Background:Idiopathic inflammatory myopathies (IIM) are essentially treated aiming improvement of muscle function and extra muscular disease manifestations. The backbone of the treatment is corticosteroids enhancing the survival and patient quality of life. The lack of consensus on target-specific immunosuppressive treatment highlights the need for further studies evaluating alternative treatment methods. Rituximab is potentially a glucocorticoid-sparing agent which was reviewed in multiple studies with small sample sizes due to the rarity of the disease.Objectives:Higher statistical power can enhance the trustworthiness of alternative treatment methods yielding the main objective of this study.Methods:This retrospective study was conducted at a tertiary rheumatology center. Patients were diagnosed with an idiopathic inflammatory myopathy (dermatomyositis [DM], polymyositis [PM]) and were treated with rituximab in order to be included in this study. Clinical signs and symptoms of the presentation were noted during the first patient encounter as well as the follow-up. Parameters of disease activity including acute phase reactants, muscle enzyme levels, and disease-specific autoantibodies were analyzed.Results:The study includes 28 patients (20 DM, 8 PM). The age of diagnosis was 43.44 ± 15.77 years, follow-up duration was 60.7 ± 70.7 months. The presenting signs and symptoms of the patients are shown in Figure 1. The parameters of disease activity before and after treatment are summarized in Table 1. The mean corticosteroid dose decreased from 31.429 ±23.934 mg to 10.278 ±12.001 (p=0.001). Other treatment methods were methotrexate (n=18), Intravenous Immunoglobulin (IVIG) (n=7), and cyclophosphamide (n=2). There were not any deaths during the follow-up. Two patients were lost to follow-up.Table 1.The Parameters of Disease Activity Before and After TreatmentBefore TreatmentAfter TreatmentP ValueCPK, mean ± std (U/L)1426 ± 2049.92263.44 ± 265.630.004LDH, mean ± std (U/L)557.5 ± 365379.78 ± 192.10.03AST, mean ± std (U/L)62.52 ± 5930.16 ± 27.590.01ALT, mean ± std (U/L)56.48 ± 49.2127.64 ± 24.520.008ESR, mean ± std (mm/hour)26.38 ± 28.9820.39 ± 18.760.36CRP, mean ± std (mg/L)19.23 ± 46.1512.53 ± 26.670.5RF, mean ± std (U/mL)0 (0)N/AN/AANA, n (%)3 (10.71)N/AN/AFigure 1.The Presenting Signs and Symptoms of the PatientsConclusion:Rituximab is shown to be effective in treating myositis along with corticosteroids as well as a corticosteroid-sparing agent in retrospective studies and open-label clinical trials; however, lack of statistical power should be underlined. Long term decrease in steroid use and decrease in disease activity markers hints the effective use of rituximab as a glucocorticoid sparing agent as well as its safety with minimal side effects.Disclosure of Interests:None declared
A7.11 Genetic Variation in Promoter Sequence of B-Cell-Activating Factor of the TNF Family (BAFF) in Patients with Idiopathic Inflammatory Myopathies (IIM)