Rethinking de novo immune hepatitis,an old concept for liver allograft rejection: Relevance of glutathione S-transferase T1 mismatch

Antibody-mediated rejection(AMR) in liver transplantation has long been underestimated. The concept of the liver as an organ susceptible to AMR has emerged in recent years, not only in the context of the major histocompatibility complex with the presence of HLA donor-specific antibodies, but also with antigens regarded as "minor", whose role in AMR has been demonstrated. Among them, antibodies against glutathione S-transferase T1 have been found in 100% of patients with de novo autoimmune hepatitis(dn AIH) when studied. In its latest update, the Banff Working Group for liver allograft pathology proposed replacing the term dn AIH with plasma cell(PC)-rich rejection. Antibodies to glutathione S-transferase T1(GSTT1) in null recipients of GSTT1 positive donors have been included as a contributory but nonessential feature of the diagnosis of PC-rich rejection. Also in this update, non-organ-specific anti-nuclear or smooth muscle autoantibodies are no longer included as diagnostic criteria. Although initially found in a proportion of patients with PC-rich rejection, the presence of autoantibodies is misleading since they are not diseasespecific and appear in many different contexts as bystanders. The cellular types and proportions of the inflammatory infiltrates in diagnostic biopsies have been studied in detail very recently. PC-rich rejection biopsies present a characteristic cellular profile with a predominance of T lymphocytes and a high proportion of PCs, close to 30%, of which 16.48% are Ig G4+. New data on the relevance of GSTT1-specific T lymphocytes to PC-rich rejection will be discussed in this review.     

Acute liver failure secondary to acute antibody mediated rejection after compatible liver transplant: A case report

BACKGROUNDThe liver has traditionally been regarded as resistant to antibody-mediated rejection (AMR). AMR in liver transplants is a field in its infancy compared to kidney and lung transplants. In our case we present a patient with alpha-1-antitrypsin disease who underwent ABO compatible liver transplant complicated by acute liver failure (ALF) with evidence of antibody mediated rejection on allograft biopsy and elevated serum donor-specific antibodies (DSA). This case highlights the need for further investigations and heightened awareness for timely diagnosis.CASE SUMMARYA 56 year-old woman with alpha-1-antitrypsin disease underwent ABO compatible liver transplant from a deceased donor. The recipient MELD at the time of transplant was 28. The flow cytometric crossmatches were noted to be positive for T and B lymphocytes. The patient had an uneventful recovery postoperatively. Starting on postoperative day 5 the patient developed fevers, elevated liver function tests, distributive shock, renal failure, and hepatic encephalopathy. She went into ALF with evidence of antibody mediated rejection with portal inflammation, bile duct injury, endothelitis, and extensive centrizonal necrosis, and C4d staining on allograft biopsy and elevated DSA. Despite various interventions including plasmapheresis and immunomodulating therapy, she continued to deteriorate. She was relisted and successfully underwent liver retransplantation.CONCLUSIONThis very rare case highlights AMR as the cause of ALF following liver transplant requiring retransplantation.     

Treating humoral rejection after cardiac transplantation

Whereas effective strategies are available to treat acute cellular cardiac rejection, humoral rejection, also called vascular or antibody-mediated rejection, is more difficult to manage. Antibody-mediated (non-cellular) rejections (AMR) are rare and few successfully treated cases have been described in the literature. We report on a female patient, diagnosed with humoral rejection, leading to severe ventricular dysfunction and haemodynamic compromise, two months after transplantation. The patient received a combination therapy, consisting of plasmapheresis and immunoglobulins, which resulted in complete resolution of immunohistochemical signs of AMR. In this report, we will overview AMR and discuss several treatment modalities.     

Yellow fever disease in a renal transplant recipient: Case report and literature review

Yellow fever (YF) is a viral disease, with clinical presentation among immunosuppressed patients not fully understood. YF vaccination (YFV), a live vaccine, is contraindicated in patients receiving immunosuppressive treatment due to the risk of developing the disease after vaccination. We report a case of a 50‐year‐old male recipient who presented wild‐type YF five years after a deceased donor kidney transplant. He lived in a YF endemic area and inadvertently received YFV. One day after YFV, the patient presented nausea, vomiting, fever, diarrhea, polyarthralgia, thrombocytopenia, and increased levels of liver function enzymes. The serological test was compatible with YF disease, and quantitative viral load confirmed the diagnosis of wild‐type YF. The patient received supportive care for twelve days, with hospital discharge in good clinical condition and stable renal function. One month after discharge, the patient developed de novo donor‐specific anti‐HLA antibodies (DSA) and histological evidence of endothelial lesion, with a diagnosis of acute antibody‐mediated rejection (AMR), treated with plasmapheresis and human IVIg therapy. Six months after therapy, he presented normal renal function with a reduction of DSA MFI. In the reported case, we observed a clinical wild‐type YF diagnosed even after YF vaccine administration, with good clinical outcome. De novo DSA and AMR occurred after the recovering of disease, with an adequate response to therapy and preserved allograft function. We reviewed the published literature on YF and YFV in solid organ transplantation.     

Challenge to ABO blood type barrier in living donor liver transplantation

ABO incompatible living donor liver transplantation has the potential to expand the donor pool for patients with end stage liver diseases on the expense of challenges to overcome immunological barriers across blood type. There is a profound impact of age on incidence and severity of antibody mediated rejection (AMR). Even children older than 1 year have chances of AMR; children aged 8 years or older have risks of hepatic necrosis similar to adult liver recipients. The mechanism of AMR is based on circulatory disturbances secondary to inflammation and injury of the vascular endothelium caused by an antibody-antigen-complement reaction. The strategy to overcome ABO blood type barrier is based on both pre-transplant desensitization and adequate treatment of this phenomenon. Nowadays, rituximab is the standard means of desensitization but unfortunately an insufficient aid to treat AMR. Because of low incidence (less than 5% in the rituximab era), in practice of AMR only some case reports about the treatment of clinical AMR are available in the literature. Initial experiences revealed that the proteasome inhibitor, bortezomib might be a promising treatment based on its capacity to deplete plasma cell agents. Although ABO blood type barrier has been counteracted in 95% of patients by applying “rituximab-desensitization”, many issues, such as prediction of high-risk patients of infection and AMR and secure treatment strategies for evoked AMR, remain to be resolved.     

小肠移植中急性抗体介导排斥反应的病理学

目的:观察重度急性抗体介导排斥反应(antibody-mediated rejection,AMR)的病理形态学改变,回顾分析相关文献,为小肠移植急性AMR的诊断总结经验.方法:切除的失功能移植肠经10%中性福尔马林固定,石蜡包埋,4?m切片并行HE染色.详细观察移植物中肠壁各层及肠系膜内组织中主要的病理形态学改变,分级评价急性排斥反应及血管病变,并进行C4d免疫组织化学染色.结果:移植物内各级血管广泛受累,包括肠壁及肠系膜内各级血管.受累血管的改变以肠壁浆膜下层内的小血管及动静脉的滋养血管最为显著,主要表现为小血管壁的纤维素性坏死和/或血管内血栓形成,受累血管周围组织中性粒细胞浸润,红细胞漏出,组织水肿,部分病变血管周围伴有纤维素性坏死.免疫组织化学染色可见病变血管内膜C4d沉积.小肠黏膜固有层内血管显著扩张伴淤血,偶见血栓形成,肠黏膜隐窝上皮细胞正常,未见急性排斥反应.结论:血管壁的纤维素性坏死及血管内血栓形成是重度急性AMR的主要病理学改变.病变可以广泛累及移植物内各级血管;小肠黏膜内血管的病变可能不代表最严重的病变;临床早期确诊AMR的发生不能单纯依赖小肠黏膜活检.     

Proteasome inhibition for antibody-mediated allograft rejection

Antibody-mediated rejection (AMR) is a major risk factor for graft loss following kidney transplantation. Traditional anti-humoral therapies provide suboptimal therapy and they do not deplete plasma cells, which are the source of antibody production. Proteasome inhibitors (PI) have been shown to deplete both transformed and nontransformed plasma cells in human transplant recipients and animal models; and therefore, offer a new paradigm for AMR, ie, plasma cell-targeted therapy. Bortezomib, a first in class proteasome inhibitor approved by the US Food and Drug Administration for treatment of multiple myeloma, has been used to treat AMR in several solid organ transplant recipients. The greatest experience with PI therapy for treating AMR is in kidney transplant recipients. Experiences to date with PI therapy have demonstrated that: (1) early AMR (within the first 6 months post-transplant) responds better than late AMR, and (2) the nature of the plasma cell clonal population influences sensitivity to PI therapy with plasma subsets greater than long-lived bone marrow niche-resident plasma cells. In conclusion, plasma cell-targeted therapy with PIs is a method for targeting plasma cells (the source of antibody production) with a well-elucidated mechanism of action and subsequent points of synergy, thereby providing an exciting new potential means for enhancing anti-humoral therapies.     

Importance of human leukocyte antigen antibodies and leukocyte antigen/killer-cell immunoglobulin-like receptor genes in liver transplantation

Many mechanisms have been proposed to explain the hypothetical state of hepatic tolerance, which is described by eventual imbalances or deregulation in the balance of cytokines, mediators, effectors, and regulatory cells in the complex milieu of the liver. In this section, we will comment on the importance of donor-specific anti-human leukocyte antigen (HLA) antibodies (DSA) as well as the compatibility and pairings of HLA and killer-cell immunoglobulin-like receptor (KIR) genotypes in the evolution of liver transplantation. Thus, HLA compatibility, viral infections, and HLA-C/KIR combinations have all been linked to liver transplant rejection and survival. There have been reports of increased risk of acute and chronic rejection with ductopenia, faster graft fibrosis, biliary problems, poorer survival, and even de novo autoimmune hepatitis when DSAs are present in the recipient. Higher mean fluorescence intensity (MFI) values of the DSAs and smaller graft size were associated with poorer patient outcomes, implying that high-risk patients with preformed DSAs should be considered for selecting the graft placed and desensitization methods, according to the investigators. Similarly, in a combined kidney-liver transplant, a pretransplant with a visible expression of several DSAs revealed that these antibodies were resistant to treatment. The renal graft was lost owing to antibody-mediated rejection (AMR). The HLA antigens expressed by the transplanted liver graft influenced antibody elimination. Pathologists are increasingly diagnosing AMR in liver transplants, and desensitization therapy has even been employed in situations of AMR, particularly in patients with DSAs in kidney-hepatic transplants and high-class II MFI due to Luminex. In conclusion, after revealing the negative impacts of DSAs with high MFI, pretransplant virtual crossmatch techniques may be appropriate to improve evolution; however, they may extend cold ischemia periods by requiring the donor to be typed.     

Emphysematous pyelonephritis in renal allograft related to antibody‐mediated rejection: A case report and literature review

Emphysematous pyelonephritis (EPN) is a rare condition which can rapidly progress to sepsis and multiple organ failure with high mortality. We experienced a rare case of EPN in a renal allograft related to antibody‐mediated rejection (AMR). The patient received a deceased donor kidney transplant due to end‐stage renal disease secondary to diabetes mellitus. Cross‐match test was negative but she had remote history of anti‐HLA‐A2 antibody corresponding with the donor HLA. Surgery concluded without any major events. Anti‐thymoglobulin was given perioperatively for induction. She was compliant with her immunosuppressive medications making urine of 2 L/d with serum creatinine of 1.9 mg/dL at discharge on post‐operative day (POD) 6. She did well until POD 14 when she presented to the clinic with features of sepsis, pain over the transplanted kidney area and decline in urine volume with elevated serum creatinine. CT revealed extensive gas throughout the transplanted kidney. Renal scan revealed non‐functional transplant kidney with no arterial flow. Based on these findings, a decision to perform transplant nephrectomy was made. At laparotomy, the kidney was completely necrotic. Pathology showed non‐viable kidney parenchyma with the tubules lacking neutrophilic casts suggestive of ischemic necrosis. Donor‐specific antibody (DSA) returned positive with high intensity anti‐HLA‐A2 antibody. This is the first case of early EPN in allograft considered to have occurred as a result of thrombotic ischemia secondary to AMR. This case suggests consideration of perioperative anti‐B‐cell and/or anti‐plasma cell therapies for historical DSA and strict post‐operative follow‐up in immunologically high‐risk recipients to detect early signs of rejection and avoid deleterious outcomes.     

Present status of ABO-incompatible living donor liver transplantation in Japan

ABO-incompatible (ABO-I) living donor liver transplantation (LDLT) has been performed in Japan to overcome the organ shortage. Reported herein are the results of this approach through March 2006 in the National Registry of the Japan Study Group for ABO-incompatible transplantation. The questionnaires consisted of patient characteristics, operative data, and strategies for preventing antibody-mediated rejection (AMR). Data of 291 patients (follow-up period, 8 months-15 years; mean, 35 months) from 28 institutions were collected. Age was younger than 1 year in 68 patients, 1 to 7 years in 60 patients, 8 to15 years in 27 patients, and 16 years or older in 136 patients. The strategy for the blood-type barrier was heterogeneous in terms of recipient age, transplant center, and era. Local infusion and rituximab prophylaxis were applied in 2000 and 2003, respectively. The 5-year patient survival rate was 85% in infants and 52% in adults. The major causes of death were infection and antibody-mediated rejection (AMR). Multivariate analysis showed that age group, preoperative condition, antibody titer, and infection significantly affected survival. Age group, antibody titer, and local infusion treatment significantly affected the incidence of AMR. Patient survival rates were significantly higher and the incidence of AMR was significantly lower in adult patients after 2000 (3 year-survival rate, 29%, 56%, and 61%; incidence of AMR, 47%, 27%, and 16%, through May 2000, from June 2000 through October 2003, and from November 2003, respectively). CONCLUSION: ABO-incompatible LDLT is a standard practice in children, and local infusion and rituximab prophylaxis are promising in adults.     

Clinical significance of donor-specific human leukocyte antigen antibodies in liver transplantation

Antibody-mediated rejection(AMR) caused by donorspecific anti-human leukocyte antigen antibodies(DSA) is widely accepted to be a risk factor for decreased graft survival after kidney transplantation. This entity also plays a pathogenic role in other solid organ transplants as it appears to be an increasingly common cause of heart graft dysfunction and an emerging issue in lung transplantation. In contrast, the liver appears relatively resistant to DSA-mediated injury. This "immune-tolerance" liver property has been sustained by a low rate of liver graft loss in patients with preformed DSA and by the intrinsic liver characteristics that favor the absorption and elimination of DSA; however, alloantibody-mediated adverse consequences are increasingly being recognized, and several cases of acute AMR after ABO-compatible liver transplant(LT) have been reported. Furthermore, the availability of new solid-phase assays, allowing the detection of low titers of DSA and the refinement of objective diagnostic criteria for AMR in solid organ transplants and particularly in LT, have improved the recognition and management of this entity. A cost-effective strategy of DSA monitoring, avoidance of class Ⅱ human leukocyte antigen mismatching, judicious immunosuppression attached to a higher level of clinical suspicion of AMR, particularly in cases unresponsive to conventional antirejection therapy, can allow a rational approach to this threat.     

Successful living donor liver retransplantation for graft failure within 7 days due to acute de novo donor‐specific anti‐human leukocyte antigen antibody‐mediated rejection

Growing evidence suggests a relationship between antibody‐mediated rejection (AMR) and early graft failure due to a previously unknown etiology in liver transplantation (LTx). We herein report a 3‐year‐old boy who developed rapid graft failure due to de novo donor‐specific antibody (DSA)‐driven AMR a week after living donor LTx, requiring a second transplant on the 10th day after the first LTx. The pathology of the first graft showed massive necrosis in zone 3 along with positive C4d and inflammatory cell infiltrates in portal areas. The mean fluorescence intensity against human leukocyte antigen (HLA)‐DR15, which was possessed by both the first and the second donor, peaked at 12 945 on the day before the second LTx. Antithymocyte globulin, plasma exchange along with i.v. immunoglobulin, rituximab, and the local infusion of prostaglandin E1, steroids, and Mesilate gabexate through a portal catheter were provided to save the second graft. To our knowledge, this is the first report to show a clear association between de novo DSA and acute AMR within 7 days of a LTx. Furthermore, we successfully rescued the recipient with a second graft despite possessing the same targeted HLA. The rapid decision to carry out retransplantation and specific strategies overcoming AMR were crucial to achieving success in this case of immunologically high‐risk LTx.     

Plasmapheresis and Intravenous Immunoglobulin in Early Antibody-Mediated Rejection of the Renal Allograft: A Single-Center Experience

Antibody-mediated rejection (AMR) is a rare complication which often results in the loss of the kidney graft. The objective of this retrospective single center study was to evaluate two different approaches to AMR. We retrospectively evaluated data files from 936 patients who had undergone renal transplantation in 2002–2006. In 2002–2003, patients with AMR were treated with five plasmapheresis sessions (PP group, N = 13), and in 2004–2006 they received five plasmapheresis session along with intravenous immunoglobulin 0.5 g/kg (PP+IVIg group, N = 11). Twelve months of follow-up data was analyzed. First year graft survival was significantly higher in the PP+IVIg group than in the PP group (90.9% vs. 46.2%; P = 0.044); similarly, patient survival was higher in the PP+IVIg group (100% vs. 76.9%; P = 0.056). The incidence of infectious complications was similar in both groups. In re-biopsies, patients in the PP group often suffered from cellular rejection. The deposition of C4d complement was similar in re-biopsies in both groups. In this large single center study we proved the superiority of plasmapheresis with intravenous immunoglobulin administration in the treatment of early AMR of renal allografts.     

Low-Dose Rituximab Therapy for Antibody-Mediated Rejection in a Highly Sensitized Heart-Transplant Recipient

Antibody-mediated rejection is the B-cell–mediated production of immunoglobulin G antibody against the transplanted heart. The currently available therapies for antibody-mediated rejection have had marginal success, and chronic manifestations of rejection can result in an increased risk of graft vasculopathy and perhaps require repeat transplantation. Rituximab, a monoclonal antibody directed against the CD20 receptor of B-lymphocytes and approved as therapy for lymphoma, can be used in heart-transplant patients for the management of antibody-mediated rejection.We present the case of a 52-year-old woman with high allosensitization (pre-transplantation panel reactive antibody level, 72%) who underwent successful orthotopic heart transplantation. Postoperatively, her acute antibody-mediated rejection with concomitant cellular rejection was successfully treated with low-dose rituximab. The patient died 5 months later because of multiple other medical problems. The present case suggests a role for low-dose rituximab as therapy for antibody-mediated rejection in heart-transplant patients.Key words: Antibodies, monoclonal/therapeutic use; antigens, CD20/immunology; B-lymphocytes/immunology; graft rejection/drug therapy; heart transplantation/pathology; HLA antigens/immunology; immunity, humoral/physiology/therapy; immunoglobulins, intravenous/metabolism; plasmapheresis; rituximab; time factorsAntibody-mediated rejection (AMR) in heart-transplant recipients is mediated by donor-specific antibodies and is histologically defined by linear deposits of immunoglobulin (Ig) and complement in the myocardial capillaries.¹ Antibody-mediated rejection is often accompanied by hemodynamic compromise and is associated with diminished graft survival. Standard immunosuppressive therapy, designed to target T-cell immune function, is largely ineffective against this B-cell–driven process. Various therapies for AMR, although available, can be of marginal use secondary to patients'' comorbidities.^2,3 We present the case of a woman with a history of ventricular assist device (VAD) implantation, dialysis dependence, and severe thrombocytopenia who responded well to the addition of anti-CD20 monoclonal antibody therapy with rituximab after heart transplantation.     

Pneumocystis jirovecii pneumonia after rituximab therapy for antibody-mediated rejection in a renal transplant recipient

Abstract: We report the case of a 54-year-old woman who underwent living-related renal transplantation for end-stage renal disease from IgA nephropathy. She was subsequently diagnosed with antibody-mediated rejection (AMR) and received rituximab, a potent B-cell suppressive agent. After therapy with rituximab, she developed Pneumocystis jirovecii pneumonia (PJP) requiring hospitalization. We discuss the increasing literature for the use of rituximab for AMR and the need for PJP prophylaxis in this setting.     

Current status of liver transplantation across ABO blood-type barrier

Outcomes of ABO-blood type incompatible liver transplantation have recently improved owing to various treatments. The typical clinical manifestations of antibody mediated rejection (AMR) are hepatic necrosis and intrahepatic biliary complication (IHBC). The prognosis of AMR is poor. AMR is the result of circulatory disturbance which is caused by injury to the endothelium due to an antibody-antigen-complement reaction. Diffuse C4d staining in the portal capillaries and periportal areas in severe AMR. Since natural antibodies against A/B carbohydrate determinants are likely to develop as a result of exposure to environmental bacteria that express similar determinants, the B-1 lineage has been speculated to be the major population of B-cell types responding to A/B determinants. Calcineurin inhibitors block B-1 cell differentiation. Rituximab can be used to deplete both cells that are producing IgM antibodies and those that have already differentiated into B-1 cells. Mycophenolate mofetil is required to inhibit the production of IgG subclass of antibodies. The outcome is now similar to that of blood-type-matched transplantation. However, there are still issues to be solved in order to further improve the outcome via a decrease of infection.     

The use of ABO-incompatible grafts in living donor liver transplantation—First report from India

ABO incompatibility is the commonest reason for rejection of donors in living donor liver transplantation (LDLT). The donor pool could be expanded by 25 % to 35 % if the ABO barrier is overcome. In the absence of pre-conditioning, transplantation across the blood groups is fraught with the almost universal risk of antibody-mediated rejection (AMR) that rapidly leads to graft loss. However, AMR can be prevented by removal of preformed antibodies and reducing their production by B cells. We describe our initial experience of three cases of ABO-incompatible (ABO-i) LDLT: a 42-year-old male, an 8-month-old male and a 28-month-old female, all of blood group O+ who received blood group B + right lobe, B + left lateral segment, and A + left lateral segment liver grafts, respectively. Pre-LDLT conditioning included administration of anti-CD20 antibody (Rituximab^®) to the adult 4 weeks prior, and four to seven sessions of double-filtration plasmapheresis to all, to remove preformed antibodies and achieve anti-donor blood group antibody (ADA) titers of ≤1:16 IgG and ≤1:8 IgM, respectively. In addition, cases 1 and 3 received mycophenolate mofetil for 7 days prior to LDLT. After LDLT, all three patients achieved normal graft function over 8–17 days with no evidence of AMR and without the need for further plasmapheresis. Postoperative complications included portal vein thrombosis (one successfully re-explored), CMV (one), Pseudomonas and Klebsiella sepsis (one each), and abdominal collection (one treated with percutaneous drainage). All are currently well with normal graft function and low ADA titers at 8, 16, and 19 months after ABO-i LDLT.     

The critical role of therapeutic plasma exchange in ABO-incompatible liver transplantation

BackgroundThe shortage of donor liver restricts liver transplantation (LT). Nowadays, donor liver with ABO blood group incompatibility between donor and recipient has become an option to expand the source of donor liver. Although it is now possible to perform ABO-incompatible (ABO-I) LT, antibody-mediated rejection (AMR) has been recognized as the primary cause of desperate outcomes after ABO-I LT. Anti-A/B antibody is the trigger of immune response to ABO-I LT graft injury. Therapeutic plasma exchange (TPE) can quickly reduce the titer of plasma antibodies and effectively inhibit humoral immunity.Data sourcesWe searched PubMed and CNKI databases using search terms “therapeutic plasma exchange”, “ABO-incompatible liver transplantation”, “ABO-I LT”, “liver transplantation”, “LT”, “antibody-mediated rejection”, and “AMR”. Additional publications were identified by a manual search of references from key articles. The relevant publications published before September 30, 2020 were included in this review.ResultsDifferent centers have made different attempts on whether to use TPE, when to use TPE and how often to use TPE. However, the control standard of lectin revision level is always controversial, the target titer varies significantly from center to center, and the standard target titer has not yet been established. TPE has several schemes to reduce antibody titers, but there is a lack of clinical trials that provide standardized procedures.ConclusionsTPE is essential for ABO-I LT. Hence, further research and clinical trials should be conducted to determine the best regimen for TPE to remove ABO antibodies and prevent AMR.     

Antimicrobial resistance in hospital wastewater in Scotland: a cross-sectional metagenomics study

BackgroundAntimicrobial resistance (AMR) is a global health crisis. It is well established that hospital wastewater can contain organisms that are on the WHO priority list of antibiotic-resistant organisms. We aimed to use metagenomics to study whether the abundances of resistance genes in hospital wastewater reflects clinical activity within the hospital.MethodsHospital wastewater was collected over a 24-h period in June, 2017 from multiple collection points representing different specialties within a tertiary hospital site in Scotland, UK and simultaneously from community sewage works. High throughput shotgun sequencing was done using Illumina HiSeq4000. Sequence reads were assigned taxonomically and to the AMR genes in the ResFinder database. The measured AMR gene abundances were correlated to hospital antimicrobial usage in defined daily doses per 100 occupied bed-days, mean patient length of stay in hospital, mean patient age per hospital collection point, and resistance levels in clinical isolates.Findings1047 bacterial genera and 174 different AMR genes were detected across all samples. Microbiota composition and AMR gene abundance and diversity varied between each collection point and AMR gene abundance was higher in hospital wastewater than in community influent. The composition of AMR genes correlated with microbiota composition (Procrustes analysis, p=0·002). Increased antimicrobial consumption at a class level was associated with higher AMR gene abundance within that class in hospital wastewater (incidence rate ratio 2·80, 95% CI 1·2–6·5, p=0·016). Prolonged mean patient length of stay was associated with higher total AMR gene abundance in hospital wastewater (2·05, 1·39–3·01, p=0·0003). No overall association was found between resistance in clinical isolates at an antimicrobial class level and AMR gene abundance in hospital wastewater.InterpretationAntimicrobial usage is a major driver of AMR gene outflow from hospitals into the sewage environment. The positive relationship between length of stay and AMR gene abundance is consistent with prolonged admission being a risk factor for carriage and infection with resistant microorganisms. Our findings show that hospital wastewater does reflect inpatient activity. With further evaluation this method might represent a useful surveillance tool to monitor hospital AMR gene outflow and guide environmental policy on AMR.FundingAcademy of Medical Sciences.     

Peritubular capillary C4d deposition in lupus nephritis different from antibody-mediated renal rejection

C4d deposition in peritubular capillaries (PTC) has been used as a marker of antibody-mediated rejection (AMR). However, PTC C4d deposition is not described in patients with lupus nephritis (LN). C4d deposition in PTC was detected in 455 patients with biopsy proven LN in the present study. Renal tissues from 21 cases of acute AMR served as controls. C4d deposition in PTC was found in 31 patients (6.81%) with LN. Patients with PTC C4d positive showed higher SLEDAI score and higher frequency of hypocomplementemia as compared to C4d negative. The prevalence of ANA, anti-dsDNA, anti-Sm and ACA were higher in C4d positive group, and most of these patients showed the diffuse proliferative glomerular lesion. In contrast with acute AMR, the staining pattern of C4d was granular deposition and the detection of C4d along PTC was accompanied by deposition of IgG and C1q or C3. Electron dense deposition on PTC was observed in most of LN patients. In conclusion, C4d deposition in PTC could be found in a small part of patients with LN. Our study suggested for the first time that C4d positive deposition were close relation with the higher disease activity of LN, and that immune complex formation might be involved in PTC C4d deposition in LN patients, Such PTC C4d deposition is distinct from that of AMR.