Objectives To determine the clinical outcomes of patients with immunoglobulin 4-related disease (IgG4-RD) treated with a defined B-cell depletion protocol using rituximab. Methods Patients were included if they had (i) an IgG4-RD diagnosis at Imperial College Healthcare NHS Trust between February 2017 and October 2022, and (ii) >9 months of follow-up data available following the first rituximab dose. The rituximab protocol targeted B-cell depletion to <10 cells/microliter for a maintenance period of two years. Electronic records were used to define patient demographics, serological and radiological variables and treatment responses according to the IgG4-RD responder index (RI). Results Forty-five patients received induction treatment with rituximab. Two patients had insufficient follow-up data for outcome analysis. All patients responded to rituximab therapy according to the IgG4-RD RI. Most patients (25/43, 58%) were also treated with low-dose glucocorticoids at the time of rituximab induction (median prednisolone dose 5 mg daily) and 4/25 (16%) remained on prednisolone at two years (median prednisolone dose 5 mg daily). Disease flares occurred in 11/43 (26%) patients; 9/11 flares occurred in the presence of B-cell repopulation; 2/11 (18.1%) flares occurred in the absence of B-cell repopulation (>10 cells/uL). All flares re-treated with rituximab (7/7, 100%) responded positively. Conclusion Rituximab administration targeting B-cell depletion for a two-year period is an effective treatment strategy for IgG4-RD and can limit the cumulative glucocorticoid exposure. Flares are uncommon and typically occur in the setting of B-cell repopulation, with good clinical responses to further rituximab administration.

The oxidized form of Macrophage Migration Inhibitory Factor (oxMIF) has been identified as the disease-related isoform of MIF, exerting pathological functions in inflamed tissue. In this study, we aimed to explore the in vivo effects of the neutralizing anti-oxMIF antibody ON104 in a rat model of crescentic glomerulonephritis (CGN), to better understand its disease modifying activities. WKY rats received a single intravenous injection of a rabbit nephrotoxic serum (NTS), targeting rat glomerular basement membrane to induce CGN. On day 4 and day 6, ON104 was given intraperitoneally (i.p.) and on day 8 urine, blood and kidney tissue were collected. ON104 substantially attenuated the severity of CGN demonstrated by reduced proteinuria, hematuria, as well as lower levels of kidney injury molecule (KIM)-1. ON104 treatment preserved the glomerular morphology and suppressed crescent formation, a hallmark of the disease. On the cellular level, oxMIF neutralization by ON104 strongly reduced the number of macrophages and neutrophils within the inflamed kidneys. In vitro, we identified human neutrophils, but not monocytes, as main producers of oxMIF among total peripheral cells. The present study demonstrates that oxMIF is a pertinent therapeutic target in a model of CGN which mechanistically resembles human immune mediated CGN. In this model, neutralization of oxMIF by ON104 leads to an improvement in both urinary abnormalities and histological pathological characteristics of the disease. ON104, thus has the potential to become a novel disease-modifying drug for the treatment of glomerulonephritis and other inflammatory kidney diseases.

Abstract Background and Aims Kidney transplant failure contributes to a considerable proportion of new dialysis starters. In some centres there are dedicated clinics for patients with failing kidney transplants, however, the specific needs of patients with dialysis after graft loss (DAGL) may be lost in the non-specific clinical review practiced in the general dialysis community. This study examines the mortality and morbidity risk in patients returning with DAGL and compares it to transplant-naïve (T-N) dialysis starters, to determine if the former warrant a more specialised approach. Method This is a retrospective observational study of mortality in all adult patients who started dialysis treatments in Fresenius Medical Care (North America, Latin America, Europe, Middle East, Africa, and Asia Pacific) from 1st January 2018 to 31st March 2021, were identified in the Apollo Dial DB dataset. DAGL was identified from the ICD-10 codes ‘Kidney transplant failure’, ‘Unspecified complication of kidney transplant’ and ‘Other complication of kidney transplant’ at dialysis start. The T-N control group had not previously received a kidney transplant and had not received immunosuppressive medication during the first six months of dialysis start. The first six months on dialysis were defined as baseline, months 7 to the end of year 5 were defined as the follow-up period. All-cause mortality was recorded during follow-up. Cox proportional hazards models were applied to explore the association between DAGL and all-cause mortality. Results A total of 360 469 dialysis starter patients from 41 countries were included in the analysis. 10 010 patients had DAGL and were compared with 350 459 in the T-N control group. In univariate analysis, DAGL patients were significantly younger in all age categories and had a higher proportion of male sex. Serum creatinine, ferritin, phosphate and neutrophil-to-lymphocyte ratio were higher in the DAGL group. Haemoglobin was lower in the DAGL group (Table 1). In the Cox proportional model adjusted for age, gender, and other laboratory and clinical markers, patients with DAGL had an equivalent survival probability compared with T-N dialysis starters (HR: 0.93, 95% CI: 0.86, 1.02) (Table 2). Conclusion DAGL patients appeared to have an increased mortality compared to T-N dialysis starters historically in the literature. Our large and recent study is in line with other recent publications suggesting a more equivalent survival in the two groups. Our results are compatible with younger patients receiving kidney transplantation early in their renal replacement therapy journey, thus constituting a significant proportion of DAGL patients. We posit that DAGL patients may start dialysis at a lower level of renal function, with higher levels of inflammation. Our analysis is preliminary and limited, not fully accounting for confounding factors. Future analysis of this large and well recorded dataset will allow us to examine these interesting associations and design a more specialised management approach to DAGL more closely.

Introduction: The National Registry of Rare Kidney Diseases (RaDaR) collects data from people living with rare kidney diseases across the UK, and is the world's largest, rare kidney disease registry. We present the clinical demographics and renal function of 25,880 prevalent patients and sought evidence of bias in recruitment to RaDaR. Methods: RaDaR is linked with the UK Renal Registry (UKRR, with which all UK patients receiving kidney replacement therapy [KRT] are registered). We assessed ethnicity and socioeconomic status in the following: (i) prevalent RaDaR patients receiving KRT compared with patients with eligible rare disease diagnoses receiving KRT in the UKRR, (ii) patients recruited to RaDaR compared with all eligible unrecruited patients at 2 renal centers, and (iii) the age-stratified ethnicity distribution of RaDaR patients with autosomal dominant polycystic kidney disease (ADPKD) was compared to that of the English census. Results: We found evidence of disparities in ethnicity and social deprivation in recruitment to RaDaR; however, these were not consistent across comparisons. Compared with either adults recruited to RaDaR or the English population, children recruited to RaDaR were more likely to be of Asian ethnicity (17.3% vs. 7.5%, P-value < 0.0001) and live in more socially deprived areas (30.3% vs. 17.3% in the most deprived Index of Multiple Deprivation (IMD) quintile, P-value < 0.0001). Conclusion: We observed no evidence of systematic biases in recruitment of patients into RaDaR; however, the data provide empirical evidence of negative economic and social consequences (across all ethnicities) experienced by families with children affected by rare kidney diseases.

Background Individuals with rare kidney diseases account for 5-10% of people with chronic kidney disease, constitute more than 25% of patients receiving kidney replacement therapy. The National Registry of Rare Kidney Diseases (RaDaR) gathers longitudinal data from patients with these conditions, which we used to study disease progression and outcomes of death and kidney failure. Methods People aged 0-96 years living with 28 types of rare kidney diseases were recruited from 108 UK renal facilities. The primary outcomes were cumulative incidence of mortality and kidney failure in individuals with kidney diseases, which were calculated and compared with that of unselected patients with chronic kidney disease. Cumulative incidence and Kaplan-Meier survival estimates were calculated for the following outcomes: median at kidney failure; median age at death; time from start of dialysis to death; and time from diagnosis to estimated glomerular filtration rate (eGFR) thresholds, allowing calculation of time from last eGFR of 75 mL/min per 173 or more to first eGFR of less than 30 mL/min per 173 m 2 (the therapeutic trial window). Findings Between Jan 18, 2010, and July 25, 2022, 27 285 participants were recruited to RaDaR. Median follow-up from diagnosis was 96 years (IQR 59-167). RaDaR participants had significantly higher 5 -year cumulative incidence of kidney failure than 281 million UK patients with all-cause chronic kidney disease (28% vs 1%; p<00001), but better survival rates (standardised mortality ratio 042 [95% CI 032-052]; p<00001). Median age at failure, median age at death, time from start of dialysis to death, time from diagnosis to eGFR thresholds, therapeutic trial window all varied substantially between rare diseases. Interpretation Patients with rare kidney diseases differ from the general population of individuals with chronic disease: they have higher 5 -year rates of kidney failure but higher survival than other patients with chronic disease stages 3-5, and so are over-represented in the cohort of patients requiring kidney replacement therapy. Addressing unmet therapeutic need for patients with rare kidney diseases could have a large beneficial effect on term kidney replacement therapy demand.

ABSTRACT Background Light chain proximal tubulopathy (LCPT) is a rare form of paraprotein-related disease, occurring in two main histopathological forms: crystalline and non-crystalline. The clinicopathological features, treatment strategies and outcomes, especially of the non-crystalline form, are not well described. Methods We conducted a single-centre retrospective case series of 12 LCPT patients, 5 crystalline and 7 non-crystalline, between 2005 and 2021. Results The median age was 69.5 years (range 47–80). Ten patients presented with CKD and significant proteinuria (median estimated glomerular filtration rate of 43.5 ml/min/1.73 m2; urine protein:creatinine ratio 328 mg/mmol). Only six patients had known haematological disease at the time of renal biopsy. Multiple myeloma (MM) was diagnosed in seven patients cases and monoclonal gammopathy of renal significance (MGRS) in five patients. A clone was detected in all cases combining serum/urine electrophoresis and free light chain (LC) assays. Crystalline and non-crystalline variants had similar clinical presentations. For the non-crystalline variant, a diagnosis was reached based on a combination of CKD without another cause, haematological workup, LC restriction on immunofluorescence and abnormalities on electron microscopy (EM). Nine of 12 patients received clone-directed treatment. Patients who achieved haematological response (including all non-crystalline LCPT) had improved renal outcomes over a median follow-up of 79 months. Conclusions The non-crystalline variant may go unrecognised because of its subtle histopathological features and requires EM to distinguish it from ‘excessive LC resorption without tubular injury’. Clone-directed treatment with good haematological response improves renal outcomes in both variants but limited data exist in MGRS. Multicentre prospective studies are needed to better define the clinicopathological characteristics associated with poor outcomes and optimize treatment strategies in patients with MGRS.

Macrophage Migration Inhibitory Factor (MIF) is a pleiotropic inflammatory cytokine, ubiquitously present in various tissues and the circulation of healthy subjects. MIF is a primary counter-actor of glucocorticoids that emerged as a pivotal regulator of chronic inflammation. During inflammation, MIF converts into oxidized (ox)MIF which was described as the pathogenic and druggable isoform of MIF. ON104, a fully human antibody, was engineered to specifically neutralize oxMIF without triggering immune cell effector functions. ON104 was tested in three experimental models of chronic inflammatory diseases (CIDs): Glomerulonephritis (GN) in WKY rats, Collagen-Induced Arthritis (CIA) in DBA/1j mice; and adoptive T-cell transfer colitis in SCID mice. At disease onset, ON104 was administered at different dose levels twice a week for 1, 3, and 8 weeks in GN, CIA, and colitis, respectively. Clinical evaluations, blood and tissue sampling were done for all individual animals. In the GN model, ON104 significantly reduced proteinuria, hematuria, and CD68 +macrophage infiltration within the inflamed kidneys. During CIA, ON104 ameliorated the severity of arthritis as indicated by reduced paw thickness, and decreased disease score. Furthermore, treatment with ON104 substantially attenuated clinical signs of colitis by preventing body weight loss and restoring stool consistency compared to the vehicle-treated controls. Our findings substantiate the role of oxMIF in the pathogenesis of various CIDs. Thus, ON104 has the potential to become a well-tolerated therapeutic antibody for treating patients with CIDs.

ObjectiveSyk is a cytoplasmic protein tyrosine kinase that plays a role in signaling via B cell and Fc receptors (FcR). FcR engagement and signaling via Syk is thought to be important in antineutrophil cytoplasm antibody (ANCA) IgG-mediated neutrophil activation. This study was undertaken to investigate the role of Syk in ANCA-induced myeloid cell activation and vasculitis pathogenesis.MethodsPhosphorylation of Syk in myeloid cells from healthy controls and ANCA-associated vasculitis (AAV) patients was analyzed using flow cytometry. The effect of Syk inhibition on myeloperoxidase (MPO)-ANCA IgG activation of cells was investigated using functional assays (interleukin-8 and reactive oxygen species production) and targeted gene analysis with NanoString. Total and phosphorylated Syk at sites of tissue inflammation in patients with AAV was assessed using immunohistochemistry and RNAscope in situ hybridization.ResultsWe identified increased phosphorylated Syk at critical activatory tyrosine residues in blood neutrophils and monocytes from patients with active AAV compared to patients with disease in remission or healthy controls. Syk was phosphorylated in vitro following MPO-ANCA IgG stimulation, and Syk inhibition was able to prevent ANCA-mediated cellular responses. Using targeted gene expression analysis, we identified up-regulation of FcR- and Syk-dependent signaling pathways following MPO-ANCA IgG stimulation. Finally, we showed that Syk is expressed and phosphorylated in tissue leukocytes at sites of organ inflammation in AAV.ConclusionThese findings indicate that Syk plays a critical role in MPO-ANCA IgG-induced myeloid cell responses and that Syk is activated in circulating immune cells and tissue immune cells in AAV; therefore, Syk inhibition may be a potential therapeutic option.

Rare kidney diseases are not well characterised, despite making a significant contribution to the burden of kidney disease globally. The National Registry of Rare Kidney Diseases (RaDaR) collects longitudinal disease and treatment related data from people living with rare kidney diseases across the UK, and is the largest rare kidney disease registry in the world. We present the clinical demographics and renal function of 25,880 prevalent patients and evaluate for any potential recruitment bias to RaDaR. RaDaR recruits patients from 108 UK hospitals and is linked with the UK Renal Registry (UKRR, with which all UK patients receiving Kidney Replacement Therapy (KRT) are registered). To assess for recruitment bias to RaDaR we performed three comparisons of ethnicity and socioeconomic status: 1) All prevalent RaDaR patients receiving KRT were compared with patients with eligible rare disease diagnoses receiving KRT in the UKRR 2) Patients recruited to RaDaR and all eligible unrecruited patients at two renal centres were compared 3) The age-stratified ethnicity distribution RaDaR patients with Autosomal Dominant Polycystic Kidney Disease (ADPKD) was compared with the English Census. We observed over-representation of individuals reporting South Asian ethnicity in some rare diseases (most markedly Cystinosis and Primary Hyperoxaluria). We found no evidence of systematic bias in recruitment to RaDaR in terms of ethnicity or social deprivation. Predominant rare kidney diseases in adults ([≥]18 years) were ADPKD (29.2%), Vasculitis (15.8%) and IgA nephropathy (15.7%), compared to Idiopathic nephrotic syndrome (43.6%), Vasculitis (10.8%) and Alport Syndrome (5.9%) in children (<18 years). Compared with either adults recruited to RaDaR or the general UK population, children recruited to RaDaR were more likely to be of Asian ethnicity and live in more socially deprived areas.

Introduction The prevalence of Diabetic Kidney Disease (DKD) secondary to Type 2 Diabetes Mellitus (T2DM) is rising worldwide. However, real-world data linking glomerular function and albuminuria to the degree of multi-morbidity is lacking. We thus utilised the Discover dataset, to determine this association. Method Patients with T2DM diagnosed prior to 1st January 2015 with no available biochemical evidence of CKD were included. Patients subsequently diagnosed and coded for CKD3a in 2015, were grouped by the degree of albuminuria. Baseline and 5-year co-morbidity was determined, as were prescribing practices with regards to prognostically beneficial medication. Results We identified 56,261 patients with T2DM, of which 1082 had CKD stage 3a diagnosed in 2015 (224-CKD3aA1,154-CKD3aA2,93-CKD3aA1; 611 patients with CKD3a but no uACR available in 2015 were excluded from follow up). No statistically significant difference was observed in the degree of co-morbidities at baseline. A significant difference in the degree of hypertension, retinopathy, ischaemic heart disease and vascular disease from baseline compared to study end point was observed for all 3 study groups. Comparing co-morbidities developed at study end point, highlighted a statistical difference between CKD3aA1 Vs CKD3aA3 for retinopathy alone and for hypertension and heart failure between CKD3aA2 Vs CKD3aA3. 40.8% of patients with CKD3aA2 or A3 were prescribed Renin Angiotensin Aldosterone inhibitors (RAASi) therapy between June-December 2021. Survival analysis showed 15% of patients with CKD3aA3 developed CKD stage 5 within 5 years of diagnosis. Discussion CKD3a secondary to DKD is associated with significant multimorbidity at baseline and 5 years post diagnosis, with CKD3aA3 most strongly associated with CKD progression to CKD 5, heart failure, hypertension and retinopathy compared to CKD3aA1 or CKD3aA2 at 5 years post diagnosis. The lack of uACR testing upon diagnosis and poor prescribing of RAASi, in those with CKD3aA2/A3, raises significant cause for concern. Conclusion DKD is associated with significant multimorbidity. Significant work is needed to be done to ensure patients undergo testing for uACR, to allow for future risk stratification and ability to be started on prognostically beneficial medication.

Introduction: We reported increased spleen tyrosine kinase (SYK) expression in kidney biopsies of tients with IgA nephropathy (IgAN) and that inhibition of SYK reduces inflammatory cytokines production from IgA stimulated mesangial cells.Methods: This study was a double-blind, randomized, placebo-controlled phase 2 trial of fostamatinib (an oral SYK inhibitor) in 76 patients with IgAN. Patients were randomized to receive placebo, fosta-matinib at 100 mg or 150 mg twice daily for 24 weeks on top of maximum tolerated dose of renin-angiotensin system inhibitors. The primary end point was reduction of proteinuria. Secondary points included change from baseline in estimated glomerular filtration rate (eGFR) and kidney histology.Results: Although we could not detect significant reduction in proteinuria with fostamatinib overall, predetermined subgroup analysis, there was a trend for dose-dependent reduction in median proteinuria (from baseline to 24 weeks by 14%, 27%, and 36% in the placebo, fostamatinib 100 mg, and 150 groups, respectively) in patients with baseline urinary protein-to-creatinine ratios (UPCR) more than mg/g. Kidney function (eGFR) remained stable in all groups. Fostamatinib was well-tolerated. Side effects included diarrhea, hypertension, and increased liver enzymes. Thirty-nine patients underwent repeat opsy showing reductions in SYK staining associated with therapy at low dose (-1.5 vs. 1.7 SYK+ glomerulus in the placebo group, P < 0.05).Conclusions: There was a trend toward reduction in proteinuria with fostamatinib in a predefined analysis of high risk patients with IgAN despite maximal care, as defined by baseline UPCR greater than 1000 Further study may be warranted.

Abstract Background and Aims Macrophage Migration Inhibitory Factor (MIF) is a pleiotropic inflammatory cytokine and a primary counter-regulator of glucocorticoids (GCs) that emerged as a pivotal regulator of immune-mediated disorders including glomerulonephritis (GN). MIF occurs in two immunologically distinct, conformational isoforms: reduced MIF, ubiquitously present in various tissues and the circulation of healthy subjects, and oxidized MIF (oxMIF), described as the pathogenic and druggable isoform of MIF [1]. We previously reported a positive correlation between disease severity and urinary oxMIF levels in patients with acute lupus nephritis, suggesting oxMIF contribution to kidney damage [2]. In this study we evaluated the anti-inflammatory effects of oxMIF neutralization using ON104 antibody during crescentic GN. Method By advanced antibody engineering we generated the fully human antibody ON104 that is specific and highly affine for human oxMIF and its orthologs. ON104 was tested for its therapeutic potential in a rodent model of GN. Nephritis was induced in male WKY rats by a single intravenous (i.v.) injection of rabbit anti-rat GBM (glomerular basement membrane) serum. On day 4 and day 6 after GN induction, ON104 was administrated intraperitoneally (i.p.). Body weight, proteinuria, and hematuria were assessed to evaluate GN severity. On day 8, kidneys were harvested for immuno-histological examinations by HE, PAS-staining and IHC staining. Results Treatment with ON104 substantially attenuated clinical signs of GN by preserving kidney function demonstrated by reduced proteinuria, and reduced hematuria. Furthermore, ON104 significantly reduced tissue injury, reduced crescentic glomerulus formation, and increased the percentage of normal glomeruli. On the cellular level, oxMIF neutralization by ON104 reduced CD68+ macrophage accumulation within the inflamed kidneys compared to untreated and isotype Ig-treated rats. Conclusion Our findings substantiate the role of oxMIF in the pathogenesis of experimental GN. Thus, targeting oxMIF may represent a new and promising treatment option for kidney diseases.

Antibody mediated rejection is a major cause of renal allograft loss. Circulating preformed donor specific antibodies (DSA) can result as a consequence of blood transfusion, pregnancy or prior transplantation. Current treatment strategies are limited due to partial or transient efficacy, adverse side-effects or patient unsuitability. Previous in vivo studies exploring autoimmune diseases have shown that spleen tyrosine kinase (SYK) signalling is involved in the development of pathogenic autoantibody. The role of SYK in allogenic antibody production is unknown, and we investigated this in a rodent model of sensitization, established by the transfusion of F344 whole blood into LEW rats. Two-week treatment of sensitized rats with selective SYK inhibitor fostamatinib strongly blocked circulating DSA production without affecting overall total immunoglobulin levels, and inhibition was sustained up to 5 weeks post-completion of the treatment regimen. Fostamatinib treatment did not affect mature B cell subset or plasma cell levels, which remained similar between non-treated controls, vehicle treated and fostamatinib treated animals. Our data indicate fostamatinib may provide an alternative therapeutic option for patients who are at risk of sensitization following blood transfusion while awaiting renal transplant.

Anemia protocols for hemodialysis patients usually titrate erythropoietin (ESA) according to hemoglobin and iron according to a threshold of ferritin, with variable response seen. A universally optimum threshold for ferritin may be incorrect, and another view is that ESA and iron are alternative anemia treatments, which should be selected based on the likely response to each. Hemodialysis patients developing moderate anemia were randomised to treatment with either an increase in ESA or a course of intravenous iron. Over 2423 patient-months in 197 patients, there were 133 anemia episodes with randomized treatment. Treatment failure was seen in 20/66 patients treated with ESA and 20/67 patients treated with iron (30.3 vs. 29.9%, p = 1.0). Successful ESA treatment was associated with lower C-reactive protein (13.5 vs. 28.6 mg/L, p = 0.038) and lower previous ESA dose (6621 vs. 9273 μg/week, p = 0.097). Successful iron treatment was associated with lower reticulocyte hemoglobin (33.8 vs. 35.5 pg, p = 0.047), lower hepcidin (91.4 vs. 131.0 μg/ml, p = 0.021), and higher C-reactive protein (29.5 vs. 12.6 mg/L, p = 0.085). A four-variable iron preference score was developed to indicate the more favorable treatment, which in a retrospective analysis reduced treatment failure to 17%. Increased ESA and iron are equally effective, though treatment failure occurs in almost 30%. Baseline variables including hepcidin can predict treatment response, and a four-variable score shows promise in allowing directed treatment with improved response rates.

P2RX7, an ionotropic receptor for extracellular adenosine triphosphate (ATP), is expressed on immune cells, including macrophages, monocytes, and dendritic cells and is upregulated on nonimmune cells following injury. P2RX7 plays a role in many biological processes, including production of proinflammatory cytokines such as interleukin (IL)-1β via the canonical inflammasome pathway. P2RX7 has been shown to be important in inflammation and fibrosis and may also play a role in autoimmunity. We have developed and phenotyped a novel P2RX7 knockout (KO) inbred rat strain and, taking advantage of the human-resembling unique histopathological features of rat models of glomerulonephritis, we induced three models of disease: nephrotoxic nephritis, experimental autoimmune glomerulonephritis, and experimental autoimmune vasculitis. We found that deletion of P2RX7 does not protect rats from models of experimental glomerulonephritis or the development of autoimmunity. Notably, treatment with A-438079, a P2RX7 antagonist, was equally protective in WKY WT and P2RX7 KO rats, revealing its 'off-target' properties. We identified a novel ATP/P2RX7/K+ efflux-independent and caspase-1/8-dependent pathway for the production of IL-1β in rat dendritic cells, which was absent in macrophages. Taken together, these results comprehensively establish that inflammation and autoimmunity in glomerulonephritis is independent of P2RX7 and reveals the off-target properties of drugs previously known as selective P2RX7 antagonists. Rat mononuclear phagocytes may be able to utilise an 'alternative inflammasome' pathway to produce IL-1β independently of P2RX7, which may account for the susceptibility of P2RX7 KO rats to inflammation and autoimmunity in glomerulonephritis. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Background The impact that rare chronic disorders, such as retroperitoneal fibrosis (RPF), can have on the physical and psychological aspects of a patient's health is poorly understood. Patient-related outcome measures and experiences provide a unique opportunity to understand the impact rare chronic disorders have on a patient's life as well as allowing healthcare providers to compare and improve performance. Aim To understand the physical and psychosocial impact that RPF has upon peoples' lives. Design An international online questionnaire was therefore created to gain insights into how patients with RPF, a rare fibro-inflammatory condition, viewed their health and experiences. Methods An international online questionnaire comprising 62 questions/free text options, was designed in collaboration with two patient advocates and the multi-disciplinary Renal Association Rare Disease Registry (RaDaR) RPF Group the questionnaire was anonymous and freely accessible on a GOOGLE Form online platform for 6 months. Results A total of 229 patients from 30 countries across 5 continents responded. Four key issues were identified; (i) pain; (ii) therapy-related side effects; (iii) lack of informed doctors/information about their condition and its management; and (iv) psychological burden. Variations in diagnosis and management are highlighted with 55% undergoing a biopsy to reach a diagnosis of RPF; 75% of patients underwent a further interventional procedure with 60% concurrently treated medically. Conclusion This study will guide further development of clinical and academic multi-disciplinary activity and shows the importance of trying to understand the impact of rare chronic disorders on the physical and psychological aspects of a patient's health.

IntroductionDiabetic patients normally have enlarged or normal-sized kidneys throughout their lifetime, but some diabetic uremic patients have small kidneys. It is uncertain if kidney size could have any negative impact on outcome in hemodialysis patients.MethodsThis longitudinal, observational cohort study recruited 301 diabetic hemodialysis patients in 2015, and followed until 2019. Patients were stratified into two subgroups according to their kidney sizes before dialysis, as small (n = 32) or enlarged or normal (n = 269). Baseline demographic, hematological, biochemical, nutritional, inflammatory and dialysis related data were collected for analysis.ResultsPatients with small kidney size were not only older (P<0.001) and had lower body mass index (P = 0.016), but had also higher blood uric acid concentration (P<0.001) compared with patients with enlarged or normal kidney size. All patients received adequate doses of hemodialysis since the Kt/V and urea reduction ratio was 1.7±0.3 and 0.7±0.1, respectively. Patients with small size kidneys received higher erythropoietin dose than patients with enlarged or normal kidney size (P = 0.031). At the end of analysis, 92 (30.6%) patients expired. Kaplan-Meier analysis revealed no survival difference between both groups (P = 0.753). In a multivariate logistic regression model, it was demonstrated that age (P<0.001), dialysis duration (P<0.001), as well as blood albumin (P = 0.012) and low-density lipoprotein (P = 0.009) concentrations were significantly correlated with mortality.ConclusionsSmall kidney size on starting hemodialysis was not related with an augmented risk for death in diabetic patients receiving hemodialysis. Further studies are necessary.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis can present with life-threatening lung-kidney syndromes. However, many controlled treatment trials excluded patients with diffuse alveolar hemorrhage or severely impaired glomerular filtration rates, and so the optimum treatment in these cases is unclear. In this retrospective cohort study, we report the outcomes of 64 patients with life-threatening disease treated with a combination regimen of rituximab, low-dose intravenous cyclophosphamide, oral glucocorticoids, and plasma exchange. At entry, the median estimated glomerular filtration rate was 9 mL/min, 47% of patients required dialysis, and 52% had diffuse alveolar hemorrhage. All patients received a minimum of seven plasma exchanges, and the median cumulative doses of rituximab, cyclophosphamide, and glucocorticoid were 2, 3, and 2.6 g, respectively, at six months. A total of 94% of patients had achieved disease remission (version 3 Birmingham Vasculitis Activity Score of 0) at this time point, and 67% of patients who required dialysis recovered independent kidney function. During long-term follow-up (median duration 46 months), overall patient survival was 85%, and 69% of patients remained free from end-stage kidney disease, which compares favorably to a historic cohort with severe disease treated with a conventional induction regimen. Combination treatment was associated with prolonged B cell depletion and low rates of relapse; 87% of patients were in continuous remission at month 36. The serious infection rate during total follow-up was 0.28 infections/patient/year, suggesting that combination treatment is not associated with an enduring risk of infection. Thus, we suggest that combination immunosuppressive therapy may permit glucocorticoid avoidance and provide rapid and prolonged disease control in patients with severe ANCA-associated vasculitis.