Clinicopathological features and outcome of antibody-negative anti-glomerular basement membrane disease

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.

Recurrent atypical antiglomerular basement membrane nephritis in the kidney transplant

Atypical antiglomerular basement membrane (anti-GBM) nephritis can be defined as linear GBM staining for monotypic or polytypic immunoglobulin (Ig) by immunofluorescence (IF) without a diffuse crescentic pattern. We describe the clinicopathologic features of 6 patients (18 biopsies) in this first series of recurrent atypical anti-GBM nephritis after kidney transplantation. Recurrent glomerulonephritis occurred at a mean of 3.8 months posttransplant (range 1-7 months). Three index biopsies were for clinical indication, and 3 were protocol biopsies. Glomerular histologic changes were mild, with 2 showing segmental endocapillary hypercellularity, 1 focal glomerular microangiopathy, and the others no significant glomerular histologic changes. All 6 allografts showed monotypic linear glomerular Ig staining by IF: IgG kappa (n = 2), IgG lambda, IgA kappa, IgA lambda, and IgM lambda. Follow-up biopsies were available for 5 patients and showed similar histologic and IF findings without evidence of significant progression. No patients had detectable serum anti-GBM antibody or monoclonal proteins. The mean serum creatinine level on follow-up (24-62 months posttransplant) was 1.8 (range 0.93-2.77) mg/dL; no grafts were lost to recurrent disease. This series demonstrates that monotypic atypical anti-GBM recurs in the allograft and supports the idea that this disease is due to a circulating monoclonal protein.

Atypical Antiglomerular Basement Membrane Disease in a Pregnant Patient with Systemic Lupus Erythematosus

Antiglomerular basement membrane disease (anti-GBM) is an unusual cause of glomerulonephritis. Patients usually present with rapidly progressive glomerulonephritis with or without pulmonary hemorrhage. The diagnosis is based on linear deposits of IgG along the GBM and the presence of anti-GBM antibodies. However, cases with atypical anti-GBM disease in which an anti-GBM antibody was not detected have been reported. We report a 29-year-old pregnant woman with underlying systemic lupus erythematosus (SLE) who presented with severe glomerulonephritis due to atypical antiglomerular basement membrane disease. She was initially diagnosed with active lupus nephritis and her renal function gradually worsened after steroid treatment, so the pregnancy was terminated due to the high maternal and fetal risks. A kidney biopsy showed linear capillary wall staining with fibrous crescents without endocapillary proliferation. The anti-GBM antibody showed negative results two times, so she was diagnosed with atypical anti-GBM disease. Treatment began with intravenous pulse methylprednisolone and continued with mycophenolate mofetil and prednisolone. Due to the intolerability of side effects, the treatment regimen was subsequently changed to intravenous cyclophosphamide. Although she had a significant improvement in clinical edema, serum albumin, and hematuria, her renal function gradually decreased during the 12 months of treatment. A review of the literature showed that the atypical anti-GBM is less aggressive than the typical anti-GBM disease. However, several patients had persistent renal dysfunction and 20-30% of patients had progression to ERSD. To the best of our knowledge, this is the first case of atypical anti-GBM disease in pregnant patients with suspected SLE reported in the literature.

Prognostic value of complement serum C3 level and glomerular C3 deposits in anti-glomerular basement membrane disease

Background and objectives

Activation of the complement system is involved in the pathogenesis of anti-glomerular basement membrane (anti-GBM) disease. Glomerular deposits of complement 3 (C3) are often detected on kidney biopsies. The primary objective of this study was to analyze the prognostic value of the serum C3 level and the presence of C3 glomerular deposits in patients with anti-GBM disease.

Methods

We conducted a retrospective cohort study of 150 single-positive patients with anti-GBM disease diagnosed between 1997 and 2017. Patients were categorized according to the serum C3 level (forming a low C3 (C3<1.23 g/L) and a high C3 (C3≥1.23 g/L) groups) and positivity for C3 glomerular staining (forming the C3+ and C3- groups). The main outcomes were kidney survival and patient survival.

Results

Of the 150 patients included, 89 (65%) were men. The median [interquartile range (IQR)] age was 45 [26-64]. At diagnosis, kidney involvement was characterized by a median [IQR] peak serum creatinine (SCr) level of 578 [298-977] µmol/L, and 106 (71%) patients required dialysis. Patients in the low C3 group (72 patients) had more severe kidney disease at presentation, as characterized by higher prevalences of oligoanuria, peak SCr ≥500 µmol/L (69%, vs. 53% in the high C3 group; p=0.03), nephrotic syndrome (42%, vs. 24%, respectively; p=0.02) and fibrous forms on the kidney biopsy (21%, vs. 8%, respectively; p=0.04). Similarly, we observed a negative association between the presence of C3 glomerular deposits (in 52 (41%) patients) and the prevalence of cellular forms (83%, vs. 58% in the C3- group; p=0.003) and acute tubulo-interstitial lesions (60%, vs. 36% in the C3- group; p=0.007). When considering patients not on dialysis at diagnosis, the kidney survival rate at 12 months was poorer in the C3+ group (50% [25-76], vs. 91% [78-100] in the C3- group; p=0.01), with a hazard ratio [95% confidence interval] of 5.71 [1.13-28.85] (p=0.04, after adjusting for SCr).

Conclusion

In patients with anti-GBM disease, a low serum C3 level and the presence of C3 glomerular deposits were associated with more severe disease and histological kidney involvement at diagnosis. In patients not on dialysis at diagnosis, the presence of C3 deposits was associated with worse kidney survival.

Atypical Anti-Glomerular Basement Membrane Disease

Atypical anti-glomerular basement membrane (anti-GBM) disease is characterized by linear immunoglobulin G (IgG) deposition along the GBM without circulating IgG anti-GBM antibodies. Compared to classic anti-GBM disease, atypical anti-GBM disease tends to be milder with a more indolent course in certain cases. Moreover, pathologic disease pattern is much more heterogenous in atypical anti-GBM disease than in the classic type, which is uniformly characterized by diffuse crescentic and necrotizing glomerulonephritis. Although there is no single well-established target antigen in atypical anti-GBM disease, the target antigen (within the GBM) and the autoantibody type are hypothesized to be different from the classic type. Some patients have the same antigen as the Goodpasture antigen that are detected only by a highly sensitive technique (biosensor analysis). Some cases of atypical anti-GBM disease have autoantibodies of a different subclass restriction like IgG4, or of monoclonal nature. Antibodies targeting antigen/epitope structure other than the Goodpasture antigen can be detected using modified assays in some cases. Patients with IgA- and IgM-mediated anti-GBM disease are known to have negative circulating antibodies because conventional assays do not detect these classes of antibodies. A significant proportion of cases with atypical anti-GBM disease do not have any identifiable antibodies despite extensive evaluation. Nevertheless, extensive evaluation of atypical autoantibodies using modified assays and sensitive techniques should be attempted, if feasible. This review summarizes the recent literature on atypical anti-GBM disease.

A case report of atypical anti-glomerular basement membrane disease

Background

Anti-glomerular basement membrane (anti-GBM) disease is characterized by crescentic necrotizing glomerulonephritis, with linear deposits of immunoglobulin G (IgG) in the GBM. Classic anti-GBM disease is clinically associated with rapidly progressive glomerulonephritis with or without pulmonary hemorrhage. Some patients have a better renal prognosis and milder symptoms than those with classic anti-GBM disease, which is termed atypical anti-GBM disease.

Case presentation

A 43-year-old Japanese woman was admitted to our hospital complaining of hematuria that had persisted for more than one month. Serological examination revealed negativity for anti-nuclear, anti-neutrophilic cytoplasmic, and anti-GBM antibodies. However, renal biopsy showed cellular crescents. Immunofluorescence revealed strong diffuse linear capillary loop staining for IgG. An indirect immunofluorescence antibody method was performed by applying the patient serum to normal kidney tissue to confirm the presence of autoantibodies binding to the GBM. Using this method, anti-GBM antibodies were detected. The patient was treated with high-dose steroids, cyclophosphamide, and plasma exchange. Aggressive treatment resolved proteinuria and hematuria and improved renal function.

Conclusions

Renal biopsy is crucial in the diagnosis of anti-GBM disease, especially when serological tests are negative. Accurately identifying the presence of anti-GBM disease is important to initiate optimal treatment.

Great prognosis of concurrent anti-GBM disease and IgA nephropathy in a young woman: A case report

RATIONALE

The causal relationship between anti-glomerular basement membrane (anti-GBM) disease and immunoglobulin A (IgA) nephropathy is still unclear and cases of concurrent anti-GBM disease and IgA nephropathy are very rare, especially with a good prognosis and long-term follow-up. Here, we report a case of concurrent anti-GBM disease and IgA nephropathy. By using corticosteroids and cyclophosphamide in combination with plasmapheresis, the patient achieved a very good prognosis with complete normalization of renal function and complete disappearance of hematuria and proteinuria at the subsequent follow-up. To our knowledge, no previous case with such a long follow-up and such a good prognosis have been reported.

PATIENT CONCERNS

This case report describes a 26-year-old Chinese woman who presented with fever as the initial symptom, followed by dysmorphic hematuria, overt proteinuria and rapidly worsening renal function. Before admission, the patient received symptomatic supportive treatment such as intravenous albumin infusion, improvement of circulation, but the symptoms were not significantly improved.

DIAGNOSIS

Per the results of kidney biopsy, the patient was diagnosed with crescentic glomerulonephritis and anti-GBM disease with IgA nephropathy.

INTERVENTIONS

The key to obtain a good prognosis was the early application of corticosteroids and cyclophosphamide in combination with plasmapheresis to make the anti-GBM antibody turn negative quickly.

OUTCOMES

After 2 weeks of therapy, the patients' anti-GBM antibody turned negative and serum creatinine improved to a normal range. After 10 months, the patient's proteinuria level reached complete remission. After 12 months, the patient's hematuria had disappeared completely.

LESSONS

This case provides experience in the treatment of concurrent anti-GBM disease and IgA nephropathy and highlights the importance of early application of plasmapheresis and immunosuppressive therapy to obtain a good prognosis.

Epidemiology, Impact, and Management Strategies of Anti-Glomerular Basement Membrane Disease

Anti-glomerular basement membrane (anti-GBM) disease is a rare but serious autoimmune disease, which is characterized by the development of pathogenic antibodies to type IV collagen antigens in the glomerular and alveolar basement membranes. This results in rapidly progressive glomerulonephritis (GN), alveolar hemorrhage, or both. A variety of environmental factors can trigger the disease in genetically predisposed patients. Temporal associations with influenza, SARS-CoV-2 infection, and COVID-19 vaccination have been described although there is insufficient evidence to suggest causality. Anti-GBM disease accounts for approximately 20% of the cases of rapidly progressive GN cases secondary to crescentic GN, but is an uncommon cause of end-stage kidney disease. Early diagnosis by detection of circulating antibodies, increased awareness of atypical as well as complex clinical variants of the disease, and combined therapy with immunosuppression and plasma exchange has improved the prognosis of patients with this potentially fatal disease. Progress has been hampered by the rarity of anti-GBM disease, but new agents and therapeutic regimens are emerging.

Anti-glomerular Basement Membrane Disease: What Have We Learned?

Since the first clinicopathologic description by Ernest Goodpasture of a patient whom he considered to have died of influenza in 1919, substantial progress has been made in our knowledge of anti-glomerular basement membrane disease. This has led to a significant decrease in the morbidity and mortality associated with this disease. In this paper, we aim to review the literature that has enhanced our understanding of classic anti-glomerular basement membrane disease and its clinic-pathologic variants in the key areas of immunopathogenesis and histopathology. We also summarize varied clinical presentations and therapeutic strategies.

Goodpasture syndrome manifesting as nephrotic-range proteinuria with anti-glomerular basement membrane antibody seronegativity: A case report

RATIONALE

The Goodpasture syndrome is an extremely rare disease, with renal and pulmonary manifestations, and is mediated by anti-glomerular basement membrane (anti-GBM) antibodies. Renal pathological changes are mainly characterized by glomerular crescent formation and linear immunofluorescent staining for immunoglobulin G on the GBM. There are few reports on the atypical course of the syndrome involving serum-negative anti-GBM antibodies. Therefore, we present a case of Goodpasture syndrome that presented with nephrotic-range proteinuria and was seronegative for anti-GBM antibodies.

PATIENT CONCERNS

A 38-year-old Chinese man presented with a lung lesion that was discovered by physical examination a month prior to presentation. The chief concern was occasional hemoptysis without fever, cough, chest pain, and edema.

DIAGNOSES

Laboratory testing revealed that the urinary protein level and urine erythrocyte count were 7.4 g/24 hours and 144/high-power field (HPF), respectively. Serological testing for anti-GBM antibodies was negative. Chest computed tomography revealed multiple exudative lesions in both lungs, indicating alveolar infiltration and hemorrhage. Electronic bronchoscopy and pathological examination of the alveolar lavage fluid indicated no abnormalities. However, kidney biopsy suggested cellular crescent formation and segmental necrosis of the globuli, with linear IgG and complement C3 deposition on the GBM. These findings were consistent with the diagnosis of anti-GBM antibody nephritis.

INTERVENTIONS

The patient underwent 7 sessions of double filtration plasmapheresis. He was also administered with intravenous methylprednisolone and cyclophosphamide. After renal function stabilization, he was discharged under an immunosuppressive regimen comprising of glucocorticoids and cyclophosphamides.

OUTCOMES

Three months later, follow-up examination revealed that the 24-hour urine protein had increased to 13 g. Furthermore, the urine erythrocyte count was 243/HPF. After a 6-month follow-up, the patient achieved partial remission, with a proteinuria level of 3.9 g/24 hours and a urine erythrocyte count of 187/HPF.

LESSONS

This extremely rare case of Goodpasture syndrome manifested with seronegativity for anti-GBM antibodies and nephrotic-range proteinuria. Our findings emphasize the importance of renal biopsy for the clinical diagnosis of atypical cases. Furthermore, because renal involvement achieved only partial remission despite therapy, early detection and active treatment of the Goodpasture syndrome is necessary to improve the prognosis of patients.

Clinical-Pathological Features and Outcome of Atypical Anti-glomerular Basement Membrane Disease in a Large Single Cohort

Background: Atypical cases of anti-glomerular basement membrane (GBM) disease had absent circulating antibodies but linear IgG deposits along GBM in the kidneys. Herein, we reported the clinical-pathological features and outcome of these rare cases.

Methods: Linear IgG deposit along GBM were examined by immunofluorescence on renal specimens, with exclusion of diabetic kidney disease. Circulating anti-GBM antibodies were tested by commercial ELISA assay. Clinical, pathological and follow-up data were retrospectively analyzed.

Results: From 2013 to 2018, a total of 60 patients were diagnosed as atypical anti-GBM disease. They had a male predominance, with an average age of 51.7 ± 15.6 years. Three (5.0%) patients had alveolar hemorrhage. Forty five percent of them presented with acute kidney disease. All patients had linear IgG deposit along GBM, some in addition on tubular basement membrane and/or Bowmans' capsules. C3 deposition was found in 65.0% of the patients. 41.7% (25/60) of the patients showed crescent formation and the percentage of crescent was (34.7 ± 23.5)% in those patients. They had higher prevalence of hematuria and C3 deposit, higher levels of serum creatinine, worse renal and patient survival than those without crescent (P < 0.05). During the follow-up of 35.7 ± 21.4 months, 14 (23.3%) patients progressed to ESRD. The serum creatinine on diagnosis [per 200 μmol/L increase, HR (95% CI): 2.663 (1.372, 5.172), P = 0.004], serum C3 [per 0.1 g/L increase, HR (95% CI): 0.689(0.483, 0.984), P = 0.040] and the intensity of kidney C3 staining [per 1+ increase, HR (95% CI): 2.770 (1.115, 6.877), P = 0.028] were independent predictive factors for kidney outcome. Nine (15.0%) patients died of all causes.

Conclusions: Atypical anti-GBM disease manifested milder kidney injury and scarce pulmonary hemorrhage compared to the classical cases. Though heterogeneous, a substantial number of the patients had complement activation and crescent formation. Patients having crescents presented with more severe clinical course and worse outcomes. The poor kidney and patient prognosis emphasize prompt interventions from physicians. The immunosuppressive intervention was not associated with kidney or patient outcome. Further studies are needed to address the optimal therapeutic regimen.

Atypical Anti-Glomerular Basement Membrane Disease With Diffuse Crescentic Membranoproliferative Glomerulonephritis: Case Report and Review of Literature

Anti-glomerular basement membrane (anti-GBM) disease occurs in fewer than two cases per million population. Patients usually present with features of rapidly progressive glomerulonephritis (RPGN) with or without pulmonary involvement. Anti-GBM disease is classically diagnosed by both demonstrating GBM linear immunofluorescence staining on kidney biopsy and detecting anti-GBM antibodies in serum. More than 90% of patients with anti-GBM disease either become dialysis-dependent or die if left untreated.

Here, we report a 37-year-old man who presented with bilateral lower limb edema, hypertension, acute kidney injury (creatinine of 212 μmol/L), microscopic hematuria, and nephrotic range proteinuria (15 g/day). His kidney biopsy showed diffuse crescentic membranoproliferative glomerulonephritis and bright linear staining of GBM by immunoglobulin G consistent with anti-GBM disease; however, serum anti-GBM antibodies were negative. The patient was diagnosed with atypical anti-GBM disease and treated aggressively with intravenous pulse steroids, plasmapheresis, oral cyclophosphamide, and oral prednisolone with significant improvement in kidney function and proteinuria.

Atypical anti-GBM disease should be considered in patients presenting with RPGN, even in the absence of serum anti-GBM antibodies. Early diagnosis and aggressive treatment in such cases are warranted to prevent irreversible kidney damage as the course of the disease might not be as benign as previously thought.

Prognostic Factors in Anti-glomerular Basement Membrane Disease: A Multicenter Study of 119 Patients

We report the overall and renal outcome in a French nationwide multicenter cohort of 119 patients with anti-glomerular basement membrane (anti-GBM) disease. Sixty-four patients (54%) had an exclusive renal involvement, 7 (6%) an isolated alveolar hemorrhage and 48 (40%) a combined renal and pulmonary involvement. Initial renal replacement therapy (RRT) was required in 78% of patients; 82% received plasmapheresis, 82% cyclophosphamide, and 9% rituximab. ANCA positive (28%) patients were older (70 vs. 47 years, p < 0.0001), less frequently smokers (26 vs. 54%, p = 0.03), and had less pulmonary involvement than ANCA- patients. The 5 years overall survival was 92%. Risk factors of death (n = 11, 9.2%) were age at onset [HR 4.10 per decade (1.89-8.88) p = 0.003], hypertension [HR 19.9 (2.52-157 0.2) p = 0.005], dyslipidemia [HR 11.1 (2.72-45) p = 0.0008], and need for mechanical ventilation [HR 5.20 (1.02-26.4) p = 0.047]. The use of plasmapheresis was associated with better survival [HR 0.29 (0.08-0.98) p = 0.046]. At 3 months, 55 (46%) patients had end-stage renal disease (ESRD) vs. 37 (31%) ESRD-free and 27 (23%) unevaluable with follow-up < 3 months. ESRD patients were older, more frequently female and had a higher serum creatinine level at presentation than those without ESRD. ESRD-free survival was evaluated in patients alive without ESRD at 3 months (n = 37) using a landmark approach. In conclusion, this large French nationwide study identifies prognosis factors of renal and overall survival in anti-GBM patients.

Seronegative atypical anti-glomerular basement membrane crescentic glomerulonephritis

A 46-year-old female presented with a chief complaint of fatigue and intermittent painless gross hematuria for one month. The patient was fluid overloaded on physical examination and noted to be in acute renal failure with a serum creatinine of 10.8 mg/dL. The patient was emergently started on hemodialysis. Serologies were negative for antinuclear antibody (ANA), anti-neutrophilic cytoplasmic antibody (ANCA), and anti-glomerular basement membrane (anti-GBM) antibody. However, renal biopsy revealed 90% glomerular involvement by temporally heterogeneous crescents ranging from cellular to fibrous. Immunofluorescence studies revealed strong, linear glomerular capillary wall staining for immunoglobulin G (IgG). Although the patient was treated with pulse dose steroids and cyclophosphamide, the patient ultimately developed infectious complications from immunosuppression, and treatment was terminated. This case highlights the atypical presentation of anti-GBM disease diagnosed based on renal biopsy with negative serologies. Although rare, the possibility of atypical anti-GBM antibodies which are not detected by standard commercial assays should be considered in such cases.