A. Neil Turner

Long-Term Outcome of Anti–Glomerular Basement Membrane Antibody Disease Treated with Plasma Exchange and Immunosuppression

Antiglomerular basement membrane (GBM) antibody disease is a rare autoimmune disorder characterized by rapidly progressive glomerulonephritis with crescentic changes that affect most glomeruli on renal biopsy; when accompanied by pulmonary hemorrhage, the condition is known as the Goodpasture syndrome (1, 2). The disease is by definition associated with development of anti-GBM autoantibodies. These antibodies have proven pathogenicity (3) and bind the noncollagenous domain (NC1) of the 3 chain of type IV collagen (4-6). Historically, untreated patients do not recover renal function and have substantial mortality, particularly from pulmonary hemorrhage (1). The introduction of oral immunosuppression did not obviously alter the prognosis of the disease; however, the use of plasma exchange in combination with prednisolone and cyclophosphamide dramatically improved outcomes (7, 8). Data on short-term renal and patient survival from most centers show that 75% to 95% of patients live for at least 1 year after presentation but no more than 40% of patients will have independent renal function at 1 year, depending on the degree of renal failure at presentation (1). Most studies have shown a clear association between the extent of glomerular crescent formation and renal outcome (9, 10), and some show a loose correlation between antibody titer and disease severity (11). The disease rapidly causes severe renal failure; as a result, many patients present at a late stage, and renal survival is poor. Recovery of renal function has been reported in very few patients with a creatinine concentration of 500 mol/L or greater (9, 10, 12). Recent data from Ireland documented overall renal recovery in only 20% of patients, and serum creatinine concentration and the percentage of glomerular crescents were strongly associated with eventual need for dialysis (12). Herody and colleagues (9) reported similar results; no patients who presented with an initial creatinine concentration greater than 600 mol/L recovered renal function, but the overall survival rate was 93%. Patients in that study received variable immunosuppressive regimens and only moderately intense plasma exchange. Merkel and associates (10) reported a 1-year patient survival rate of 89% and a 1-year renal survival rate of 40%, but only 1 of 32 patients (3%) who presented with severe renal failure (creatinine concentration > 500 mol/L [5.7 mg/dL]) recovered renal function. No data have been published on long-term outcome in patients with the Goodpasture syndrome; in particular, the risk for progressive renal dysfunction after initial treatment has not been reported. It is well documented that late recurrence of nephritis or pulmonary hemorrhage is rare (13), although early exacerbations during the initial illness are common in the presence of circulating antibody. We sought to establish the long-term outcome in a large cohort of patients with anti-GBM antibody disease who were treated uniformly with intensive immunosuppression and plasma exchange and to document the extent of recovery from severe renal failure. Methods Patients All adult patients with anti-GBM antibody disease treated at Hammersmith Hospital, London, United Kingdom, since 1975 were included in the study. Patients had had at least 12 months of follow-up from the time of presentation. All patients had circulating anti-GBM antibodies detected by standard assays against either purified human GBM (radioimmunoassay) or, more recently, sheep noncollagenous domain (NC1) of the 3 chain of type IV collagen (enzyme-linked immunosorbent assay) (14). The specificity of autoantibodies detected by enzyme-linked immunosorbent assay was confirmed by Western blot assay against human GBM. All patients had renal biopsy confirming the diagnosis of crescentic glomerulonephritis. In 82% of cases, direct immunofluorescence was performed on the biopsy samples; all showed linear deposition of immunoglobulin along the GBM. Patients were excluded if they also had detectable antineutrophil cytoplasm antibodies, since these double positive patients may respond differently to treatment. Stored serum samples from the time of presentation were tested retrospectively for all patients who presented before the antineutrophil cytoplasm antibody assay was routinely used (starting in 1985). Serum samples were not available for most patients who presented from 1975 to 1985. Pulmonary hemorrhage was diagnosed by overt hemoptysis, chest radiography, and an increased carbon monoxide transfer factor (15). Patients received a standard immunosuppressive regimen of plasma exchange, oral prednisolone (approximately 1 mg/kg of body weight per day to a maximum of 60 mg/d) and oral cyclophosphamide (2 to 3 mg/kg per day; the dosage was reduced in persons older than 55 years of age). Plasma exchange (50 mL/kg to a maximum of 4 L) was usually performed by using a centrifugal cell separator (or occasionally by using a hollow-fiber plasma filter) daily for at least 14 days or until anti-GBM antibody was undetectable. Human albumin (5%) with added calcium and potassium was used as replacement fluid. Fresh frozen plasma (150 to 300 mL at the end of the exchange) was used in patients with recent surgery or renal biopsy (within 3 days) and those with pulmonary hemorrhage. Most patients received fresh frozen plasma for 1 or 2 days. Cyclophosphamide was given for 2 to 3 months only (30 patients received treatment for 2 months), and prednisolone treatment was withdrawn slowly over 6 to 9 months. Nineteen patients treated in the 1970s and early 1980s also received oral azathioprine (1 to 2 mg/kg daily) for 8 weeks. No patient received high-dose intravenous methylprednisolone at our institution. Patients were classified according to their level of renal function at presentation (serum creatinine concentration < 500 mol/L or 500 mol/L [5.7 mg/dL] with no need for immediate dialysis, or dialysis dependent). Dialysis-dependent renal failure was defined as the need for dialysis within 72 hours of admission to the hospital. Patients underwent dialysis (mostly by hemodialysis) as clinically indicated, but the serum creatinine concentration was greater than 600 mol/L (6.8 mg/dL) in all patients and greater than 1000 mol/L (11.4 mg/dL) in most patients. The concentration of 500 mol/L (5.7 mg/dL) was chosen before analysis of the results because most patients presenting with a higher serum creatinine concentration would now undergo dialysis regardless of other characteristics. Independent renal function was defined as the lack of need for dialysis. Outcome Measures Follow-up data were obtained from the referring hospital or family physician, if the patient was not being seen at Hammersmith Hospital. The primary outcomes of interest were patient and renal survival. The research ethics committee approved this study. Statistical Analysis The log-rank test was used to compare survival curves, KaplanMeier statistics were used to calculate survival rates, and the MannWhitney test was used to analyze unpaired data. Ninety-five percent CIs were calculated for the main results. Patients who presented in the 1970s and early 1980s were included in previous reports from the Hammersmith Hospital (8, 11). Role of the Funding Source No funding was used specifically for this study, although grants to study the Goodpasture syndrome have been awarded to the authors from the Medical Research Council, Wellcome Trust, and National Kidney Research Fund. Results Patient Characteristics Eighty-five patients with anti-GBM antibody disease were seen at our center over the past 25 years. Ten patients did not receive plasma exchange or immunosuppressive drugs, usually because of late presentation from other hospitals; 2 were children; and records were lost for 2 patients (Figure 1). No untreated patient had pulmonary hemorrhage, and all patients became dialysis dependent during follow-up, predominantly from the time of first presentation. Figure 1. Flow chart showing patients in the study and outcomes at 1 year. We report on the 71 adult patients who received a full course of treatment, including plasma exchange (Figure 1). The median age was 40 years (range, 17 to 76 years), 44% of patients were women, and 62% had pulmonary hemorrhage (Figure 2). The age distribution of patients was bimodal, with peak incidence in the third and sixth decades and increased incidence of pulmonary hemorrhage in younger patients. Men tended to present at a younger age (median, 35 years for men and 45 years for women). Overall, 39 patients (55%) required dialysis immediately on presentation, and 13 (18%) had an initial creatinine concentration of at least 500 mol/L (5.7 mg/dL) but did not receive dialysis in the first 72 hours. The median creatinine concentration in patients who did not undergo dialysis at presentation was 318 mol/L (3.6 mg/dL) (range, 53 to 955 mol/L [0.6 to 10.9 mg/dL]). Figure 2. Age and incidence of pulmonary hemorrhage at presentation in patients with antiglomerular basement membrane antibody disease. Short-Term and Medium-Term Outcome Table 1 and Figure 1 show renal and patient survival data for treated patients at 1 year, according to initial renal function. Prognosis was excellent in patients who presented with an initial serum creatinine concentration less than 500 mol/L (5.7 mg/dL); the 1-year patient and renal survival rates were 100% and 95% (95% CI for renal survival, 85% to 100%). One-year rates of patient and renal survival were 83% and 82% among patients with creatinine concentration of 500 mol/L (5.7 mg/dL) or greater but no need for dialysis and 65% and 8% among those presenting with dialysis-requiring renal failure. Patient and renal survival differed significantly between patients who presented with an initial serum creatinine concentration less than 500 mol/L (5.7 mg/dL) and those in whom the creatinine concentration was 500 mol/L or greater (P=0.007 for patient survival and P<0.001 for

Patient access to complex chronic disease records on the Internet

BackgroundAccess to medical records on the Internet has been reported to be acceptable and popular with patients, although most published evaluations have been of primary care or office-based practice. We tested the feasibility and acceptability of making unscreened results and data from a complex chronic disease pathway (renal medicine) available to patients over the Internet in a project involving more than half of renal units in the UK.MethodsContent and presentation of the Renal PatientView (RPV) system was developed with patient groups. It was designed to receive information from multiple local information systems and to require minimal extra work in units. After piloting in 4 centres in 2005 it was made available more widely. Opinions were sought from both patients who enrolled and from those who did not in a paper survey, and from staff in an electronic survey. Anonymous data on enrolments and usage were extracted from the webserver.ResultsBy mid 2011 over 17,000 patients from 47 of the 75 renal units in the UK had registered. Users had a wide age range (<10 to >90 yrs) but were younger and had more years of education than non-users. They were enthusiastic about the concept, found it easy to use, and 80% felt it gave them a better understanding of their disease. The most common reason for not enrolling was being unaware of the system. A minority of patients had security concerns, and these were reduced after enrolling.Staff responses were also strongly positive. They reported that it aided patient concordance and disease management, and increased the quality of consultations with a neutral effect on consultation length. Neither patient nor staff responses suggested that RPV led to an overall increase in patient anxiety or to an increased burden on renal units beyond the time required to enrol each patient.ConclusionsPatient Internet access to secondary care records concerning a complex chronic disease is feasible and popular, providing an increased sense of empowerment and understanding, with no serious identified negative consequences. Security concerns were present but rarely prevented participation. These are powerful reasons to make this type of access more widely available.

The 2014 International Workshop on Alport Syndrome.

Alport syndrome, historically referred to as hereditary glomerulonephritis with sensorineural deafness and anterior lenticonus, is a genetic disease of collagen α3α4α5(IV) resulting in renal failure. The collagen α3α4α5(IV) heterotrimer forms a network that is a major component of the kidney glomerular basement membrane (GBM) and basement membranes in the cochlea and eye. Alport syndrome, estimated to affect 1 in 5000–10,000 individuals, is caused by mutations in any one of the three genes that encode the α chain components of the collagen α3α4α5(IV) heterotrimer: COL4A3, COL4A4, and COL4A5. Although angiotensin-converting enzyme inhibition is effective in Alport syndrome patients for slowing progression to end-stage renal disease, it is neither a cure nor an adequate long-term protector. The 2014 International Workshop on Alport Syndrome, held in Oxford, UK, from January 3–5, was organized by individuals and families living with Alport syndrome, in concert with international experts in the clinical, genetic, and basic science aspects of the disease. Stakeholders from diverse communities—patient families, physicians, geneticists, researchers, Pharma, and funding organizations—were brought together so that they could meet and learn from each other and establish strategies and collaborations for the future, with the overall aim of discovering much needed new treatments to prolong kidney function.

Patients' continuing use of an online health record: a quantitative evaluation of 14,000 patient years of access data

Background Online access to all or part of their health records is widely demanded by patients and, where provided in form of patient portals, has been substantially used by at least subgroups of patients, particularly those with chronic disease. However, little is reported regarding the longer-term patient use of patient-accessible electronic health record services, which is important in allocating resources. Renal PatientView (RPV) is an established system that gives patients with chronic kidney disease access to live test results and information about their condition and treatment. It is available in most UK renal units with up to 75% of particular patient groups registered in some centers. We have analyzed patient use out to 4 years and investigated factors associated with more persistent use. Objective Our aim was to investigate RPV use by patients over time from initial registration in order to understand which patients choose to access RPV and the endurance of its appeal for different patient groups. Methods We analyzed an anonymized extract of the database underlying RPV containing information on patient registration and events including patient access and the arrival of new blood test results or letters that patients might wish to view. Results At the time of the extract, there were 11,352 patients registered on RPV for 0-42 months (median 17). More than half of registrants became persistent users, logging in a median of 2.0 times each month over post-registration intervals of up to 42 months (median 18.9). Provision of assistance with first logon was strongly associated with becoming a persistent user, even at 3 years. Logons by persistent users occurred around the time of consultations/tests, strongly suggestive of patient engagement. While indices indicative of greater deprivation were the strongest determinants of non-participation, they had negligible influence on drop-out rates among established users. Conclusions In this mature patient portal system, a large proportion of patients made regular use of their online health records over protracted periods. The patterns and timing of use indicate strong patient interest in detailed information such as recent test results and clinic letters. Supporting patients through the first steps of establishing access to their online records is associated with much higher rates of long-term use of RPV and likely would increase use of other electronic health records provided for patients with chronic disease.

The Alloantigenic Sites of α3α4α5(IV) Collagen PATHOGENIC X-LINKED ALPORT ALLOANTIBODIES TARGET TWO ACCESSIBLE CONFORMATIONAL EPITOPES IN THE α5NC1 DOMAIN

Anti-glomerular basement membrane (GBM) antibody nephritis is caused by an autoimmune or alloimmune reaction to the NC1 domains of α3α4α5(IV) collagen. Some patients with X-linked Alport syndrome (XLAS) develop post-transplant nephritis mediated by pathogenic anti-GBM alloantibodies to collagen IV chains present in the renal allograft but absent from the tissues of the patient. In this work, the epitopes targeted by alloantibodies from these patients were identified and characterized. All XLAS alloantibodies recognized conformational epitopes in the NC1 domain of α5(IV) collagen, which were mapped using chimeric α1/α5 NC1 domains expressed in mammalian cells. Allograft-eluted alloantibodies mainly targeted two conformational alloepitopes mapping to α5NC1 residues 1-45 and 114-168. These regions also encompassed the major epitopes of circulating XLAS alloantibodies, which in some patients additionally targeted α5NC1 residues 169-229. Both kidney-eluted and circulating alloantibodies to α5NC1 distinctively targeted epitopes accessible in the α3α4α5NC1 hexamers of human GBM, unlike anti-GBM autoantibodies, which targeted sequestered α3NC1 epitopes. The results identify two immunodominant α5NC1 epitopes as major alloantigenic sites of α3α4α5(IV) collagen specifically implicated in the pathogenesis of post-transplant nephritis in XLAS patients. The contrast between the accessibility of these alloepitopes and the crypticity of autoepitopes indicates that distinct molecular forms of antigen may initiate the immunopathogenic processes in the two forms of anti-GBM disease.

Advances and unmet needs in genetic, basic and clinical science in Alport syndrome: report from the 2015 International Workshop on Alport Syndrome.

Abstract Alport syndrome (AS) is a genetic disease characterized by haematuric glomerulopathy variably associated with hearing loss and anterior lenticonus. It is caused by mutations in the COL4A3, COL4A4 or COL4A5 genes encoding the α3α4α5(IV) collagen heterotrimer. AS is rare, but it accounts for >1% of patients receiving renal replacement therapy. Angiotensin-converting enzyme inhibition slows, but does not stop, the progression to renal failure; therefore, there is an urgent requirement to expand and intensify research towards discovering new therapeutic targets and new therapies. The 2015 International Workshop on Alport Syndrome targeted unmet needs in basic science, genetics and diagnosis, clinical research and current clinical care. In three intensive days, more than 100 international experts including physicians, geneticists, researchers from academia and industry, and patient representatives from all over the world participated in panel discussions and breakout groups. This report summarizes the most important priority areas including (i) understanding the crucial role of podocyte protection and regeneration, (ii) targeting mutations by new molecular techniques for new animal models and potential gene therapy, (iii) creating optimal interaction between nephrologists and geneticists for early diagnosis, (iv) establishing standards for mutation screening and databases, (v) improving widespread accessibility to current standards of clinical care, (vi) improving collaboration with the pharmaceutical/biotech industry to investigate new therapies, (vii) research in hearing loss as a huge unmet need in Alport patients and (viii) the need to evaluate the risk and benefit of novel (including ‘repurposing’) therapies on an international basis.

Following specific podocyte injury captopril protects against progressive long term renal damage

Background: Angiotensin converting enzyme inhibitors (ACEi) reduce proteinuria and preserve kidney function in proteinuric renal diseases. Their nephroprotective effect exceeds that attributable to lowering of blood pressure alone. This study examines the potential of ACEi to protect from progression of injury after a highly specific injury to podocytes in a mouse model. Methods: We created transgenic (Podo-DTR) mice in which graded specific podocyte injury could be induced by a single injection of diphtheria toxin. Transgenic and wild-type mice were given the ACEi captopril in drinking water, or water alone, commencing 24h after toxin injection. Kidneys were examined histologically at 8 weeks and injury assessed by observers blinded to experimental group. Results: After toxin injection, Podo-DTR mice developed acute proteinuria, and at higher doses transient renal impairment, which subsided within 3 weeks to be followed by a slow glomerular scarring process. Captopril treatment in Podo-DTR line 57 after toxin injection at 5ng/g body weight reduced proteinuria and ameliorated glomerular scarring, matrix accumulation and glomerulosclerosis almost to baseline (toxin: 17%; toxin + ACEi 10%, p<0.04; control 7% glomerular scarring). Podocyte counts were reduced after toxin treatment and showed no recovery irrespective of captopril treatment (7.1 and 7.3 podocytes per glomerular cross section in water and captopril-treated animals compared with 8.2 of wild-type controls, p<0.05). Conclusions: Observations in Podo-DTR mice support the hypothesis that continuing podocyte dysfunction is a key abnormality in proteinuric disease. Our model is ideal for studying strategies to protect the kidney from progressive injury following podocyte depletion. Demonstrable protective effects from captopril occur, despite indiscernible preservation or restoration of podocyte counts, at least after this degree of relatively mild injury.

The alloantigenic sites of α3α4α5(IV) collagen

Anti-glomerular basement membrane (GBM) antibody nephritis is caused by an autoimmune or alloimmune reaction to the NC1 domains of α3α4α5(IV) collagen. Some patients with X-linked Alport syndrome (XLAS) develop post-transplant nephritis mediated by pathogenic anti-GBM alloantibodies to collagen IV chains present in the renal allograft but absent from the tissues of the patient. In this work, the epitopes targeted by alloantibodies from these patients were identified and characterized. All XLAS alloantibodies recognized conformational epitopes in the NC1 domain of α5(IV) collagen, which were mapped using chimeric α1/α5 NC1 domains expressed in mammalian cells. Allograft-eluted alloantibodies mainly targeted two conformational alloepitopes mapping to α5NC1 residues 1-45 and 114-168. These regions also encompassed the major epitopes of circulating XLAS alloantibodies, which in some patients additionally targeted α5NC1 residues 169-229. Both kidney-eluted and circulating alloantibodies to α5NC1 distinctively targeted epitopes accessible in the α3α4α5NC1 hexamers of human GBM, unlike anti-GBM autoantibodies, which targeted sequestered α3NC1 epitopes. The results identify two immunodominant α5NC1 epitopes as major alloantigenic sites of α3α4α5(IV) collagen specifically implicated in the pathogenesis of post-transplant nephritis in XLAS patients. The contrast between the accessibility of these alloepitopes and the crypticity of autoepitopes indicates that distinct molecular forms of antigen may initiate the immunopathogenic processes in the two forms of anti-GBM disease.

Teaching web authoring: valuable skills, paperless courses

The Internet has become a core resource in higher education but has predominantly been used by institutions to provide resources for teaching, and by students to find information, which they then present in more or less traditional ways. In medical practice, the Internet has advanced more slowly but its importance is advancing rapidly. Already, it is the single most important source of information for patients when they learn of a new disease. Little has so far been done to encourage physicians or students to provide information in this way. The authors explored the feasibility of combining such education with a simplified method for assessment of group projects. These were produced as websites, which were then assessed online by tutors and examiners. Feedback was strongly positive. Drawbacks were few, and often shared with other types of publication. The resources needed to set up such a course are significant but most higher education institutions already have expertise and resources for Internet publishing. The course becomes almost paperless. Students become practically familiar with the benefits and pitfalls of providing medical information on the Internet, and capable of doing so themselves.

Genetic Disorders of the Glomerular Basement Membrane

Basement membranes are specialised noncellular matrices, found beneath epithelial and endothelial cell layers in all organs of the body. In the kidney, the glomerular basement membrane forms part of the barrier between blood and filtrate.