Systemic Lupus Erythematosus-Associated Serositis Managed With Intravenous Belimumab: A Case Report

Systemic lupus erythematosus (SLE) is an autoimmune disease that involves multiple organ systems. Due to the heterogeneity of its presentation, it is challenging for clinicians to diagnose and manage the symptoms. SLE has a wide range of presentations from mild to severe and involves various organ systems like mucocutaneous, musculoskeletal, cardiopulmonary, renal, gastrointestinal, and central nervous system. Various novel treatment modalities are being used based on clinical presentation. Prednisone and methylprednisolone are commonly used as needed for acute flares of SLE. Some patients may need a low dose of oral prednisone to keep their SLE under control, which carries a risk of coronary artery disease (CAD) and many other metabolic side effects of steroids. Other long-term medications that are commonly used include hydroxychloroquine, methotrexate, azathioprine, mycophenolate, cyclosporine, and cyclophosphamide. Intravenous cyclophosphamide is used only in severe lupus with renal, pulmonary, or CNS involvement. Rituximab is a human monoclonal B-cell cluster of differentiation (CD)20 receptor antibody used for severe SLE not responding with other medications. Other newer medications are belimumab and anifrolumab. Anifrolumab is a fully human monoclonal antibody that binds to subunit 1 of the type I interferon receptor. We present a case of a 25-year-old female with a chronic history of SLE presented to the outpatient clinic with abdominal distension that needed frequent abdominal paracenteses. She was using hydroxychloroquine, mycophenolate mofetil, and prednisone, but her symptoms were not adequately controlled. After we started the patient on monthly intravenous belimumab, her symptoms and the frequency of visits for paracentesis gradually reduced. B-cells are known to play an essential role in the pathogenesis of SLE, and the use of belimumab, an anti-BLys (B-lymphocyte stimulator) human monoclonal antibody that inhibits B-cell growth, can play a significant role in the management of SLE associated chronic serositis.