A 35-year-old woman with lupus nephritis class IV undergoes repeat biopsy after 6 months of mycophenolate mofetil plus steroids. The biopsy now shows class II (mesangial) pattern. The NIH activity index has decreased from 14 to 3, but chronicity index is 7. What is the most appropriate next clinical decision?
- A Escalate to cyclophosphamide given persistent proteinuria
- B Initiate rituximab targeting CD20 B cells for refractory class IV
- C Renal transplant evaluation given high chronicity index indicating irreversible damage
- D Transition to maintenance therapy with low-dose MMF and hydroxychloroquine ✓
Explanation
Histological transformation from class IV to class II after induction therapy reflects treatment response — a favorable finding. The high chronicity index (CI ≥ 5–6) indicates significant irreversible fibrosis but does not immediately mandate transplant if there is clinical improvement and residual functioning nephrons. The EULAR/ERA 2019 guidelines recommend transitioning to maintenance therapy (MMF 1–2 g/day + low-dose steroids + hydroxychloroquine) when induction goals are achieved. Cyclophosphamide escalation is appropriate for refractory disease. Rituximab is used in refractory/relapsing lupus nephritis.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
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