A 30-year-old woman with SLE presents with fatigue, arthralgia, and new-onset proteinuria of 1.2 g/day. Complement C3 and C4 are low. Anti-dsDNA titers have risen significantly. Renal biopsy shows mesangial proliferation with immune complex deposits limited to the mesangium. What ISN/RPS class of lupus nephritis is this?

• A Class II (mesangial proliferative lupus nephritis) ✓
• B Class III (focal lupus nephritis)
• C Class IV (diffuse lupus nephritis)
• D Class V (membranous lupus nephritis)

Explanation

ISN/RPS Class II lupus nephritis shows mesangial hypercellularity and mesangial immune deposits without endocapillary or extracapillary proliferation. It typically presents with mild proteinuria and hematuria. Class III involves less than 50% of glomeruli with segmental lesions. Class IV involves 50% or more of glomeruli. Class V shows subepithelial deposits with membranous pattern.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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