ABSTRACT
HIV-1 diagnosis of perinatally exposed children is usually performed by molecular biology-based methods, allowing the direct detection of the virus. Thus, HIV-1 genomic variability within and across strains plays a major role in relation to the sensitivity of these tests, often leading to misdiagnosis. We describe the performance of an in-house multiplex nested PCR (nPCR) for early detection of HIV-1 infection in perinatally exposed children born in Argentina, where the percentage of diverse BF recombinants is as high as 80%. After evaluation of 1316 HIV-1 perinatally exposed children collected over a 7-year period, the specificity and sensitivity of the diagnostic nPCR was of 100% and 99.2% respectively, with only two false negative cases indicating a good performance of the diagnostic nPCR in the Argentine pediatric cohort. In search of unusual HIV-1 subtypes among 22 HIV-1 infected cases presenting partial or complete HIV-1 gene amplification failure, we performed phylogenetic and recombination analysis of a vpu-env fragment in addition to gag and env Heteroduplex Mobility Assay screening. The most unusual findings included two subtypes A and a novel BC recombinant, while the majority of the strains were a variety of different BF recombinants. These results indicate the presence of novel and heterogeneous genotypes in our country and the need of continuous viral surveillance not only for diagnostic test optimization but also for the eventual implementation of a successful vaccine.
Subject(s)
Child , Female , Humans , Male , HIV-1 , HIV Infections/virology , Polymerase Chain Reaction/methods , Recombination, Genetic/genetics , Argentina , False Negative Reactions , Genotype , Heteroduplex Analysis , HIV-1 , Infectious Disease Transmission, Vertical , HIV Infections/diagnosis , HIV Infections/transmission , Perinatal Care , Retrospective Studies , Sensitivity and Specificity , Sequence Analysis, DNA , Viral LoadABSTRACT
Para determinar la infección vertical por HIV-1 en niños en forma temprana es necesario el uso de técnicas de diagnóstico virológico directo tales como la detección del ADN proviral por la reacción en cadena de la polimerasa (PCR), el aislamiento viral por cocultivo y la detección de antígeno p24 en plasma. Con el uso de estos métodos se describieron casos con resultados positivos en niños que finalmente resultaron no estar infectados. En este trabajo se describen dos casos de niñas hijas de madres HIV-1 positivas que presentaron dificultad para su diagnóstico. Se realizó el seguimiento clínico y de laboratorio de las dos pacientes hasta los 40 meses de edad. Las dos pacientes presentaron un desarrollo pondoestatural y madurativo normal, sin síntomas de enfermedad relacionados con el HIV. En ambas pacientes se encontró, como único hallazgo, la detección del genoma proviral por PCR en más de una muestra. Sin embargo la pérdida de anticuerpos específicos en pacientes con función inmune normal, clínicamente sanas, descartaría la infección por HIV-1. Cabría plantearse la infección con una variante defectuosa, una infección silente o la expresión de tolerancia inmunológica. Además podría plantearse como hipótesis el clearence viral
Subject(s)
Infant , Infectious Disease Transmission, Vertical , Acquired Immunodeficiency Syndrome/diagnosis , Acquired Immunodeficiency Syndrome/transmission , ArgentinaABSTRACT
Se comparó la eficiencia diagnóstica de la inmunofluorescencia indirecta (IFI) como método confirmatorio de la infección por HIV-1 en muestras de suero de 362 personas con conductas de alto y bajo riesgo. El panel compuesto por 220 positivos, 122 negativos y 20 indeterminados por Western blot (WB) fue ensayado por una técnica de IFI desarrollada en nuestro laboratorio. La sensibilidad calculada fue 98,63 por ciento y la espicificidad 98,36 por ciento, indicando que la IFI es un método alternativo para la confirmación de la presencia de anticuerpos contra el HIV-1. Dado que su costo es menor que el 10 por ciento comparado con el del WB, se justifica su introducción en el algoritmo de diagnóstico serológico de HIV-1. Se observó también una relación directa entre la reactividad de las proteínas del WB y los resultados de IFI. En 15 muestras con resultado indeterminado por WB e inespecífico por IFI, las bandas más observadas fueron la p24 seguida de la gp160; por otro lado los anticuerpos contra las glicoproteínas virales son los que presentan mayor frecuencia en las muestras positivas débiles, demostrando su alto valor predictivo
Subject(s)
Humans , Male , Female , HIV-1 , AIDS Serodiagnosis/methods , Acquired Immunodeficiency Syndrome/diagnosis , Fluorescent Antibody Technique, Indirect/standards , ArgentinaABSTRACT
Se estudiaron 204 mujeres de la ciudad de Buenos Aires, con el objeto de determinar los factores de riesgo de infección por el virus de la inmunodeficiencia humana tipo 1. Se recogieron datos epidemiológicos sobre factores de riesgo y se realizó un estudio serológico en muestras de sangre tomadas en el momento de la admisión. Las mujeres adictas a drogas por vía endovenosa tuvieron una tasa de infección del 65,85 por ciento, 8 veces superior al de las no adictas; esta tasa se elevó al 90,62 por ciento en aquellas mujeres que además tenían contactos sexuales con hombres seropositivos para el virus de la inmunodeficiencia humana tipo 1. En 7 casos registrados de transfusión sanguínea como único factor de riesgo reconocido, uno solo fue seropositivo. En este estudio, de las 64 pacientes con serología positiva el 84,37 por ciento de ellas eran drogadictas endovenosas, confirmando nuevamente que la drogadicción endovenosa fue el factor de mayor riesgo de infección por el virus de la inmunodeficiencia humana tipo 1
Subject(s)
Humans , Female , Adolescent , Adult , Middle Aged , HIV Infections/diagnosis , Risk Factors , Acquired Immunodeficiency Syndrome/epidemiology , Substance-Related Disorders/complications , Women , HIV Infections/transmission , Sexually Transmitted Diseases/diagnosis , Sexually Transmitted Diseases/epidemiology , Acquired Immunodeficiency Syndrome/diagnosis , Acquired Immunodeficiency Syndrome/blood , Substance-Related Disorders/epidemiologyABSTRACT
The main goal of the present paper was to analyze the molecular diversity of the principal neutralizing domain (V3 loop) of the HIV 1 gp120 in samples from patients of Argentina. The study was carried out on a total of 30 HIV 1 positive blood samples, obtained during 1991-1992, belonging to 15 intravenous drug users (group A), 5 homosexual men (group B), 8 children born to HIV 1 positive mothers (group C) and 2 AIDS patients (group D). By using extracted DNA from peripheral blood lymphocytes and from infected cells of the viral isolates in the case of the 2 AIDS patients, the V3 loop region was amplified by means of polymerase chain reaction. Direct sequencing by Sanger methodology was then performed on DNA fragments and nucleotide sequences obtained were translated into the correspondent amino acids. Consensus sequences for each group and a general consensus sequence were established (Table 1). Its alignment with V3 loop amino acid sequences of the major HIV 1 strains isolated worldwide is showed in table 2. Homology analysis between each sequence of the study population and sequence of different HIV 1 isolates showed that most of these samples share high homology with SF2 and BH10 strains. In contrast a low homology was found with JH3 and MN isolated (table 3). The presence of highly conserved amino acid residues as substitutions and insertions was determined in the Argentinian V3 loop sequences giving them a local pattern. The present paper is of great importance for our country, considering that the V3 loop is the main neutralizing domain becoming a major target in the development of HIV 1 vaccine. To our knowledge, this is the first report on the sequencing of the principal neutralizing domain of the Human Immunodeficiency Virus type 1 in Latin America.
ABSTRACT
The main goal of the present paper was to analyze the molecular diversity of the principal neutralizing domain (V3 loop) of the HIV 1 gp120 in samples from patients of Argentina. The study was carried out on a total of 30 HIV 1 positive blood samples, obtained during 1991-1992, belonging to 15 intravenous drug users (group A), 5 homosexual men (group B), 8 children born to HIV 1 positive mothers (group C) and 2 AIDS patients (group D). By using extracted DNA from peripheral blood lymphocytes and from infected cells of the viral isolates in the case of the 2 AIDS patients, the V3 loop region was amplified by means of polymerase chain reaction. Direct sequencing by Sanger methodology was then performed on DNA fragments and nucleotide sequences obtained were translated into the correspondent amino acids. Consensus sequences for each group and a general consensus sequence were established (Table 1). Its alignment with V3 loop amino acid sequences of the major HIV 1 strains isolated worldwide is showed in table 2. Homology analysis between each sequence of the study population and sequence of different HIV 1 isolates showed that most of these samples share high homology with SF2 and BH10 strains. In contrast a low homology was found with JH3 and MN isolated (table 3). The presence of highly conserved amino acid residues as substitutions and insertions was determined in the Argentinian V3 loop sequences giving them a local pattern. The present paper is of great importance for our country, considering that the V3 loop is the main neutralizing domain becoming a major target in the development of HIV 1 vaccine. To our knowledge, this is the first report on the sequencing of the principal neutralizing domain of the Human Immunodeficiency Virus type 1 in Latin America.