Role of Surveillance Kidney Biopsy in Management of Lupus Nephritis

Background: Lupus nephritis (LN) is one of the most serious complications of systemic lupus erythematous. The benefit of early surveillance biopsies to prevent future relapses and to monitor treatment response is not established. In our institution, we implemented surveillance biopsies 6 months after induction therapy. This study aims to assess the value of surveillance biopsies in concordance with the clinical findings in medical management. Methods: Patients diagnosed with Class III or IV LN on initial kidney biopsy and who had a surveillance biopsy were included in this retrospective chart review. Patients received monthly cyclophosphamide infusions based on NIH protocol or mycophenolate mofetil (MMF) as induction therapy. The clinical history, treatment course, pathology results, and biochemical results were assessed. Proteinuria was determined by urine protein/creatinine mg:mg (UPC) ratio. Estimated glomerular filtration rate (eGFR) was assessed by the CKiD U25 calculation. LN classification and activity index (AI) was determined by pathology on initial and surveillance biopsies. Results: Nineteen patients fulfilled inclusion criteria. Seven and 12 patients were initially diagnosed with Class III and Class IV respectively. AI was 8.4±5.6, UPC was 2.57±2.1, and eGFR was 79.09±35 at presentation. LN classification improved in 15 (79%) patients on surveillance biopsy. 16 (84%) patients changed from cyclophosphamide to MMF after the surveillance biopsy, and the other 3 received additional cyclophosphamide or rituximab infusions. Six patients experienced a relapse. Of the patients who switched to MMF, 3 (16%) relapsed. The AI improved in 14 (74%) patients, and mean AI on surveillance biopsy was 1.56. The mean AI on surveillance biopsy was 4.8 and 0.43 between relapsers and non-relapsers respectively (p<0.05). Patients who relapsed had a higher LN class (Class III vs Class I/II) on surveillance biopsy in comparison to non-relapsers (p<0.05). UPC and eGFR at the time of surveillance biopsy did not predict patient relapse. Conclusion: The results of surveillance biopsies often guided treatment for patients with LN. The AI and degree of improvement in classification on LN on the surveillance biopsy may be a useful tool in predicting likelihood of LN relapse. We propose that surveillance biopsies should be considered as part of standard care in management of patients with LN.