Both lupus and systemic sclerosis have direct impacts on the kidneys. For each image can you determine if it is more consistent with lupus or systemic sclerosis?

Compare the following:

• Glomeruli:
  • Is there an increase in the amount of mesangial matrix?
  • Do the capillary walls appear thickened?
  • Are there any partially or globally sclerotic glomeruli?
• Interstitium:
  • Is there fibrosis? inflammation?
• Vessels
  • Are the arteriole walls normal?
  • Is there periarteriolar fibrosis? fibrinoid necrosis? intimal proliferation?

Nephritis affects 50% of lupus patients, and is principally caused by the deposition of immune complexes in the glomerular, tubular, and vascular basement membranes. There are 5 general classes of lupus nephritis (I to V) which we won't address until next year. The H&E here demonstrates the increased matrix deposition in the mesangium and mild mesangiocapillary proliferation (Class III/IV). "Wire-loop" changes in the glomerular capillaries are consistent with the subendothelial deposits see in the electron micrographs on the next page. In addition to subendothelial deposits, there are mesangial deposits and a solitary subendothelial deposit (on EM). Immune deposits tend to have a "fingerprint" appearance. Glomeruli in lupus nephritis can stain diffusely for IgG, IgA, IgM, complement components C1q, C3 or all five (the so-called "full house" staining).

Renal pathology occurs in >60% of patients with systemic sclerosis. Renal arterioles show intimal thickening with the deposition of collagenous material and concentric proliferation of the intimal cells. These changes can result in hypertension, which can become severe ("malignant") and cause renal failure (without proper treatment).