Belimumab shows promise in neuropsychiatric lupus: Another challenge to find the offender

Introduction Agents that can be used for the treatment of neuropsychiatric lupus (NPSLE) are lacking in the therapeutic armamentarium. Belimumab is a monoclonal antibody targeting the B‐cell activating factor (BAFF) and is approved by the US Food and Drug Administration as an additional treatment for systemic lupus erythematosus patients with persistent disease activity and lupus nephritis (LN); however, severe active central nervous system manifestations were excluded. Case Report We report on a treatment‐naïve LN patient with refractory NPSLE complicated with progressive posterior reversible encephalopathy syndrome (PRES) who was successfully treated via the combination of mycophenolate and belimumab, resulting in reversal of persistent headache and neuroradiologic manifestations. Conclusion Research on this topic could be relevant for identifying a possible correlation between BAFF and psychiatric NPSLE manifestations. Belimumab shows promise in neuropsychiatric lupus. Posterior reversible encephalopathy syndrome (PRES) frequently occurs during active systemic lupus erythematosus (SLE). The nephrotic state is a unique risk for PRES. Therapy of belimumab could promote the normalization of serologic activity and reduce BAFF‐dependent B‐cell subsets in serologically and clinically active SLE. BAFF, B‐cell activating factor; BAFF‐R, BAFF‐receptor; NPSLE: Neuropsychiatric SLE. Key points The nephrotic state is a specific risk factor for posterior reversible encephalopathy syndrome (PRES) in patients with lupus renal flares. Belimumab showed efficacy and safety in a lupus nephritis patient with PRES.