AB1141 Rituximab converts paediatric rheumatoid factor positivity to negativity
Authors: E. Mosley, D. Hawley, R. Tattersall, A.-M. McMahon
Journal: Annals of the Rheumatic Diseases (2013)

<h3>Background</h3> In the paediatric population there are no reported cases of the use of rituximab beyond 5 doses, for any inflammatory condition.<sup>1,2,</sup> Literature regarding the use of rituximab in paediatric mixed connective tissue disease is sparse.<sup>3</sup> It is generally accepted that complete B-cell depletion after the first rituximab infusion is a predictor of good response. However, serum markers of B cell activation including rheumatoid factor may predict response to Rituximab.<sup>4</sup> <h3>Objectives</h3> We present a 13 year old girl, with a 5 year history of Mixed Connective Tissue Disease (MCTD), with Rheumatoid factor positive, ANA positive, anti-RNP positive autoantibody profile. Management of her severe, aggressive polyarthritis has been a challenging clinical probelm. <h3>Results</h3> Treatment has been tailored to the predominant clinical picture, within an established transition clinic, ensuring collaboration of adult and paediatric care strategies. Previous immunosuppressive management, included methotrexate, mycophenylate mofetil and azathioprine, with no improvement in her clinical condition. Etanercept was introduced in 2008, with short term improvement (less than 3 months). Infliximab was withdrawn after an anaphylactic reaction to the second dose. Joint injections with triamcinolone hexacetonide occurred as clinical need dicatated. Rituximab therapy commenced August 2009 (750mg/m<sup>2</sup>), with 6 monthly cycles. Subcutaneous Methotrexate was re-introduced in 2010, with hydroxychloroquine, to supplement her long term steroid therapy. Rheumatoid Factor antibody, which has been as high as 803units, is now negative. Having been steroid dependent since diagnosis, steroid therapy ceased in September 2011. The 5th course of rituximab with cyclophosphamide commenced December 2011. Rheumatoid Factor antibody, which has been as high as 803IU/ml, is now negative. <h3>Conclusions</h3> This is the first report in paediatric rheumatology of rituximab therapy inducing a rheumatoid factor negative serological status in a paediatric patient with previously significantly high rheumatoid factor positive disease. <h3>References</h3> Long term follow up of patients with neuromyelitis potica after repeated therapy with ritixumab: Pellkofer HL et al: Neurology 2011 Apr 12;76(15):1310-5 Efficacy &amp; safety of repeated courses of rituximab treatment in patients with severe refractory juvenile idiopathic arthritis, Alexeeva EI et al; Clin Rheumatology 2011, Sept; 30(9): 1163-72. Rituximab and ANA positive Juvenile idiopathic arthritis with uveitis; Baildam EM, Saladi S; Peaditaric rheumatology 2008, (suppl 1):P71 B cell activation biomarkers as predictive factors for the response to rituximab in rheumatoid arthritis: a six-month, national, multicenter, open-label study. Sellam J, Hendel-Chavez H, Rouanet S, Abbed K, Combe B, Le Loët X, Tebib J, Sibilia J, Taoufik Y, Dougados M, Mariette X. Arthritis Rheum. 2011 Apr;63(4):933-8. <h3>Disclosure of Interest</h3> None Declared