Kidney Biopsies

Anatomy of the Bowman’s Capsule

Kidney bx cartoon copy

EP : epithelial membrane
LRE : Lamina rara externa
LD : Lamina densa
LRI : Lamina rara interna
EN : Endothelial membrane

The Glomerular Basement Membrane

Layer Location Composition Function
lamina rara externa adjacent to podocyte processes heparan sulfate blocks by charge
lamina densa dark central zone type 4 collagen and laminin blocks by size (Molecular Weight > 5800kDa)
lamina rara interna adjacent to endothelial cells heparan sulfate blocks by charge

Linear IgG deposition, occurs in:

  • Anti GBM disease (crescents, very strong staining)
  • Diabetes (no crescents, diabetic glomerosclerosis, IgG is non selectively absorbed into the highly permeable capillary wall, there is deposition of albumin & other plasma proteins)
  • Fibrillary GN (IgG absorbed into the fibrils)
  • Light chain disease
  • Alport’s after transplantation

Nodular mesangium:

  • Light chains
  • Amyloid
  • Diabetes
  • Chronic MPGN
  • Organised glomerular deposits disease
    • fibrillary GN
    • immunotactoid GN
    • fibronectin GN
    • collagen III GN
  • Idiopathic
    • Smoking
    • HTN
  • Chronic hypoxic/ischaemic conditions
    • Takayasu’s , RAS
    • cyanotic congenital heart disease
    • CF

Granular IgG deposition:

  • membranous
  • MPGN
  • PIGN

Mesangial Proliferation Differential Diagnosis:

DD mesangial prolif copy

EM

Presence of tubuloreticular inclusion bodies:

  • lupus nephritis
  • Alfa interferon therapy
  • HIV(AN)
  • Viral infections

Full house Ig staining:

  • Lupus
  • HIVICK
  • SBE / shunt nephritis
  • PIGN (Rare)

Kidney bx of SLE copy

 

Anti Ro/SSA Ab : Associated with SLE/PBC

Anti La/SSB Ab : Sjogrens

Anti – RNP Ab : MCTD/SLE. More prominent in Raynaud’s with mild renal involvment

Anti Scl-70 Ab : Systemic sclerosis

Anti Sm Ab : SLE. Assoc with increased severity and activity of renal disease. Can be induced by EBV by molecular mimicry.

Anti Mi-2 : 25% of dermatomyositis

Anti Jo-1 : Polymyositis (+/- dermatomyositis)

 

MM copy

Appearances of monoclonal immunoglobulin deposition disease

monoclonal deposition copy

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