Wire loop lesions are often characteristics for the following class of lupus nephritis
Mesangial proliferative glomerulonephritis(wHO class2)
Focal proliferative glomerulonephritis (WHO class3)
Diffused proliferative glomerulonephritis (WHO class4)
Membranous glomerulonephritis (WHO class5)
Ref Robbins illustrated 8/e p218, 9/e p224 Diffuse lupus nephritis (class IV) is the most serious form of renal lesions in SLE and is also the most commonly encountered in renal biopsies, occurring in 35% to 60% of patients. It is distinguished from focal lupus nephritis (class III) by involvement of half or more of glomeruli. Most of the glomeruli show endothelial and mesangial prolifera- tion, leading to diffuse hypercellularity of these structures (Fig. 4-18, B) and producing in some cases epithelial crescents that fill Bowman's space. When extensive, sub- endothelial immune complexes create a circumferential thickening of the capillary wall, resembling rigid "wire loops" on routine light microscopy (Fig. 4-18, C). Electron microscopy reveals prominent electron-dense subendo- thelial immune complexes (between endothelium and basement membrane) (Fig. 4-18, D), but immune com- plexes are also usually present in other pas of the capil- lary wall and in the mesangium. Immune complexes can be visualized by staining with fluorescent antibodies directed against immunoglobulins or complement, result- ing in a granular fluorescent staining pattern (Fig. 4-18, E). In due course, glomerular injury may give rise to scarring (glomerulosclerosis). Most affected patients have hematu- ria with moderate to severe proteinuria, hypeension, and renal insufficiency.
General anatomy