Seronegative polyarthritis revealing antisynthetase syndrome: a multicentre study of 40 patients

Objective. The aim of this study was to determine the frequency and characteristics of antisynthetase syndrome (ASS) revealed by polyarthritis. Methods. First we conducted a retrospective single-centre study to assess the frequency of ASS patients who presented with polyarthritis without pulmonary and/or muscle symptoms. Secondly, we conducted a larger, multicentre study in order to describe the clinical characteristics of these patients. Exclusion criteria were the presence of RF, the presence of ACPA and overlap with another CTD. Results. In the single-centre study, polyarthritis was the first manifestation in 12 of 45 ASS patients (27%). An additional 28 patients were collected for the multicentre study, resulting in a total population of 40 ASS patients who presented with polyarthritis. The mean delay from polyarthritis onset to ASS diagnosis was 27 months (S.D. 40). Pulmonary and muscle symptoms were uncommon at ASS diagnosis (40% and 32.5%, respectively) and were dramatically delayed [mean delay after polyarthritis onset of 41 months (S. D. 53) and 21 months (S. D. 14), respectively]. Mechanic's hands and cutaneous signs of DM occurred in 25% and 22.5%, respectively, with a mean delay of 10 months (S. D. 10) and 31 months (S. D. 21), respectively. When present (32%), RP was the earliest non-articular manifestation [mean delay 3 months (S. D. 23) after polyarthritis onset]. On HEp-2 cells, antinuclear and/or cytoplasmic fluorescence was found in 70% of cases, with specificity for various anti-aminoacyl tRNA synthetase (anti-ARS) antibodies. Conclusion. ASS may be revealed by polyarthritis. To decrease the delay in diagnosis of ASS, pulmonary and muscle symptoms and anti-ARS antibodies might usefully be searched for in seronegative polyarthritis patients, especially in those with RP.