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Arai M, Mii A, Hirama A, Kaneko T, Kashiwagi T, Shimizu A, Sakai Y. A possible role of classical complement pathway activation in the pathogenesis of immunoglobulin G nephropathy: a case report. CEN Case Rep 2023; 12:14-22. [PMID: 35711019 PMCID: PMC9892394 DOI: 10.1007/s13730-022-00710-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 05/24/2022] [Indexed: 02/05/2023] Open
Abstract
Immunoglobulin G (IgG) nephropathy refers to a rare group of diseases characterized by deposits of IgG in the mesangial region. However, IgG nephropathy is controversial as a single disease entity, and its pathogenesis remains to be elucidated. In the present report, we discuss a case of IgG nephropathy in which we observed activation of the classical complement pathway.A 47-year-old woman was admitted to our hospital with nephrotic syndrome. Light-microscopic examination revealed neither proliferative nor sclerotic lesions in the glomeruli. However, unusual and large deposits were observed in the paramesangial area. An immunofluorescence study revealed predominant IgG and C1q and slight C3 deposits in the paramesangial area, suggesting immune-complex-type glomerular disease. An electron microscopic study also revealed different sizes of non-organized electron-dense deposits with a similar pattern of distribution, which were accompanied by foot process effacement. Clinically, there was no evidence of systemic diseases, such as infectious or autoimmune diseases (including systemic lupus erythematosus). Based on these findings, she was diagnosed with IgG nephropathy and treated with prednisolone. Steroid therapy was effective, and complete remission was maintained.Additional immunological examination revealed that IgG deposits were polyclonal and consisted mainly of the IgG1 and IgG3 subclasses. Furthermore, staining was positive for C4d and C5b-9. The present findings indicate that the pathogenesis of IgG nephropathy in our patient may have involved activation of the classical complement pathway.
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Affiliation(s)
- Momoko Arai
- Department of Nephrology, Nippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan
| | - Akiko Mii
- Department of Nephrology, Nippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan.
| | - Akio Hirama
- Department of Nephrology, Nippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan
| | - Tomohiro Kaneko
- Department of Nephrology, Nippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan
| | - Tetsuya Kashiwagi
- Department of Nephrology, Nippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan
| | - Akira Shimizu
- Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - Yukinao Sakai
- Department of Nephrology, Nippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan
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Yang J, Zhang BL. [Advances in clinical research on C1q nephropathy]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2016. [PMID: 27817791 DOI: 10.7499/j.issn.1008-8830.2016.11.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
C1q nephropathy is a rare type of glomerulonephritis manifested as the deposition of C1q in the glomerular mesangium during immunofluorescent staining. Systemic lupus erythematosus and type I membranoproliferative glomerulonephropathy need to be excluded in the diagnosis of C1q nephropathy. C1q nephropathy has various manifestations under a light microscope, mainly including minimal change disease, focal segmental glomerulosclerosis, and proliferative glomerulonephritis. This disease is mainly manifested as persistent proteinuria or nephrotic syndrome and occurs more frequently in boys. Currently, glucocorticoids are mainly used for the treatment of this disease. Patients with C1q nephropathy show a good response to immunosuppressant treatment, but have a high rate of glucocorticoid resistance. Therefore, in this case, methylprednisolone pulse therapy or a combination with immunosuppressant treatment helps to achieve a good prognosis.
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Affiliation(s)
- Juan Yang
- Department of Nephrology, Tianjin Children's Hospital, Tianjin 300074, China.
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