ABSTRACT
No presente estudo foi investigado o impacto dos múltiplos ciclos de congelamento e descongelamento na estabilidade das amostras de soro estocadas a -20 °C quanto à reatividade de anticorpos anti-HIV. As amostras analisadas foram provenientes de painéis de soros (constituídos de amostras anti-HIV positivo e negativo), produzidos no Centro de Imunologia Instituto Adolfo Lutz (IAL), os quais têm sido material de referência para o preparo de amostras do controle de qualidade interno de testes imunodiagnósticos de HIV/Aids. A avaliação da estabilidade dos soros foi efetuada por meio de ELISA/EIA, Western blot e imunofluorescência indireta, em amostras submetidas a 11 consecutivos ciclos de congelamento e descongelamento, que variaram de 7 a 60 ciclos. Nenhum efeito estatisticamente significante na reatividade dos anticorpos específicos foi observado. Portanto, o procedimento de congelamento e descongelamento, em até 60 ciclos, não causou efeitos adversos na reatividade das amostras de soro positivas para detecção de anticorpos anti-HIV, sem ocorrência de reações falso-negativas, tampouco de resultados falso-positivos em amostras negativas para HIV.(AU)
The present study investigated the impact of multiple and consecutive freeze-thaw cycles on the reactivity of anti-HIV antibodies in stored serum samples by using different methodologies for detecting the specific antibodies. The analyzed sera were part of serum panels (comprised of anti-HIV positive and negative samples), produced at the Center of Immunology Instituto Adolfo Lutz, which have been the reference specimens for producing internal quality assurance sera of HIV/Aids immunodiagnostic assays. After performing every step of 11 consecutive and multiple freeze-thaw cycles procedure (varying from 7 to 60 cycles), the HIV antibody reactivity in the respective sera was evaluated by means of EIA/ELISA, Western blot and indirect immunofluorescence methodologies. No statistically significant effect on the specific antibody reactivity was found in sera after completing the freeze-thaw process up to 60 cycles. Neither false-negative reactions in HIV antibody positive sera, nor false-positive results in HIV-negative samples were detected.(AU)
Subject(s)
Freezing/adverse effects , HIV Antibodies/adverse effects , Quality Control , Immunologic Tests/adverse effects , Reactivity-Stability , Enzyme-Linked Immunosorbent Assay/adverse effectsABSTRACT
OBJECTIVE: To report the results of open challenge tests performed in children fed with cow's milk-free diet. DESCRIPTION: Cross-sectional study evaluating cow's milk open challenge performed under supervision in a hospital setting during 2.5 hours and ambulatory follow-up for 30 days when no immediate reaction occurred. One hundred and twenty-one patients were included, with ages between 4 and 95 months. Cow's milk open challenge tests were positive in 28 patients (23.1%). A clinical manifestation of cow's milk allergy different from the one presented at diagnosis occurred in 12 (24.9%) patients with positive challenge. Positive challenge was more frequent (p = 0.042) in patients fed with extensively hydrolyzed formulae or amino acid-based formulae (30.3%) when compared to those fed with other exclusion diets (14.5%). CONCLUSION: Open challenge allowed the interruption of exclusion diet in a significant proportion of the patients.
Subject(s)
Immunologic Tests/adverse effects , Immunologic Tests/methods , Milk Hypersensitivity/diagnosis , Milk/adverse effects , Animals , Child , Child, Preschool , Cross-Sectional Studies , Female , Humans , Infant , Male , Milk Hypersensitivity/diet therapy , Milk Hypersensitivity/etiologyABSTRACT
OBJETIVO: Relatar os resultados de testes de desencadeamento aplicados em crianças alimentadas com dieta de exclusão das proteínas do leite de vaca. DESCRIÇÃO: Estudo transversal que avaliou testes de desencadeamento oral aberto, com leite de vaca, realizados sob supervisão em ambiente hospitalar por 2,5 horas e ambulatoriamente por 30 dias quando não ocorreu reação imediata. Foram incluídos 121 pacientes, com idades entre 4 e 95 meses. O teste de desencadeamento com leite de vaca foi positivo em 28 (23,1 por cento) pacientes. Manifestação clínica de alergia ao leite de vaca diferente da apresentada por ocasião da suspeita diagnóstica ocorreu em 12 (42,9 por cento) pacientes com desencadeamento positivo. O desencadeamento positivo foi mais frequente (p = 0,042) nos pacientes alimentados com fórmulas extensamente hidrolisadas ou de aminoácidos (30,3 por cento) quando comparados com os alimentados com outras dietas de exclusão (14,5 por cento). CONCLUSÃO: O teste de desencadeamento permitiu que fosse suspensa a dieta de exclusão de grande parte dos pacientes.
OBJECTIVES: To report the results of open challenge tests performed in children fed with cow's milk-free diet. DESCRIPTIONS: Cross-sectional study evaluating cow's milk open challenge performed under supervision in a hospital setting during 2.5 hours and ambulatory follow-up for 30 days when no immediate reaction occurred. One hundred and twenty-one patients were included, with ages between 4 and 95 months. Cow's milk open challenge tests were positive in 28 patients (23.1 percent). A clinical manifestation of cow's milk allergy different from the one presented at diagnosis occurred in 12 (24.9 percent) patients with positive challenge. Positive challenge was more frequent (p = 0.042) in patients fed with extensively hydrolyzed formulae or amino acid-based formulae (30.3 percent) when compared to those fed with other exclusion diets (14.5 percent). CONCLUSION: Open challenge allowed the interruption of exclusion diet in a significant proportion of the patients.