Crescentic glomerulonephritis due to linear IgA anti-glomerular basement membrane disease: report of a rare case.

Anti-glomerular basement membrane (GBM) disease is a rare and severe vasculitis that affects the glomerular and pulmonary capillaries and has an incidence of less than 2 cases per million individuals per year. Anti-GBM disease is mediated by autoantibodies against the α3 chain of type IV collagen. In the majority of cases, the autoantibodies are of the immunoglobulin G (IgG) class, with rare cases being mediated by immunoglobulin M (IgM) or immunoglobulin A (IgA); there are less than 15 IgA-mediated cases reported in the literature worldwide. The classic form of this disease manifests with rapidly progressive glomerulonephritis (RPGN), with or without pulmonary hemorrhage, and the diagnosis consists of identifying high titers of autoantibodies in the serum and/or deposited in the tissues. IgA antibodies are not identified in routine immunoassay tests, and renal biopsy with immunofluorescence is essential for diagnosis. We present a case of RPGN due to anti-GBM disease with linear IgA deposition, whose diagnosis was made exclusively by renal biopsy and with an unfavorable prognosis.

Atypical anti-glomerular basement membrane disease with membranous hyperplasia: diagnostic challenges and treatment variability.

This case report presents a detailed analysis of a 31-year-old male patient who presented with a complex array of clinical symptoms, including proteinuria, hematuria, edema, and kidney insufficiency. Despite undergoing multiple tests, the results for anti-glomerular basement membrane antibodies yielded negative findings. Subsequently, kidney biopsy pathology revealed a distinct diagnosis of atypical anti-glomerular basement membrane (anti-GBM) disease with membrane hyperplasia. Treatment was initiated with a comprehensive approach involving high doses of corticosteroids therapy and cyclophosphamide (CTX). However, contrary to expectations, the patient's kidney function exhibited rapid deterioration following this therapeutic regimen. The culmination of these complications necessitated a pivotal transition to maintenance hemodialysis. This case underscores the intricate challenges associated with diagnosing and managing rare and atypical presentations of kidney disorders. The negative anti-GBM antibody results and subsequent identification of atypical anti-GBM nephropathy highlight the need for tailored diagnostic strategies to discern subtle nuances within complex clinical scenarios. Additionally, the unexpected response to the treatment regimen emphasizes the potential variability in individual patient responses, underlining the necessity for vigilant monitoring and adaptable treatment strategies. This case report contributes to the evolving understanding of atypical kidney pathologies and the complexities involved in their management.

Coexistence of anti-glomerular basement membrane disease and IgA nephropathy: an illustrative case and comprehensive literature review.

Anti-glomerular basement membrane (GBM) disease is a rare autoimmune condition characterized by the presence of positive anti-GBM autoantibodies, linear deposition of immunoglobulin G (IgG) along the GBM and severe kidney injury. In a limited number of cases, the association of anti-GBM disease with other glomerulonephritis has been reported. Herein, we present the case of a 66-year-old female patient with progressive worsen kidney function and decreased urine output. A renal biopsy revealed crescent glomerulonephritis with lineal IgG deposition along the GBM and mesangial IgA deposition, which supported the diagnosis of concurrent anti-GBM disease and IgA nephropathy (IgAN). In an extensive literature review, we identified a total of thirty-nine patients were reported anti-GBM disease combined with IgAN. The clinical characteristics of these patients demonstrate that the anti-GBM disease combined with IgAN tends to be milder with a more indolent course and a better prognosis than the classic anti-GBM disease, and its potential pathogenesis deserves to be further explored.

Goodpasture syndrome: a rare case presenting with recurrent haemoptysis.

Goodpasture syndrome is a rare autoimmune disease which affects young adults with a male preponderance and can be triggered at any point in life with a classical clinical triad of rapidly progressive glomerulonephritis, diffuse pulmonary haemorrhage and circulating anti-glomerular basement membrane antibody (anti-GBM antibody). Here we are presenting a case of a young man with hypertension in his early 20s who presented with fatigue, recurrent haemoptysis, breathlessness and decreased urine output without features of infection. He was diagnosed at an early stage of the disease with the help of clinical, serological and radiological findings. An early diagnosis with effective treatment using plasma exchange, intravenous high-dose methylprednisolone, and cyclophosphamide showed a rapid improvement in the patient's condition with an immediate decrease in anti-GBM titres and proteinuria.

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.

An Unusual Case of Anti-Glomerular Basement Membrane Disease and Phospholipase A2 Receptor-Associated Membranous Nephropathy After Exposure to Hydrocarbons.

We present a rare case of a patient with toluene exposure manifesting as anti-glomerular basement membrane (GBM) disease on a background of phospholipase A2 receptor (PLA2R)-associated membranous nephropathy. A 23-year-old man presented to the emergency department with hypertension, headache, hemoptysis, anemia, acute kidney injury, glomerular hematuria, and proteinuria. He endorsed repeated exposure to toluene-containing products while repairing dirt bikes. Serologies were positive for anti-GBM antibodies. Kidney biopsy showed crescentic glomerulonephritis with linear immunoglobulin G and granular PLA2R staining by immunofluorescence. He was initially treated with high-dose steroids, plasmapheresis, and hemodialysis for pulmonary-renal syndrome followed by oral cyclophosphamide and prednisone, which were discontinued after 3 months when follow-up biopsies confirmed little chance for renal recovery. He remained on dialysis 1 year later. This case exhibits a unique presentation of anti-GBM syndrome and underlying membranous nephropathy following repeated hydrocarbon exposure. Inhaled toxins promote recurrent localized inflammation, unmasking previously hidden epitopes. Early diagnosis and appropriate use of immunosuppressive and extracorporeal therapies are necessary to prevent morbidity and to improve survival in this rare condition.

Atypical form of Goodpasture's disease.

Goodpasture's disease and anti-glomerular basement membrane nephritis (anti-GBM nephritis) are rare autoimmune small vessel vasculitis predominantly affecting young men. Goodpasture's disease plays an important part in differential diagnosis of pulmonary - renal syndrome. The evidence of circulating autoantibodies, a typical histological appearance of the kidney biopsy with finding of the crescent glomerulonephritis and clinical presentation of nephritic syndrome play an important role in diagnosis. Our case report describes a case of a young male with anti-GBM nephritis that presents as rapidly progressive glomerulonephritis (RPGN) with progression to dialysis-dependent renal failure. The atypical sign of the case was development of nephrotic syndrome with volume-dependent hypertension. The case was complicated by heparin-induced thrombocytopenia. During combined immunosuppressive therapy with plasmapheresis, the condition of the patient has stabilized. However, renal function did not recover. This previously fatal disease has nowadays a very good survival rate because of immunosuppresion therapy, plasmapheresis and hemodialysis.

Goodpasture syndrome and anti-glomerular basement membrane disease.

Anti-glomerular basement membrane (anti-GBM) disease is a rare life-threatening small vessel vasculitis that typically affects the capillaries of kidneys and lungs, with most of patients developing rapidly progressive crescentic glomerulonephritis, and 40%-60% concomitant alveolar haemorrhage. It is caused by the deposition in alveolar and glomerular basement membrane of circulating autoantibodies directed against antigens intrinsic to the basement membrane. The exact mechanism that induces the formation of autoantibodies is unknown, but probably environmental factors, infections or direct damage to kidneys and lungs may trigger the autoimmune response in genetically susceptible individuals. Initial therapy includes corticosteroids and cyclophosphamide to prevent autoantibodies production, and plasmapheresis to remove the circulating autoantibodies. Good renal outcomes may be achieved by a prompt treatment initiation. However, when patients present with severe renal failure requiring dialysis or with a high proportion of glomerular crescents at biopsy, renal outcomes are bad. Relapses are rare and when renal involvement is present, the suspect of concomitant diseases, such as ANCA-associated vasculitis and membranous nephropathy, should be raised. Imlifidase is showing promising results, which if confirmed will cause a paradigm shift in the treatment of this disease.

An atypical anti-GBM disease complicated by idiopathic nodular glomerulosclerosis: Case report.

Both atypical anti-glomerular basement membrane (anti-GBM) disease and idiopathic nodular glomerulosclerosis are rare diseases. We report a case of a 53-year-old non-diabetic male who presented with leg edema, nephritic range proteinuria, microscopic hematuria, and decreased renal function. The renal biopsy demonstrated membranoproliferative glomerulonephritis (MPGN) pattern of glomerular injury with focal crescent and segmental nodular glomerulosclerosis. The immunofluorescence studies showed intense linear IgG (IgG1 and IgG4) deposits along the GBM but negative serology. Electron microscopy demonstrated GBM thickening and fibrillar deposition. The presence of MPGN with crescents and the linear IgG along the GBM were consistent with a diagnosis of atypical ant-GBM disease. Superimposed nodular glomerulosclerosis was considered to be idiopathic by excluding other glomerular diseases characterized by fibrillar deposition and nodular glomerulosclerosis. Both diseases were found to have a strong causative association with patient's history of long-term heavy smoking. This unusual case with combination of atypical anti-GBM disease and idiopathic nodular glomerulosclerosis, has brought great challenge for the diagnosis and also made the clinical course highly complicated. This nodular glomerulosclerosis with anti-GBM-like glomerulonephritis may represent a distinct pattern of kidney injury observed in heavy smokers.

Clinical features and prognosis of MPO-ANCA and anti-GBM double-seropositive patients.

Background: Several lines of evidence implicate that there are distinct differences between patients with myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody (ANCA) and anti-glomerular basement membrane (GBM) antibody double-seropositive patients (DPPs) and single-positive patients. Hence, we conducted a retrospective study from a single center in China to analyze the clinical and pathological features, and prognosis of DPPs. Methods: 109 patients with MPO-ANCA-associated vasculitis (MPO-AAV), 20 DPPs and 23 patients diagnosed with anti-GBM disease from a large center in China were included in this study. The ratio of patients with renal biopsy in three groups were 100%, 50% and 100%, respectively. Their clinical and pathological characteristics, and outcomes were analyzed. The intensity of immune deposits in the kidney at diagnosis was detected by immunofluorescence (IF). Furthermore, multivariate Cox hazard model analysis was used to assess the clinical and histological predictors of end-stage renal disease (ESRD) and death for DPPs. Results: In our study, we found that patients in the DPPs group were older than the other two groups (p = 0.007, MPO-AAV vs. DPPs; p < 0.001, DPPs vs. anti-GBM). The DPPs group had a higher value of serum creatinine (p = 0.041) and lower estimated glomerular filtration rate (eGFR) (p = 0.032) compared with MPO-AAV patients. On the contrary, the DPPs group had a lower serum creatinine (p = 0.003) compared with patients with anti-GBM group. The proportion of patients with cardiac system involvement in the DPPs group was higher than anti-GBM patients (p = 0.014). Cellular crescents could be generally observed in renal biopsy of DPPs and patients with anti-GBM glomerulonephritis. In addition, Bowman's capsule rupture was more common in DPPs than MPO-AAV patients (p = 0.001). MPO-AAV had a better renal and overall survival outcome than DPPs (p < 0.001). There was no significant difference of renal and overall survival outcome between DPPs and patients with anti-GBM disease. The incidence of ESRD in DPPs was negatively associated with lymphocyte count (HR 0.153, 95% CI 0.027 to 0.872, p = 0.034) and eGFR (HR 0.847, 95% CI 0.726 to 0.989, p = 0.036). Elevated serum creatinine was confirmed as a risk factor of both renal (HR 1.003, 95% CI 1.000 to 1.005, p = 0.019) and patient survival in DPPs (HR1.461, 95% CI 1.050 to 2.033, p = 0.024). Conclusion: In summary, compared with anti-GBM disease, DPPs tended to involve multi-organ damage rather than limited to the kidney. It is highlighted that serologic DPPs have a worse renal and patient prognosis than MPO-AAV. Moreover, we found that the risk factors of renal survival of DPPs include low lymphocyte count, elevated serum creatinine and reduced eGFR, and serum creatinine can predict patient survival.

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.

A unique case of anti-GBM disease with concomitant anti-PLA2R positivity.

BACKGROUND: Concomitant occurrence of anti-GBM disease and anti-PLA2R positive membranous nephropathy have been previously described. However, to the best of our knowledge, this is the first case report that documents the co-occurrence of the diseases proven by both serologic and histologic methods. CASE PRESENTATION: A 51-year-old woman presented to hospital with nausea, bilateral lower extremity edema, dyspnea, dark urine, and then anuria. Symptoms developed one month after an upper respiratory tract infection. Laboratory results showed acute kidney injury, and hypoalbuminemia. Immunologic examination revealed both anti-GBM and anti-PLA2R positivity. Kidney biopsy demonstrated the histological features of Goodpasture's disease and anti-PLA2R positive membranous nephropathy. Steroid, cyclophosphamide, and plasmapheresis were commenced. Despite the combined immunosuppressive, the patient remained on renal replacement therapy. CONCLUSIONS: Microbial kidney injury can trigger multiple autoimmune diseases. The simultaneous occurrence of anti-glomerular basement (anti-GBM) disease and membranous nephropathy is extremely rare. Delayed recognition leads to delayed treatment, causing worse renal and patient outcomes, as well as increased financial costs.

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.

Acquired aplastic anemia complicated with anti-glomerular basement membrane disease successfully treated with immunosuppressive therapy: a case report.

BACKGROUND: Aplastic anemia (AA) is a rare but fatal disorder characterized by pancytopenia due to bone marrow hypoplasia. Anti-glomerular basement membrane disease (anti-GBM disease) is an immune complex small-vessel vasculitis that presents as rapidly progressive glomerulonephritis and/or pulmonary hemorrhage. Although both involve autoreactive T cells that are partially triggered by human leukocyte antigen (HLA)-DR15, there have been no reports of their co-existence and the treatment strategy is not well understood. CASE PRESENTATION: A 67-year-old woman presented with fever, malaise, and acute kidney injury with proteinuria and hematuria requiring hemodialysis. She was diagnosed with anti-GBM antibody disease based on high serum anti-GBM antibody titer and crescentic glomerulonephritis on a renal biopsy. Pulse administration of methylprednisolone (MP), oral prednisolone (PSL), and plasmapheresis were performed. Only 2 weeks after the diagnosis of anti-GBM disease, the patient developed pancytopenia requiring frequent blood transfusions. The blood cell count did not recover even 1 month after discontinuing the drugs that could cause pancytopenia. Bone marrow examination showed hypocellularity without abnormal infiltrates or fibrosis, which led to the diagnosis of severe acquired AA. Further HLA phenotyping revealed that she had HLA-DR15. Increased dose of PSL with the secondary MP pulse and the addition of cyclosporine improved pancytopenia. Although she remained dialysis-dependent, anti-GBM disease and pancytopenia did not recur for more than 2 years. CONCLUSIONS: We report the first case of acquired AA complicated with anti-GBM disease in an elderly woman with HLA-DR15, which was successfully treated with immunosuppressive therapy (IST). This report is valuable not only because it shows they may co-occur, but also because it provides a therapeutic option for this complex condition. It was also suggested that pancytopenia in patients with anti-GBM disease recalls serious hematologic diseases including AA that require immediate treatment based on bone marrow examination.

Anti-glomerular basement membrane disease with intense nephrotic syndrome: a new case report.

Anti-glomerular basement membrane (anti-GBM) disease was usually described as a small vessel vasculitis presenting with acute kidney injury, haematuria and non-nephrotic proteinuria. We report a case of anti-GBM disease revealed by an intense nephrotic syndrome. The urinary protein level was 12g/day. Renal biopsy only showed crescent glomerulonephritis with linear staining of IgG in direct immunofluorescence without other glomerulonephritis. Immunoglobulin G (IgG) anti-GBM antibody titer was elevated.

Accuracy of Anti-GBM Antibodies in Diagnosing Anti-Glomerular Basement Membrane Disease: A Systematic Review and Meta-Analysis.

BACKGROUND: The sensitivity and specificity of anti-glomerular basement membrane (GBM) antibodies have not been systematically analyzed. In this systematic review, we aimed to evaluate the diagnostic accuracy of anti-GBM antibodies for anti-GBM disease. SUMMARY: Potential studies were searched using MEDLINE, Embase, the Cochrane Library, and the International Clinical Trials Registry Platform based on the index test and target condition. The inclusion criteria were prospective or retrospective cohort studies or case-control studies assessing the sensitivity and specificity of anti-GBM antibodies, and the reference standard was clinical diagnosis including biopsy results. The exclusion criteria were review articles, case reports, animal studies, and in vitro studies. Quality assessment was conducted based on the Quality Assessment of Diagnostic Accuracy Studies-2. The pooled estimates of sensitivity and specificity were calculated using a bivariate random-effects model. The overall quality was evaluated using the Grades of Recommendation, Assessment, Development, and Evaluation. Six studies (1,691 patients) and 11 index tests were included in our systematic review. A high risk of bias and concerns regarding the applicability of patient selection were noted because of the case-control design in 67% of the included studies. The pooled sensitivity and specificity were 93% (95% CI: 84-97%) and 97% (95% CI: 94-99%), respectively. The certainty of evidence was low because of the high risk of bias and indirectness. Key Messages: Anti-GBM antibodies may exhibit high sensitivity and specificity in the diagnosis of anti-GBM disease. Further cohort studies are needed to confirm their precise diagnostic accuracy and compare diagnostic accuracies among different immunoassays.

Anti-glomerular basement membrane disease and IgA nephropathy in a patient with previous renal cell carcinoma.

A 66-year-old Asian woman presented with severe kidney injury, microscopic haematuria and subnephrotic range proteinuria with elevated serum anti-glomerular basement membrane (anti-GBM) titre. She had a history of renal cell carcinoma. Renal biopsy revealed dual pathology with immunofluorescence showing 3+ linear glomerular IgG staining and 3+ IgA mesangial staining. Cellular crescents were present on light microscopy and electron microscopy revealed increased mesangial matrix. She was treated with plasma exchange and immunosuppression and remained in stage 4 chronic kidney disease. This case describes the coexistence of anti-GBM disease and IgA nephropathy, a phenomenon not well described in the literature. The report also explores the association of malignancy and glomerulonephritis as well as the role of genetics and the utility of human leukocyte antigen (HLA) typing in risk stratification.

Anti-glomerular basement membrane disease associated with thin basement membrane nephropathy: A case report.

RATIONALE: Simultaneous occurrence of anti-glomerular basement membrane (anti-GBM) disease and thin basement membrane nephropathy (TBMN), both of which invade the type IV collagen subunits, is very rare. Here, we present the case of a 20-year-old male patient diagnosed with both anti-GBM disease and TBMN upon presenting dyspnea and hemoptysis. PATIENT CONCERNS: No laboratory abnormalities, except arterial hypoxemia (PaO275.4 mmHg) and microscopic hematuria, were present. Chest computed tomography revealed bilateral infiltrations in the lower lung fields; thus, administration of empirical antibiotics was initiated. Gross hemoptysis persisted nonetheless, and bronchoscopy revealed diffuse pulmonary hemorrhage with no endobronchial lesions. Broncho-alveolar lavage excluded bacterial pneumonia, tuberculosis, and fungal infection. DIAGNOSIS: Enzyme-linked immunosorbent assay of his serum was positive for anti-GBM antibody (95.1 U/mL). Human leukocyte antigen (HLA) test was positive for both HLA-DR15/-DR04. Other than diffuse thinning of the GBM (average thickness, 220 nm), index kidney biopsy did not demonstrate any specific abnormalities such as crescent formation. INTERVENTIONS: Methylprednisolone was administered intravenously for 7 consecutive days (500 mg/day), followed by the daily dose of oral prednisolone (80 mg). Cyclophosphamide was also orally administered every day for 3 months (250 mg/day). Following 6 sessions of plasmapheresis, the anti-GBM antibody in serum became negative. OUTCOMES: There was no clinical evidence suggesting recurrence of pulmonary hemorrhage or azotemia during hospitalization and 12-month follow-up period. Twelve months after hospital discharge, oral prednisolone was discontinued. LESSONS: The patients with concurrent anti-GBM disease and TBMN will have a favorable prognosis after proper therapy. However, further research is needed to elucidate the pathogenesis and long-term outcome of the comorbidity of these 2 diseases.

Atypical anti-glomerular basement membrane disease with anti-GBM antibody negativity and ANCA positivity: a case report.

BACKGROUND: Anti-glomerular basement membrane (anti-GBM) disease is an organ-specific autoimmune disease that involves the lung and kidneys and leads to rapid glomerulonephritis progression, with or without diffuse alveolar hemorrhage, and even respiratory failure. Classic cases of anti-GBM disease are diagnosed based on the presence of the anti-GBM antibody in serum samples and kidney or lung biopsy tissue samples. However, atypical cases of anti-GBM disease are also seen in clinical practice. CASE PRESENTATION: We herein report the rare case of a patient with atypical anti-GBM disease whose serum was negative for the anti-GBM antibody but positive for the myeloperoxidase (MPO) anti-neutrophil cytoplasmic antibody (p-ANCA) and another atypical ANCA. Laboratory test results showed severe renal insufficiency with a creatinine level of 385 µmol/L. Renal biopsy specimen analysis revealed 100% glomeruli with crescents; immunofluorescence showed immunoglobulin G (IgG) linearly deposited alongside the GBM. Finally, the patient was discharged successfully after treatment with plasmapheresis, methylprednisolone and prednisone. CONCLUSION: This patient, whose serum was negative for the anti-GBM antibody but positive for p-ANCA and another atypical ANCA, had a rare case of anti-GBM disease. Insights from this unusual case might help physicians diagnose rare forms of glomerulonephritis and treat affected patients in a timely manner.