Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 54 10 2016 11 19 683 685 EN Maryam Mobini Department of Rheumatology, Diabetes Research Center, Mazandaran University of Medical Sciences, Mazandaran, Iran. Roya Ghasemian Department of Infectious Diseases, Antimicrobial Resistance Research Center, Mazandaran University of Medical Sciences, Mazandaran, Iran. Fatemeh Zameni Department of Infectious Diseases, Antimicrobial Resistance Research Center, Mazandaran University of Medical Sciences, Mazandaran, Iran. 2016 11 05 2016 11 05 Adult-onset Still’s disease (AOSD) is a rare systemic inflammatory disorder of unknown etiology. There is not currently any specific serological markers for AOSD , and  diagnosis still relying on the exclusion of other likely diagnoses. Yamaguchi’s criteria are used as a diagnostic criterion which contains negative serologic markers for other collagen vascular diseases including systemic lupus erythematosus and rheumatoid arthritis. Here we report a 28-year-old woman with arthralgia, fever, rash, leukocytosis, lymphadenopathy, sore throat, abnormal liver function and negative rheumatoid factor and ANA but  seropositive for anti-CCP, anti-dsDNA, and C-ANCA. It seems that despite AOSD is considered as a seronegativedisorder; it should be remembered in patients with compatible findings who are seropositive. https://acta.tums.ac.ir/index.php/acta/article/view/5998 https://acta.tums.ac.ir/index.php/acta/article/download/5998/4855