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.

[Kidney biopsy in Reunion Island between 2015 and 2017, an epidemiological study]. / Données épidémiologiques des biopsies rénales à l'île de la Réunion entre 2015 et 2017.

INTRODUCTION: Reunion Island's population is characterized by a multiethnic origin, which makes it impossible to transpose epidemiological data of Metropolitan France. Only REIN Registry provides a macroscopic view of kidney disease, limited to the causes of end stage renal disease. METHODS: This is a regional retrospective study whose main objective is to describe renal pathologies in Reunion Island's adults over a period of 3 years. Kidney transplants are excluded. RESULTS: Between 2015 and 2017, 338 native adult kidney biopsies performed on the island are collected. The annual biopsy rate is 132/million/year with preponderance in the northern part of the island due to a higher density of nephrologists. Nephrotic syndrome is the first indication with 30% of cases. The four main results are represented by IgA nephropathy (16%), diabetic nephropathy (12.4%), lupus nephropathy (11.2%) and isolated vascular nephropathy (11%). Incidence of glomerulopathies is similar to the worldwide incidence, nevertheless a preponderant place of diabetic nephropathy is found. On the biopsies performed, incidence of complications is evaluated at 7.5%, with no difference between the detection technique used. CONCLUSION: This is the first study illustrating main renal pathologies in Reunion Island. Diabetes' frequency in general population is a major confounding factor in diagnosis and management of kidney diseases on the island.

Recurrent coronary syndromes in a patient with isolated very-high lipoprotein (a) and the prothrombin genetic variant rs1799963 (G20210A): a case report.

BACKGROUND: Elevated lipoprotein (a) [Lp(a)] is an under-diagnosed genetically inherited risk factor for coronary heart disease (CHD) and calcific aortic valve stenosis. Premature myocardial infarction (MI) could stem from the association between elevated Lp(a) and other non-traditional cardiovascular risk factors. CASE SUMMARY: Here, we report a male patient with extremely high Lp(a) plasma levels [610 nmol/L (244 mg/dL); normal <75 nmol/L (<30 mg/dL)] associated with the prothrombin genetic variant rs1799963 (G20210A) and no other CHD risk factor. At the age of 32, he suffered recurrent episodes of MI treated by coronary angioplasty and drug eluting stents. The patient who was initially prescribed antiplatelet therapy, beta-blockers, and statins, has subsequently been treated by lipoprotein apheresis every fortnight for 43 months. He has never experienced any recurrent episode of angina or chest pain since. DISCUSSION: The rare association between extremely elevated circulating Lp(a) levels and prothrombotic genetic variants of coagulation factors appears to be a deadly combination that can only be adequately treated by antiplatelet therapy and lipoprotein apheresis.

Atypical anti-glomerular basement membrane disease presenting as macroscopic haematuria, loin pain and acute kidney injury after intensive exercise.

We report a 35-year-old man who suffered from recurrent macroscopic haematuria after intensive exercise. One episode was associated with bilateral loin (flank) pain and severe acute kidney injury. His kidney biopsy revealed an atypical anti-glomerular basement membrane (GBM) disease typified by bright linear GBM staining for monotypic immunoglobulin G but without a diffuse crescentic phenotype and no circulating anti-GBM antibody. Outcome was spontaneously favourable. The patient had no recurrence or urine abnormality without running. The original presentation emphasized that exercise could reveal an underlying glomerulopathy.

Daily urinary creatinine predicts the weaning of renal replacement therapy in ICU acute kidney injury patients.

BACKGROUND: In acute kidney injury (AKI), useless continuation of renal replacement therapy (RRT) may delay renal recovery and impair patient's outcome. In this study, we aimed to identify predictive parameters that may help to a successful RRT weaning for AKI patients. METHODS: We studied 54 surviving AKI patients in which a weaning of RRT was attempted. On the day of weaning (D0) and the following 2 days (D1 and D2), SAPS II and SOFA scores, 24-h diuresis, 24-h urinary creatinine and urea (UCr and UUr), creatinine and urea generation rates (CrGR and UrGR) and clearances (CrCl and UrCl) were collected. Patients who remained free of RRT 15 days after its discontinuation were considered as successfully weaned. RESULTS: Twenty-six RRT weaning attempts succeeded (S+) and 28 failed (S-). Age, previous renal function, SAPS II and SOFA scores were comparable between groups. At D0, 24-h diuresis was 2300 versus 1950 ml in S+ and S-, respectively, p = 0.05. At D0, D1 and D2, 24-h UUr and UCr levels, UrCl and CrCl, and UUr/UrGR and UCr/CrGR ratios were significantly higher in S+ group. By multivariate analysis, D1 24-h UCr was the most powerful parameter that was associated with RRT weaning success with an area under the ROC curve of 0.86 [0.75-0.97] and an odds ratio of 2.01 [1.27-3.18], p = 0.003. CONCLUSIONS: In ICU AKI, 24-h UCr appeared as an efficient and independent marker of a successful weaning of RRT. A 24-h UCr ≥5.2 mmol was associated with a successful weaning in 84 % of patients.