Comparison of clinical features between patients with anti-synthetase syndrome and dermatomyositis: results from the MYONET registry
Authors: Hum Ryan Malcolm , Lilleker James B , Lamb Janine A , Oldroyd Alexander G S , Wang Guochun , Wedderburn Lucy R , Diederichsen Louise P , Schmidt Jens , Danieli Maria Giovanna , Oakley Paula , Griger Zoltan , Nguyen Thi Phuong Thuy , Kodishala Chanakya , Vazquez-Del Mercado Monica , Andersson Helena , De Paepe Boel , De Bleecker Jan L , Maurer Britta , McCann Liza , Pipitone Nicolo , McHugh Neil , New Robert Paul , Ollier William E , Krogh Niels Steen , Vencovsky Jiri , Lundberg Ingrid E , Chinoy Hector ,   MYONET Registry, D’Hose Sophie , Lu Xin , Tian Xiaolan , Mann Heřman , Kryštůfková Olga , Pleštilová Lenka , Klein Martin , Barochová Tereza , Kubínová Kateřina , Gelardi Chiara , Paladini Alberto , Piga Mario Andrea , Jara Luis J , Saavedra Miguel A , Cruz-Reyes Claudia V , Vera-Lastra Olga , Andrade-Ortega Lilia , Medrano-Ramírez Gabriel , Satoh Minoru , Salazar-Páramo Mario , Chavarría-Ávila Efrain , Aguilar-Vazquez Andrea , Anda Jesus-Aureliano Robles-de , Petri Marcelo H , Molberg Øyvind , Dastmalchi Maryam , Notarnicola Antonella , Gheorghe Karina , Rönnelid Johan , Liden Maria , Hanna Balsam , Jalal Awat , Hellström Helena , Martineus Jehns Christian , Lan Nguyen Thi Ngoc , Padyukov Leonid , New Paul , Platt Hazel , Rothwell Simon , Ahmed Yasmeen , Armstrong Raymond , Bernstein Robert , Black Carol , Bowman Simon , Bruce Ian , Butler Robin , Carty John , Chattopadhyay Chandra , Chelliah Easwaradhas , Clarke Fiona , Dawes Peter , Denton Christopher , Devlin Joseph , Edwards Christopher , Emery Paul , Fordham John , Fraser Alexander , Gaston Hill , Gordon Patrick , Griffiths Bridget , Gunawardena Harsha , Hall Frances , Hanna Michael , Harrison Beverley , Hay Elaine , Hilton-Jones David , Horden Lesley , Isaacs John , Isenberg David , Jones Adrian , Kamath Sanjeet , Kennedy Thomas , Kitas George , Klimiuk Peter , Knights Sally , Lambert John , Lanyon Peter , Laxminarayan Ramasharan , Lecky Bryan , Luqmani Raashid , Machado Pedro , Marks Jeffrey , Martin Michael , McGonagle Dennis , McHugh Neil , McKenna Francis , McLaren John , McMahon Michael , McRorie Euan , Merry Peter , Miles Sarah , Miller James , Nicholls Anne , Nixon Jennifer , Ong Voon , Over Katherine , Packham John , Pipitone Nicolo , Plant Michael , Pountain Gillian , Pullar Thomas , Roberts Mark , Sanders Paul , Scott David , Scott David , Shadforth Michael , Sheeran Thomas , Srinivasan Arul , Swinson David , Teh Lee-Suan , Webley Michael , Williams Brian , Winer Jonathan 
Published: September 2023

Abstract

Objectives
To compare clinical characteristics, including the frequency of cutaneous, extramuscular manifestations and malignancy, between adults with anti-synthetase syndrome (ASyS) and DM.

Methods
Using data regarding adults from the MYONET registry, a cohort of DM patients with anti-Mi2/-TIF1γ/-NXP2/-SAE/-MDA5 autoantibodies, and a cohort of ASyS patients with anti-tRNA synthetase autoantibodies (anti-Jo1/-PL7/-PL12/-OJ/-EJ/-Zo/-KS) were identified. Patients with DM sine dermatitis or with discordant dual autoantibody specificities were excluded. Sub-cohorts of patients with ASyS with or without skin involvement were defined based on presence of DM-type rashes (heliotrope rash, Gottron’s papules/sign, violaceous rash, shawl sign, V-sign, erythroderma, and/or periorbital rash).

Results
In total 1054 patients were included (DM, n = 405; ASyS, n = 649). In the ASyS cohort, 31% (n = 203) had DM-type skin involvement (ASyS-DMskin). A higher frequency of extramuscular manifestations, including Mechanic’s hands, Raynaud’s phenomenon, arthritis, interstitial lung disease and cardiac involvement differentiated ASyS-DMskin from DM (all P &lt; 0.001), whereas higher frequency of any of four DM-type rashes—heliotrope rash (n = 248, 61% vs n = 90, 44%), violaceous rash (n = 166, 41% vs n = 57, 9%), V-sign (n = 124, 31% vs n = 28, 4%), and shawl sign (n = 133, 33% vs n = 18, 3%)—differentiated DM from ASyS-DMskin (all P &lt; 0.005). Cancer-associated myositis (CAM) was more frequent in DM (n = 67, 17%) compared with ASyS (n = 21, 3%) and ASyS-DMskin (n = 7, 3%) cohorts (both P &lt; 0.001).

Conclusion
DM-type rashes are frequent in patients with ASyS; however, distinct clinical manifestations differentiate these patients from classical DM. Skin involvement in ASyS does not necessitate increased malignancy surveillance. These findings will inform future ASyS classification criteria and patient management.