Nephropathology
   
Case 89
Diagnosis
 
     
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Diagnosis: Immune complexes mediated membranoproliferative glomerulonephritis

Whereas early classifications of glomerulonephritis (GN) were based on morphologic features, the modern approach is directed at immunofluorescence findings. In the present case the histological features are characteristics of "type I" membranoproliferative GN (MPGN) and there are Igs (IgG and IgM) and complement fractions C3 and C1q. Although we usually divide MPGN in types I, II and III according to morphological features, it now seems more important to determine whether there are immune complexes or only C3. Glomerular deposits of C3 alone, without immunoglobulins, are the hallmark of alternative complement pathway dysregulation through inherited or acquired defects. These immunoglobulin-negative forms are referred to as C3 glomerulopathy, which encompasses both dense deposit disease and C3 glomerulonephritis. Distinguishing C3 glomerulopathy from immunoglobulin-mediated GN is opening the way to better diagnostic, prognostic, and treatment algorithms (D'Agati VD, Bomback AS. C3 glomerulopathy: what's in a name? Kidney Int. 2012;82(4):379-81. [PubMed link])

MPGN can be subdivided into idiopathic and secondary types. The secondary types are more common than the idiopathic types and are diagnosed by carefully reviewing clinical features, laboratory data, and renal histopathology.

Immune complexes mediated GN can be secondary to autoimmune diseases, chronic infections, cryoglobulinemia, and malignant neoplasms. Idiopathic forms of membranoproliferative glomerulonephritis or of unknown association include cases with immune complexes glomerular deposition.

Idiopathic MPGN is a diagnosis of exclusion, at least in many adults and a portion of children, and a systematic approach to evaluation will often uncover a secondary cause, such as an infection, autoimmune disease, monoclonal gammopathy, neoplasia, complement dysregulation or a chronic thrombotic microangiopathy. Idiopathic MPGN remains an 'endangered species' after its separation from these known causes (Fervenza FC, et al. Idiopathic membranoproliferative glomerulonephritis: does it exist? Nephrol Dial Transplant. 2012;27:4288-94. [PubMed link]).

See the chapter Membranoproliferative Glomerulonephritis of our tutorial.

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References

  • Lu Y, Shen P, Li X, Xu Y, Pan X, Wang W, Chen X, Zhang W, Ren H, Chen N. Re-evaluation of the classification system for membranoproliferative glomerulonephritis. Contrib Nephrol. 2013;181:175-84. [PubMed link]
  • Kawamura T, Usui J, Kaseda K, Takada K, Ebihara I, Ishizu T, Iitsuka T, Sakai K, Takemura K, Kobayashi M, Koyama A, Kanemoto K, Sumazaki R, Uesugi N, Noguchi M, Nagata M, Suka M, Yamagata K. Primary membranoproliferative glomerulonephritis on the decline: decreased rate from the 1970s to the 2000s in Japan. Clin Exp Nephrol. 2013;17(2):248-54. [PubMed link]
  • Takei T, Itabashi M, Moriyama T, Shimizu A, Tsuruta Y, Ochi A, Nakayama K, Iwasaki C, Uchida K, Nitta K. Positive C1q staining associated with poor renal outcome in membranoproliferative glomerulonephritis. Clin Exp Nephrol. 2013;17(1):92-8. [PubMed link]
  • Fervenza FC, Sethi S, Glassock RJ. Idiopathic membranoproliferative glomerulonephritis: does it exist? Nephrol Dial Transplant. 2012;27(12):4288-94. [PubMed link]
  • Appel GB. Membranoprolferative glomerulonephritis - mechanisms and treatment. Contrib Nephrol. 2013;181:163-74. [PubMed link]

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