Case Report: Sequential eculizumab and belimumab in a paediatric patient with lupus nephritis and immune complex-mediated renal microangiopathy.

BACKGROUND: Renal microangiopathy is a severe complication of systemic lupus erythematosus, particularly when mediated by immune complex deposition. The optimal management of paediatric immune complex-mediated renal microangiopathy with rapid clinical deterioration remains unclear, and data on sequential complement and B-cell targeted therapy in this setting are scarce. CASE SUMMARY: A previously healthy 14-year-old Chinese male patient presented with joint pain and generalised oedema. He was diagnosed with systemic lupus erythematosus, and the renal biopsy confirmed lupus nephritis (IV combined with V type) and immune complex-mediated renal microangiopathy (IC-RMA). The patient received a first-line intensive treatment regimen and showed an insufficient clinical response. Considering the severity and suspected complement-driven injury, we then initiated eculizumab, and his joint pain, generalised oedema, haematuria, proteinuria, and SLEDAI score were all improved. Belimumab was subsequently administered after 3 months of eculizumab therapy, and there was no recurrence for 1 year later. CONCLUSION: Sequential eculizumab and belimumab may be potential alternatives for selected paediatric patients with IC-RMA, although further studies are needed to confirm their efficacy and safety.