Membranoproliferative glomerulonephritis classification

Like many forms of glomerulopathies, membranoproliferative glomerulonephritis (glomerulopathy) has been a diagnosis of tissue pathology rather the diagnosis of a specific disease entity. Therefore the term membranoploriferative glomerulonephritis (MPGN) relates to a pattern of glomerular injury which can be caused by many disease states. Historically the nephropathologists divided MPGN into 3 distinctive categories to shed light into what may be causing this type of kidney injury: MPGN type 1: mesangial and subendothelial electron dense deposits MPGN type 2: electron dense material in the glomerular basement membrane MPGN type 3: subepithelial deposits with basement membrane spikes This categorization, however is now out of date. The recognition of several new disorders as the underlying cause of MPGN, and the lack of clinical, prognostic or therapeutic relevance made this categorization less useful. For completeness and to help better accommodate the transition from old to new classification, below both classifications are reviewed. Classification of MPGN based on immunofluorescence microscopy is a result of all advances in the understanding of the pathogenesis of the disease. Based on this advanced techniques, there are three types of MPGN ^[1]:Immune-complex-mediated MPGN (Type I) ,Complement-mediated MPGN (Type II), Non-Ig/complement-mediated MPGN (Type III)

MPGN can be classified three types based on immunofluorescence microscopy techniques . ^[2];

• Immune-complex-mediated MPGN (Type I)
• Complement-mediated MPGN (Type II)
• Non-Ig/complement-mediated MPGN (Type III)

It is the most common type.

• Circulating immune complexes are present in approximately 33% .
• Immune complexes are found in the mesangium and subendothelial spaces.

• Dense deposits are observed in MPGN type II.
• Complement mediated

• They are continuous, dense ribbon along the basement membranes of the glomeruli, tubules, and Bowman’s capsule .

Type III is very rare

• It is characterized by a combination of subepithelial deposits, deposits in the mesangium and subendothelial space.
• There is complex disruption of the glomerular basement membrane with large lucent area.

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