Case report: Eculizumab rescue of severe accelerated antibody-mediated rejection after ABO-incompatible kidney transplant

Targeting the Complement Pathway in Kidney Transplantation

The complement system is paramount in the clearance of pathogens and cell debris, yet is increasingly recognized as a key component in several pathways leading to allograft injury. There is thus a growing interest in new biomarkers to assess complement activation and guide tailored therapies after kidney transplantation (KTx). C5 blockade has revolutionized post-transplant management of atypical hemolytic uremic syndrome, a paradigm of complement-driven disease. Similarly, new drugs targeting the complement amplification loop hold much promise in the treatment and prevention of recurrence of C3 glomerulopathy. Although unduly activation of the complement pathway has been described after brain death and ischemia reperfusion, any clinical attempts to mitigate the ensuing renal insults have so far provided mixed results. However, the intervention timing, strategy, and type of complement blocker need to be optimized in these settings. Furthermore, the fast-moving field of ex vivo organ perfusion technology opens new avenues to deliver complement-targeted drugs to kidney allografts with limited iatrogenic risks. Complement plays also a key role in the pathogenesis of donor-specific ABO- and HLA-targeted alloantibodies. However, C5 blockade failed overall to improve outcomes in highly sensitized patients and prevent the progression to chronic antibody-mediated rejection (ABMR). Similarly, well-conducted studies with C1 inhibitors in sensitized recipients yielded disappointing results so far, in part, because of subtherapeutic dosage used in clinical studies. The emergence of new complement blockers raises hope to significantly reduce the negative effect of ischemia reperfusion, ABMR, and nephropathy recurrence on outcomes after KTx.

Current Therapies in Kidney Transplant Rejection

Despite significant advancements in immunosuppressive therapies, kidney transplant rejection continues to pose a substantial challenge, impacting the long-term survival of grafts. This article provides an overview of the diagnosis, current therapies, and management strategies for acute T-cell-mediated rejection (TCMR) and antibody-mediated rejection (ABMR). TCMR is diagnosed through histological examination of kidney biopsy samples, which reveal the infiltration of mononuclear cells into the allograft tissue. Corticosteroids serve as the primary treatment for TCMR, while severe or steroid-resistant cases may require T-cell-depleting agents, like Thymoglobulin. ABMR occurs due to the binding of antibodies to graft endothelial cells. The most common treatment for ABMR is plasmapheresis, although its efficacy is still a subject of debate. Other current therapies, such as intravenous immunoglobulins, anti-CD20 antibodies, complement inhibitors, and proteasome inhibitors, are also utilized to varying degrees, but their efficacy remains questionable. Management decisions for ABMR depend on the timing of the rejection episode and the presence of chronic changes. In managing both TCMR and ABMR, it is crucial to optimize immunosuppression and address adherence. However, further research is needed to explore newer therapeutics and evaluate their efficacy.

Lack of Efficacy and Safety of Eculizumab for Treatment of Antibody-Mediated Rejection Following Renal Transplantation

BACKGROUND

We evaluated the efficacy and safety of eculizumab in comparison with plasmapheresis and intravenous immunoglobulin therapy in renal transplant recipients diagnosed with antibody-mediated rejection (AMR).

METHODS

This was a multicenter, open-label, prospective, randomized analysis. The patients were randomized by therapy type (eg, eculizumab infusions or standard of care [SOC]: plasmapheresis/intravenous immunoglobulin). The patients (ie, eculizumab arm: 7 patients, SOC arm: 4 patients) were evaluated for the continued presence of donor-specific antibodies (DSAs) and C4d (staining on biopsy), as well as histologic evidence, using repeat renal biopsy after treatment.

RESULTS

The allograft biopsies revealed that eculizumab did not prevent the progression to transplant glomerulopathy. Only 2 patients in the SOC arm experienced rejection reversal, and no graft losses occurred in either group. After AMR treatment, the DSA titers generally decreased compared to titers taken at the time of AMR diagnosis. There were no serious adverse effects in the eculizumab arm.

CONCLUSIONS

Eculizumab alone cannot treat AMR effectively and does not prevent acute AMR from progressing to chronic AMR or transplant glomerulopathy. However, it should be considered as a potential alternative therapy because it may be associated with decreased DSA levels.

Transplantation and immunosuppression: a review of novel transplant-related immunosuppressant drugs

Immunosuppressive drugs used in the transplantation period are generally defined as induction and maintenance therapy. The use of immunosuppressants, which are particularly useful and have fewer side effects, decreased both mortality and morbidity. Many drugs such as steroids, calcineurin inhibitors (cyclosporine-A, tacrolimus), antimetabolites (mycophenolate mofetil, azathioprine), and mTOR inhibitors (sirolimus, everolimus) are used as immunosuppressive agents. Although immunosuppressant drugs cause many side effects such as hypertension, infection, and hyperlipidemia, they are the agents that should be used to prevent organ rejection. This shows the importance of individualized drug use. The optimal immunosuppressive therapy post-transplant is not established. Therefore, discovering less toxic but more potent new agents is of great importance, and new experimental and clinical studies are needed in this regard.Our review discussed the mechanism of immunosuppressants, new agents' discovery, and current therapeutic protocols in the transplantation.

Eculizumab exposure in children and young adults: indications, practice patterns, and outcomes-a Pediatric Nephrology Research Consortium study

BACKGROUND

Eculizumab is approved for the treatment of atypical hemolytic uremic syndrome (aHUS). Its use off-label is frequently reported. The aim of this study was to describe the broader use and outcomes of a cohort of pediatric patients exposed to eculizumab.

METHODS

A retrospective, cohort analysis was performed on the clinical and biomarker characteristics of eculizumab-exposed patients < 25 years of age seen across 21 centers of the Pediatric Nephrology Research Consortium. Patients were included if they received at least one dose of eculizumab between 2008 and 2015. Traditional summary statistics were applied to demographic and clinical data.

RESULTS

A total of 152 patients were identified, mean age 9.1 (+/-6.8) years. Eculizumab was used "off-label" in 44% of cases. The most common diagnoses were aHUS (47.4%), Shiga toxin-producing Escherichia coli HUS (12%), unspecified thrombotic microangiopathies (9%), and glomerulonephritis (9%). Genetic testing was available for 60% of patients; 20% had gene variants. Dosing regimens were variable. Kidney outcomes tended to vary according to diagnosis. Infectious adverse events were the most common adverse event (33.5%). No cases of meningitis were reported. Nine patients died of noninfectious causes while on therapy.

CONCLUSIONS

This multi-center retrospective cohort analysis indicates that a significant number of children and young adults are being exposed to C5 blockade for off-label indications. Dosing schedules were highly variable, limiting outcome conclusions. Attributable adverse events appeared to be low. Cohort mortality (6.6%) was not insignificant. Prospective studies in homogenous disease cohorts are needed to support the role of C5 blockade in kidney outcomes.

Current protocols and outcomes of ABO-incompatible kidney transplantation

One of the principal obstacles in transplantation from living donors is that approximately 30% are immunologically incompatible because of the presence in the recipient of antibodies directed against the human leukocyte antigen system of the donor or because of the incompatibility of the ABO system. The aim of this review is to describe the more recent data from the literature on the different protocols used and the clinical outcomes of ABO-incompatible kidney transplantation. Two different strategies are used to overcome these barriers: desensitization of the recipient to remove the antibodies and to prevent their rebound after transplantation and the exchange of organs between two or more pairs. The largest part of this review is dedicated to describing the techniques of desensitization. Even if the first reports of successful renal transplantation between ABO-incompatible pairs have been published by 1980, the number of ABO-incompatible transplants increased substantially in this century because of our improved knowledge of the immune system and the availability of new drugs. Rituximab has substantially replaced splenectomy. The technique of apheresis has improved and more recently a tailored desensitization proved to be the more efficient strategy avoiding an excess of immunosuppression with the related side effects. Recent reports document outcomes for such transplantation similar to the outcomes of standard transplantation.

Complement-Based Therapy in the Management of Antibody-Mediated Rejection

Antibody-mediated rejection (AMR) is one of the leading causes of kidney allograft failure and is usually mediated by anti-human leukocyte antigen donor-specific antibodies (DSAs). Activation of classical pathway of the complement system is responsible for downstream effects of DSA and account for significant manifestations of AMR. Currently, the treatment of AMR is based on strategies to remove preformed antibodies or to prevent their production; however, these strategies are often unsuccessful. It is theoretically possible to inhibit complement activity to prevent the effect of DSA on kidney allograft function. Complement inhibitors such as eculizumab, a complement 5 monoclonal antibody, and complement 1 esterase inhibitors (C1 INHs) have been used in prevention and treatment of AMR with variable success. Eculizumab and C1 INH seem to reduce the incidence of early AMR and allow transplantation in highly sensitized kidney transplant recipients, but data on their long-term effect on kidney allograft function are limited. Several case reports described the successful use of eculizumab in the treatment of AMR, but there are no randomized controlled studies that showed efficacy. Treatment of AMR with C1 INH, in addition to standard of care, did not change short-term outcome but long-term studies are underway.

Emerging immunotherapies for autoimmune kidney disease

Autoimmunity is a leading cause of chronic kidney disease and loss of native and transplanted kidneys. Conventional immunosuppressive therapies can be effective but are non-specific, noncurative, and risk serious side effects such as life-threatening infection and cancer. Novel therapies and targeted interventions are urgently needed. In this brief review we explore diverse strategies currently in development and under consideration to interrupt underlying disease mechanisms in immune-mediated renal injury. Because autoantibodies are prominent in diagnosis and pathogenesis in multiple human glomerulopathies, we highlight several promising therapies that interfere with functions of early mediators (IgG and complement) of the effector arm and with an epicenter (the germinal center) for induction of humoral immunity.

Complement-mediated renal diseases after kidney transplantation - current diagnostic and therapeutic options in de novo and recurrent diseases

For decades, kidney diseases related to inappropriate complement activity, such as atypical hemolytic uremic syndrome and C3 glomerulopathy (a subtype of membranoproliferative glomerulonephritis), have mostly been complicated by worsened prognoses and rapid progression to end-stage renal failure. Alternative complement pathway dysregulation, whether congenital or acquired, is well-recognized as the main driver of the disease process in these patients. The list of triggers include: surgery, infection, immunologic factors, pregnancy and medications. The advent of complement activation blockade, however, revolutionized the clinical course and outcome of these diseases, rendering transplantation a viable option for patients who were previously considered as non-transplantable cases. Several less-costly therapeutic lines and likely better efficacy and safety profiles are currently underway. In view of the challenging nature of diagnosing these diseases and the long-term cost implications, a multidisciplinary approach including the nephrologist, renal pathologist and the genetic laboratory is required to help improve overall care of these patients and draw the optimum therapeutic plan.

Long-term desensitization for ABO-incompatible living related kidney transplantation recipients with high refractory and rebound anti-blood type antibody: case report

Background

ABO-incompatible living related kidney transplantation (ABO-iLKT) has increased the possibilities for kidney transplantation in patients with end stage renal disease. Due to advancements in immunosuppressive agents and the identification of immunological conditions following ABO-iLKT, this transplantation technique has achieved the same success rate as ABO-compatible LKT. However, some patients continue to generate anti-blood type antibodies, despite conventional immunosuppressant treatment.

Case presentation

A 60-year-old man was referred to our hospital for kidney transplantation. The proposed transplant was ABO incompatible, from a donor with blood-type A to a recipient with blood-type O. The recipient’s anti-A blood-type IgG antibody titer was measured at 4096-fold dilution. Following desensitization therapy, including mycophenolate mofetil (MMF) 750 mg/day for 3 months, intravenous Rituximab 200 mg, and two sessions of double filtration plasmapheresis, the anti-A blood-type IgG antibody titer decreased to only 516-fold dilution and did not meet our target of less than 128-fold dilution. MMF was thus continued for an additional 4 months and four additional sessions of plasmapheresis were undertaken. Following these interventions, antibody titers decreased to 128-fold dilution and ABO-iLKT was performed. Following transplant, antibody-mediated rejection was not observed and renal function was preserved. However, a post-operative renal biopsy 1.5 months later showed evidence of T-cell-mediated rejection IB. The patient was treated with steroids, with no increase in serum creatinine.

Conclusion

Our findings suggest that the long-term single MMF desensitization therapy could be a suitable option for ABO-iLKT with high refractory and rebound anti-blood type antibody. Further studies are required to establish the optimal immunosuppression regimen to control B cell- mediated immunity in ABO-iLKT.

Thrombotic microangiopathy after renal transplantation: Current insights in de novo and recurrent disease

Thrombotic microangiopathy (TMA) is one of the most devastating sequalae of kidney transplantation. A number of published articles have covered either de novo or recurrent TMA in an isolated manner. We have, hereby, in this article endeavored to address both types of TMA in a comparative mode. We appreciate that de novo TMA is more common and its prognosis is poorer than recurrent TMA; the latter has a genetic background, with mutations that impact disease behavior and, consequently, allograft and patient survival. Post-transplant TMA can occur as a recurrence of the disease involving the native kidney or as de novo disease with no evidence of previous involvement before transplant. While atypical hemolytic uremic syndrome is a rare disease that results from complement dysregulation with alternative pathway overactivity, de novo TMA is a heterogenous set of various etiologies and constitutes the vast majority of post-transplant TMA cases. Management of both diseases varies from simple maneuvers, e.g., plasmapheresis, drug withdrawal or dose modification, to lifelong complement blockade, which is rather costly. Careful donor selection and proper recipient preparation, including complete genetic screening, would be a pragmatic approach. Novel therapies, e.g., purified products of the deficient genes, though promising in theory, are not yet of proven value.

Developments in anti-complement therapy; from disease to clinical trial

The complement system is well known for its role in innate immunity and in maintenance of tissue homeostasis, providing a first line of defence against infection and playing a key role in flagging apoptotic cells and debris for disposal. Unfortunately complement also contributes to pathogenesis of a number of diseases; in some cases driving pathology, and in others amplifying or exacerbating the inflammatory and damaging impact of non-complement disease triggers. The role of complement in pathogenesis of an expanding number of diseases has driven industry and academia alike to develop an impressive arsenal of anti-complement drugs which target different proteins and functions of the complement cascade. Evidence from genetic and biochemical analyses, combined with improved identification of complement biomarkers and supportive data from sophisticated animal models of disease, has driven a drug development landscape in which the indications selected for clinical trial cluster in three 'target' tissues: the kidney, eye and vasculature. While the disease triggers may differ, complement activation and amplification is a common feature in many diseases which affect these three tissues. An abundance of drugs are in clinical development, some show favourable progression whereas others experience significant challenges. However, these hurdles in themselves drive an ever-evolving portfolio of 'next-generation' drugs with improved pharmacokinetic and pharmacodynamics properties. In this review we discuss the indications which are in the drug development 'spotlight' and review the relevant indication validation criteria. We present current progress in clinical trials, highlighting successes and difficulties, and look forward to approval of a wide selection of drugs for use in man which give clinicians choice in mechanistic target, modality and route of delivery.

Eculizumab for Thrombotic Microangiopathy Associated with Antibody-Mediated Rejection after ABO-Incompatible Kidney Transplantation

Thrombotic microangiopathy is a form of antibody-mediated rejection (ABMR): it is the main complication of ABO-incompatible (ABOi) kidney transplantation (KT). Herein, we report on two cases of ABMR with biological and histological features of thrombotic microangiopathy (TMA) that were treated by eculizumab after ABOi KT. The first patient presented with features of TMA at postoperative day (POD) 13. Because of worsening biological parameters and no recovery of kidney function, despite seven sessions of immunoadsorption, a salvage therapy of eculizumab was started on POD 23. Kidney function slightly improved during the first 4 months after transplantation. Eculizumab was stopped at month 4. However, kidney function worsened progressively, leading to dialysis at month 13 after transplantation. The second patient presented with features of TMA at POD 1. In addition to immunoadsorption therapy, eculizumab was started on POD 6. Kidney function improved. Eculizumab was stopped on POD 64 and immunoadsorption sessions were stopped on POD 102. At the last follow-up (after 9 months), eGFR was at 43 mL/min/1.73 m². Our case reports show the beneficial effect of eculizumab to treat ABMR after ABOi KT. However, it should be given early after diagnosing TMA associated with ABMR.

De novo thrombotic microangiopathy after kidney transplantation

Thrombotic microangiopathy (TMA) is a serious complication of transplantation that adversely affects kidney transplant recipient and allograft survival. Post-transplant TMA is usually classified into two categories: 1) recurrent TMA and 2) de novo TMA. Atypical hemolytic uremic syndrome (aHUS) resulting from dysregulation and over-activation of the alternate complement pathway is a rare disease but the most common diagnosis associated with recurrence in the allografts. De novo TMA, on the other hand, represents an overwhelming majority of the cases of post-transplant TMA and is a substantially more heterogeneous entity than recurrent aHUS. Here, we review the etio-pathogenesis, diagnosis and treatment options for de novo post-transplant TMA. It is usually in the setting of calcineurin inhibitor use, mammalian target of rapamycin inhibitor use, or antibody mediated rejection; recently genetic mutations in complement regulatory genes for Factor H and Factor I similar to those described in aHUS have been reported in up to a third of these patients. Systemic signs of TMA are frequently absent, and a renal allograft biopsy is often needed to establish the diagnosis. Although withdrawal of the offending agents is usually the first line of treatment and resolution of laboratory abnormalities has been documented with this approach in several case reports and case series, available retrospective data demonstrate lack of benefit in long-term graft outcomes. Co-stimulation blockage with belatacept provides an effective alternate immunosuppressive strategy for these patients. Anti-complement therapy with eculizumab is effective in some cases; further work is required to define which patients with TMA (with and without concomitant antibody-mediated rejection) would benefit from receiving this treatment, and what biomarkers can be used to identify them.

Complement-Activating Anti-HLA Antibodies in Kidney Transplantation: Allograft Gene Expression Profiling and Response to Treatment

Complement-activating anti-HLA donor-specific antibodies (DSAs) are associated with impaired kidney transplant outcome; however, whether these antibodies induce a specific rejection phenotype and influence response to therapy remains undetermined. We prospectively screened 931 kidney recipients for complement-activating DSAs and used histopathology, immunostaining, and allograft gene expression to assess rejection phenotypes. Effector cells were evaluated using in vitro human cell cultures. Additionally, we assessed the effect of complement inhibition on kidney allograft rejection phenotype and the clinical response to complement inhibition in 116 independent kidney recipients with DSAs at transplant receiving rejection prophylaxis with eculizumab or standard of care (plasma exchange and intravenous Ig) at ten international centers. The histomolecular rejection phenotype associated with complement-activating DSA was characterized by complement deposition and accumulation of natural killer cells and monocytes/macrophages in capillaries and increased expression of five biologically relevant genes (CXCL11, CCL4, MS4A7, MS4A6A, and FCGR3A) indicative of endothelial activation, IFNγ response, CD16-mediated natural killer cell activation, and monocyte/macrophage activation. Compared with standard of care, eculizumab specifically abrogated this histomolecular rejection phenotype and associated with a decreased 3-month rejection incidence rate in patients with complement-activating DSAs (56%; 95% confidence interval [95% CI], 38% to 74% versus 19%; 95% CI, 8% to 35%; P=0.001) but not in those with noncomplement-activating DSAs (9%; 95% CI, 2% to 25% versus 13%; 95% CI, 2% to 40%; P=0.65). In conclusion, circulating complement-activating anti-HLA DSAs are associated with a specific histomolecular kidney allograft rejection phenotype that can be abrogated by complement inhibition.

Complement C5-inhibiting therapy for the thrombotic microangiopathies: accumulating evidence, but not a panacea

Thrombotic microangiopathy (TMA), characterized by organ injury occurring consequent to severe endothelial damage, can manifest in a diverse range of diseases. In complement-mediated atypical haemolytic uraemic syndrome (aHUS) a primary defect in complement, such as a mutation or autoantibody leading to over activation of the alternative pathway, predisposes to the development of disease, usually following exposure to an environmental trigger. The elucidation of the pathogenesis of aHUS resulted in the successful introduction of the complement inhibitor eculizumab into clinical practice. In other TMAs, although complement activation may be seen, its role in the pathogenesis remains to be confirmed by an interventional trial. Although many case reports in TMAs other than complement-mediated aHUS hint at efficacy, publication bias, concurrent therapies and in some cases the self-limiting nature of disease make broader interpretation difficult. In this article, we will review the evidence for the role of complement inhibition in complement-mediated aHUS and other TMAs.

Antibodies Against Complement Components: Relevance for the Antiphospholipid Syndrome-Biomarkers of the Disease and Biopharmaceuticals

PURPOSE OF REVIEW

Laboratory criterion for the diagnosis of antiphospholipid syndrome (APS) is the presence of antiphospholipid antibodies (aPL Abs). Complement system has a role in mediating aPL Abs-induced thrombosis in animal models. The importance of antibodies against complement components (potential biomarkers of APS) and the importance of antibodies with beneficial anti-complement effects in APS (as biopharmaceuticals) are reviewed.

RECENT FINDINGS

Antibodies against complement components described in APS patients, so far, are anti-C1q and anti-factor H Abs, although anti-factor B Abs and anti-C5a Abs were described in animal models of APS. Clinical studies in APS patients are limited to a small number of case reports. Studies that would confirm potential role of Abs against complement components (as potential biomarkers of APS) are lacking. Lack of randomized clinical trials (that would provide complete data for confirmation of beneficial effects of biopharmaceuticals in complement inhibition) in APS is alarming.

Complement in Kidney Transplantation

The complement system is considered to be an important part of innate immune system with a significant role in inflammation processes. The activation can occur through classical, alternative, or lectin pathway, resulting in the creation of anaphylatoxins C3a and C5a, possessing a vast spectrum of immune functions, and the assembly of terminal complement cascade, capable of direct cell lysis. The activation processes are tightly regulated; inappropriate activation of the complement cascade plays a significant role in many renal diseases including organ transplantation. Moreover, complement cascade is activated during ischemia/reperfusion injury processes and influences delayed graft function of kidney allografts. Interestingly, complement system has been found to play a role in both acute cellular and antibody-mediated rejections and thrombotic microangiopathy. Therefore, complement system may represent an interesting therapeutical target in kidney transplant pathologies.

Pharmacologic Complement Inhibition in Clinical Transplantation

Purpose of Review

Over the past two decades, significant strides made in our understanding of the etiology of antibody-mediated rejection (AMR) in transplantation have put the complement system in the spotlight. Here, we review recent progress made in the field of pharmacologic complement inhibition in clinical transplantation and aim to understand the impact of this therapeutic approach on outcomes in transplant recipients.

Recent Findings

Encouraged by the success of agents targeting the complement cascade in disorders of unrestrained complement activation like paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS), investigators are testing the safety and efficacy of pharmacologic complement blockade in mitigating allograft injury in conditions ranging from AMR to recurrent post-transplant aHUS, C3 glomerulopathies and antiphospholipid anti-body syndrome (APS). A recent prospective study demonstrated the efficacy of terminal complement inhibition with eculizumab in the prevention of acute AMR in human leukocyte antigen (HLA)-incompatible living donor renal transplant recipients. C1 esterase inhibitor (C1-INH) was well tolerated in two recent studies in the treatment of AMR and was associated with improved renal allograft function.

Summary

Pharmacologic complement inhibition is emerging as valuable therapeutic tool, especially in the management of highly sensitized renal transplant recipients. Novel and promising agents that target various elements in the complement cascade are in development. Graphical Abstractᅟ.

Use of polyclonal/monoclonal antibody therapies in transplantation

INTRODUCTION

For over thirty years, antibody (mAb)-based therapies have been a standard component of transplant immunosuppression, and yet much remains to be learned in order for us to truly harness their therapeutic capabilities. Current mAbs used in transplant directly target and destroy graft-destructive immune cells, interrupt cytokine and costimulation-dependent T and B cell activation, and prevent down-stream complement activation. Areas covered: This review summarizes our current approaches to using antibody-based therapies to prevent and treat allograft rejection. It also provides examples of promising novel mAb therapies, and discusses the potential for future mAb development in transplantation. Expert opinion: The broad capability of antibodies, in parallel with our growing ability to synthetically modulate them, offers exciting opportunities to develop better biologic therapeutics. In order to do so, we must further our understanding about the basic biology underlying allograft rejection, and gain better appreciation of how characteristics of therapeutic antibodies affect their efficacy.

Eculizumab for the Treatment of Severe Antibody-Mediated Rejection: A Case Report and Review of the Literature

In renal transplantation, treatment options for antibody-mediated rejection are limited. Here, we report a case of severe AMR treated with eculizumab. A 50-year-old woman known for end stage kidney disease secondary to IgA nephropathy received a kidney transplant from a 50-year-old deceased donor. At 5 months after transplantation, she presented with acute graft dysfunction and biopsy showed a severe antibody-mediated rejection associated with thrombotic microangiopathy. Despite an aggressive conventional immunosuppressive regimen, signs of rejection persisted and the patient was treated with 3 doses of eculizumab. Following the therapy, markers of TMA improved and graft function stabilized. However, ongoing signs of rejection remained in the repeated biopsy. In kidney transplantation, eculizumab is an expensive treatment and its role in the treatment of antibody-mediated rejection remains to be determined.

C1 Inhibitor in Acute Antibody-Mediated Rejection Nonresponsive to Conventional Therapy in Kidney Transplant Recipients: A Pilot Study

Complement inhibitors have not been thoroughly evaluated in the treatment of acute antibody-mediated rejection (ABMR). We performed a prospective, single-arm pilot study to investigate the potential effects and safety of C1 inhibitor (C1-INH) Berinert added to high-dose intravenous immunoglobulin (IVIG) for the treatment of acute ABMR that is nonresponsive to conventional therapy. Kidney recipients with nonresponsive active ABMR and acute allograft dysfunction were enrolled between April 2013 and July 2014 and received C1-INH and IVIG for 6 months (six patients). The primary end point was the change in eGFR at 6 months after inclusion (M+6). Secondary end points included the changes in histology and DSA characteristics and adverse events as evaluated at M+6. All patients showed an improvement in eGFR between inclusion and M+6: from 38.7 ± 17.9 to 45.2 ± 21.3 mL/min/1.73 m(2) (p = 0.0277). There was no change in histological features, except a decrease in the C4d deposition rate from 5/6 to 1/6 (p = 0.0455). There was a change in DSA C1q status from 6/6 to 1/6 positive (p = 0.0253). One deep venous thrombosis was observed. In a secondary analysis, C1-INH patients were compared with a similar historical control group (21 patients). C1-INH added to IVIG is safe and may improve allograft function in kidney recipients with nonresponsive acute ABMR.

Eculizumab use in kidney transplantation

PURPOSE OF REVIEW

Eculizumab suppresses the effector functions of the complement system and represents a therapeutic breakthrough for patients with paroxysmal nocturnal hemoglobinuria or atypical hemolytic uremic syndrome (aHUS). Safety monitoring is ongoing; so far, most notable is the expected increase in infection risk with encapsulated organisms. Despite potential applicability in multiple complement-mediated disorders, the off-label use of eculizumab has been limited, mainly by its prohibitive cost. The purpose of this review is to summarize the current data relevant to the use of eculizumab in kidney transplantation.

RECENT FINDINGS

In aHUS, prone to high rates of recurrence and allograft loss, eculizumab has made the most notable therapeutic impact. Further clarification of complement defects may help predict therapeutic responses and hopefully guide treatment duration. In C3 glomerulopathies, the clinical response to eculizumab appears more heterogeneous and less effective in processes mediated by upstream to C5 complement deregulation. A large clinical trial of eculizumab for prevention of delayed graft function is ongoing. In antibody-mediated rejection, the role of eculizumab is unclear as its use has been limited to very complex, mostly presensitized, patients in mixed combinations of therapeutic modalities.

SUMMARY

Overall, eculizumab has raised awareness of complement-mediated disorders as an exciting, new therapeutic option with multiple potential applications in kidney transplantation. Further research is needed to develop a better understanding of eculizumab applicability, efficacy, and treatment monitoring and beyond, to future therapeutic tools targeting the complement.

Off-label use of the expensive orphan drug eculizumab in France 2009-2013 and the impact of literature: focus on the transplantation field

PURPOSE

The orphan drug eculizumab (Soliris ®) is one of the most expensive in the world and based on expenditures is classed among the highest in France, a scenario suggestive of off-label use. Given its pharmacological properties, it is likely to be used in organ transplantation. Our purposes were to describe the consumption trends of eculizumab for off-label indications overall and in the organ transplantation field and to assess the impact of publications on the latter use.

METHODS

We carried out a temporal ecological study within the French national hospitalization database (PMSI). First, the trend of eculizumab consumption (2009-2013) was compared to our estimate of the maximum on-label consumption (overall and for transplantation). Second, we evaluated the impact of the publications supporting the effectiveness of eculizumab in the transplantation field on temporal trends of eculizumab consumption.

RESULTS

Eculizumab total consumption exceeded our estimate of the maximum on-label consumption since the end of 2011 and increased until the end of the study. The off-label consumption represented at least 50 % of the total consumption. The off-label consumption in organ transplantation also increased since 2011. The amount of publications grew through the study period, but overall, the evidence level remained low. Statistically, publications were neither associated with the drug consumption for transplantation in the long term nor in the short term.

CONCLUSION

Eculizumab started being notably used for off-label indications in France since the end of 2011, and this use increased until the end of the study. We found only low-level evidence concerning the off-label use of eculizumab in the transplantation field through the studied period.

Eculizumab for rescue of thrombotic microangiopathy in PM-Scl antibody-positive autoimmune overlap syndrome

A 46-year-old female with interstitial lung disease presented with proximal muscle weakness, worsening hypertension, microangiopathic hemolysis, thrombocytopenia and deteriorating renal function. She had no sclerodactyly, but had abnormal capillaroscopy. She tested positive for PM-Scl antibodies, and a renal biopsy showed an acute thrombotic microangiopathy consistent with scleroderma renal crisis (SRC). She failed to respond to corticosteroids, plasmapheresis and renin–angiotensin pathway inhibitors. She recovered quickly with the anti-C5 antibody, eculizumab. She had no genetic abnormalities associated with atypical hemolytic uremic syndrome except a DNA variant of unknown significance in C3. This case suggests that eculizumab may be effective for SRC.

Polyclonal and monoclonal antibodies in renal transplant: an update

PURPOSE OF REVIEW

There are several monoclonal and polyclonal antibodies used in renal transplantation today, this article will discuss several agents, their updates and newer agents.

RECENT FINDINGS

Antithymocyte globulin and interleukin-2 (IL-2) receptor blocker continue to be used as induction agents. The risk of acute rejection was higher in IL-2 receptor blockers mainly in the first year, but graft survivals were similar in both groups long term. Belatacept is the only approved intravenous maintenance immunosuppressive therapy which provides the benefit of glomerular filtration rate preservation, but it was associated with a higher risk of acute rejection and post-transplant lymphoproliferative disorder. Bortezomib may help decrease donor-specific antibody levels, but there are limited data to support its use for desensitization or rejection. Eculizumab may help in antibody-mediated rejection in some cases but has not shown promising long-term effects in high-risk individuals. Newer agents have been continuously tested for improved efficacy and safety.

SUMMARY

Transplantation is the standard of care for end-stage renal disease patients, but we still have a long way to go, as we need to improve long-term outcomes. The manipulation of the immune system is a delicate undertaking, with risks of adverse events; therefore, risk versus benefit needs to be carefully evaluated and treatment needs to be individualized.

Current progress in ABO-incompatible kidney transplantation

ABO-incompatible kidney transplantation (ABOi KT) was introduced to expand the donor pool and minimize shortage of kidneys for transplantation. Because improved outcomes of ABOi KT were reported in Japan in the early 2000s, the number of ABOi KTs has been increasing worldwide. In addition, a better understanding of immune pathogenesis and subsequent aggressive immunosuppression has helped to make effective desensitization protocols. Current strategies of ABOi KT consist of pretransplant antibody removal using plasmapheresis or immunoadsorption to prevent hyperacute rejection and potent maintenance immunosuppression, such as tacrolimus and mycophenolate mofetil, to inhibit antibody-mediated rejection. Recent outcomes of ABOi KT are comparable with ABO-compatible KT. However, there are still many problems to be resolved. Very high anti-ABO antibody producers are difficult to desensitize. In addition, ABOi KT is associated with an increased risk of infection and possibly malignancy due to aggressive immunosuppression. Optimization of desensitization and patient-tailored immunosuppression protocols are needed to achieve better outcomes of ABOi KT. This review provides an overview of the history, immune mechanism, immunosuppressive protocol, outcomes, current obstacles, and future perspectives in ABOi KT.

Eculizumab to treat antibody-mediated rejection in a 7-year-old kidney transplant recipient

We report on successful early eculizumab administration to treat acute antibody-mediated rejection (ABMR) in a highly sensitized kidney transplant recipient. The recipient is a 7-year-old boy who received, 6 months after a desensitization protocol with monthly intravenous immunoglobulin infusion, a second kidney transplant in the presence of low donor-specific antibodies (DSAs). Both pretransplant lymphocytotoxic and flow cytometric crossmatch were negative. Allograft function recovered promptly, with excellent initial function. On postoperative day (POD) 4, the child developed significant proteinuria with an acute rise in serum creatinine. Allograft biopsy showed severe acute ABMR. Intravenous eculizumab (600 mg), preceded by a single session of plasmapheresis, was administered on POD 5 and 12 along with a 4-day thymoglobulin course. After the first dose of eculizumab, a strikingly rapid normalization of allograft function with a decrease in proteinuria occurred. However, because circulating DSA levels remained elevated, the child received 3 doses of intravenous immunoglobulin (POD 15, 16, and 17), with a significant subsequent decrease in DSA levels. At 9 months after transplant, the child continues to maintain excellent allograft function with undetectable circulating DSA levels. This unique case highlights the potential efficacy of using early eculizumab to rapidly reverse severe ABMR in pediatric transplantation, and therefore it suggests a novel therapeutic approach to treat acute ABMR.

Efficacy of plasmapheresis on donor-specific antibody reduction by HLA specificity in post-kidney transplant recipients

BACKGROUND

Donor-specific antibodies (DSAs) to HLA antigens can cause acute antibody-mediated rejection (AMR) after kidney transplantation (Txp). Therapeutic plasma exchange (TPE) has been used for AMR treatment; however, DSA reduction rates are inconsistent. We investigated DSA reduction rates by HLA specificity and clinical outcome.

STUDY DESIGN AND METHODS

Sixty-four courses of TPE for 56 kidney Txp recipients with high DSA were investigated. Dates of TPE procedures and Txp, patients' age, sex, race, creatinine (Cr), and mean fluorescent intensity (MFI) of DSA were retrieved. MFI reduction rate after one to three TPE and four to six TPE procedures were calculated by HLA DSA specificity in each patient, and the mean reduction rates were compared. The relationship of TPE treatment, MFI or Cr improvement rate, and graft age was also investigated.

RESULTS

Patients received a mean 6.0 TPE procedures. Most received intravenous immunoglobulin after TPE and immunosuppressives. Forty-two cases (65.6%) had DSA to HLA Class I and 54 cases (84.4%) to Class II, including 32 cases (50.0%) to both. Mean MFI reduction rates after one to three TPE and four to six TPE procedures were 25.7 and 37.1% in HLA Class I, 25.1 and 34.2% in Class II, and 14.3 and 19.9% in DR51-53. The mean Cr improvements at the end of TPE and 3 and 6 months after TPE were 3.41, -0.37, and -0.72%, respectively.

CONCLUSION

Six TPE procedures decreased DSA more than three TPE procedures, but reduction rate was lower by the second three TPE procedures than the first three TPE procedures. Although the mean Cr improvement was minimal, the treatment has good potential to stop further deterioration of kidney function. Better Cr improvement rate is correlated with the graft age.

Peptide inhibitor of complement c1, a novel suppressor of classical pathway activation: mechanistic studies and clinical potential

The classical pathway of complement plays multiple physiological roles including modulating immunological effectors initiated by adaptive immune responses and an essential homeostatic role in the clearance of damaged self-antigens. However, dysregulated classical pathway activation is associated with antibody-initiated, inflammatory diseases processes like cold agglutinin disease, acute intravascular hemolytic transfusion reaction (AIHTR), and acute/hyperacute transplantation rejection. To date, only one putative classical pathway inhibitor, C1 esterase inhibitor (C1-INH), is currently commercially available and its only approved indication is for replacement treatment in hereditary angioedema, which is predominantly a kinin pathway disease. Given the variety of disease conditions in which the classical pathway is implicated, development of therapeutics that specifically inhibits complement initiation represents a major unmet medical need. Our laboratory has identified a peptide that specifically inhibits the classical and lectin pathways of complement. In vitro studies have demonstrated that these peptide inhibitors of complement C1 (PIC1) bind to the collagen-like region of the initiator molecule of the classical pathway, C1q. PIC1 binding to C1q blocks activation of the associated serine proteases (C1s–C1r–C1r–C1s) and subsequent downstream complement activation. Rational design optimization of PIC1 has resulted in the generation of a highly potent derivative of 15 amino acids. PIC1 inhibits classical pathway mediated complement activation in ABO incompatibility in vitro and inhibiting classical pathway activation in vivo in rats. This review will focus on the pre-clinical development of PIC1 and discuss its potential as a therapeutic in antibody-mediated classical pathway disease, specifically AIHTR.

Section 13. Short-course pretransplant antiviral therapy is a feasible and effective strategy to prevent hepatitis C recurrence after liver transplantation in genotype 2 patients

BACKGROUND

Hepatitis C virus (HCV) recurrence in recipients who are viremic at time of liver transplantation (LT) is universal and carries poor prognosis. Pretransplant antiviral therapy to eradicate HCV reduces recurrence, but withdrawal rate is high. We conducted a short-course (4 weeks) of pegylated interferon alpha-2a (Peg-IFN-α2a) plus ribavirin (RBV) to prevent of HCV recurrence.

PATIENTS AND METHODS

From October 2009 to December 2011, eighty-eight consecutive HCV patients for living donor LT with potential living donor at Kaohsiung Chang Gung Memorial Hospital were included. Patients were divided into treatment and nontreatment group depending on presence of HCV-RNA. Fixed dosage of Peg-IFN-α2a (135 μg/week) plus RBV (10 mg/kg per day) were given for 4 weeks to treatment group who passed the 4-week waiting time according to clinical safety assessment.

RESULTS

Forty-eight patients with genotypes 1, 2, and 3 (n=29/18/1) were treated with IFN and RBV combination for 4 (range, 1-9) weeks. Serum HCV RNA became undetectable at transplantation in 26 (54%) patients. No difference between genotypes 1 (n= 14, 48%) and 2/3(n=12, 63%, P=0.25) was observed. Most patients experienced cytopenia during treatment, but no mortality was noted. In the treatment group, 13 patients remained free of HCV infection 6 months after transplant. Virologic response at transplantation (48% vs. 100%, P=0.015) and genotype 2/3 (50% vs. 84%, P=0.01) are strong predictors of lower HCV recurrence rate. Multivariate analysis showed that genotype 2/3 was the only independent predictive factor affecting HCV RNA negativity 6 months after liver transplantation (OR:11.25; P=0.014).

CONCLUSIONS

Short-term pretransplant antiviral therapy is a feasible strategy in preventing HCV recurrence after LDLT especially in genotypes 2 and 3 recipients.

De novo glomerular diseases after renal transplantation

Glomerular diseases developing in the kidney allograft are more often recurrences of the original disease affecting the native kidneys. However, in an undefined number of cases de novo, glomerular diseases unrelated to the original disease in the native kidneys can develop in the transplanted kidney. The clinical presentation and histologic features of de novo diseases are often similar to those features observed in patients with primary or secondary GN in the native kidneys. However, in transplanted kidneys, the glomerular, vascular, and tubulointerstitial changes are often intertwined with structural abnormalities already present at the time of transplant or caused by antibody- or cell-mediated allograft rejection, immunosuppressive drugs, or superimposed infection (most often of a viral nature). The pathophysiology of de novo glomerular diseases is quite variable. In rare cases of de novo minimal change disease, circulating factors increasing the glomerular permeability likely participate. Maladaptive hemodynamic changes and tissue fibrosis caused by calcineurin inhibitors or other factors may be involved in the pathogenesis of de novo FSGS. The exposure of cryptic podocyte antigens may favor the development of de novo membranous nephropathy. Many cases of de novo membranoproliferative GN are related to hepatitis C virus infection. Patients with Alport syndrome lacking antigenic epitopes in their glomerular basement membrane may develop antibodies against these glomerular basement membrane antigens expressed in the transplanted kidney. Infection may cause acute GN to have a heterogeneous clinical presentation and outcome. De novo pauci-immune GN in renal transplant is rare. Preexisting or acquired intolerance to glucose may, in the long term, cause diabetic nephropathy. The prognosis of de novo diseases depends on the type of GN, the severity of lesions caused by the alloimmune response, or the efficacy of immunosuppressive therapy. In most cases, the management of de novo glomerular diseases is empirical or elusive.

Complement modulation in solid-organ transplantation

The complement system is a major constituent of the innate immune system. It has a critical role in defense against pathogens but dysregulation of complement activation may lead to tissue injury and modulate the adaptive immune response. In organ transplantation, local complement activation is involved in hyper-acute rejection and antibody-mediated rejection. This last decade, interest in complement activation has increased due to new insights into the pathophysiology of antibody-mediated rejection, but also since the availability of news drugs that target terminal complement activation. In this review, we discuss our current understanding of how local complement activation induces acute and chronic graft injury, and review recent advances in clinical trials that block complement activation using the anti-C5 monoclonal antibody, eculizumab. Finally, we discuss how complement-targeted therapy may be integrated into our current immunosuppressive regimen and what type of patient will benefit most from this therapy.

Late antibody-mediated rejection after ABO-incompatible kidney transplantation during Gram-negative sepsis

Background

The major challenge in ABO-incompatible transplantation is to minimize antibody-mediated rejection. Effective reduction of the anti-ABO blood group antibodies at the time of transplantation has made ABO-incompatible kidney transplantation a growing practice in our hospital and in centers worldwide. ABO antibodies result from contact with A- and B-like antigens in the intestines via nutrients and bacteria. We demonstrate a patient with fulminant antibody-mediated rejection late after ABO-incompatible kidney transplantation, whose anti-A antibody titers rose dramatically following Serratia marcescens sepsis.

Case presentation

A 58-year-old woman underwent an ABO-incompatible kidney transplantation for end-stage renal disease secondary to autosomal dominant polycystic kidney disease. It concerned a blood group A1 to O donation. Pre-desensitization titers were 64 for anti-blood group A IgM and 32 for anti-blood group A IgG titers. Desensitization treatment consisted of rituximab, tacrolimus, mycophenolate mofetil, corticosteroids, immunoadsorption and intravenous immunoglobulines. She was readmitted to our hospital 11 weeks after transplantation for S. marcescens urosepsis. Her anti-A IgM titer rose to >5000 and she developed a fulminant antibody-mediated rejection.

We hypothesized that the (overwhelming) presence in the blood of S. marcescens stimulated anti-A antibody formation, as S. marcescens might share epitopes with blood group A antigen. Unfortunately we could not demonstrate interaction between blood group A and S. marcescens in incubation experiments.

Conclusion

Two features of this post-transplant course are remarkably different from other reports of acute rejection in ABO-incompatible kidney transplantation: first, the late occurrence 12 weeks after kidney transplantation and second, the very high anti-A IgM titers (>5000), suggesting recent boosting of anti-A antibody formation by S. marcescens.

Novel immunosuppressive agents in kidney transplantation

Excellent outcomes have been achieved in the field of renal transplantation. A significant reduction in acute rejection has been attained at many renal transplant centers using contemporary immunosuppressive, consisting of an induction agent, a calcineurin inhibitor, an antiproliferative agent plus or minus a corticosteroid. Despite improvements with these regimens, chronic allograft injury and adverse events still persist. The perfect immunosuppressive regimen would limit or eliminate calcineurin inhibitors and/or corticosteroid toxicity while providing enhanced allograft outcomes. Potential improvements to the calcineurin inhibitor class include a prolonged release tacrolimus formulation and voclosporin, a cyclosporine analog. Belatacept has shown promise as an agent to replace calcineurin inhibitors. A novel, fully-human anti-CD40 monoclonal antibody, ASKP1240, is currently enrolling patients in phase 2 trials with calcineurin minimization and avoidance regimens. Another future goal of transplant immunosuppression is effective and safe treatment of allograft rejection. Novel treatments for antibody mediated rejection include bortezomib and eculizumab. Several investigational agents are no longer being pursed in transplantation including the induction agents, efalizumab and alefacept, and maintenance agents, sotrastaurin and tofacitinib. The purpose of this review is to consolidate the published evidence of the effectiveness and safety of investigational immunosuppressive agents in renal transplant recipients.

Late and chronic antibody-mediated rejection: main barrier to long term graft survival

Antibody-mediated rejection (AMR) is an important cause of graft loss after organ transplantation. It is caused by anti-donor-specific antibodies especially anti-HLA antibodies. C4d had been regarded as a diagnosis marker for AMR. Although most early AMR episodes can be successfully controlled or reversed, late and chronic AMR remains the leading cause of late graft loss. The strategies which work in early AMR have limited effect on late/chronic episodes. Here, we reviewed the lines of evidence that late/chronic AMR is the leading cause of late graft loss, characteristics of late AMR, and current strategies in managing late/chronic AMR. More effort should be put on the management of late/chronic AMR to make a better long term graft survival.

Kidney transplantation across HLA and ABO antibody barriers

PURPOSE OF REVIEW

A significant number of kidney transplantations in industrialized countries is currently performed over human leukocyte antigen (HLA) or ABO antibody barriers after living donation to encounter the increasing shortage of organs from deceased donors. Although patients with moderate titers of anti-A/B antibodies may easily be desensitized with no negative impact on allograft survival, recipients with high titers and HLA sensitized patients demonstrate a substantial risk for antibody-mediated rejection, limiting long-term outcomes.

RECENT FINDINGS

The use of powerful desensitization strategies including plasmapheresis and immunoadsorption, extended therapeutic options such as the application of the recently introduced complement inhibitors, and refined antibody detection techniques may further facilitate transplantations, especially in the HLA-sensitized kidney transplant recipient. On the contrary, special strategies such as the Eurotransplant Acceptable Mismatch Program or kidney paired exchange help improving long-term outcomes in these difficult to transplant patients by circumventing the HLA (or ABO) antibody barrier.

SUMMARY

As compared with waiting for a compatible deceased donor organ, HLA and ABO incompatible transplantations performed in experienced centers have become a reasonable alternative for end-stage kidney disease patients with an incompatible live donor. Whenever possible, however, the transplantation should be performed between ABO compatible donor-recipient pairs in the absence of positive crossmatch results.

The complement cascade and renal disease

Serum complement cascade, a part of innate immunity required for host protection against invading pathogens, is also a mediator of various forms of disease and injury. It is activated by classical, lectin, and alternative pathways that lead to activation of C3 component by C3 convertases, release of C3b opsonin, C5 conversion and eventually membrane attack complex formation. The tightly regulated activation process yields also C3a and C5a anaphylatoxins, which target a broad spectrum of immune and non-immune cells. The review discusses the involvement of the complement cascade in kidney disease pathogenesis and injury. The role of the complement pathways in autoantibody-mediated forms of glomerulonephritis (lupus nephritis, anti-glomerular basement membrane disease, anti-neutrophil cytoplasmic autoantibody-induced or membranoproliferative glomerulonephritis, membranous nephropathy), C3 glomerulopathy, atypical forms of hemolytic uremic syndrome, ischemic-reperfusion injury of transplanted kidney, and antibody-mediated renal allograft rejection are discussed. The disturbances in complement activation and regulation with underlying genetics are presented and related to observed pathology. Also promising strategies targeting the complement system in complement-related disorders are mentioned.

Laparoscopic splenectomy to salvage renal transplants from severe acute antibody-mediated rejection

Purpose. Acute antibody-mediated rejection, a complication of cross match positive and sensitized renal transplants, occurs despite the use of standard desensitization protocols. Rescue therapy consists of plasmapheresis and intravenous immunoglobulin (IVIg). In patients with preformed donor specific antibodies, rejection can be aggressive. We report here a case in which laparoscopic splenectomy was added to the standard rescue regimen. Case Report and Results. A 40-year-old Hispanic female with end stage renal disease had been receiving hemodialysis. The patient had numerous class 1 unacceptable antigens. She was scheduled to undergo an incompatible 1-1-1 mismatch living related donor kidney transplant. Preoperatively, the patient received plasmapheresis, IVIG, and thymoglobulin. There was good graft function until postoperative day 5. At that point, worsening renal function was noted. Renal biopsy was consistent with AMR. The patient became anuric and dialysis was initiated. To salvage the transplant, the patient underwent laparoscopic splenectomy. Postoperatively, renal function improved. Two years after transplant, the patient continues to have excellent graft function. Conclusion. In a small but significant number of renal transplants, antibody production occurs at a rate that traditional treatments are unable to reduce effectively. Based on our experience, the addition of splenectomy to standard rescue therapy can salvage renal transplants.

Eculizumab for rescue of thrombotic microangiopathy in PM-Scl antibody-positive autoimmune overlap syndrome

A 46-year-old female with interstitial lung disease presented with proximal muscle weakness, worsening hypertension, microangiopathic hemolysis, thrombocytopenia and deteriorating renal function. She had no sclerodactyly, but had abnormal capillaroscopy. She tested positive for PM-Scl antibodies, and a renal biopsy showed an acute thrombotic microangiopathy consistent with scleroderma renal crisis (SRC). She failed to respond to corticosteroids, plasmapheresis and renin-angiotensin pathway inhibitors. She recovered quickly with the anti-C5 antibody, eculizumab. She had no genetic abnormalities associated with atypical hemolytic uremic syndrome except a DNA variant of unknown significance in C3. This case suggests that eculizumab may be effective for SRC.