A 32-year-old woman with newly diagnosed systemic lupus erythematosus (SLE) presents with nephrotic-range proteinuria and hematuria. Renal biopsy shows proliferative lupus nephritis with wire-loop lesions and subendothelial immune complex deposits. All of the following statements regarding lupus nephritis are correct EXCEPT:

Explanation

## Immunofluorescence Pattern in Lupus Nephritis **Key Point:** Lupus nephritis is characterized by a **full-house** immunofluorescence pattern (IgG, IgA, IgM, C3, and C1q all present), NOT IgA-dominant. IgA-dominant staining is characteristic of IgA nephropathy, not lupus nephritis. ## Immunofluorescence Patterns: Comparison | Condition | IF Pattern | Characteristic | |-----------|-----------|----------------| | **Lupus Nephritis** | Full-house (IgG, IgA, IgM, C3, C1q) | All immunoglobulins present | | **IgA Nephropathy** | IgA-dominant | Predominantly IgA | | **PSGN** | Granular IgG, C3 | Selective staining | | **Membranous GN** | IgG, C3 (subepithelial) | Granular pattern | ## Wire-Loop Lesions in Lupus Nephritis **High-Yield:** Wire-loop lesions are: - Thickened capillary walls with a wire-like appearance - Caused by **subendothelial immune complex deposition** - Seen on light microscopy as eosinophilic thickening - Pathognomonic for lupus nephritis ## Serologic Markers and Prognosis **Clinical Pearl:** Anti-dsDNA and anti-C1q antibodies are strong predictors of lupus nephritis activity: - Anti-dsDNA: correlates with disease activity and flares - Anti-C1q: predicts renal involvement and poor prognosis - Both are used to monitor treatment response ## Proliferative vs. Membranous Lupus Nephritis | Class | Type | Prognosis | |-------|------|----------| | **III/IV** | Proliferative | Higher risk of ESRD; requires aggressive therapy | | **V** | Membranous | Better prognosis; slower progression | | **III+V** | Mixed | Intermediate risk | **Warning:** Do not confuse IgA nephropathy (IgA-dominant IF) with lupus nephritis (full-house IF). This is a common exam trap.