164 resultados para virus antibody


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The genotypes of hepatitis B (HBV) and delta (HDV) viruses circulating among fulminant hepatitis cases from the western Amazon Basin of Brazil were characterized in this study. HBV and HDV isolates were obtained from liver samples from 14 patients who developed fulminant hepatitis and died during 1978-1989. HBV DNA and HDV RNA were detected in all samples. Phylogenetic analyses of HDV sequences showed that they all clustered with previously characterized sequences of HDV genotype 3 (HDV-3). HBV genotypes F, A and D were found in 50.0, 28.6 and 21.4% of cases, respectively. These results confirm the predominance of HDV-3 in South America and its association with the severe form of hepatitis, and the finding of the co-infection of HDV-3 with different genotypes of HBV suggests that the association between HDV-3 and HBV-F is not necessarily causally related to a more severe clinical course of infection.

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Hepatitis delta virus (HDV) is widely distributed and associated with fulminant hepatitis epidemics in areas with high prevalence of HBV. Several studies performed in the 1980s showed data on HDV infection in South America, but there are no studies on the viral dynamics of this virus. The aim of this study was to conduct an evolutionary analysis of hepatitis delta genotype 3 (HDV/3) prevalent in South America: estimate its nucleotide substitution rate, determine the time of most recent ancestor (TMRCA) and characterize the epidemic history and evolutionary dynamics. Furthermore, we characterized the presence of HBV/HDV infection in seven samples collected from patients who died due to fulminant hepatitis from Amazon region in Colombia and included them in the evolutionary analysis. This is the first study reporting HBV and HDV sequences from the Amazon region of Colombia. Of the seven Colombian patients, five were positive for HBV-DNA and HDV-RNA. Of them, two samples were successfully sequenced for HBV (subgenotypes F3 and Fib) and the five samples HDV positive were classified as HDV/3. By using all HDV/3 available reference sequences with sampling dates (n = 36), we estimated the HDV/3 substitution rate in 1.07 x 10(-3) substitutions per site per year (s/s/y), which resulted in a time to the most recent common ancestor (TMRCA) of 85 years. Also, it was determined that HDV/3 spread exponentially from early 1950s to the 1970s in South America. This work discusses for the first time the viral dynamics for the HDV/3 circulating in South America. We suggest that the measures implemented to control HBV transmission resulted in the control of HDV/3 spreading in South America, especially after the important raise in this infection associated with a huge mortality during the 1950s up to the 1970s. The differences found among HDV/3 and the other HDV genotypes concerning its diversity raises the hypothesis of a different origin and/or a different transmission route. (C) 2011 Elsevier B.V. All rights reserved.

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Hepatitis B virus (HBV) causes one of the most important chronic viral infections worldwide. HBV is classified into eight genotypes whose epidemiology varies geographically. In Brazil, genotypes A, D, and F are more frequent, while in East Asia, genotypes B and C predominate. Several studies showed that immigrants retain the HBV infection pattern of their ancestral country. To identify HBV genotypes infecting chronic carriers in Brazilian families of Western and Asian descent by Hepatitis B surface antigen gene sequencing and analyze the route of viral transmission by phylogenetic analysis of viral sequences. Eighty-seven people chronically infected with HBV were separated into two groups: Western descent (27) and Asian descent (60). Surface and pre-core/core genes were amplified from serum HBV-DNA and sequences were subjected to phylogenetic analysis. HBV genotype A was found in 74% of Western subjects, while genotype C was found in 94% of Asian patients. Thirty-eight percent of Western families were infected with HBV with similar pre-core/core sequences, while only 25% of Asian families showed similarity in these sequences. Phylogenetical analysis of pre-core/core HBV gene suggested intra-familial transmission of HBV in 38% of Western families and 25% of Asian families. Analysis of HBsAg gene sequences helped to define the HBV genotype but did not allow inferring route of transmission as its sequences showed a smaller phylogenetic signal than pre-core/core sequences. Chronic HBV carriers of Asian descent born in or living in Brazil were infected with the same HBV genotype predominant in their ancestral country.

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Hepatitis D virus (HDV) is a defective hepatotropic virus whose infectivity is dependent on hepatitis B virus (HBV). HDV super- or co-infiection leads to an increased risk of fulminant hepatitis or progression to severe chronic liver disease in HBV infected patients. The Brazilian Amazon Basin has been reported to be endemic for HBV and HDV, especially in the Western Amazon Basin. In this region, HDV infection is frequently associated with acute fulminant hepatitis with characteristic histologic features. HDV is classified into seven major clades (HDV-1 to HDV-7) and HBV is subdivided into eight genotypes (A-H). HDV and HBV genotypes have been shown to have a distinct geographic distribution. The aim of this study was to determine the HBV and HDV genotypes harbored by chronically infected patients from the Eastern Amazon Basin, Brazil. We studied 17 serum samples from HBV and HDV chronically infected patients admitted to a large public hospital (Santa Casa de Misericordia) at Belem, state of Para, Brazil, between 1994 and 2002. HDV-3 and HBV genotype A (subtype adw2) have been identified in all cases, in contrast to previous studies from other regions of the Amazon, where HBV genotype F has been found co-infecting patients that harbored HDV-3. The HDV-3/HBV-A co-infection suggests that there is not a specific interaction between HBV and HDV genotypes, and co-infection might merely reflect the most frequent genotypes found in a particular geographic area. The analysis of the carboxy-terminal region of the large hepatitis D antigen (L-HDAg), which interacts with the hepatitis B surface antigen (HBsAg) and is essential for HDV assembly, showed some diversity between the different isolates from the Eastern Amazon. This diversity is not observed among HDV-3 sequences from other South American regions. (C) 2008 Elsevier B.V. All rights reserved.

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Paracoccidioidomycosis is endemic in Latin America, and ca. 80% of all cases occur in Brazil. Little is known about antibody avidity or the evolution of such avidity in the posttherapeutic period for the different clinical presentations of the disease. In the present study, we evaluated 53 patients with paracoccidioidomycosis and calculated the avidity index. Medium-and high-avidity antibodies were found in 79.5% of patients with chronic presentation (n = 39). Among patients with the acute form (n = 14), 57.1% of the antibodies presented low avidity. In the posttherapeutic period, there was a significant increase in antibody avidity in patients presenting with the chronic multifocal form. In our preliminary study, which needs to be confirmed using a larger number of samples, the optimized method for studying antibody avidity detected differences among the clinical presentations of the mycosis and indicated the value of the avidity index as a marker of posttherapeutic evolution of patients with a multifocal chronic form of the disease.

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Background: Using enzyme immunoassays and Western blot (Wb) tests, HTLV serodiagnosis yields indeterminate results in a significant number of cases. Objective: To determine the prevalence of HTLV infection among HTLV-seroindeterminate individuals. Study design: We studied peripheral blood mononuclear cells from 65 anti-HTLV Wb-seroindeterminate individuals by attempting to amplify proviral DNA sequences (tax and pot) to identify HTLV-I and HTLV-2 infections. Results: These 65 specimens exhibited predominantly (43%) anti-HTLV antibodies to gag-coded antigens in the absence of anti-p24 on Wb analysis. Tax proviral sequences were detected in 6 (9.2%) samples. According to restricted fragment polymorphism analysis (RFLP), we identified HTLV-1 proviral DNA in 4 samples. HTLV-2 in one and sequences from both in another. Nested PCR for the pot region was positive in 3 (4.6%) specimens, which were also positive for tax sequences. After hybridization HTLV-1 infection was confirmed in 2 samples (3.1%) and HTLV-2 in another (1.5%). Detection of a single HTLV DNA sequence may be due to infection by defective provirus, but its significance remains undefined. In this cohort, no Wb reactivity pattern was predictive of proviral detection. HTLV-I infection was demonstrated in an individual who had Wb reactivity to gag-coded antigens only. Conclusions: This emphasizes the importance of clinical and laboratory follow-up of HTLV-seroindeterminate individuals from endemic areas. (c) 2009 Elsevier B.V. All rights reserved.

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The findings of a neurological evaluation in 85 patients with confirmed, acute, dengue virus infection are described. Signs of central nervous system involvement were present in IS patients (21.2%). The most frequent neurological symptom was mental confusion. The frequency of neurological involvement did not differ between patients with primary and secondary dengue infection, and the prevalence of central nervous system involvement in dengue fever and dengue hemorrhagic fever also did not differ significantly. The presence of CNS involvement did not influence the prognosis of dengue infection. Dengue viral CSF RNA was found in 7 of 13 patients submitted to a spinal tap, the CSF viral load being less than 1000 copies/ml. PCR was negative in serum samples obtained from three patients on the same day as the CSF samples, suggesting that the dengue virus actively enters the CNS and that the presence of the virus in the CNS does not result from passive crossing of the blood-brain barrier. (C) 2007 Elsevier B.V. All rights reserved.

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The incidence of CRS and CRI has decreased markedly worldwide with the implementation of efficient vaccination programs. We report a congenital rubella case with fetal death occurred at 29th week of gestation. RV was confirmed in placenta. The results of phylogenetic analysis showed that the RVs/Sao-Paulo01.- BRA/08.CRI belongs to the genotype 2B of RV. J. Med. Virol. 83:2048-2050, 2011. (C) 2011 Wiley-Liss, Inc.

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Introduction: Chronic active Epstein-Barr virus (CAEBV) infection is characterized by chronic or recurrent symptoms for at least 3 months, such as fever, hepatosplenomegaly and lymphadenopathy. The diagnosis is established due to the presence of anti-EBV antibodies or isolation of this infectious agent in affected tissues. Three cases of CAEBV infection mimicking Henoch-Schonlein purpura (HSP) were described. Case 1: Female 3-year old patient with cervical adenomegaly, anemia and fever developed palpable purpura, haematuria and arthritis. CAEBV infection was established by serology test. She received methylprednisolone and acyclovir. She had generalized lymphadenopathy, hepatomegaly, splenomegaly, disseminated intravascular coagulation and deceased. Case 2: Male 12-year old patient with persistent anemia, lymphadenopathy, hepatomegaly and splenomegaly had CAEBV infection diagnosis by serology test. He developed purpura and arthritis and received methylprednisolone. Case 3: Male 13-year old patient had purpura, abdominal pain, haematuria, hepatomegaly, splenomegaly, lymphadenopathy, anemia and elevated liver enzymes. The cervical lymph node biopsy was positive to EBV infection. He received methylprednisolone and acyclovir, developing acute fulminant hepatitis and death. Discussion: CAEBV infection mimicking HSP was rarely observed in our population

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Whether gestational immunization of HIV-infected mothers with the 23-valent pneumococcal polysaccharide vaccine (PPV) confers maternal and infant early life, passive protection is not known. We evaluated safety, immunogenicity and placental transfer of antibodies in 44 HIV-infected women. Pneumococcal IgG antibodies against serotypes 1, 3, 5, 613, 9V, and 14 were measured in mothers (pre-vaccination and at delivery), and infants (at birth, 1, 2, 3, and 6 months). PPV was safe and immunogenic in mothers. Newborns received 46-72% of maternal antibody titers. Overall, infants had antibody levels lower than protective by 2 months of age. Alternative pneumococcal vaccination of HIV-infected pregnant women should be explored with the aim of prolonging passive protection in their infants. (C) 2009 Elsevier Ltd. All rights reserved.

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Patients with antibody deficiencies are more prone to develop acute neutropenic episodes even during immunoglobulin replacement. The aims of this study were to evaluate the presence of acute neutropenia in 42 patients with primary antibody immunodeficiencies, currently receiving intravenous immunoglobulin (IVIG), and to describe the clinical and laboratory findings during neutropenic episodes. Of all patients, 10 (23.8%) presented acute neutropenia (absolute neutrophil count < 1500 cells/mm(3)) during follow up (mean of 6.4 yr). The absolute neutrophil count ranged from 71 to 1488 cells/mm(3). Neutropenia was not clearly associated with antibiotic prophylactic therapy or immunoglobulin levels, while infections were associated with neutropenia in the majority of episodes. Most acute neutropenia episodes were mild or moderate, except in CVID patients who present more severe neutropenia. Although IVIG may have contributed to reducing the severity of neutropenia, it does not prevent its occurrence in all patients. In conclusion, primary immunodeficient patients, even submitted to IVIG replacement therapy, must be regularly evaluated for neutropenia in order to minimize the risk of infections and its appropriate approach.

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Pneumococcal vaccination has been recommended for immunocompromised children, including patients with chronic kidney disease. We determined pneumococcal immunoglobulin (Ig) G antibodies to serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F before and after 48 pediatric patients with chronic renal failure were administered heptavalent conjugated pneumococcal vaccine. The patients were between 1 and 9 years of age and were separated into a conservative treatment group (Group 1) and a dialysis group Group 2). The antibody response to the vaccinal serotypes was evaluated by measuring antibody concentrations before the first dose and 60 days after the second one. Pre-vaccinal IgG concentrations >= 0.35 mu g/ml were detected for all serotypes in at least 50% of the patients in both groups. Patients from both groups showed a statistically indistinguishable behavior in terms of the medians of post-vaccination IgG levels. An ""adequate"" vaccine response was defined as a post-immunization level of specific pneumococcal serotype antibody >= 0.35 mu g/ml, based on the World Health Organization`s (WHO) protective antibody concentration definition for pneumococcal conjugate vaccines, or on a fourfold increase over baseline for at least five of the seven antigens of the vaccine. An ""adequate"" vaccinal response was obtained in 100% of the patients of both groups using WHO`s definition, or in 45.8% of Group 1 patients and 37.5% of Group 2 patients when the criterion was a fourfold antibody increase over baseline antibody concentrations.

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Background Infective dermatitis (ID) is a rare dermatologic condition of childhood that has been linked to human T-cell lymphotropic virus type 1 (HTLV-1). Objective To analyze the clinical and laboratory features associated with adult-onset ID linked to HTLV-1. Methods From December 1995 to December 2007, four patients with ID were followed in the dermatology outpatient clinic of the ""Hospital das Clinicas"" of the University of Sao Paulo Medical School, Sao Paulo, Brazil. Epidemiologic data were collected and dermatologic examination was performed. Patients were submitted to histopathologic, hematologic, virologic, and immunologic investigations. Results All patients had a diagnosis of ID according to previously established criteria, despite being adults. HTLV-1 infection was demonstrated by enzyme-linked immunosorbent assay, Western blotting assays, and polymerase chain reaction. The male to female ratio was 1 : 3 and the median age at diagnosis was 42 years. The cutaneous manifestations were erythematous, scaly, and crusted lesions in all patients, and ichthyosis in three of the four cases. Histopathologic study showed lymphocytic epidermotropism in two cases. The median proviral load was 281 copies/10,000 peripheral blood mononuclear cells. Immunodeficiency was not observed in any case. The therapies used were antimicrobials, corticosteroids, and phototherapy. Conclusions Although many authors have considered ID to be a form of childhood dermatitis, we have described four cases that fulfilled the major criteria for ID, except for onset in adulthood.

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Human immunodeficiency virus type 1 (HIV-1) and human T-cell lymphotropic virus types 1 and 2 (HTLV-1 and -2) are retroviruses that share similar routes of transmission and some individuals may have a dual infection. These co-infected subjects may be at increased risk for tropical spastic paraparesis/HTLV-1-associated myelopathy (TSP/HAM)-like. To study the prevalence of tropical spastic paraparesis/HTLV-1-associated myelopathy (TSP/HAM) among coinfected HIV-1/HTLV-1 subjects. Since July 1997, our group has been following a cohort to study the interaction of HTLV with HIV and/or hepatitis C virus (HCV), as well as HTLV-1-only infected asymptomatic carriers or those already presenting with TSP/HAM. During these 9 years, 296 HTLV-1-infected individuals were identified from a total of 538 patients who were referred to our clinic at the Institute of Infectious Diseases ""Emilio Ribas,"" in Sao Paulo, Brazil. All subjects were evaluated by two neurologists, blinded to the HTLV status. TSP/HAM diagnosis was based on Kagoshima diagnostic criteria. Results: A total of 38 HIV-1/HTLV-1 co-infected subjects were identified in this cohort: Twenty-six had already been diagnosed with AIDS and 12 remained asymptomatic. Six of 38 co-infected subjects (18%) were diagnosed as having TSP/HAM and also AIDS, and for 5 of them TSP/HAM was their first illness. One additional incident case was diagnosed after 2 years of follow-up. No modifications on HIV-1 viral load was seen. In contrast, the co-infected with TSP/HAM-like group showed higher HTLV-1 proviral load (505 +/- 380 vs. 97 +/- 149 copies/10(4) PBMC, P= 0.012) than asymptomatic co-infected subjects, respectively. The incidence of myelopathy among HIV-1/HTLV-1 co-infected subjects is probably higher than among patients infected only with HTLV-1, and related to a higher HTLV-1 proviral load. Thus, HTLV-1/2 screening should be done for all HIV-1-infected patients in areas where HTLV-1 infection is endemic.

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The aim of the current study was to investigate the apoptosis of neurons, astrocytes and immune cells from human patients that were infected with rabies virus by vampire bats bite. Apoptotic neurons were identified by their morphology and immune cells were identified using double immunostaining. There were very few apoptotic neurons present in infected tissue samples, but there was an increase of apoptotic infiltrating CD4+ and TCD8+ adaptive immune cells in the rabies infected tissue. No apoptosis was present in NK, macrophage and astrocytes. The dissemination of the human rabies virus within an infected host may be mediated by viral escape of the virus from an infected cell and may involve an anti-apoptotic mechanism, which does not kill the neuron or pro-apoptosis of TCD4+ and TCD8+ lymphocytes and which allows for increased proliferation of the virus within the CNS by attenuation of the adaptive immune response. (C) 2011 Elsevier B.V. All rights reserved.