抗RSV—iRNA对细胞融合病变影响的研究

用RSV-iRNA对BALB/C鼠致敏注射,以融合细胞计数法检测致敏鼠血清的抗融合活性。试验结果表明:RSV-iRNA致敏鼠血清能抑制由RSV引起的典型细胞融合病变,且这种活性可因吸附血清特异抗体而消失。     

小儿病毒性急性下呼吸道感染临床及病原流行情况分析

目的了解昆明地区小儿急性下呼吸道感染（ALRI）七种呼吸道病毒感染状况。方法对昆明地区2006～2007年收治的3354例ALRI住院患儿抽取鼻咽深部分泌物,对呼吸道病毒病原谱、病原年龄分布特点及临床流行病学特点进行分析。结果检出呼吸道病毒阳性病例911例,阳性率27.2%;混合感染17例,感染率0.51%。婴儿呼吸道病毒感染率及病毒混合感染率居各年龄组首位。新生儿、3岁以下婴幼儿以RSV感染为主,年长儿以IVA、PIVⅢ等多种病原感染为特点。年龄越小临床症状、体征越重。昆明地区小儿呼吸道病毒流行在每年7月至次年2月,流行时间持续近8个月,每年秋季均出现流行高峰,3～6月病毒感染阳性率呈下降趋势,但两年间呼吸道病毒感染率仍存在差异,2007年秋、冬季高于2006年,呈现呼吸道病毒流行趋势。结论RSV是昆明地区3岁以内小儿病毒性ALRI的主要病原,本地区呼吸道病毒流行持续时间长,秋季为流行高峰季,病毒流行具地区特点。     

Recognition of a novel naturally processed, A2 restricted, HCV-NS4 epitope triggers IFN-gamma release in absence of detectable cytopathicity

Using short term CTL lines derived from HLA A2/K^b transgenic mice and IFN-gamma release assays we demonstrate that the NS4.1769 epitope, is generated from natural processing of the NS4 antigen, and presented in the context of the A2/K^b molecules. Interestingly, T cell recognition of the naturally processed form of the NS4.1769 epitope was associated with significant IFN-gamma release, but no direct cytolytic activity. Epitopes of this phenotype might be of interest, in terms of therapy of chronic HCV infection by associating the benefit of localized lymphokine release with low or absent direct cytopathicity.     

Development of allergy in children. I. Association with virus infections.

Children born into allergic families, with two allergic parents, are at high risk of developing allergy within the first 5 years of life. In order to observe possible external factors in the sensitization process, a prospective study of 13 such children was done, in which serial clinical and immunologic observations were made at 3- to 6-month intervals over a period of 1 to 4 yr. Eleven of these children are now clinically allergic; 5 have asthma. Immunologic evidence for allergic sensitization was observed in these 11 children by RAST, antigen-induced leukocyte histamine release, lymphoblastogenesis, and rise in serum IgE. Upper respiratory infections (URI) occurred in these 11 allergic children 1 to 2 months prior to the onset of allergic sensitization. In 10 of these 11 URI children, complement-fixing antibodies to viruses (parainfluenza, RSV, CMV) increased in the same blood samples in which immunologic allergic sensitization was first evidenced. This coincidence suggests that certain viruses may contribute to the allergic sensitization process.     

RSV-induced bronchiolitis but not upper respiratory tract infection is accompanied by an increased nasal IL-18 response

The aim of this study was to investigate potential differences in the local nasal immune response between bronchiolitis and upper respiratory tract infection induced by respiratory syncytial virus (RSV). Nasal brush samples were obtained from 14 infants with RSV bronchiolitis and from 8 infants with RSV upper respiratory tract infection. The samples were taken during infection (acute phase) and 2-4 weeks later (convalescent phase). Cytospin preparations were stained immunohistochemically for T cells, macrophages, and eosinophils. Staining also took place for intercellular adhesion molecule-1 (ICAM-1), T-helper 1 (Th1)-like (interleukin-12 [IL-12], interferon-gamma [IFN-gamma]), Th2-like (IL-4, IL-10), and proinflammatory cytokines (IL-6, IL-8, IL-18). During both RSV-induced bronchiolitis and upper respiratory tract infection, cellular inflammation was observed. This was characterised by an increase in the numbers of nasal macrophages, which tended to be higher in bronchiolitis than in upper respiratory tract infection. Numbers of T lymphocytes and ICAM-1 positive cells increased during both bronchiolitis and upper respiratory tract infection. There were no differences between numbers in the groups. Interestingly, a distinct nasal proinflammatory cytokine response was observed in RSV-induced bronchiolitis. This is characterised by an increase in the number of IL-18 positive cells. This increase is specific for bronchiolitis, as a similar increase could not be detected in RSV-induced upper respiratory tract infection. Numbers of IL-6 and IL-12 positive cells were higher in both bronchiolitis and upper respiratory tract infection, and there were no differences between the groups. By contrast, the number of IL-8, IFN-gamma, IL-4, and IL-10-positive cells remained constant. In conclusion, clear differences were found in nasal immune responses of children with RSV-induced upper respiratory tract infection or bronchiolitis. The induction of a strong IL-18 response was typical for bronchiolitis, as this could not be observed in RSV-induced upper respiratory tract infection, and could explain the eosinophilia that is observed frequently during bronchiolitis.     

Antibody response after RSV infection in children younger than 1 year of age living in a rural area of Mozambique

Serological responses have been studied in respiratory syncytial virus (RSV) infected children < 1 year of age attending the outpatient department of the Manhiça District Hospital (Mozambique). Molecular characterization of viral RNA in nasopharyngeal aspirates from the infected children indicated a high level of genetic uniformity among the infecting viruses, all of which belonged to a single genotype of RSV group A. A representative virus strain, Moz00, was isolated from one of the infants and was used, together with the group A strain A2 and the group B strain 8/60, as antigens in the quantification of infant antibody responses. In this study, 97.5% (39/40) and 96.4% (27/28) of infected children produced an antibody response against Moz00 detected by the membrane fluorescent antibody test (MFAT) and the neutralization test (NT), respectively. Seroconversion rates decreased when the A2 and 8/60 strains were used as antigen in MFAT (95.4% and 88.2%, respectively) or NT (81.8% and 54.5%, respectively), indicating that antibody responses had both group‐ and strain‐specific components. Antibodies in convalescent sera of infected children were compared with maternally derived antibodies detected in a group of children also < 1 year of age, but with no evidence of RSV infection. The convalescent sera exhibited reduced neutralizing capacity when the 8/60 strain was used as antigen (P = 0.028), suggesting that the infant antibody response lacks neutralizing capacity against strains of the heterologous virus group. Restricted cross‐reactivity and neutralizing capacity of antibodies generated by young children might be expected to induce only moderate protection in subsequent epidemics against genetically distant strains. J. Med. Virol. 69:579–587, 2003. © 2003 Wiley‐Liss, Inc.     

Bronchiolitis: Recommendations for diagnosis,monitoring and management of children one to 24 months of age

Bronchiolitis is the most common reason for admission to hospital in the first year of life. There is tremendous variation in the clinical management of this condition across Canada and around the world, including significant use of unnecessary tests and ineffective therapies. This statement pertains to generally healthy children ≤2 years of age with bronchiolitis. The diagnosis of bronchiolitis is based primarily on the history of illness and physical examination findings. Laboratory investigations are generally unhelpful. Bronchiolitis is a self-limiting disease, usually managed with supportive care at home. Groups at high risk for severe disease are described and guidelines for admission to hospital are presented. Evidence for the efficacy of various therapies is discussed and recommendations are made for management. Monitoring requirements and discharge readiness from hospital are also discussed.