Atypical Anti-Glomerular Basement Membrane Nephritis: A Case Series From the French Nephropathology Group.

RATIONALE & OBJECTIVE: Atypical anti-glomerular basement membrane (GBM) nephritis is characterized by a bright linear immunoglobulin staining along the GBM by immunofluorescence without a diffuse crescentic glomerulonephritis nor serum anti-GBM antibodies by conventional enzyme-linked immunosorbent assay (ELISA). We characterized a series of patients with atypical anti-GBM disease. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: Patients identified by the French Nephropathology Group as having atypical anti-GBM nephritis between 2003 and 2022. FINDINGS: Among 38 potential cases, 25 were included, of whom 14 (56%) were female and 23 (92%) had hematuria. The median serum creatinine at diagnosis was 150 (IQR, 102-203) µmol/L and median urine protein-creatinine ratio (UPCR) was 2.4 (IQR, 1.3-5.2) g/g. Nine patients (36%) had endocapillary proliferative glomerulonephritis (GN), 4 (16%) had mesangial proliferative GN, 4 (16%) had membranoproliferative GN, 2 (8%) had pure and focal crescentic GN, 1 (4%) had focal segmental glomerulosclerosis, and 5 had glomeruli that were unremarkable on histopathology. Nine patients (36%) had crescents, involving a median of 9% of glomeruli. Bright linear staining for IgG was seen in 22 cases (88%) and for IgA in 3 cases (12%). The 9 patients (38%) who had a monotypic staining pattern tended to be older with less proteinuria and rarely had crescents. Kidney survival rate at 1 year was 83% and did not appear to be associated with the light chain restriction. LIMITATIONS: Retrospective case series with a limited number of biopsies including electron microscopy. CONCLUSIONS: Compared with typical anti-GBM disease, atypical anti-GBM nephritis frequently presents with an endocapillary or mesangial proliferative glomerulonephritis pattern and appears to have a slower disease progression. Further studies are needed to fully characterize its pathophysiology and associated clinical outcomes. PLAIN-LANGUAGE SUMMARY: Atypical anti-glomerular basement membrane (GBM) nephritis is characterized histologically by bright linear immunoglobulin staining along the GBM without diffuse crescentic glomerulonephritis or circulating anti-GBM antibodies. We report a case series of 25 atypical cases of anti-GBM nephritis in collaboration with the French Nephropathology Group. Compared with typical anti-GBM disease, we observed a slower disease progression. Patients frequently presented with heavy proteinuria and commonly had evidence of endocapillary or mesangial proliferative glomerulonephritis. About half of the patients displayed a monotypic immune staining pattern; they tended to be older, with less proteinuria, and commonly without glomerular crescents in biopsy specimens. No concomitant circulating monoclonal gammopathy was detected. Further studies are needed to fully characterize its pathophysiology and associated clinical outcomes.

Immunogenicity of SARS-CoV-2 vaccines in patients treated with chronic double filtration plasmapheresis.

BACKGROUND: The impact of chronic therapeutic plasmapheresis on humoral response following COVID-19 vaccination is poorly documented, especially among patients treated with double filtration plasmapheresis (DFPP). OBJECTIVES: This retrospective single-center study evaluated the humoral response after SARS-CoV-2 vaccination and studied anti-SPIKE seropositivity and antibody dynamics in patients with chronic DFPP at our institution. METHOD: All patients undergoing chronic DFPP at a tertiary center in France from December 2020 to November 2022 were included. We defined one patient subgroup as Group 1 to evaluate anti-SPIKE seropositivity after vaccination, with three groups based on their anti-SPIKE titers: (Group 1A) nonresponders (<0.8 UI/mL), (Group 1B) weak responders (0.8 to <250 binding antibody unit [BAU]/mL), and (Group 1C) strong responders (>250 BAU/mL). Group 2 served to evaluate antibody dynamics with anti-SPIKE levels measured 3 months after initial vaccination, Group 2A having a sustained level and Group 2B a declining pattern. RESULTS: The 21 patients included had a median age of 63 years, and 13 (56%) were male. The indications for chronic DFPP mainly included dysimmune pathologies (15; 71%) and familial dyslipidemia (6; 29%). For the humoral response to vaccination in Patient Group 1, the only nonresponder was a patient who had undergone kidney transplantation 30 months earlier and was on immunosuppressive medication. For Patient Group 2, the median follow-up of antibody titers was 13 months [12-13]. Two distinct patterns of anti-SPIKE dynamics were observed: a rapid decline in anti-SPIKE antibody titers within 6 months following the initial vaccination or booster dose (n = 10 [71.4%] Group 2A) and stable anti-SPIKE levels above 250 BAU/mL over >6 months (n = 4 [28.6%] Group 2B) with more patients with familial dyslipidemia in the former. CONCLUSIONS: Humoral response to SARS-CoV-2 vaccination appears robust in patients undergoing chronic DFPP and may be linked to patients' immune status rather than DFPTP itself. Our results support current recommendations for administering three doses of vaccine with a booster every 6 months.

Interest of therapeutic plasmapheresis in a chronic hemodialysis patient with severe bullous pemphigoid.

Bullous pemphigoid is the most common autoimmune blistering disease induced by autoantibodies against basement membrane anchoring proteins (anti-BP-180 and anti-BP-230). The disease generally appears after the age of 70 and is associated with a 23.5% 1-year mortality, especially in diabetics, or in the presence of ischemic heart disease and high anti-BP-180. Treatment starts with topical steroids but some patients may require oral steroids and systemic immunosuppression. We, hereby, discuss a diabetic patient on chronic hemodialysis, with severely relapsed bullous pemphigoid under biotherapy with omalizumab, who was successfully treated with five sessions of double filtration plasmapheresis, thus avoiding the need for systemic steroids.

Feasibility, Efficacy, and Safety of Peripheral Venous Access for Chronic Double-Filtration Plasmapheresis with Regional Citrate Anticoagulation.

INTRODUCTION: Peripheral venous access (PVA) is recommended as a first-line vascular approach for therapeutic plasmapheresis with centrifugation methods but not filtration, which usually requires high blood flow. We evaluated the feasibility, efficacy, and safety of double-filtration plasmapheresis (DFPP) with PVA, using ultrasound guidance and regional citrate anticoagulation (RCA), i.e., PVA-RCA-DFPP in patients undergoing chronic DFPP. Secondly, we assessed the number of central venous catheters (CVCs) avoided. METHODS: A single-center retrospective study evaluated 22 adult patients on chronic DFPP to perform PVA-RCA-DFPP. They were classified into 3 groups: successful (i.e., completion of sessions with PVA), primary failure (i.e., no sessions completed), secondary failure (i.e., ≥1 session with PVA completed but secondary return with CVC or arteriovenous fistula). RESULTS: Among the 22 patients included (64% men), 7 patients (32%) were classified as primary failures (2 patient refusals, 5 inadequate PVAs), 1 patient (5%) as a secondary failure (due to uncomfortable venipunctures), and 14 patients (64%) as successful. In the successful group including 12 patients treated for chronic inflammatory demyelinating polyneuropathy (CIDP) and 2 patients for familial hypercholesterolemia (FH) (2 patients), 116 sessions were performed, with a median treated plasma volume of 4.3 L [IQR 3.6-4.6] (45 mL/kg) for a median duration of 134 min [IQR 122-144], and a median blood flow of 94 mL/min [IQR 87-103]. For the CIDP group, 90% of sessions achieved a plasma volume >1 TPV, and for the FH group 91% of sessions achieved an LDLc reduction >60%. Eleven sessions out of 116 (9%) were interrupted, mostly due to PVA dysfunction (5/11) and circuit clotting (4/11). Session interruptions decreased significantly between each patient's first and following sessions (29% to 7%, p = 0.009). CONCLUSION: Chronic PVA-RCA-DFPP can be performed safely and efficiently, avoiding the use of CVCs.

Direct Determination rather than Oscillometric Estimation of Systolic Blood Pressure in Patients with Severe Chronic Kidney Disease.

INTRODUCTION: Although arterial hypertension is a major concern in patients with chronic kidney disease (CKD), obtaining accurate systolic blood pressure (SBP) measurement is challenging in this population for whom automatic oscillometric devices may yield erroneous results. METHODS: This cross-sectional study was conducted in 89 patients with stages 4, 5, and 5D CKD, for whom we compared SBP values obtained by the recently described systolic foot-to-apex time interval (SFATI) technique which provides direct SBP determination, the standard technique (Korotkoff sounds), and oscillometry. We investigated the effects of age, sex, diabetes, CKD stage, and pulse pressure to explain measurement errors defined as biases or misclassification relative to the SBP thresholds of 110-130-mm Hg. RESULTS: All 3 techniques showed satisfactory reproducibility for SBP measurement (CCC > 0.84 and >0.91, respectively, in dialyzed and nondialyzed patients). The mean ± SD from SBP as determined via Korotkoff sounds was 1.7 ± 4.6 mm Hg for SFATI (CCC = 0.98) and 5.9 ± 9.3 mm Hg for oscillometry (CCC = 0.88). Referring to the 110-130-mm Hg SBP range outside which treatment prescription or adaptation is recommended for CKD patients, SFATI underestimated SBP in 3 patients and overestimated it in 1, whereas oscillometry underestimated SBP in 12 patients and overestimated it in 3. Higher pulse pressure was the main explanatory factor for measurement and classification errors. DISCUSSION/CONCLUSION: SFATI provides accurate SBP measurements in patients with severe CKD and paves the way for the standardization of automated noninvasive blood pressure measurement devices. Before prescribing or adjusting antihypertensive therapy, physicians should be aware of the risk of misclassification when using oscillometry.

Choosing the right chronic medication for hemodialysis patients. A short ABC for the dialysis nephrologist.

BACKGROUND: Adapting drug treatments for patients on hemodialysis with multiple chronic pathologies is a complex affair. When prescribing a medication, the risk-benefit analysis usually focuses primarily on the indication of the drug class prescribed. However, the pharmacokinetics of the chosen drug should also be taken into account. The purpose of our review was to identify the drugs to be favored in each therapeutic class, according to their safety and pharmacokinetic profiles, for the most common chronic diseases in patients on chronic hemodialysis. METHODS: We conducted a narrative review of the literature using Medline and Web of Science databases, targeting studies on the most commonly-prescribed drugs for non-communicable diseases in patients on chronic hemodialysis. RESULTS: The search identified 1224 articles, 95 of which were further analyzed. The main classes of drugs included concern the cardiovascular system (anti-hypertensives, anti-arrhythmics, anti-thrombotics, hypocholesterolemics), the endocrine and metabolic pathways (anti-diabetics, gastric anti-secretory, anticoagulant, thyroid hormones, anti-gout) and psychiatric and neurological disorders (antidepressants, anxiolytics, antipsychotics and anti-epileptics). CONCLUSION: We report on the most often prescribed drugs for chronic pathologies in patients on chronic hemodialysis. Most of them require adaptation, and in some cases one better alternative stands out among the drug class. More pharmacokinetic data are needed to define the pharmacokinetics in the various dialysis techniques.

Characteristics of outpatients referred for a first consultation with a nephrologist: impact of different guidelines.

INTRODUCTION: Chronic kidney disease (CKD) affects > 10% of the population but not all CKD patients require referral to a nephrologist. Various recommendations for referral to nephrologists are proposed worldwide. We examined the profile of French patients consulting a nephrologist for the first time and compared these characteristics with the recommendations of the International Kidney Disease: Improving Global Outcomes (KDIGO), the French "Haute Autorité de Santé" (HAS), and the Canadian Kidney Failure Risk Equation (KFRE). METHODS: University Hospital electronic medical records were used to study patients referred for consultation with a nephrologist for the first time from 2016 to 2018. Patient characteristics (age, sex, diabetic status, estimated glomerular filtration rate (eGFR) and urine protein-to-creatinine ratio (PCR), etiology reported by the nephrologist) and 1-year patient follow-up were analyzed and compared with the KDIGO, HAS and Canadian-KFRE recommendations for referral to a nephrologist. The stages were defined according to the KDIGO classification, based upon kidney function and proteinuria.  RESULTS: The 1,547 included patients had a median age of 71 [61-79] years with 56% males and 37% with diabetes. The main nephropathies were vascular (40%) and glomerular (20%). The KDIGO classification revealed 30%, 47%, 19%, 4% stages G1-2 to G5, and 50%, 22%, 28% stages A1-A3, respectively. According to KDIGO, HAS and KFRE scores, nephrologist referral was indicated for 42%, 57% and 80% of patients respectively, with poor agreement between recommendations. Furthermore, we observed 890 (57%) patients with an eGFR> 30 ml/min and  a urine protein to creatinine ratio 0.5 g/g, mostly aged over 65 years (67%); 40% were diabetic, and 57% had a eGFR > 45 ml/min/1.73m2, 56% were diagnosed as vascular nephropathy and 11% with unknown nephropathy. CONCLUSION: These results underline the importance of better identifying patients for referral to a nephrologist and informing general practitioners. Other referral criteria (age and etiology of the nephropathy) are debatable.

Low performance of prognostic tools for predicting death before dialysis in older patients with advanced CKD.

INTRODUCTION: Chronic kidney disease (CKD) is a disease which is spreading worldwide, especially among older patients. Several prognostic scores have been developed to predict death in older CKD patients, but they have not been validated. We aimed to evaluate the existing risk scores for predicting death before dialysis start, identified via an in-depth review, in a cohort of elderly patients with advanced CKD. METHODS: We performed a review to identify scores predicting death, developed in and applicable to CKD patients. Each score was evaluated with an absolute risk calculation from the patients' baseline characteristics. We used a French prospective multicentre cohort of elderly patients (> 75 years) with advanced CKD [estimated glomerular filtration rate (eGFR) < 20 mL/min/1.73 m2], recruited from nephrological centres, with a 5-year follow-up. The outcome considered was death before initiating dialysis. Discrimination [area under curve (AUC)], calibration and Brier score were calculated for each score at its time frame. RESULTS: Our review found 6 equations predicting death before dialysis in CKD patients. Four of these (GOLDFARB, BANSAL, GRAMS 2 and 4 years) were evaluated. The validation cohort (Parcours de Soins des Personnes Âgées Parcours de Soins des Personnes Âgées, PSPA) included 573 patients, with a median age of 82 years and a median eGFR of 13 mL/min/1.73 m2. At the end of follow-up, 287 (50%) patients had started dialysis and 238 (41%) patients had died before dialysis. The four equations evaluated showed average discrimination (AUC 0.61-0.70) and, concerning calibration, a global overestimation of the risk of death. DISCUSSION: The available scores predicting death before dialysis showed low performance among older patients with advanced CKD in a French multicentre cohort, indicating the need to upgrade them or develop new scores for this population.

Low performance of prognostic tools for predicting dialysis in elderly people with advanced CKD.

INTRODUCTION: Clinical decision-making about care plans can be difficult for very elderly people with advanced chronic kidney disease (CKD). Current guidelines propose the use of prognostic tools predicting end stage renal disease (ESRD) to assist in a patient-centered shared decision-making approach. Our objective was to evaluate the existing risk model scores predicting ESRD, from data collected for a French prospective multicenter cohort of mainly octogenarians with advanced CKD. METHODS: We performed a rapid review to identify the risk model scores predicting ESRD developed from CKD patient cohorts and evaluated them with data from a prospective multicenter French cohort of elderly (> 75 years) patients with advanced CKD (estimated glomerular filtration rate [eGFR] < 20 mL/min/1.75m2), followed up for 5 years. We evaluated these scores (in absolute risk) for discrimination, calibration and the Brier score. For scores using the same time frame, we made a joint calibration curve and compared areas under the curve (AUCs). RESULTS: The PSPA cohort included 573 patients; their mean age was 83 years and their median eGFR was 13 mL/min/1.73 m2. At the end of follow-up, 414 had died and 287 had started renal replacement therapy (RRT). Our rapid review found 12 scores that predicted renal replacement therapy. Five were evaluated: the TANGRI 4-variable, DRAWZ, MARKS, GRAMS, and LANDRAY scores. No score performed well in the PSPA cohort: AUCs ranged from 0.57 to 0.65, and Briers scores from 0.18 to 0.25. CONCLUSIONS: The low predictiveness for ESRD of the scores tested in a cohort of octogenarian patients with advanced CKD underlines the need to develop new tools for this population.

Physiological role of plasma and its components and the clinical implications of different methods of apheresis: A narrative review.

Nowadays, therapeutic plasmapheresis (TP) is accepted as part of the treatment for specific groups of diseases. The availability of different methods, including double filtration and adsorption, increases selectivity for the removal of substances. However, the use of these techniques requires a thorough understanding of the characteristics and components of plasma. By considering pivotal papers from several databases, the aim of this narrative review is to describe the characteristics of plasma related to apheresis techniques. We have tried to cover the clinical implications including physiology, estimation of plasma volume, viscosity, and a description of its components including the size, volume of distribution, and half-lives of the different substances to be removed or maintained depending on the clinical situation and applied apheresis technique. Applying this knowledge will help us to choose the right method and dosage and improve the efficacy of the procedure by preventing or addressing any complications.

Use of double filtration plasmapheresis for the treatment of acquired thrombocytopenic thrombotic purpura.

Double filtration plasmapheresis (DFPP) could be an alternative method to simple plasma exchange plasmapheresis in the treatment of acquired thrombotic thrombocytopenic purpura (aTTP). In a retrospective single center case series, we studied clinical presentation, management care, and prognosis of aTTP patients from our academic center treated with DFPP and IV infusion of fresh frozen plasma (FFP) between 2009 and 2018. Nine patients were included for 11 episodes. Median age was 38 years old (IQR 26-53) with 78% women. Six episodes (55%) required admission to the ICU, four of which required mechanical ventilation. Median FFP volume transfused was 35.2 mL/kg/d of session. Response was complete for nine episodes (82%). Four patients presented an early relapse, two a late relapse. Four patients died: one had an active untreated HCV infection, and two were over 80-year-old polymorbid patients. DFPP seems to be an efficient method of therapeutic plasmapheresis in TTP when combined with FFP transfusion and immunosuppressive treatments.

An Association between BK Virus Replication in Bone Marrow and Cytopenia in Kidney-Transplant Recipients.

The human polyomavirus BK (BKV) is associated with severe complications, such as ureteric stenosis and polyomavirus-associated nephropathy (PVAN), which often occur in kidney-transplant patients. However, it is unknown if BKV can replicate within bone marrow. The aim of this study was to search for BKV replication within the bone marrow of kidney-transplant patients presenting with a hematological disorder. Seventy-two kidney-transplant patients underwent bone-marrow aspiration for cytopenia. At least one virus was detected in the bone marrow of 25/72 patients (35%), that is, parvovirus B19 alone (n = 8), parvovirus plus Epstein-Barr virus (EBV) (n = 3), cytomegalovirus (n = 4), EBV (n = 2), BKV alone (n = 7), and BKV plus EBV (n = 1). Three of the eight patients who had BKV replication within the bone marrow had no detectable BKV replication in the blood. Neutropenia was observed in all patients with BKV replication in the bone marrow, and blockade of granulocyte maturation was observed. Hematological disorders disappeared in all patients after doses of immunosuppressants were reduced. In conclusion, an association between BKV replication in bone marrow and hematological disorders, especially neutropenia, was observed. Further studies are needed to confirm these findings.