of donor‐specific antibodies (DSAs) posttransplantation leads to chronic active antibody‐mediated rejection (cAMR) and transplant glomerulopathy (TG), resulting in the majority of graft losses that occur in the United States. This reduces the quality and length of life for patients and increases cost. There are no approved treatments for cAMR. Evidence suggests the proinflammatory cytokine interleukin 6 (IL‐6) may play an important role in DSA generation and cAMR. We identified 36 renal transplant patients with cAMR plus DSAs and TG who failed standard of care treatment with IVIg plus rituximab with or without plasma exchange. Patients were offered rescue therapy with the anti–IL‐6 receptor monoclonal tocilizumab with monthly infusions and monitored for DSAs and long‐term outcomes. Tocilizumab‐treated patients demonstrated graft survival and patient survival rates of 80% and 91% at 6 years, respectively. Significant reductions in DSAs and stabilization of renal function were seen at 2 years. No significant adverse events or severe adverse events were seen. Tocilizumab provides good long‐term outcomes for patients with cAMR and TG, especially compared with historical published treatments. Inhibition of the IL‐6–IL‐6 receptor pathway may represent a novel approach to stabilize allograft function and extend patient lives.     

Acquisition of C3d‐Binding Activity by De Novo Donor‐Specific HLA Antibodies Correlates With Graft Loss in Nonsensitized Pediatric Kidney Recipients

Alloantibody‐mediated graft injury is a major cause of kidney dysfunction and loss. The complement‐binding ability of de novo donor‐specific antibodies (dnDSAs) has been suggested as a prognostic tool to stratify patients for clinical risk. In this study, we analyzed posttransplant kinetics of complement‐fixing dnDSAs and their role in antibody‐mediated rejection development and graft loss. A total of 114 pediatric nonsensitized recipients of first kidney allograft were periodically monitored for dnDSAs using flow bead assays, followed by C3d and C1q assay in case of positivity. Overall, 39 patients developed dnDSAs, which were C1q⁺ and C3d⁺ in 25 and nine patients, respectively. At follow‐up, progressive acquisition over time of dnDSA C1q and C3d binding ability, within the same antigenic specificity, was observed, paralleled by an increase in mean fluorescence intensity that correlated with clinical outcome. C3d‐fixing dnDSAs were better fit to stratify graft loss risk when the different dnDSA categories were evaluated in combined models because the 10‐year graft survival probability was lower in patients with C3d‐binding dnDSA than in those without dnDSAs or with C1q⁺/C3d^? or non‐complement‐binding dnDSAs (40% vs. 94%, 100%, and 100%, respectively). Based on the kinetics profile, we favor dnDSA removal or modulation at first confirmed positivity, with treatment intensification guided by dnDSA biological characteristics.     

T Cells Promote Bronchial Epithelial Cell Secretion of Matrix Metalloproteinase‐9 via a C‐C Chemokine Receptor Type 2 Pathway: Implications for Chronic Lung Allograft Dysfunction

Chronic lung allograft dysfunction (CLAD) is the major limitation of long‐term survival after lung transplantation. CLAD manifests as bronchiolitis obliterans syndrome (BOS) or restrictive allograft syndrome (RAS). Alloimmune reactions and epithelial‐to‐mesenchymal transition have been suggested in BOS. However, little is known regarding the role of allogenicity in epithelial cell differentiation. Primary human bronchial epithelial cells (BECs) were treated with activated T cells in the presence or absence of transforming growth factor (TGF)‐β. The expression of epithelial and mesenchymal markers was investigated. The secretion of inflammatory cytokines and matrix metalloproteinase (MMP)‐9 was measured in culture supernatants and in plasma from lung transplant recipients (LTRs): 49 stable, 29 with BOS, and 16 with RAS. We demonstrated that C‐C motif chemokine 2 secreted by T cells supports TGF‐β–induced MMP‐9 production by BECs after binding to C‐C chemokine receptor type 2. Longitudinal investigation in LTRs revealed a rise in plasma MMP‐9 before CLAD onset. Multivariate analysis showed that plasma MMP‐9 was independently associated with BOS (odds ratio [OR] = 6.19, p = 0.002) or RAS (OR = 3.9, p = 0.024) and predicted the occurrence of CLAD 12 months before the functional diagnosis. Thus, immune cells support airway remodeling through the production of MMP‐9. Plasma MMP‐9 is a potential predictive biomarker of CLAD.     

Immediate and Catastrophic Antibody‐Mediated Rejection in a Lung Transplant Recipient With Anti–Angiotensin II Receptor Type 1 and Anti–Endothelin‐1 Receptor Type A Antibodies

Preexisting donor‐specific anti‐HLA antibodies (DSAs) have been associated with reduced survival of lung allografts. However, antibodies with specificities other than HLA may have a detrimental role on the lung transplant outcome. A young man with cystic fibrosis underwent lung transplantation with organs from a suitable deceased donor. At the time of transplantation, there were no anti‐HLA DSAs. During surgery, the patient developed a severe and intractable pulmonary hypertension associated with right ventriular dysfunction, which required arteriovenous extracorporeal membrane oxygenation. After a brief period of clinical improvement, a rapid deterioration in hemodynamics led to the patient's death on postoperative day 5. Postmortem studies showed that lung specimens taken at the end of surgery were compatible with antibody‐mediated rejection (AMR), while terminal samples evidenced diffuse capillaritis, blood extravasation, edema, and microthrombi, with foci of acute cellular rejection (A3). Immunological investigations demonstrated the presence of preexisting antibodies against the endothelin‐1 receptor type A (ET_AR) and the angiotensin II receptor type 1 (AT₁R), two of the most potent vasoconstrictors reported to date, whose levels slightly rose after transplantation. These data suggest that preexisting anti‐ET_AR and anti‐AT₁R antibodies may have contributed to the onset of AMR and to the catastrophic clinical course of this patient.     

Prophylactic Azithromycin Therapy After Lung Transplantation: Post hoc Analysis of a Randomized Controlled Trial

Prophylactic azithromycin treatment has been demonstrated to improve freedom from bronchiolitis obliterans syndrome (BOS) 2 years after lung transplantation (LTx). In the current study, we re‐evaluated the long‐term effects of this prophylactic approach in view of the updated classification system for chronic lung allograft dysfunction (CLAD). A retrospective, intention‐to‐treat analysis of a randomized controlled trial comparing prophylactic treatment with placebo (n = 43) versus azithromycin (n = 40) after LTx was performed. Graft dysfunction (CLAD), graft loss (retransplantation, mortality), evolution of pulmonary function and functional exercise capacity were analyzed 7 years after inclusion of the last study subject. Following LTx, 22/43 (51%) patients of the placebo group and 11/40 (28%) patients of the azithromycin group ever developed CLAD (p = 0.043). CLAD‐free survival was significantly longer in the azithromycin group (p = 0.024). No difference was present in proportion of obstructive versus restrictive CLAD between both groups. Graft loss was similar in both groups: 23/43 (53%) versus 16/40 (40%) patients (p = 0.27). Long‐term pulmonary function and functional exercise capacity were significantly better in the azithromycin group (p < 0.05). Prophylactic azithromycin therapy reduces long‐term CLAD prevalence and improves CLAD‐free survival, pulmonary function, and functional exercise capacity after LTx.     

Proteasome Inhibitor Carfilzomib‐Based Therapy for Antibody‐Mediated Rejection of the Pulmonary Allograft: Use and Short‐Term Findings

We present this observational study of lung transplant recipients (LTR) treated with carfilzomib (CFZ)‐based therapy for antibody‐mediated rejection (AMR) of the lung. Patients were considered responders to CFZ if complement‐1q (C1q)‐fixing ability of their immunodominant (ID) donor‐specific anti‐human leukocyte antibody (DSA) was suppressed after treatment. Treatment consisted of CFZ plus plasma exchange and immunoglobulins. Fourteen LTRs underwent CFZ for 20 ID DSA AMR. Ten (71.4%) of LTRs responded to CFZ. DSA IgG mean fluorescence intensity (MFI) fell from 7664 (IQR 3230–11 874) to 1878 (653–7791) after therapy (p = 0.001) and to 1400 (850–8287) 2 weeks later (p = 0.001). DSA C1q MFI fell from 3596 (IQR 714–14 405) to <30 after therapy (p = 0.01) and <30 2 weeks later (p = 0.02). Forced expiratory volume in 1s ( FEV₁) fell from mean 2.11 L pre‐AMR to 1.92 L at AMR (p = 0.04). FEV₁ was unchanged after CFZ (1.91 L) and subsequently rose to a maximum of 2.13 L (p = 0.01). Mean forced expiratory flow during mid forced vital capacity (25–75) (FEF_25–75) fell from mean 2.5 L pre‐AMR to 1.95 L at AMR (p = 0.01). FEF_25–75 rose after CFZ to 2.54 L and reached a maximum of 2.91 L (p = 0.01). Responders had less chronic lung allograft dysfunction or progression versus nonresponders (25% vs. 83%, p = 0.04). No deaths occurred within 120 days and 7 patients died post CFZ therapy of allograft failure. Larger prospective interventional studies are needed to further describe the benefit of CFZ‐based therapy for pulmonary AMR.     

When tissue is the issue: A histological review of chronic lung allograft dysfunction

Although chronic lung allograft dysfunction (CLAD) remains the major life‐limiting factor following lung transplantation, much of its pathophysiology remains unknown. The discovery that CLAD can manifest both clinically and morphologically in vastly different ways led to the definition of distinct subtypes of CLAD. In this review, recent advances in our understanding of the pathophysiological mechanisms of the different phenotypes of CLAD will be discussed with a particular focus on tissue‐based and molecular studies. An overview of the current knowledge on the mechanisms of the airway‐centered bronchiolitis obliterans syndrome, as well as the airway and alveolar injuries in the restrictive allograft syndrome and also the vascular compartment in chronic antibody‐mediated rejection is provided. Specific attention is also given to morphological and molecular markers for early CLAD diagnosis or histological changes associated with subsequent CLAD development. Evidence for a possible overlap between different forms of CLAD is presented and discussed. In the end, “tissue remains the (main) issue,” as we are still limited in our knowledge about the actual triggers and specific mechanisms of all late forms of posttransplant graft failure, a shortcoming that needs to be addressed in order to further improve the outcome of lung transplant recipients.     

Plasma‐Derived C1 Esterase Inhibitor for Acute Antibody‐Mediated Rejection Following Kidney Transplantation: Results of a Randomized Double‐Blind Placebo‐Controlled Pilot Study

Antibody‐mediated rejection (AMR) is typically treated with plasmapheresis (PP) and intravenous immunoglobulin (standard of care; SOC); however, there is an unmet need for more effective therapy. We report a phase 2b, multicenter double‐blind randomized placebo‐controlled pilot study to evaluate the use of human plasma‐derived C1 esterase inhibitor (C1 INH) as add‐on therapy to SOC for AMR. Eighteen patients received 20 000 units of C1 INH or placebo (C1 INH n = 9, placebo n = 9) in divided doses every other day for 2 weeks. No discontinuations, graft losses, deaths, or study drug‐related serious adverse events occurred. While the study's primary end point, a difference between groups in day 20 pathology or graft survival, was not achieved, the C1 INH group demonstrated a trend toward sustained improvement in renal function. Six‐month biopsies performed in 14 subjects (C1 INH = 7, placebo = 7) showed no transplant glomerulopathy (TG) (PTC+cg≥1b) in the C1 INH group, whereas 3 of 7 placebo subjects had TG. Endogenous C1 INH measured before and after PP demonstrated decreased functional C1 INH serum concentration by 43.3% (p < 0.05) for both cohorts (C1 INH and placebo) associated with PP, although exogenous C1 INH–treated patients achieved supraphysiological levels throughout. This new finding suggests that C1 INH replacement may be useful in the treatment of AMR.     

Antibodies to K‐α 1 Tubulin and Collagen V Are Associated With Chronic Rejection After Lung Transplantation

Bronchiolitis obliterans syndrome (BOS), the clinical correlate of chronic rejection after lung transplantation, is the leading obstacle to better long‐term outcomes. We previously instituted a clinical protocol to screen for donor‐specific human leukocyte antigen (HLA) antibodies (DSA) and a preemptive antibody‐directed therapy protocol consisting of rituximab and/or intravenous immune globulin. In this study, we retrospectively analyzed serum samples from lung transplant recipients (n = 108) for antibodies to self‐antigens (K‐α 1 tubulin and collagen V) before and after antibody‐directed therapy and correlated the results with the subsequent development of BOS. Seventy‐two of the 108 recipients developed antibodies to self‐antigens. There was a correlation between the development of antibodies to self‐antigens and DSA. Sixteen of the 54 patients who had antibodies to self‐antigens and were treated with antibody‐directed therapy cleared the antibodies, and they were significantly less likely to develop BOS than those who had persistent antibodies. Furthermore, those who cleared DSA after treatment but had persistent antibodies to self‐antigens were significantly more likely to develop BOS than those who cleared these antibodies. We conclude that antibodies to self‐antigens are an important risk factor for the development of BOS.     

Isolated vascular “v” lesions in liver allografts: How to approach this unusual finding

According to the Banff criteria for kidney allografts, isolated vascular or “v” lesions are defined as intimal inflammation, age‐inappropriate fibro‐intimal hyperplasia, or both, without the presence of associated interstitial T cell‐mediated rejection (TCMR). In general, these lesions portend a worse outcome for kidney allografts, particularly in those where the “v” lesions are identified in patients with coexistent donor specific antibodies (DSA) or later after transplantation. Although affected arteries are rarely sampled in liver allograft biopsies, we identified nine patients at a mean of 1805 days posttransplantation and compared these to matched controls. Almost half (4 of 9) of the study patient biopsies showed inflammatory arteritis associated with focal or diffuse C4d positivity, which was not observed in matched controls. One “v” lesion patient progressed to rejection‐related graft failure and two developed moderate/severe TCMR in subsequent biopsies, whereas only one rejection episode occurred in follow‐up biopsies, and no rejection‐related deaths or graft failures were detected in controls. In conclusion, patients with liver allograft isolated “v” lesions should undergo further evaluation and closer follow‐up for impending TCMR and/or underlying co‐existent chronic antibody‐mediated rejection (AMR).     

“White‐Out” After Lung Transplantation: A Multicenter Cohort Description of Late Acute Graft Failure

Graft failure represents a leading cause of mortality after organ transplantation. Acute late‐onset graft failure has not been widely reported. The authors describe the demographics, CT imaging–pathology findings, and treatment of patients presenting with the latter. A retrospective review was performed of lung transplant recipients at two large‐volume centers. Acute late‐onset graft failure was defined as sudden onset of bilateral infiltrates with an oxygenation index <200 without identifiable cause or concurrent extrapulmonary organ failure. Laboratory, bronchoalveolar lavage (BAL), radiology, and histology results were assessed. Between 2005 and 2016, 21 patients were identified. Median survival was 19 (IQR 13–36) days post onset. Twelve patients (57%) required intensive care support at onset, 12 (57%) required mechanical ventilation, and 6 (29%) were placed on extracorporeal life support. Blood and BAL analysis revealed elevated neutrophilia, with CT demonstrating diffuse ground‐glass opacities. Transbronchial biopsy samples revealed acute fibrinoid organizing pneumonia (AFOP), organizing pneumonia, and diffuse alveolar damage (DAD). Assessment of explanted lungs confirmed AFOP and DAD but also identified obliterative bronchiolitis. Patients surviving to discharge without redo transplantation (n = 2) subsequently developed restrictive allograft syndrome. This study describes acute late‐onset graft failure in lung allograft recipients, without known cause, which is associated with a dismal prognosis.     

Recurrent IgG4‐related tubulointerstitial nephritis concurrent with chronic active antibody mediated rejection: A case report

IgG4‐related disease is a relatively newly described entity that can affect nearly any organ, including the kidneys, where it usually manifests as tubulointerstitial nephritis (IgG4‐TIN). The diagnosis can be suggested by characteristic histological features, including an inflammatory infiltrate with increased IgG4‐positive plasma cells associated with “storiform” fibrosis. Serum IgG4 is usually elevated. In the native kidney and other organs, there is typically a brisk response to treatment with immunosuppression. Recurrence of IgG4‐TIN after renal transplant has not been described in the literature. Here, we describe the first case of recurrent IgG4‐TIN in a young patient concomitant with chronic active antibody mediated rejection five years after kidney transplant. Recurrent IgG4‐TIN could be diagnosed by the characteristic histopathologic features and increased IgG4‐positive plasma cells. Despite maintenance immunosuppression, this disease may recur in the kidney allograft.     

Association of Higher CD4+CD25highCD127low,FoxP3+, and IL‐2+ T Cell Frequencies Early After Lung Transplantation With Less Chronic Lung Allograft Dysfunction at Two Years

Regulatory T cells (Treg) can regulate alloantigens and may counteract chronic lung allograft dysfunction (CLAD) in lung transplantation. We analyzed Treg in peripheral blood prospectively and correlated percentages of subpopulations with the incidence of CLAD at 2 years. Among lung‐transplanted patients between January 2009 and July 2011, only patients with sufficient Treg measurements were included into the study. Tregs were measured immediately before lung transplantation, at 3 weeks and 3, 6, 12, and 24 months after transplantation and were defined as CD4⁺CD25^high T cells and further analyzed for CTLA4, CD127, FoxP3, and IL‐2 expressions. Between January 2009 and July 2011, 264 patients were transplanted at our institution. Among the 138 (52%) patients included into the study, 31 (22%) developed CLAD within 2 years after transplantation. As soon as 3 weeks after lung transplantation, a statistically significant positive association was detected between Treg frequencies and later absence of CLAD. At the multivariate analysis, increasing frequencies of CD4⁺CD25^highCD127^low, CD4⁺CD25^highFoxP3⁺ and CD4⁺CD25^highIL‐2⁺ T cells at 3 weeks after lung transplantation emerged as protective factors against development of CLAD at 2 years. In conclusion, higher frequencies of specific Treg subpopulations early after lung transplantation are protective against CLAD development.     

Preemptive treatment of early donor‐specific antibodies with IgA‐ and IgM‐enriched intravenous human immunoglobulins in lung transplantation

This retrospective study presents our 4‐year experience of preemptive treatment of early anti‐HLA donor specific antibodies with IgA‐ and IgM‐enriched immunoglobulins. We compared outcomes between patients with antibodies and treatment (case patients) and patients without antibodies (control patients). Records of patients transplanted at our institution between March 2013 and November 2017 were reviewed. The treatment protocol included one single 2 g/kg immunoglobulin infusion followed by successive 0.5 g/kg infusions for a maximum of 6 months, usually combined with a single dose of anti‐CD20 antibody and, in case of clinical rejection or positive crossmatch, with plasmapheresis or immunoabsorption. Among the 598 transplanted patients, 128 (21%) patients formed the case group and 452 (76%) the control group. In 116 (91%) patients who completed treatment, 106 (91%) showed no antibodies at treatment end. Fourteen (13%) patients showed antibody recurrence thereafter. In case versus control patients and at 4‐year follow‐up, respectively, graft survival (%) was 79 versus 81 (P = .59), freedom (%) from biopsy‐confirmed rejection 57 versus 53 (P = .34), and from chronic lung allograft dysfunction 82 versus 78 (P = .83). After lung transplantation, patients with early donor‐specific antibodies and treated with IgA‐ and IgM‐enriched immunoglobulins had 4‐year graft survival similar to patients without antibodies and showed high antibody clearance.