RESUMO
Human caliciviruses (HuCVs) are increasingly recognized as common pathogens that cause acute sporadic diarrhea in children; however, regional antigenic and genetic diversity complicate detection techniques. Stool samples from children seeking medical attention in 2 outpatient clinics, a large emergency department, and 2 hospital wards were evaluated for HuCVs by reverse transcription-polymerase chain reaction, using primers based on a conserved sequence of the polymerase region of a previously sequenced Chilean strain. HuCVs were detected in 53 (8%) of 684 children 1 month to 5 years of age (mean, 13 months). Detection occurred year-round without a clear seasonal peak, and detection frequency declined from 16% in 1997 to 2% in 1999. The decline may have been due to a change in virus genotype. HuCVs are a significant pathogen of acute sporadic diarrhea in Chilean children, and continuous characterization of genetic diversity will be crucial for appropriate detection.
Assuntos
Caliciviridae/isolamento & purificação , Diarreia/virologia , Doença Aguda , Pré-Escolar , Chile , Fezes/virologia , Humanos , Lactente , Fatores de TempoRESUMO
Respiratory syncytial virus (RSV) and adenovirus (Advs) serotype 3 (Adv3) and 7h (Adv7h) are associated with mild to severe respiratory infection and are indistinguishable during the acute phases of the illnesses. However, outcome and long-term prognosis are different with both infections. RSV infection is associated with later development of asthma, and Adv, mainly Adv7h, with severe lung damage, bronchiectasis, and hyperlucent lung. We hypothesized that this difference could be partly due to different immune responses induced by these viruses. To test this hypothesis we quantified TCD4+, TCD8+, and BCD19+ expressing the interleukin-2 receptor-alpha chain (CD25) and interferon-gamma (IFN-gamma), interleukin (IL)-10, and IL-4 in the supernatant of peripheral blood mononuclear cells (PBMC) from school children infected in vitro with and without RSV, Adv7h, and Adv3 and after phytohemagglutinin (PHA) stimulation in the presence or absence of these viruses at a multiplicity of infection (MOI) of 1. PBMC from every child produced more IL-10 (p
Assuntos
Adenovírus Humanos/fisiologia , Citocinas/metabolismo , Leucócitos Mononucleares/metabolismo , Vírus Sincicial Respiratório Humano/fisiologia , Infecções por Adenovirus Humanos/imunologia , Células Cultivadas , Criança , Humanos , Interferon gama/metabolismo , Interleucina-10/metabolismo , Interleucina-4/metabolismo , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/virologia , Ativação Linfocitária , Subpopulações de Linfócitos/metabolismo , Receptores de Interleucina-2/metabolismo , Infecções por Vírus Respiratório Sincicial/imunologiaRESUMO
The frequency of astrovirus infection in 456 Chilean children with diarrhea was determined by enzyme-linked immunosorbent assay, reverse transcriptase PCR, and cell culture. Astrovirus was detected in 16.5% of rotavirus-negative and 7% of rotavirus-positive samples obtained from emergency rooms or hospitals and in 11% of samples from day care centers. HAst-1 was the predominant serotype identified.
Assuntos
Infecções por Astroviridae/epidemiologia , Gastroenterite/virologia , Doença Aguda , Pré-Escolar , Chile/epidemiologia , Ensaio de Imunoadsorção Enzimática , Fezes/virologia , Humanos , Lactente , Recém-Nascido , PrevalênciaRESUMO
Viral infections have been associated with cellular immune responses and production of Th-1 cytokines. Respiratory syncytial virus (RSV), however, induces virus-specific IgE, which might be a consequence of a Th-2-like activation. To test this hypothesis we quantified interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) in the supernatant of peripheral blood mononuclear cells cultured for 24 and 48 h in the presence or absence of phytohemaglutinin and pokeweed mitogen and the lymphocyte phenotypes to analyze subsets and their activation markers, from 15 hospitalized infants during an acute lower respiratory infection caused by RSV and 17 healthy control infants from 1 to 15 mo of age. Compared with the control infants, those infected with RSV had an increase in the number of B-cells (p < 0.02) and decreases in both CD8+ T-cells (p < 0.01) and activated CD8+/CD25+ suppressor/ cytotoxic T-cells (p < 0.007). In RSV-infected infants, IFN-gamma production was subtotally suppressed, whereas IL-4 production was decreased to a lesser degree, giving significantly (p < 0.001) increased IL-4/IFN-gamma ratio compared with that in the control infants. These findings suggest a predominant Th-z-like response in RSV-infected infants, which could explain some aspects of the immunopathogenesis of RSV infection and the RSV-specific and nonspecific IgE antibody responses observed.
Assuntos
Interferon gama/sangue , Interleucina-4/sangue , Infecções por Vírus Respiratório Sincicial/imunologia , Antígenos Virais/sangue , Estudos de Casos e Controles , Células Cultivadas , Humanos , Lactente , Leucócitos Mononucleares/imunologia , Ativação Linfocitária , Subpopulações de Linfócitos/imunologia , Vírus Sinciciais Respiratórios/imunologiaRESUMO
We studied the evolution of HIV-1 infection and immune response during six years in two twins born from an infected mother. The children had a continuous progression of the infection, proved by CD4+ cell count, serum anti-HIV antibodies, cultivable virus and proviral load. Now, both children are on antiviral treatment. The analysis of serum antibodies showed a different immune response in both children. One of them developed higher levels of antibodies directed against viral proteins and synthetic peptides derived from their aminoacid sequence. In this child, the amount of cultivable virus increased less than in his twin. Nucleotide sequencing of a part of viral genoma, showed that the virus belonged to the B subtype, prevalent in America and Europe. The observed differences in viral sequences suggest a different selective pressure in both twins. This phenomenon could be related to the observed differences in immune response.
Assuntos
Síndrome da Imunodeficiência Adquirida/imunologia , Doenças em Gêmeos/etiologia , Anticorpos Anti-HIV/sangue , Síndrome da Imunodeficiência Adquirida/sangue , Síndrome da Imunodeficiência Adquirida/terapia , Síndrome da Imunodeficiência Adquirida/transmissão , Adulto , Sequência de Aminoácidos , Sequência de Bases , Contagem de Linfócito CD4 , Pré-Escolar , Doenças em Gêmeos/genética , Feminino , Seguimentos , Genoma Viral , Proteína gp120 do Envelope de HIV/fisiologia , Soropositividade para HIV/imunologia , HIV-1/genética , HIV-1/isolamento & purificação , Humanos , Transmissão Vertical de Doenças Infecciosas , Masculino , Dados de Sequência Molecular , Fatores de TempoRESUMO
Preincubation of peripheral blood lymphocytes with the microtubule disturbing agents estramustine (ETMN; n = 7, final conc. 20 microM) or taxol (TX; n = 13, final conc. 10 microM), resulted in a statistically significant inhibition of natural killer cell activity [(NKCA); baseline (x +/- SD; expressed as percentage of specific chromium release) of 32.2 +/- 30.5 and 34.4 +/- 27.7 and drug treated samples of 13.9 +/- 19.9 and 12.5 +/- 20.8, respectively; Student's paired t-test p < 0.005]. Furthermore, most individual values for NKCA in the drug preincubated samples were at least 20% below the same subject baseline lytic function (except for TX sample No.1), and NKCA was non detectable in 4 out of 7 and 5 out of 13 samples (pretreatment with either ETMN or TX< respectively). The use of other concentrations and different preincubation times for these chemotherapeutic agents also produced NKCA inhibition, which was time and dose dependent. Preincubation with lipopolysaccharide (LPS; n = 16, final conc. 50 micrograms/ml), an endotoxin prominently involved in the etiology of septic shock, resulted in a statistically significant enhancement of NKCA [baseline (x +/- SD; expressed as percentage of specific chromium release) of 25.4 +/- 20.4 and LPS treated sample of 36.6 +/- 17.4, respectively; Student's t paired t-test p < 0.005]. At least a 20% increase in NKC lytic function over its own baseline value was recorded for each and everyone of the samples tested with LPS.2+ the pathophysiology associated with septic shock.
Assuntos
Antineoplásicos/farmacologia , Estramustina/farmacologia , Células Matadoras Naturais/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Paclitaxel/farmacologia , Linfócitos T/efeitos dos fármacos , Adulto , Feminino , Humanos , Células Matadoras Naturais/citologia , Células Matadoras Naturais/fisiologia , Masculino , Pessoa de Meia-Idade , Método Simples-Cego , Linfócitos T/citologiaRESUMO
We studied the transmission of rotavirus (RV) in 950 patients under 2 years of age hospitalized for diarrhea in Santiago, Chile. Stool samples were collected every other day from all patients during their entire hospital stay. To trace nosocomial transmission, we mapped the ward at the time of detection of RV. Comparative study by polyacrylamide gel electrophoresis of 315 RV isolates (180 detected upon admission of patients and 135 attributed to nosocomial transmission) allowed the identification of 18 different electropherotypes. An electropherotype similar to that of a community-acquired case was found in the same room in 81% of nosocomial cases and in the ward in 92% of nosocomial cases. It was concluded that the infants admitted shedding RV are the major source of nosocomial transmission and there was not a RV strain that was particularly transmissible.
Assuntos
Infecção Hospitalar/transmissão , Infecções por Rotavirus/transmissão , Chile/epidemiologia , Infecção Hospitalar/epidemiologia , Diarreia/epidemiologia , Diarreia/microbiologia , Eletroforese em Gel de Poliacrilamida , Métodos Epidemiológicos , Humanos , Lactente , Rotavirus/classificação , Rotavirus/isolamento & purificação , Infecções por Rotavirus/epidemiologiaRESUMO
Nasopharyngeal aspirates were obtained on admission from 614 patients younger than 2 years of age who were hospitalized in a ward for acute respiratory infections from June 1988 through October, 1989, in Santiago, Chile. Patients in two rooms were followed during the cold seasons by sampling aspirates every other day during the child's entire hospital stay. Clinical features were recorded daily. Indirect monoclonal immunofluorescent assay and isolation in HEp-2 were used for respiratory syncytial virus (RSV) diagnosis. The mean RSV detection rate was 39% at the time of admission, ranging from 8% in April, 1989, to 62% in July, 1988. During the cold months 43 of 288 (15%) nosocomial RSV cases were detected. Pneumonia and wheezing bronchitis were the principal diagnoses of both groups admitted, whether they were shedding RSV or not. It is concluded that RSV plays a major role in admissions for acute respiratory infections, as well as in nosocomial infections, in Santiago. Because clinical features do not allow one to differentiate viral from bacterial acute respiratory infections, the importance of rapid viral diagnosis is emphasized.
Assuntos
Infecção Hospitalar/epidemiologia , Vírus Sinciciais Respiratórios/isolamento & purificação , Infecções Respiratórias/epidemiologia , Infecções por Respirovirus/epidemiologia , Chile/epidemiologia , Infecção Hospitalar/microbiologia , Imunofluorescência , Humanos , Lactente , Nasofaringe/microbiologia , Infecções Respiratórias/microbiologia , Infecções por Respirovirus/microbiologia , Estações do AnoRESUMO
It is well known that an immunosuppressive response occurs after acute trauma. Some cellular mediators participate in the pathogenesis of septic shock. However, the exact role of the lymphocyte subsets and natural killer (NK) activity in this condition is not clear. We studied NK cytolytic activity through a 51Cr liberation assay using K-562 target cells in 20 patients with initial septic shock (10 men and 10 females, mean age 41 years old). Lymphocyte subsets CD3 (T3), CD4 (T4), CD8 (T8), CD16 (Leu-11) and CD56 (Leu-19) were also studied by indirect immunofluorescence. Compared to results obtained in 20 healthy volunteers, patient's NK activity was decreased (4.6 +/- 3.9 vs 26.1 +/- 10, p less than 0.025), CD16 was lower (10%/187 vs 15%/280 per ul) and CD56 was also lower (6%/120 vs 12%/224 per ul), p less than 0.05. T lymphocyte subsets were also decreased: CD3 cells (1100 vs 1352 per ul) and CD4 cells (634 vs 873 per ul), p less than 0.05. Thus, a severe decrease in NK cells and NK cell function as well as decreases in CD3 and CD4 lymphocyte subsets are present in the initial stages of septic shock. The predictive value of these findings is currently under study.
Assuntos
Células Matadoras Naturais/fisiologia , Choque Séptico/imunologia , Subpopulações de Linfócitos T/fisiologia , Adolescente , Adulto , Idoso , Anticorpos Monoclonais , Feminino , Imunofluorescência , Humanos , Células Matadoras Naturais/química , Masculino , Pessoa de Meia-Idade , Subpopulações de Linfócitos T/químicaRESUMO
We evaluated the usefulness of the direct immunofluorescence test with monoclonal antibodies and the enzyme immunoassay in comparison with isolation in cell cultures for the diagnosis of Chlamydia trachomatis in 55 endocervical specimens from female prostitutes and 21 urethral specimens from men with diagnosis of nongonococcal urethritis. In comparison with culture, the enzyme immunoassay had a sensitivity of 100% and a specificity of 95%. The immunofluorescence test had a sensitivity of 92% and a specificity of 98%. The positive and negative predictive values for the enzyme immunoassay were 81% and 100% and for immunofluorescence 92% and 98% respectively. The immunologic methods appear to be satisfactory alternatives to culture for detecting C trachomatis in genital specimens in the studied populations.