Immunofluorescence
Membranous nephropathy
- Subepithelial (aka on basement membrane) deposits of IgG and C3 (dense deposits) → spike and dome appearance
Minimal change disease
- EM: effacement of podocyte foot processes
Renal amyloidosis
Poststreptococcal glomerulonephritis
Characteristic by granular (lumpy-bumpy) pattern of staining of the GBM
Membranoproliferative glomerulonephritis
Type I MPGN:
- Electron microscopy: Characterized by the presence of discrete subendothelial electron dense deposits
- Mesangial and occasional subepithelial deposits may also be present
- Immunofluorescence shows IgG, IgM and C3 deposited in a granular pattern and every complement components (C1Q and C4) are often also present indicating are immune complexes pathogenesis
Type II MPGN (more diverse, more dense!)
- Is characterised by deposition of dark, ribbon like electron dense material in the central layer of (Lamina Densa) of glomerular basement membrane
- Immunofluorescence – C3 deposition on both sides of the basement membrane in irregular granular or linear pattern
- C3 can also be identified in mesangium in the ring shaped aggregates
Diffuse proliferative glomerulonephritis
Diagnostics
- ↓ Serum C3 complement levels
- ANA, anti-dsDNA antibodies
- LM
- Thickening of glomerular capillaries (appear as wire loops)
- Characterized by increased glomerular cellularity in more than half of the glomeruli
- Thickening of glomerular capillaries (appear as wire loops)
- EM
- An immunofluorescence pattern containing IgG, IgM, IgA and C3, C1q is highly characteristic of lupus nephritis and is referred to as a full-house (三带一对, ie, a poker hand with three of a kind 3 immunoglobulin classes and two of a kind 2 complement components).
- The full-house pattern reflects the pathogenesis of lupus: loss of immune tolerance to self-antigens (eg, double-stranded DNA) leads to generation of polyclonal autoantibodies that form circulating immune complexes; these deposit in the glomeruli, where they cause local injury by activating the classical complement cascade.
- An immunofluorescence pattern containing IgG, IgM, IgA and C3, C1q is highly characteristic of lupus nephritis and is referred to as a full-house (三带一对, ie, a poker hand with three of a kind 3 immunoglobulin classes and two of a kind 2 complement components).
IgA nephropathy
Note that the pattern is that of mesangial deposition in the glomerulus.
Goodpasture syndrome
This immunofluorescence pattern shows positivity with antibody to IgG and has a smooth, diffuse, linear pattern that is characteristic for deposition of glomerular basement membrane antibody with Goodpasture syndrome. Serologic testing for anti-GBM in patient serum is often positive.
Tip
Only this one has linear appearance.