Publicação
Membranous Nephropathy as a Manifestation of IgG4‑Related Disease (IgG4‑RD): A Case Report
| Resumo: | Abstract IgG4‑related disease (IgG4‑RD) is an immune‑mediated, inflammatory condition that can affect multiple organs, marked by lymphoplasmocytic infiltration and IgG4‑positive plasma cells. Elevated serum IgG4 is common but not essential. Sole renal manifestation is rare, usually appearing as tubulointerstitial nephritis (TIN) or, less commonly, membranous nephropathy (MN). We present a case of an 87‑year‑old man with a medical history of hypertension, dyslipidemia, ischemic cardiomyopathy, and COPD. The patient presented with nephrotic syndrome (proteinuria/creatininuria ratio (P/C ratio) of 11 g/g) and acute kidney injury (creatinine 4 mg/dL). Urinalysis indicated proteinuria and haematuria without dysmorphic erythrocytes. Investigation revealed normochromic normocytic anaemia, hypoalbuminemia, and no evidence of monoclonal gammopathy or hypocomplementemia. Serologies for HIV, hepatitis B, and hepatitis C were negative. Antinuclear, anti‑neutrophil, and anti‑phospholipase A2 antibodies (anti‑PLA2r) were also negative. Treatment including anti‑proteinuric and anticoagulation therapies was initiated. Kidney biopsy displayed membranous nephropathy and interstitial nephritis; immunofluorescence showed parietal granular deposits of IgG‑κ and IgG‑λ; immunohistochemistry revealed lymphocytes, plasma cells (with more than 10 IgG4‑positive cells per high‑power field), and IgG4 deposits on the glomerular basement membrane. Serum IgG subclass levels detected a slight elevation of IgG4. Other organ involvements hinting at IgG4‑RD were ruled out. Assuming IgG4‑RD with renal involvement therapy with prednisolone (40 mg/day) was started and after one month the patient demonstrated a significant improvement in kidney function, anaemia, hypoalbuminemia, and proteinuria. Although renal manifestation as the first and/or only manifestation of IgG4‑RD is rare, should be suspected in renal cases showing MN with or without TIN, especially when anti‑PLA2R is negative. |
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| Autores principais: | Quaresma,Marta |
| Outros Autores: | Cunha,Teresa Stock da; Ferreira,Joel; Góis,Mário; Azevedo,Ana |
| Assunto: | Glomerulonephritis, Membranous Immunoglobulin G4‑Related Disease |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | relatório |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Fundação para a Ciência e Tecnologia |
| Idioma: | inglês |
| Origem: | SciELO Portugal |
| Resumo: | Abstract IgG4‑related disease (IgG4‑RD) is an immune‑mediated, inflammatory condition that can affect multiple organs, marked by lymphoplasmocytic infiltration and IgG4‑positive plasma cells. Elevated serum IgG4 is common but not essential. Sole renal manifestation is rare, usually appearing as tubulointerstitial nephritis (TIN) or, less commonly, membranous nephropathy (MN). We present a case of an 87‑year‑old man with a medical history of hypertension, dyslipidemia, ischemic cardiomyopathy, and COPD. The patient presented with nephrotic syndrome (proteinuria/creatininuria ratio (P/C ratio) of 11 g/g) and acute kidney injury (creatinine 4 mg/dL). Urinalysis indicated proteinuria and haematuria without dysmorphic erythrocytes. Investigation revealed normochromic normocytic anaemia, hypoalbuminemia, and no evidence of monoclonal gammopathy or hypocomplementemia. Serologies for HIV, hepatitis B, and hepatitis C were negative. Antinuclear, anti‑neutrophil, and anti‑phospholipase A2 antibodies (anti‑PLA2r) were also negative. Treatment including anti‑proteinuric and anticoagulation therapies was initiated. Kidney biopsy displayed membranous nephropathy and interstitial nephritis; immunofluorescence showed parietal granular deposits of IgG‑κ and IgG‑λ; immunohistochemistry revealed lymphocytes, plasma cells (with more than 10 IgG4‑positive cells per high‑power field), and IgG4 deposits on the glomerular basement membrane. Serum IgG subclass levels detected a slight elevation of IgG4. Other organ involvements hinting at IgG4‑RD were ruled out. Assuming IgG4‑RD with renal involvement therapy with prednisolone (40 mg/day) was started and after one month the patient demonstrated a significant improvement in kidney function, anaemia, hypoalbuminemia, and proteinuria. Although renal manifestation as the first and/or only manifestation of IgG4‑RD is rare, should be suspected in renal cases showing MN with or without TIN, especially when anti‑PLA2R is negative. |
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