Reduced schedule of human anti rabies immunization with Fuenzalida & Palacios vaccine

The present study evaluates the humoral and cellular immune responses in 35 volunteers submited to short antirabies vaccination schedules with the Fuenzalida & Palacios vaccine based on the administration of doses on non consecutive days. The volunteers were divided into two groups. The first group received a total number of five doses given on days 0, 4, 7, 20 and 35. The other group received four doses, the first one being a double dose given on day 0 and than three other single doses on days 7, 20 and 35. The evaluation of humoral immune response was carried out by serum neutralization (SN) and indirect immunofluorescense (IIF) tests, while the cellular immune response was evaluated by lymphoblastic transformation assay (LTA) and skin test (ST). According to our results these reduced schedules elicited early and effective humoral and cellulafimmune responses to rabies antigen suggesting that new reduced schedules should be extensively studied in order to give the proper bases to the proposition of changes in the current long-term schedule.

Comparison of serum hepatitis B virus replication markers in patients with chronic hepatitis B: studies on HBeAg/Anti-HBe system, viral dna polymerase and HBV-DNA

The detection of HBV-DNA in serum by molecular hybridization is the most sensitive and specific marker of replication and infectivity of hepatitis B virus and currently is proposed as a routine diagnostic technique in the follow-up of HBV - related diseases. Comparing different techniques already described, we found that direct spotting of serum samples on nitrocellulose membranes under vacuum filtration, followed by denaturing and neutralizing washes is more practical, simple, sensible and reproducible. DNA polymerase assay using phosphonoformic acid as specific viral inhibitor has shown 86.8% of concordance with HBV-DNA detection, and so, it is an useful alternative in the follow-up of hepatitis B chronic patients. We found 19.2% HBeAg positive samples with no other markers of viral replication and no anti-HBe positive sample had detectable HBV-DNA. Discordance between the 2 systems have been extensively described, and we confirm this for the first time in our country. Molecular biological techniques are essential to determine the replication status of chronic hepatitis B patients.

Enzyme linked immunosorbent assay: determination of anti-adenovirus antibodies in an infant population

In order to define an accurate assay for anti-adenovirus antibody detection, a recently developed ELISA was compared with IFA and CF. On 58 sera, the ELISA was more sensitive than both CF and IFA, which showed relative sensitivities of 63% and 94%, respectively. It was not possible to determine the exact specificity of the tests because of the lack of a gold standard. Furthermore, the ELISA was used to define the prevalence of adenovirus antibodies in 116 infants between 1 and 24 months old (mean 7.28). The data showed that maternal antibodies waned by the age of 5 to 6 months and that more than 80% of the children had been infected by adenoviruses by the age of 10 months.

Toxoplasmose aguda: avaliação da técnica de imunoensaio em camada delgada para a detecção de anticorpos IgM, anti-Toxoplasma gondii

Um método de reação antígeno-anticorpo denominado IMUNOENSAIO EM CAMADA DELGADA (ICD) foi padronizado e avaliado para o imunodiagnóstico da toxoplasmose aguda, através da detecção de anticorpos IgM, anti-Toxoplasma gondii (ICD-IgM). Um total de 300 amostras de soros, tendo ou não o perfil sorológico da toxoplasmose aguda, foi estudado pelo ICD-IgM e os resultados analisados quanto aos aspectos qualitativos e quantitativos em relação aos testes convencionais de imunofluorecência indireta para a detecção de IgM, (IFI-IgM) e de hemaglutinação pré e após tratamento com 2-mercaptoetanol (HA-2ME). Foram calculados os coeficientes de correlação entre os resultados fornecidos pelo ICD-IgM e as técnicas convencionais, de acordo com as concentrações do antígeno, assim como, foi verificada a influência dessas concentrações antigênicas nos índices relativos de sensibilidade e de especificidade. O estudo estatístico mostrou reprodutibilidades significativas dos resultados inter e intra testes, assim como no reaproveitamento do antígeno por 10 vezes. Os resultados de ICD-IgM mostraram que as concentrações antigênicas ideais foram de 70 a 100µg/ml, para o ensaio em questão, para se obter máximas sensibilidade e especificidade. Portanto, ICD-IgM, por fornecer resultados tão sensíveis e específicos quanto aqueles dos testes convencionais referidos, poderá ser empregado para fins diagnósticos.

Teste imunoenzimático para pesquisa de anticorpos anti-Cysticercus cellulosae em líquidos cefalorraquianos de pacientes com meningites de etiologia indeterminada

Foi empregado o teste imunoenzimático com componentes antigênicos de Cysticercus cellulosae quimicamente ligados a suporte inerte constituído por discos de tecido-resina, ELISA-d, com a finalidade de investigar a entidade neurocisticercose (NC) em líquidos cefalorraquianos (LCR) de pacientes com meningites de etiologia indeterminada. Foram ensaiados 277 LCR de 128 crianças e 149 adultos. A densidade óptica média (DO) obtida para os 22 LCR de pacientes nos quais foi afastada a possibilidade diagnóstica de meningite foi de 0,03. Os 44 LCR de pacientes com meningites determinadas por diversos agentes etiológicos, não cisticercose, apresentaram DO de 0,05. O limiar de reatividade do teste ELISA-d calculado a partir desses dois grupos (controle) foi de 0,13 (DO + 3SD). No grupo de 13 LCR de pacientes com NC comprovada em episódio meningítico por essa causa, foi observada DO de 0,41 (0,10 a 0,91) no teste ELISA-d. Dos 198 LCR de meningites por agente etiológico não identificado pelos métodos usualmente empregados, 23 (11,6%) apresentaram DO acima de 0,13, sugerindo que a possível causa da meningite tenha sido por cisticercose, uma vez que o teste ELISA-d tem apresentado elevadas sensibilidade, especificidade e reprodutibilidade. Em cinco dos 23 LCR a alteração no exame quimiocitológico era às custas do aumento do número de células predominantemente linfomononucleares, em 13 o predomínio era de polimorfonucleares e nos cinco restantes ambos os tipos de células estavam em número aumentado.

DOT-ELISA for detection of anti-Cysticercus cellulosae antibodies in human cerebrospinal fluid using a new solid-phase (resin-treated polyester fabrics): preliminary report

A dot enzyme-linked immunosorbent assay (DOT-ELISA) was developed to detect specific antibodies in cerebrospinal fluid (CSF) for human neurocysticercosis immunodiagnosis, with Cysticercus cellulosae antigen dotted on a new solid-phase. This was represented by sheets of a synthetic polyester fabric impregnated with a polymerized resin (N-methylol-acrylamide). A very stable preparation was thus obtained, the antigen being covalently bound by cross-linking with free N-methylol groups on the resin. Since robust, no special care was necessary for handling the solid-phase. The test could be performed at room-temperature. From 30 CSF samples assayed, 14 were positive, from a group of 15 cases of neurocysticercosis, with titers from 1 to 128; 15 other samples, from normals or other neurological diseases, were all negative. Test characteristics seem to indicate it as adequate for epidemiological surveys. A more detailed study on sensitivity, specificity, reproducibility and the use in serum samples is being conducted.

UltramicroELISA para la detección de anticuerpos IgM anti M. leprae

La disponibilidad del sistema Ultramicroanalítico (SUMA) y de un antígeno especie-específico del M. leprae obtenido mediante síntesis química, permitió la normalización y validación de un ultramicroELISA para la detección de anticuerpos IgM específicos a esta micobacteria. El análisis de 433 sueros de banco de sangre y 265 sueros usados para validar el método y clasificados en un grupo control de donantes de banco de sangre (100), un grupo de pacientes tuberculosos (50), un grupo de enfermos de lepra (65) y un grupo de contactos de estos enfermos (50), mostró la especificidad del ensayo para evidenciar la infección con el M. leprae. Los resultados obtenidos del estudio adicional de 140 muestras de suero de contactos de enfermos estuvieron estrechamente correlacionados (r = 0,98) con los resultados obtenidos por la técnica de microELISA convencional. La utilización del SUMA no solo permite un notable ahorro de reactivos si no además facilita la lectura, cálculo, validación y almacenamiento automático de los resultados.

Prevalências do HBsAg, do anti-HBc e do anti-HCV na população de candidatos a doadores de sangue do Hemocentro-Campinas

Em 29833 doadores pesquisados encontramos prevalência de 1,52% para o HBsAg e de 11% para o anti-HBc. A co-positividade anti-HBc/anti-HBs em 2783 doadores HBsAg negativos/anti-HBc positivos foi de 81,9%. A prevalência para o HBsAg é baixa nos doadores de Campinas, enquanto o anti-HBc apresenta-se com prevalência elevada quando comparado a outros países. A pesquisa do anti-HCV, em doadores de sangue de Campinas, mostrou prevalência de 2,6% para este marcador, que é bem maior que as observadas nos EUA e Europa. Cerca de 36% dos doadores anti-HCV positivos são anti-HBc reagentes, permitindo inferir, que estas duas viroses acometem simultânea ou sequencialmente os doadores de sangue brasileiros.

Hepatites pós-transfusionais na cidade de Campinas, SP, Brasil: II. Presença dos anticorpos anti-HBc e anti-HCV em candidatos a doadores de sangue e ocorrência de hepatites pós-transfusionais pelo vírus C nos receptores de sangue ou derivados

Pesquisamos os anticorpos anti-HBc e anti-HCV em amostras de soros provenientes de 799 candidatos a doadores, que tiveram suas unidades de sangue ou derivados transfundidas a 111 receptores. O anti-HBc e o anti-HCV foram reagentes, em respectivamente 9 e 2,1% dos doadores testados. Observamos que entre os 111 receptores, 44 haviam recebido pelo menos uma unidade anti-HBc positiva e 67 haviam sido transfundidos somente com unidades anti-HBc negativas. Houve um risco 4,5 vezes maior de aquisição de hepatite por vírus C pelos receptores que receberam pelo menos uma unidade anti-HBc positiva Se a pesquisa do anti-HBc fosse realizada na triagem sorológica dos doadores de sangue, cerca de 56% dos casos de HVC nos receptores saiam evitados. A população de receptores que recebeu pelo menos uma unidade anti-HCV reagente, apresentou um risco 29 vezes maior de adquirir esta hepatite, quando comparada aos receptores transfundidos com todas as unidades anti-HCV negativas. A realização do teste para a pesquisa do anti-HCV na triagem dos doadores de sangue, preveniria 79% dos casos de HVC pós-transfusionais. Os candidatos a doadores brasileiros parecem ser acometidos simultânea ou sequencialmente, pelos vírus B e C das hepatites, pois, 44,4% dos doadores anti-HCV positivos, também foram anti-HBc positivos. A realização dos testes para as pesquisas dos anticorpos anti-HBc e anti-HCV, nas triagens hemoterápicas, está indicada para prevenir a transmissão de hepatites pós-transfusionais, em nosso meio.

Reduced schedule of human anti-rabies immunization with Fuenzalida & Palacios vaccine: additional data

It was reevaluated a reduced schedule for anti-rabies post-exposure immunization with newborn mice nervous tissue vaccine (Fuenzalida 8c Palacios) in a group of 30 non exposed volunteers. The vaccine was administered by intramuscular injections on days zero, 2, 4, 16 and 27, in the deltoid area. Antibody levels were determinated by a simplified serum neutralization microtest on days zero, 16 and 37. On days 16 and 37 the antibody levels of the whole group was >0.5 IU/ml and >1.0 IU/ml, respectively. The cell mediated immunity was precociously detected (on day 4) by the delayed type hipersensitivity skin test. Our results show that this reduced schedule elicited an early and effective humoral and cellular immune response. However it is necessary other studies with larger groups of vaccinees in order to obtain definitive conclusion.

Detection of hepatitis B virus DNA by the polymerase chain reaction in anti-HBE positive chronic hepatitis B patients

Detection of HBV-DNA by PCR was compared with other serological markers (HBsAg, HBeAg and anti-HBe) in a series of49 Chronic Hepatitis B patients, including 12 with a spontaneous clearance of HBsAg. None of these HBsAg negative cases were PCR positive, but 33/37 (89.2%) HBsAg positive cases were PCR positive (p < 0.0001). Among HBsAg positive samples, nine cases were HBeAg positive and anti-HBe negative, all of them PCR positive. Other 3 patients were HBeAg and anti-HBe positive and these cases were also found PCR positive. A third group included 21 patients anti-HBe positive and HBeAg negative: 19 of them were PCR positive and 2 were PCR negative. The last 4 cases were HBeAg and anti-HBe negative, two of them were PCR positive. The detection of anti-HBe viremic cases in the present series suggest that preC variants could occur in our country. In conclusion, the integrated phase o f chronic hepatitis B seems to be less frequent than it was assumed, when only HBeAg or dot blot hybridization techniques were used. The new term "low replication phase" might favorably replace the former "integrated phase".

Seasonal variation of anti-resa/Pf155 Plasmodium falciparum antibodies in three localities from the state of Amapá, Brazil

Anti-RESA/Pf155 antibodies were assayed in sera of individuals from three localities (Laranjal do Jari, Vila Padaria and Vila Paraíso) in the State of Amapá, Brazil, during the long-rains and short-rains seasons. All of these had negative blood smears for malaria. Most of the sera collected were positive in Indirect Fluorescent Antibody (IFA) with P. falciparum parasites, with no seasonal variation. A high percentage of these sera (62% to 100%) was RESA positive by Modified Indirect Fluorescent Antibody (MIFA), with a significant (p < 0.05) increase of geometric mean titers during the short-rains season, when the transmission of the disease is highest. ELISA with three repetitive RESA peptides (EENV)3 (4x3), (EENVEHDA)2 (8x2) and (DDEHVEEPTVA)2(11x2) did not reveal statistically significant seasonal variations, although a small enhancement of positivity was observed in V. Padaria (15.3 to 38.8%) in the short-rains season with the 8x2 peptides, and with 4x3 and 8x2 peptides in V. Paraíso, with a decrease in 11x2. MIFA titers appeared to be correlated mainly to the peptide 4x3 and it was the immunodominant in the three localities.