Childhood-onset systemic lupus erythematosus-related antiphospholipid syndrome: A multicenter study with 1519 patients

Objective: To assess childhood-onset systemic lupus erythematosus-related antiphospholipid syndrome(cSLE-APS) in a large Brazilian population. Methods: A retrospective observational cohort study was carried-out in 27 Pediatric Rheumatology university centers, including 1519 cSLE patients. Results: cSLE-APS was observed in 67/1519 (4%) and was diagnosed at disease onset in 39/67 (58%). The median disease duration was 4.9 (0-17) years. Thrombosis recurrences were evidenced in 18/67 (27%) cSLE-APS patients. The most frequent thrombosis sites in cSLE-APS patients were: venous thrombosis in 40/67 (60%), especially deep vein thrombosis in 29/40 (72%); arterial thrombosis in 35/67 (52%), particularly stroke; small vessels thrombosis in 9/67 (13%) and mixed thrombosis in 3/67 (4%). Pregnancy morbidity was observed in 1/67 (1%). Non-thrombotic manifestation associated to cSLE-APS occurred in 21/67 (31%), mainly livedo reticularis in 14/67 (21%), valvar thickening in 4/67 (6%) and valvar vegetations not related to infections in 2/67 (3%). None of them had catastrophic APS. Further analysis demonstrated that the median of SLICC/ACR-DI [1 (0-5) vs. 0(0-7),p < 0.0001] was significantly higher in cSLE-APS patients compared to cSLE without APS. The frequencies of cerebrovascular disease (40% vs. 1%,p < 0.0001), polyneuropathy (9% vs. 1%,p < 0.0001), SLICC/ACR-DI >= 1 (57% vs. 27%, p < 0.0001) and intravenous cyclophosphamide use (59% vs. 37%, p < 0.0001) were significantly higher in the former group. Conclusions: Our large multicenter study demonstrated that cSLE-APS was a rare condition, occurring during disease course with a high accrual damage. Central and peripheral neuropsychiatric involvements were distinctive features of this autoimmune thrombosis.