A 32-year-old woman with known SLE on hydroxychloroquine develops a serum creatinine rise from 0.8 to 2.4 mg/dL over 4 weeks. Urine shows red cell casts and 3+ proteinuria. Renal biopsy shows diffuse proliferative changes with wire-loop lesions on light microscopy and granular 'full house' immunofluorescence (IgG, IgM, IgA, C3, C1q). This is CLASS:
- A Class II lupus nephritis (mesangial proliferative)
- B Class IV lupus nephritis (diffuse proliferative) ✓
- C Class III lupus nephritis (focal proliferative)
- D Class V lupus nephritis (membranous)
Correct answer: B. Class IV lupus nephritis (diffuse proliferative)
Explanation
Class IV (diffuse proliferative) lupus nephritis involves >50% of glomeruli with diffuse mesangial and endocapillary proliferation; wire-loop lesions represent subendothelial immune complex deposits seen on light microscopy, and 'full house' immunofluorescence (all Ig classes plus complement) is characteristic. It is the most severe class and requires aggressive immunosuppression with mycophenolate mofetil or cyclophosphamide plus high-dose corticosteroids.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.