Symptomatic polyautoimmunity at diagnosis of 1463 childhood-onset lupus: A Brazilian multicenter study.

OBJECTIVE: To evaluate symptomatic polyautoimmunity (PA) at childhood-onset systemic lupus erythematosus(cSLE) diagnosis, and its association with demographic data, disease activity, clinical manifestations and laboratorial abnormalities in a large Brazilian cSLE population. METHODS: A multicenter retrospective study was performed in 1463 cSLE(ACR criteria) patients from 27 Pediatric Rheumatology services. Symptomatic PA was defined according to the presence of more than one concomitant autoimmune disease(AD) and symptomatic multiple autoimmune syndrome(MAS) was defined as three or more AD. An investigator meeting was held to define the protocol. Demographic data, SLICC classification criteria and SLEDAI-2K were evaluated. RESULTS: At cSLE diagnosis symptomatic PA was observed in 144/1463(9.8%) and symptomatic MAS occurred in solely 10/1463(0.7%). In the former group the more frequently observed associated AD were Hashimoto thyroiditis n = 42/144(29%), antiphospholipid syndrome n = 42/144(29%), autoimmune hepatitis n = 26/144(18%) and type 1 diabetes mellitus n = 23/144(15.9%). Further comparisons between cSLE patients with and without PA showed a higher median age(p = 0.016) and lower mean SLICC criteria (p = 0.039) in those with PA. Additionally, these cSLE patients had less renal involvement(35% vs. 44%, p = 0.038) and red blood cell cast(6% vs. 12%, p = 0.042) and more antiphospholipid antibodies(29% vs. 15%, p < 0.0001). CONCLUSIONS: Approximately 10% of cSLE had symptomatic PA at diagnosis, particularly endocrine autoimmune disorders and antiphospholipid syndrome. Lupus was characterized by a mild disease onset and MAS was infrequently evidenced. Further studies are necessary to determine if this subgroup of cSLE patients have a distinct genetic background with a less severe disease and a better long-term outcome.