OBJECTIVE: To analyze the prevalence of myositis-specific and myositis-associated autoantibodies and their clinical correlations in a large series of patients with dermatomyositis/polymyositis. METHOD: This cross-sectional study enrolled 127 dermatomyositis cases and 95 polymyositis cases. The disease-related autoantibody profiles were determined using a commercially available blood testing kit. RESULTS: The prevalence of myositis-specific autoantibodies in all 222 patients was 34.4%, whereas myositis-associated autoantibodies were found in 41.4% of the patients. The most frequently found autoantibody was anti-Ro-52 (36.9%), followed by anti-Jo-1 (18.9%), anti-Mi-2 (8.1%), anti-Ku (4.1%), anti-SRP (3.2%), anti-PL-7 (3.2%), anti-PL-12 (2.7%), anti-PM/Scl75 (2.7%), and anti-PM/Scl100 (2.7%). The distributions of these autoantibodies were comparable between polymyositis and dermatomyositis, except for a higher prevalence of anti-Jo-1 in polymyositis. Anti-Mi-2 was more prevalent in dermatomyositis. Notably, in the multivariate analysis, anti-Mi-2 and anti-Ro-52 were associated with photosensitivity and pulmonary disorders, respectively, in dermatomyositis. Anti-Jo-1 was significantly correlated with pulmonary disorders in polymyositis. Moreover, anti-Ro-52 was associated with anti-Jo-1 in both diseases. No significant correlation was observed between the remaining autoantibodies and the clinical and/or laboratory findings. CONCLUSIONS: Our data are consistent with those from other published studies involving other populations, although certain findings warrant consideration. Anti-Ro-52 and anti-Jo-1 were strongly associated with one another. Anti-Ro-52 was correlated with pulmonary disorders in dermatomyositis, whereas anti-Jo-1 was correlated with pulmonary alterations in polymyositis.

A síndrome do lúpus neonatal (SLN) é uma doença auto-imune associada à presença de auto-anticorpos na circulação materno-fetal contra complexos ribonucléicos, SSA/Ro e SSB/La, e se caracteriza principalmente por bloqueio cardíaco congênito isolado (BCCI) e/ou manifestações cutâneas e hematológicas. A despeito da sua raridade, a SLN é a principal causa de BCCI, sendo responsável pela importante mortalidade (20% a 30%) e morbidade desses pacientes. A denominação de lúpus neonatal se baseia na semelhança das lesões cutâneas associadas à SLN nos neonatos com aquelas observadas em pacientes com lúpus eritematoso sistêmico (SLE). Por outro lado, o termo "isolado", para designar o BCC na SLN, é utilizado para especificar a ausência de malformações cardíacas congênitas e a ausência de infecções que causam alterações na condução átrio-ventricular (BAV). A SLN constitui-se num clássico modelo de auto-imunidade adquirida, no qual os anticorpos IgG maternos atravessam a barreira placentária e na circulação fetal podem exercer um papel importante na patogênese da síndrome. A presença quase universal dos anticorpos anti-Ro/SSA e anti-SSB/La no soro materno e fetal os inclui como marcadores para a SLN. Ao contrário da lesão cardíaca que compromete irreversivelmente a condução átrio-ventricular, os acometimentos cutâneos e/ou hematológicos são transitórios e podem regredir após o desaparecimento dos anticorpos maternos da circulação do lactente. Clinicamente, a SLN representa um desafio para profissionais reumatologistas, obstetras, neonatalogistas, dermatologistas e cardiologistas pediátricos que têm como meta identificar o risco gestacional de desenvolvimento da doença fetal, diagnosticar a síndrome precocemente e definir uma estratégia terapêutica adequada quando "in utero" ou pós-natal.

Neonatal Lupus Syndrome (NLS) is an autoimmune disease associated to the presence of autoantibodies against ribonucleoproteins SSA/Ro and/or SSB/La in the maternal-fetal circulation and is characterized by isolated congenital heart block (ICHB) and/or cutaneous and hematological manifestations. Despite the rarity, NLS is the main cause of ICHB, which is responsible for the significant mortality (20%-30%) and morbidity of these patients. The neonatal lupus designation comes from the observation of cutaneous lesions similarities between NLS and systemic lupus erythematosus. The isolated term to define the CHB in NLS is employed to exclude cardiac abnormalities secondary to congenital structural malformations or infections. NLS is considered a model of passively acquired autoimmunity in which maternal autoantibodies cross the placenta and, once in fetal circulation, may play a role in the pathogenesis of the syndrome. The almost universal presence of anti-SSA/Ro and/or anti-SSB/La antibodies in the maternal and fetal circulation validates them as serological markers of NLS. Contrasting with the fetal cardiac tissue lesion, which is an irreversible process, cutaneous and hematological involvements are transitory manifestations and disappear after the clearance of maternal autoantibodies from the infant's circulation. It is important to notice that NLS represents a multidisciplinary challenge involving rheumatologists, obstetricians, neonatologists, dermatologists and pediatric cardiologists to identify the pregnancy at risk for NLS development and to introduce appropriate in utero or postnatal therapeutic strategies.