Deteccao de anticorpos antinucleares por imunofluorescencia indireta em celulas HEp-2: definindo a diluicao de triagem adequada para o diagnostico das doencas reumaticas autoimunes / Detection of anti-nuclear antibodies by indirect immunofluorescence on HEp-2 cells: setting the appropriate screening dilution for the diagnosis of autoimmune rheumatic diseases

Objetivo: Definir o título anormal e a diluição de triagem adequada para o teste de FAN (fator antinúcleo) por imunofluorescência indireta em células HEp-2 (FAN HEp-2). Métodos: Realizamos a pesquisa do FAN HEp-2 em amostras de soro de 126 indivíduos saudáveis. As amostras foram triadas na diluição de 1:80, e aquelas positivas diluídas até o título de 1:5120. O título anormal de FAN foi definido como aquele correspondente ao percentil 95 do teste nesta população. A sensibilidade dos diferentes títulos do FAN foi determinada em um grupo de 136 pacientes com diagnóstico de doença reumática autoimune, e a especificidade em um grupo de 118 pacientes com diagnóstico de outras doenças reumáticas. O valor de corte ótimo do teste foi determinado pelo estudo da curva ROC. Resultados: A frequência de FAN positivo em indivíduos saudáveis foi de 13,2%. Não houve diferença na frequência de resultados positivos de acordo com o gênero ou a idade. O título anormal do FAN foi definido como a diluição de 1:160. A diluição dos soros de 1:80 apresentou sensibilidade de 87,7% e especificidade de 67,8%, enquanto a diluição de 1:160 apresentou sensibilidade de 82% e especificidade de 73,7%. Pela análise da curva ROC, a diluição de 1:160 correspondeu ao valor de corte ótimo. Conclusão: O título anormal e o valor de corte ótimo do FAN HEp-2 na população avaliada foram de 1:160. A diluição de 1:160 é, portanto, a diluição de triagem ideal, com melhor especificidade, porém sem comprometimento significativo da sensibilidade diagnóstica do teste. .

Objective: To establish the abnormal title and the appropriate screening dilution for ANA (antinuclear antibodies) test by indirect immunofluorescence on HEp-2 cells (ANA HEp-2). Methods: An analysis of ANA Hep-2 in serum samples from 126 healthy individuals was performed. The samples were screened at a dilution of 1:80, and those positive were diluted to the title of 1:5120. The abnormal title of ANA was defined as that corresponding to the 95th percentile of the test in this population. The sensitivity of the different titles of antinuclear antibodies was determined in a group of 136 patients with a diagnosis of autoimmune rheumatic disease, and the specificity was determined in a group of 118 patients with other rheumatic diseases. The optimal cutoff value of the test was determined by ROC curve analysis. Results: The frequency of ANA positivity in healthy subjects was 13.2%. There was no difference in the frequency of positive results according to gender or age. The abnormal title of ANA was defined as the dilution of 1:160. The 1:80 dilution had sensitivity of 87.7% and specificity of 67.8%, while the 1:160 dilution had sensitivity of 82% and specificity of 73.7%. By ROC curve analysis, a dilution of 1:160 corresponded to the optimal cutoff value. Conclusion: The abnormal title and the optimal cutoff value of ANA HEp-2 in the population was 1:160. Therefore, the dilution of 1:160 is the optimal screening dilution, with better specificity but without significantly compromising the sensitivity of the diagnostic test. .

Acidosis tubular renal distal y litiasis renal en tres casos de síndrome de Sjögren primario / Distal renal tubular acidosis and renal lithiasis in 3 cases of primary Sjögren's syndrome

Tubulo interstitial nephritis, the main manifestation of renal involvement in Sjögren syndrome, may lead to a tubular dysfunction that is usually subclinical. We report 3 women, aged 32, 35 and 35 years old, with a primary Sjögren's syndrome and symptomatic type I or distal tubular acidosis. Two patients had nephrolithiasis and one a nephrocalcinosis. Two had a basal hyperchloremic metabolic acidosis. The ammonium chloride acidification test was abnormal in all, demonstrating a distal tubular defect. None had proximal tubular dysfunction. All had an urinary pH over 6.5 and hypocitraturia and none had hypercalciuria. Renal calculi were composed of calcium oxalate and calcium phosphate in 2 patients and calcium phosphate and ammonium phosphate in the other. All women had positive antinuclear antibodies with mottled pattern, 2 had anti Ro antibodies and positive rheumatoid factor and 1 had hypergammaglobulinemia. None had anti La antibodies, crioglobulinemia or monoclonal proteins

Anticuerpos anticitoplasmas de neutrófilos y colitis ulcerosa inespecífica / Neutrophil anticytoplasmic antibodies and idiopathic ulcerative colitis

We studied tha presence of antineutrophil cytoplasmic antibodies in 16 patients with idiopathic ulcerative colitis, using an indirect immunofluorescence technique and specific ELISA for myeloperoxidase and proteinase 3. Twelve patients had an active disease and in ten, antineutrophil cytoplasmic antibodies were positive, with a predominantly perinuclear distribution and without specificity for myeloperoxidase or proteinase 3. These antiantineutrophil cytoplasmic antibodies could be serologic indicators of disease activity in patients with ulcerative colitis

Producción y análisis de proteínas recombinantes obtenidas de la cepa lisogénica Ro-531

La expresión del cDNA que codifica al antígeno Ro, fue evaluada usando la clona Ro=531 gt11 cuyos productos de traducción fueron inmunorreconocidos por un suero anti-Ro. La producción de proteína Ro recombinante, fue inducida en la cepa lisogénica E. coli Y1089. La antigenicidad de la proteína fue probada por Western blot y por ELISA. En la primera prueba, 15 de los 20 sueros anti-Ro positivos presentaron fuerte reactividad a la proteína de funsión Ro y 4 de los 20 sueros controles, mostraron reactividad débil. Por la técnica de ELISA, se observó una reacción más específica, ya que 15 de los 20 sueros anti-Ro positivos exhibieron afinidad por la proteína Ro recombinante y ninguno de los controles presentó falsos positivos