Detecção e quantificação de anticorpos anti-rábicos neutralizantes pela técnica de citometria de fluxo

The determination of the rabies neutralizing antibody (VNA) response after immunization against rabies is an acceptable index of the efficacy of a vaccine and a successful treatment. Several tests have been developed in attempt to improve the assessment of VNA, from mice inoculation to cell-culture fluorescence inhibition tests. All of them, however, present special difficulties in terms of reading or accuracy. The present study describes a neutralization test performed in cell-culture appraised by flow cytometry (FC). Serial dilutions of the serum samples were mixed in vitro with rabies virus before the addition of BHK-21 cells. After 24h-incubation, cells were released by trypsin treatment, fixed and permeabilized with a p-formaldehyde solution and stained with a rabies virus nucleocapsid protein-specific antibody conjugate. The percentage of virus infection inhibition caused by specific antibodies present in the serum were evaluated in a Beckton & Dickinson FACSCalibur® flow cytometer. A correlation curve between the IU/ml content and the percentage of infective inhibition was built with a reference serum and the VNA titers of serum samples were obtained by extrapolation. Titers obtained by FC and standard test showed an effective pairing results (p < 0.01), with a correlation coefficient (r) = 0.7. These results permit to envisage the FC as a suitable technique to evaluate VNA in sera from immunized animals and likely in human serum samples. Nevertheless, new studies comparing FC to gold-standard techniques are required for determining the FC values of Sensibility and Specificity .A titulação de anticorpos neutralizantes contra o vírus rábico (AcN) pós-imunização é um parâmetro aceito como indicador de eficácia da vacina e do sucesso do processo de imunização. Este estudo descreve um teste de neutralização realizado em cultura de células, analisado através da técnica de citometria de fluxo. Diluições seriadas de amostras de soro foram misturadas in vitro com vírus rábico e adicionados a células BHK-21. Após incubação de 24 h, as células foram individualizadas por tratamento com tripsina, fixadas e permeabilizadas com p-formaldeído e coradas com conjugado específico. A porcentagem de inibição da infecção viral causada pelos anticorpos específicos presentes nas amostras de soro foi determinada em citômetro de fluxo Beckton & Dickinson FACSCalibur® e comparada com um soro de referência internacional. Os títulos de AcN foram determinados por extrapolação. Os níveis de correlação (r) entre os títulos obtidos com CF e SFIMT foi de 0.7712 (p < 0,001), e entre CF e ELISA de 0,6702 (p < 0,001). Os resultados indicam que a CF pode ser utilizada na análise de títulos de anticorpos neutralizantes em amostras de soro, com a vantagem de ser um método automatizado. No entanto, devem ser realizados novos estudos, comparando a CF com as técnicas consideradas como padrão ouro, para que os valores reais de Sensibilidade e Especificidade sejam determinados

NAPSI utilization as an evaluation method of nail psoriasis in patients using acitretin

BACKGROUND: assessment instruments of nail psoriasis have been published in literature as means to standardize the previous subjective assessments of authors. OBJECTIVES: Using Nail Psoriasis Severity Index for evaluation in patients with plaque psoriasis during treatment with acitretin. METHODS: Thirty volunteers with plaque psoriasis were selected for the study. Twenty patients (8 women and 12 men) completed the study. The initial dose of acitretin was 0.3 mg/kg/day for 30 days and was later raised to 0.5 mg/kg/day. Nail Psoriasis Severity Index was collected in the first evaluation, after 2 and 4 months. Nails of both hands were evaluated. RESULTS: nail lesions were present in all patients at first evaluation. The initial Nail Psoriasis Severity Index median was 20 and the final score 20.5 (2.5% of worsening at the end of the study). No statistically significant difference between the three evaluations was found (X2 = 0.8084, GL = 2, p = 0.6657). Seven patients worsened in the final score. Three patients improved 50% of the initial Nail Psoriasis Severity Index and only one had an improvement of 75%. Linear correlation showed a weak association between the improvement percentage in PASI and Nail Psoriasis Severity Index (r = 0.105, F = 2.12, p = 0.162). CONCLUSION: The method was easy and of rapid execution while potentially bringing information about changes in nail plate and matrix during treatment. The Nail Psoriasis Severity Index does not quantify the existing lesions and might not have the sensitivity to detect small changes

Perfil de autoanticorpos e correlação clínica em um grupo de pacientes com esclerose sistêmica na região sul do Brasil Autoantibody profile and clinical correlation in a group of patients with systemic sclerosis in southern Brazil

OBJETIVOS: Este estudo visou à análise das manifestações da esclerose sistêmica (ES), com ênfase na pesquisa dos autoanticorpos e de suas correlações clínicas, na população de pacientes em acompanhamento no ambulatório de ES do Hospital de Clínicas da Universidade Federal do Paraná. METODOLOGIA: Realizou-se um estudo transversal com 96 pacientes em acompanhamento no ambulatório de ES do hospital, entre setembro de 2007 e setembro de 2009. RESULTADOS: A maioria dos pacientes era do sexo feminino, com idade entre a quarta e quinta décadas e tempo de doença com mediana de 10 anos. A forma cutânea limitada de ES foi a mais prevalente. Na análise dos autoanticorpos, o anticorpo anticentromérico (ACA) associou-se a ES forma limitada, idade mais avançada ao diagnóstico, maior tempo de doença, intervalo maior entre o surgimento do fenômeno de Raynaud (FRy) e o primeiro sintoma não FRy, maior prevalência de hipertensão arterial sistêmica (HAS) e de bloqueios de condução cardíaca. O anticorpo antitopoisomerase-1 (antitopo-1, previamente denominado anti-Scl-70) foi mais comum na forma difusa da ES, na presença de doença ativa e de úlceras digitais. O anticorpo anti-RNA polimerase III (antipol III) correlacionou-se com a forma difusa de ES, presença de doença ativa e sinovite. CONCLUSÕES: Este estudo vem ressaltar e ratificar o papel relevante dos autoanticorpos na avaliação dos pacientes com ES, sendo possível correlacionar o perfil autoimune dessa população com manifestações específicas da doença<br>OBJECTIVES: To assess the manifestations of systemic sclerosis (SSc), with an emphasis on the analysis of autoantibodies and their clinical correlations, in a population of patients followed up at the SSc Outpatient Clinics of the Hospital de Clínicas of the Universidade Federal do Paraná. METHODOLOGY: Cross-sectional study with 96 patients followed up at the SSc Outpatient Clinics of the hospital between September 2007 and September 2009. RESULTS: Most patients were of the female sex, in their forties or fifties, and the median time of disease was ten years. The limited cutaneous form of SSc was more prevalent. The analysis of the autoantibodies showed the association of anticentromere antibody (ACA) with the following: the limited form of SSc; more advanced age at the time of diagnosis; longer disease time; longer interval between the appearance of the Raynaud's phenomenon (RyP) and the first non-RyP symptom; systemic arterial hypertension (SAH); and cardiac conduction blocks. The antitopoisomerase-1 antibody (ATA-1, previously called anti-Scl-70) was more common in the presence of the diffuse form of SSc, active disease, and digital ulcers. The anti-RNA polymerase III antibody (anti-Pol III) correlated with the diffuse form of SSc, disease activity, and synovitis. CONCLUSIONS: This study emphasizes and confirms the important role of autoantibodies in assessing patients with SSc, allowing the correlation between the autoimmune profile of patients with SSc and specific manifestations of the diseas

Calculating rabies virus neutralizing antibodies titres by flow cytometry

The determination of the rabies neutralizing antibody (VNA) response after immunization against rabies is an acceptable index of the efficacy of a vaccine and a successful treatment. Several tests have been developed in attempt to improve the assessment of VNA, from mice inoculation to cell-culture fluorescence inhibition tests. All of them, however, present special difficulties in terms of reading or accuracy. The present study describes a neutralization test performed in cell-culture appraised by flow cytometry (FC). Serial dilutions of the serum samples were mixed in vitro with rabies virus before the addition of BHK-21 cells. After 24h-incubation, cells were released by trypsin treatment, fixed and permeabilized with a p-formaldehyde solution and stained with a rabies virus nucleocapsid protein-specific antibody conjugate. The percentage of virus infection inhibition caused by specific antibodies present in the serum were evaluated in a Beckton &amp; Dickinson FACSCalibur® flow cytometer. A correlation curve between the IU/ml content and the percentage of infective inhibition was built with a reference serum and the VNA titers of serum samples were obtained by extrapolation. Titers obtained by FC and standard test showed an effective pairing results (p < 0.01), with a correlation coefficient (r) = 0.7. These results permit to envisage the FC as a suitable technique to evaluate VNA in sera from immunized animals and likely in human serum samples. Nevertheless, new studies comparing FC to gold-standard techniques are required for determining the FC values of Sensibility and Specificity