Annals of Clinical and Analytical Medicine 625 Annals of Clinical and Analytical Medicine Original Research Işılay Taşkaldıran 1 , Şükran Erten 2 , Selçuk Akan 3 , Orhan Küçükşahin 2 , Turan Hilmi Yeşil 2 , Didem Şener Dede 4 1 Department of Internal Medicine, Ankara Training and Research Hospital 2 Department of Rheumatology, Yıldırım Beyazıt University, Ankara Cıty Hospital 3 Department of Internal Medicine, Ankara Cıty Hospital 4 Department of Medical Oncology, Yıldırım Beyazıt University, Ankara Cıty Hospital, Ankara, Turkey Seropositive spondyloarthritis frequency Investigation of autoantibody positivity in patients with spondyloarthritis DOI: 10.4328/ACAM.20163 Received: 2020-03-14 Accepted: 2020-04-14 Published Online: 2020-04-20 Printed: 2020-11-01 Ann Clin Anal Med 2020;11(6):625-629 Corresponding Author: Selçuk Akan, Yıldırım Beyazıt University, Ankara Cıty Hospital, Universities Quarter, Bilkent Blv. No: 1 , Çankaya, 06800, Ankara / Turkey. E-mail: dr_selcukakan@hotmail.com P: +90 312 552 60 00 Corresponding Author ORCID ID: https://orcid.org/0000-0002-5053-6896 Abstract Aim: Although ankylosing spondylitis (AS) and undiferentiated spondyloarthritis (uSpA) are included in seronegative spondyloarthropathy (SpA) classifcation, autoantibody positivity has been observed in the clinical practice. However, there is no study evaluating the frequency of autoantibody positivity in this group of patients in the literature. The objective of this study is to evaluate the frequency of serologic markers in AS and uSpA, and to compare it with the normal population. Material and Methods: In total, 1486 patients with spondyloarthropathy were included in the study. Autoantibodies used in the diagnosis of rheumatic diseases were evaluated in patients. In addition, 149 healthy volunteers without known chronic diseases were selected as the control group. Results: Among 1486 patients with SpA, 950 subjects (63.9%) had uSpA and 536 subjects (36.1%) had AS. Autoantibody positivity was observed in 96 patients. In this seropositive patients group, accompanying systemic lupus erythematosus (SLE) and Sjögren’s syndrome (SS) were observed in 6 patients (6.3%) and 23 patients (24%), respectively. Discussion: There was no signifcant diference in terms of autoantibody positivity between patients with SpA and healthy controls. Autoantibody positivity was higher in the uSpA subgroup with female predominance and peripheral joint involvement. Keywords Spondyloarthritis; Ankylosing spondylitis; Undiferentiated spondyloarthritis; Autoantibody positivity