INTRODUCTION: Rheumatic diseases are considered public health problems affecting millions of people worldwide resulting in high and rising health-care costs. In this work, Fourier Transform Infrared spectroscopy associated to Partial Least Square regression (PLS) analysis was used to diagnose rheumatoid arthritis (RA) from human serum. METHODS: The sera of 94 individuals were collected, which included 47 from rheumatic patients and 47 from healthy individuals. The results from PLS analysis were compared to standard clinical trials such as anti-citrullinated peptide antibodies, C- Reactive protein, and Rheumatoid factor. RESULTS: For clinical diagnosis, the anti-citrullinated peptide antibodies of second generation proved to be the most specific to diagnosis rheumatoid arthritis even after long periods of drug therapy. CONCLUSIONS: The qualitative PLS analysis has shown higher values of IgM of RA group, but the difference was very small. The RA patients were under medication, which interfered with the IgM concentration.

OBJETIVOS: Determinar a frequência de anticorpos contra componentes da cromatina no lúpus eritematoso sistêmico juvenil (LESJ) e correlacionar a presença desses autoanticorpos com manifestações clínicas e atividade da doença. MÉTODOS: Os anticorpos anticromatina (anti-CHR), antinucleossomo (anti-NCS) e anti-dsDNA foram medidos em 175 indivíduos, incluindo 37 pacientes com LESJ ativo e 41 com doença inativa, 47 com doenças autoimunes não lúpicas, e 50 crianças saudáveis. Um teste ELISA in house foi desenvolvido com nucleossomos purificados a partir de timo de bezerro para determinar os anticorpos IgG e IgG3 anti-NCS. Anti-CHR e anti-dsDNA foram detectados por kits comerciais de ELISA (INOVA). RESULTADOS: Anticorpos anti-NCS e anti-CHR exibiram não só uma alta especificidade para LESJ, mas também uma frequência semelhante em LESJ ativo e inativo. Os níveis séricos de anti-CHR e IgG/IgG3 anti-NCS não diferiram entre LESJ ativo e inativo. Houve correlação entre o SLEDAI e os anticorpos anti-dsDNA, mas não com os anticorpos contra outros componentes da cromatina. Houve associação de anticorpos anti-dsDNA, anti-CHR e IgG/IgG3 anti-NCS com proteinúria e baixos níveis séricos de C4. Foram observados anticorpos anti-NCS em 14% dos pacientes com LESJ na ausência de anticorpos anti-dsDNA. CONCLUSÕES: Nossos dados indicam que os anticorpos anti-NCS e anti-CHR são marcadores diagnósticos relevantes para LESJ e parecem estar correlacionados com a atividade da nefrite lúpica no LESJ. O anticorpo IgG3 anti-NCS não parece ser mais relevante como marcador de atividade da doença ou nefrite ativa no LESJ em comparação ao anticorpo IgG anti-NCS.

OBJECTIVES: To determine the frequency of antibodies to chromatin components in juvenile systemic lupus erythematosus (JSLE), and to correlate the presence of these autoantibodies with clinical manifestations and disease activity. METHODS: Anti-chromatin (anti-CHR), anti-nucleosome core particle (anti-NCS) and anti-dsDNA antibodies were measured in 175 individuals, including 37 patients with active JSLE and 41 with inactive disease, 47 non-lupus autoimmune disease patients (non-lupus AD), and 50 healthy children. An in-house ELISA was developed with purified nucleosome core particles from calf thymus to determine IgG and IgG3 anti-NCS antibodies. Anti-CHR and anti-dsDNA antibodies were detected by commercial ELISA kits (INOVA). RESULTS: Anti-NCS and anti-CHR antibodies exhibited high specificity for JSLE and similar frequency in active and inactive JSLE. Anti-CHR and IgG/IgG3 anti-NCS serum levels did not differ between active and inactive JSLE. SLEDAI correlated with anti-dsDNA antibodies but not with antibodies to other chromatin components. There was association of anti-dsDNA, anti-CHR and IgG/IgG3 anti-NCS antibodies with proteinuria and low C4 serum levels. Anti-NCS antibodies in the absence of anti-dsDNA were observed in 14% of the JSLE patients. CONCLUSIONS: Our data indicate that anti-NCS and anti-CHR antibodies are relevant diagnostic markers for JSLE and appear to be correlated with JSLE lupus nephritis activity. IgG3 isotype anti-NCS antibodies do not seem to be more relevant than IgG anti-NCS antibodies as markers of disease activity or active nephritis in JSLE.

OBJETIVO: Avaliar a associação entre a presença de anticorpos antinucleossomo (anti-NCS) e a síndrome antifosfolipídica primária (SAFP) e o posterior desenvolvimento de lúpus eritematoso sistêmico (LES). MATERIAIS E MÉTODOS: Trinta e seis mulheres com o diagnóstico de SAFP foram avaliadas prospectivamente para manifestações de doenças reumáticas autoimunes e para a presença de anticorpos antifosfolípides, anticorpos antinucleares e anti-NCS/cromatina. RESULTADOS: Após um período médio de seguimento de 45,7 meses, anticorpos anti-NCS/cromatina foram detectados em apenas uma paciente (2,8%), que desenvolveu manifestações de LES tais como poliartrite, linfopenia, neurite óptica, lesões compatíveis com esclerose múltipla em substância branca cerebral e perfil de autoanticorpos altamente sugestivo de LES. CONCLUSÃO: A frequência de anticorpos anti-NCS/cromatina é baixa em pacientes com SAFP, e sua presença pode associar-se ao desenvolvimento de manifestações de LES.

OBJECTIVE: To study the association of anti-nucleosome (anti-NCS) antibodies in primary antiphospholipid syndrome (APS) and the development of systemic lupus erythematosus (SLE) during follow-up. MATERIALS AND METHODS: Thirty-six women with primary APS were evaluated prospectively for clinical features of systemic autoimmune diseases and for the presence of antiphospholipid antibodies, antinuclear antibodies and anti-NCS/chromatin antibodies. RESULTS: After a mean follow-up period of 45.7 months, anti-NCS/chromatin antibodies were detected in only one patient (2.8%), who developed features of SLE including polyarthritis, lymphopenia, optic neuritis, multiple sclerosis-like lesions, and an autoantibody profile suggestive of SLE. CONCLUSION: The frequency of anti-NCS/chromatin antibodies in primary APS patients is very low, and they may be associated with the development of SLE manifestations.