Case 6Helmut Hopfer, University Hospital Basel, Switzerland
morphological features
• increased number of endocapillary leukocytes• endothelial swelling• dilatation of capillary loops• occlusion or near occlusion of capillary lumina with cells
usually a focal and segmental lesion!
EM differential diagnosis
transplant glomerulitis endocapillary glomerulonephritis (intravascular lymphoma)
• recognizing a pattern:1. increased number of endocapillary leukocytes2. endothelial swelling3. dilatation of capillary loops4. occlusion or near occlusion of capillary lumina with cells
• counting mononuclear cells (arbitrary cut-off)
→ no clear distinction between cell types by light microscopy!→ immunohistochemistry, definition of cut-off by ROC
Example: endocapillary immune-complex GN
transplant glomerulitis: definition
CD5 CD20 CD68 ERG
counting cells will not tell youanything about the pathogenesis
glomerular rejection: pathogenesis
antibodies & complement↓
endothelial cell damage
lytic sublytic
necrotic procoagulant proinflammatory proliferative / reparative
1.
2.3.
1.
2.
3.
antibodies & complement↓
endothelial cell damage
lytic sublytic
proliferative / reparativeproinflammatoryprocoagulant
necrotic
discussion & conclusions
• Why are the leukocytes there?
• What are the monocytes / macrophages doing there?
• What are the lymphocytes doing there?
→ monocytes exert an early endocapillary reparative function on the endothelial cells
case presentation
Clinical history:39 year old male. Renal transplantation (TR) in 2005 due to hypertension. Malcompliance with immunosuppresion → two episodes of interstitial cellular rejection.Diagnostic biopsy (BX) 40 months after TR, rise in creatinine and newly diagnosed proteinuria.
Diagnosis:Transplant glomerulitis (by EM), severe diffuse interstitial cellular rejection, C4d negative. Focal IFTA (10-20%).
Follow up:Dialysis dependence 7 months later. BX with mixed T cell- and antibody-mediated rejection, C4d positive.