A novel therapeutic approach in pulmonary arterial hypertension as a complication of adult-onset Still's disease: targeting IL-6.

Adult-onset Still's Disease (AOSD), often though as the adult variant of systemic juvenile idiopathic arthritis (JIA), has an incidence of 1-3 cases per 1 million. Cardinal manifestations include fever, arthritis, skin rash, sore throat, hepatosplenomegaly and lymphadenopathy. Prolongation in diagnosing this disease results from its similarity to infectious, malignant and rheumatic diseases and lack of biomarkers. Pulmonary arterial hypertension (PAH) is a rare pulmonary complication of AOSD, and we are aware of only six cases reported in literature to date. Here we present a patient with AOSD who has developed pulmonary hypertension as a complication. We report a case of AOSD complicated by PAH treated successfully with tocilizumab, a humanized monoclonal antibody to human interleukin (IL)-6 receptor. A Pubmed and Medline search for evidence of pulmonary hypertension in AOSD and use of IL-6 inhibition in management was performed. Data for this study was collected from the patient's chart records. No infectious or neoplastic cause of her disease was identified and after extensive diagnostic workup, the patient was diagnosed with AOSD fulfilling Yamaguchi criteria. After initiation of IL-6 therapy the patient was followed over time to monitor the hemodynamic changes in pulmonary vasculature. Following treatment with Tocilizumab, the patient showed dramatic improvement in her clinical symptoms and remains in remission, through combination of tocilizumab (8 mg/kg), methotrexate and prednisone. Improvement of systemic symptoms, right heart catheterization (RHC) findings and the VECTRA-DA score served as a measure of treatment response. Tocilizumab has been effective in demonstrating marked improvement in both the clinical and laboratory parameters. Tocilizumab is an effective novel treatment for AOSD with PAH. This is the first documented report of successful use of tocilizumab in AOSD patients presenting with PAH. Prospective comparative studies could help validate its efficacy and safety.