Stool examination and rectal biopsy in the diagnosis and evaluation of therapy of schistosomiasis mansoni

From each of a group of 217 adult males selected through enzyme-immunoassay or skin-test (Group A), six stool samples were examined by both the Lutz/Hoffman, Pons & Janer (Lutz/HPJ) and Kato/Katz methods. In addition, one oogram of the rectal mucosa was performed. By these methods, schistosomiasis was detected in 44.7%, 47.5% and 40.1% of the individuals respectively. To evaluate the methods in the assessment of cure, the last 40 patients from group A, treated with a single oral dose of oxamniquine at 15 mg/kg were followed up for six months (Group B). The criteria for parasitological cure included three stool examinations by Kato/Katz and Lutz/HPJ methods, one, three and six months post-treatment and a rectal biopsy between the fourth and sixth months post-treatment. The examinations were negative in 87.5%, 90% and 95% of the patients, respectively. The efficacy of oxamniquine was 82.5% when the three methods were considered together and there was no statistically significant difference between the sensitivity of the individual methods.

Antibodies against non-structural c100/3 and structural core antigen of hepatitis C virus (HCV) in hemodialysis patients

Two groups of patients undergoing hemodialysis (HD) maintenance were evaluated for their antibody response to non-structural c100/3 protein and structural core protein of hepatitis C virus (HCV). Forty-six patients (Group 1) never presented liver abnormalities during HD treatment, while 52 patients (Group 2) had either current or prior liver enzyme elevations. Prevalence rates of 32.6% and 41.3% were found for anti-c100/3 and anti-HCV core antibodies, respectively, in patients with silent infections (Group 1). The rate of anti-c100/3 in patients of Group 2 was 71.15% and reached 86.5% for anti-HCV core antibodies. The recognition of anti-c100/3 and anti-core antibodies was significantly higher in Group 2 than in Group 1. A line immunoassay composed of structural and non-structural peptides was used as a confirmation assay. HBV infection, measured by the presence of anti-HBc antibodies, was observed in 39.8% of the patients. Six were HBsAg chronic carriers and 13 had naturally acquired anti-HBs antibodies. The duration of HD treatment was correlated with anti-HCV positivity. A high prevalence of 96.7% (Group 2) was found in patients who underwent more than 5 years of treatment. Our results suggest that anti-HCV core ELISA is more accurate for detecting HCV infection than anti-c100/3. Although the risk associated with the duration of HD treatment and blood transfusion was high, additional factors such as a significant non-transfusional spread of HCV seems to play a role as well. The identification of infective patients by more sensitive methods for HCV genome detection should help to control the transmission of HCV in the unit under study.

Diagnosis of an EPS module

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Electrotécnica e Computadores

Acute schistosomiasis: clinical, diagnostic and therapeutic features

Three distinct syndromes caused by schistosomiasis have been described: cercarial dermatitis or swimmer's itch, acute schistosomiasis or Katayama fever, and chronic schistosomiasis. Complications of acute schistosomiasis have also been reported. The absence of a serological marker for the acute stage has hindered early diagnosis and treatment. Recently, an ELISA test using KLH (keyhole limpet haemocyanin) as antigen, has proved useful in differentiating acute from chronic schistosomiasis mansoni. Clinical and experimental evidence indicate that steroids act synergistically with schistosomicides in the treatment of Katayama syndrome. In this paper, clinical, diagnostic and therapeutic features of acute schistosomiasis are updated.

Clinical and laboratorial features of visceral toxocariasis in infancy

Forty children with a diagnosis of Visceral Toxocariasis were evaluated prospectively from February 1982 to June 1989. Diagnosis was established by clinical, laboratorial and serological (ELISA - ES Toxocara canis antigen) evaluations. A great clinical polymorphism was found in our patients, ranging from unspecific or absent manifestations to an exhuberant symptomatology. The laboratorial findings were: leukocytosis,eosinophilia and elevation of serum gammaglobulin and isohemagglutinin levels. No significant relationship between clinical findings and laboratorial parameters was found. Serology (ELISA) was a method of great diagnostic support but did not show a correlation with clinical and laboratorial findings in this study. There was a significant relationship between pulmonary manifestations and the presence of signs and/or symptoms, when the patients were sent to us. Our findings, especially the high incidence of pulmonary manifestations, suggest that Visceral Toxocariasis has to be included in the differential diagnostic of children with pulmonary manifestations, characteristic epidemiological data and associated eosinophilia.

Measles serodiagnosis: standardization and evaluation of a dot-ELISA

A Dot-ELISA using a measles virus (MV) antigen obtained by sodium deoxycholate treatment was standardized and evaluated for IgM and IgG antibody detection in measles patients and measles-vaccinated subjects. A total of 192 serum samples were studied, comprising 47 from patients with acute and convalescent measles, 55 from 9-month old children prior to measles vaccination and 41 from children of the same age after vaccination, and 49 from patients with unrelated diseases. The diagnostic performances of the IgG Dot-ELISA and IgG immuno fluorescence test (IFT) were found to be close, varying from 0.97 to 1.00 in sensitivity and the specificities were maximum (1.00). Nevertheless, the sensitivity of the IgM Dot-ELISA (0.85) was higher than that (0.63) of the IgM IFT, although both assays had comparably high (1.00) specificities. The IgM Dot-ELISA in particular proved to be more sensitive in relation to other assays studied by revealing antibodies in 80.0% (12/15) of vaccinated children on the 15th day after immunization. In contrast the IgM IFT, failed to detect antibodies in the same group of vaccinated children. The stability of the MV antigen was longer than that of the IFT antigen, and the reproducibility of the Dot-Elisa was satisfactory.

Schistosoma mansoni: identification of a 46KDa antigen of the schistosomular surface by monoclonal antibody

An IgG2a subclass monoclonal antibody, C6G9, was obtained by immunization of BALB/c mice with Schistosoma mansoni egg antigens. With this monoclonal antibody, it was possible to identify a schistosomular antigen with a molecular weight of 46 kilodaltons (KDa), and its expression being evaluated by means of indirect immunofluorescence. The antigen persisted in the integument of the developing schistosomulum, for at least 96 hours post-transformation. The monoclonal antibody also reacted with the cercaria surface, but not with that of adult worm. The C6G9 was also able to mediate significant levels of cytotoxicity in the presence of complement for newly transformed schistosomula.

Difficulties in diagnosing atypical primary HIV-1 infection

Several cases of primary HIV-1 infection are not identified, either because the diagnosis is not suspected or because they test negative for HIV-1 antibody. This work presents an uncommon case of primary HIV-1 infection in an young parenteral drug abuser man, who presented symptoms of acute hepatitis. During the initial acute phase the serum sample of the patient tested negative for the presence of antibodies against several viruses, including HIV-1. Nevertheless, the diagnosis of primary HIV-1 infection was suspected by using an alternative method for"in vitro" induced antibody production (IVIAP), and confirmed by p24 antigen serum positivity and seroconversion in serial plasma samples of the patient. The authors suggest the use of the IVIAP and others complementary assays to help the diagnosis of acute HIV-1 infection in persons at high risk conditions.

Dot-enzyme-linked immunosorbent assay (Dot-ELISA) for detection of pneumococcal polysaccharide antigens in pleural fluid effusion samples.: Comparison with bacterial culture, counterimmunoelectrophoresis and latex agglutination

A dot-enzyme-linked immunosorbent assay (Dot-ELISA) for pneumococcal antigen detection was standardized in view of the need for a rapid and accurate immunodiagnosis of acute pneumococcal pneumonia. A total of 442 pleural fluid effusion samples (PFES) from children with clinical and laboratory diagnoses of acute bacterial pneumonia, plus 38 control PFES from tuberculosis patients and 20 negative control serum samples from healthy children were evaluated by Dot-ELISA. The samples were previously treated with 0.1 M EDTA pH 7.5 at 90°C for 10 min and dotted on nitrocellulose membrane. Pneumococcal omniserum diluted at 1:200 was employed in this assay for antigen detection. When compared with standard bacterial culture, counterimmunoelectrophoresis and latex agglutination techniques, the Dot-ELISA results showed relative indices of 0.940 to sensitivity, 0.830 to specificity and 0.760 to agreement. Pneumococcal omniserum proved to be an optimal polyvalent antiserum for the detection of pneumococcal antigen by Dot-ELISA. Dot-ELISA proved to be a practical alternative technique for the diagnosis of pneumococcal pneumonia.

Pattern of mycobacterial antigen detection in leprosy

Immunohistochemistry reaction (Peroxidase anti-peroxidase - PAP) was carried out on fifty-two skin biopsies from leprosy patients with the purpose to identify the antigenic pattern in mycobacteria and to study the sensitivity of this method. Five different patterns were found: bacillar, granular, vesicular, cytoplasmatic and deposits, classified according to the antigenic material characteristics. Deposits (thinely particulate material) appeared more frequently, confirming the immunohistochemistry sensitivity to detect small amounts of antigens even when this material is not detected by histochemical stainings.

Análise do polimorfismo HLA/DR-DQ em Angolanos portadores de Diabetes Mellitus tipo I

A diabetes mellitus do tipo 1 (DM1) é o distúrbio endócrino-metabólico mais frequente em crianças. É uma doença autoimune resultado da destruição selectiva das células beta pancreáticas. A velocidade de destruição das células beta pode ser rápida em algumas pessoas e lenta em outras; esta última é típica de adulto é conhecido como diabetes autoimune latente em adulto (LADA). A sua etiologia envolve factores ambientais e genéticos, dos genes envolvidos a maior contribuição vem da região do genoma onde estão localizados os genes do Complexo Principal de Histocompatibilidade (MHC). A combinação de diferentes alelos do sistema de antigénio leucocitário humano tipo II (HLAII) esta associada a susceptibilidade da doença e as principais molécula envolvidas são a DQ e DR. O estágio pré-clínico da doença se caracteriza pela presença de auto-anticorpos, sendo o anti-GAD o mais sensível nesta patologia. OBJECTIVO: Analizar a frequência dos polimorfismos HLA-DR/DQ em angolanos portadores de diabetes tipo 1, residentes em Luanda. O tipo de estudo adotado foi casocontrolo num universo de voluntários provenientes da consulta externa de hospitais e clínicas locais no período de outubro de 2012 a outubro 2013. A amostra biológica utilizada foi sangue total, tendo sido processada no laboratório LABGENE, da Faculdade de Medicina (FM) da Universidade Agostinho Neto (UNA). Os auto-anticorpos, anti-GAD, foram doseados pelo método de ELISA. O ADN genómico foi extraído à partir de sangue total periférico e tipagem genética foi realizada mediante PCR-SSP.O alelo DQB1*02 (DQ2/DQ2) (p=0,033, OR= 4, IC (1,2-13,3) foi associado a susceptibilidade da DM1; os alelos DQB1*06 (DQ6/DQ6) (p=0,000, OR=0,30, IC (0,17-0,54); *11 (p=0,011, OR=0,14, IC=0,032-0,62); *13 (p=0,006, OR=0,13, IC=0,049-0,588) e *15 (p=0,001, OR=0,044, IC=0,005-0,39) foram associados a proteção. Foi encontrado 29,2% de positividade para o anti-GAD, não houve associação significativa (p=0,69) entre a resposta positiva do anti-GAD e a idade. Não foi encontrada associação significativa (p=0,39) entre o tempo de diagnóstico e resposta humoral. Observou-se associação significativa entre os alelos de risco DQB1*02 (p=0.000) e resposta positiva para anti-GAD; da mesma maneira houve uma associação significativa para os alelos DQB1*06 (p=0,002), DRB1*11 (p=0,048); *13 (p=0,004) e *15 (p=0,021) e a resposta negativa do anti-GAD.Os dados demostram o forte envolvimentos do gene HLA-II (DQ) com a suceptibilidade a DM1 e sugere que a autoimunidade se desenvolve na presença de susceptibilidade genética, quer dizer, em associação com alelos HLA-II específicos.

Dot-ELISA for the detection of IgM and IgG antibodies to Schistosoma mansoni worm and egg antigens, associated with egg excretion by patients

Human schistosomiasis, caused by Schistosoma mansoni, is highly prevalent in Brazil and usually diagnosed by time consuming stool analysis. Serological tests are of limited use in this disease, mainly for epidemiological studies, showing no discrimination between previous contact with the parasite and active infections. In the present study, we standardized and compared a Dot-ELISA for IgM and IgG antibodies against S. mansoni antigens from eggs and worms with a routine IgG and IgM immunofluorescence assay using similar antigens, in the study of sera from 27 patients who had quantified egg stool excretion. The positivity obtained for IgG Dot-ELISA was 96.3% and 88.9% for IgM Dot-ELISA with worm antigen and 92.6% and 90.9% with egg antigen. The IFI presented similar positivities using worm antigen, 92.6% (IgG) and 96.3% (IgM),and lower results with egg antigen, 77.8% (IgG and IgM). The patients studied were divided into two groups according to their egg excretion, with greater positivity of serological tests in higher egg excreters. When comparing the quantitative egg excretion and the serological titers of the patients, we detected a correlation only with IgM Dot-ELISA, with r=0.552 (p=0.0127). These data show that Dot-ELISA can be used for the detection of specific antibodies against S. mansoni in sera from suspected patients or in epidemiological studies and, with further purification of egg antigen and larger samples, IgM Dot-ELISA could be a possible tool for rough estimates of parasite burden in epidemiological studies.