TY - JOUR T1 - Seronegative Polyarthritis in Association With Anti-NXP2 Antibodies: A Case Series JF - The Journal of Rheumatology JO - J Rheumatol SP - 153 LP - 155 DO - 10.3899/jrheum.220248 VL - 50 IS - 1 AU - Aurélie Mourot AU - Josiane Bourré-Tessier AU - Valérie Nadon AU - Océane Landon-Cardinal Y1 - 2023/01/01 UR - http://www.jrheum.org/content/50/1/153.abstract N2 - To the Editor:Antinuclear matrix protein 2 (anti-NXP2) are dermatomyositis (DM)-specific autoantibodies.1 A recent metanalysis outlined their association with muscle weakness, myalgia, dysphagia, edema, and calcinosis.2 We report 3 cases of seronegative polyarthritis, without myositis or DM rash, attributed to anti-NXP2 autoantibodies (Table 1).View this table:In this windowIn a new windowTable 1. Clinical features of 3 patients with anti-NXP2 isolated polyarthritis.Written informed consent from study patients were obtained as part of their participation in the Canadian Inflammatory Myopathy Study. Approval by our local ethics committee (Comité d’Éthique, Centre de Recherche du CHUM, Université de Montréal) was not required for case reports with fewer than 4 patients.Case 1. A 51-year-old female presented with acute polyarthritis of the hands. Examination did not show muscle weakness or DM rash. She had normal inflammatory markers … ER -