Incidence and prognosis of cytomegalovirus infections following allogenic bone marrow transplantation

The incidence and the outcome of cytomegalovirus (CMV) infections were evaluated in 83 adult recipients of allogenic bone marrow transplantation. Virological and serological surveillance was performed weekly for 3 months posttransplant, and then every other week or every month until 1 year. CMV infection occurred in 45 patients, with a cumulative risk of 62% at 1 year and 66% at 2 years. In multivariate analysis, two factors significantly influenced the incidence of CMV infection: patients with pretransplant positive anti-CMV titres had a risk of infection of 72% at 1 year versus 33% for patients with negative titres. Patients with acute myeloid leukemia were also infected more frequently (85% at 1 year) than patients with acute lymphoblastic leukemia (56%), chronic granulocytic leukemia (45%), or aplastic anemia (47%). In both univariate and multivariate analysis, CMV infection was not associated with a worse prognosis. However, 5 (out of 10) cases of lethal interstitial pneumonitis were associated with CMV, and two patients died of possible CMV encephalitis. All these patients had been suffering from severe acute or chronic graft versus host disease.     

Experimental respiratory syncytial virus pneumonia in cebus monkeys.

Into 14 juvenile cebus monkeys that lacked serum antibodies for RS virus 10(8) plaque-forming units (pfu) of wild-type respiratory syncytial (RS) virus were inoculated transtracheally. Roentgenographic evidence of pneumonia developed in 13 of 14 infected animals. Gross pathologic changes occurred in each of the 13 monkeys that were sacrificed. Patchy areas of red consolidation were seen in the lower lobes 24 hours after inoculation, and there was progression to gray consolidation seven days later. Each of the infected animals had histologic evidence of interstitial pneumonia. Changes were detected in the lung as early as 24 hours after inoculation; they consisted primarily of infiltration of the alveolar wall. By the fourth to sixth day after inoculation there was marked interstitial thickening, pulmonary consolidation, formation of multinucleated giant cells and development of eosinophilic cytoplasmic inclusion bodies within alveolar cells. RS viral antigens, detected by indirect immunofluorescence, were distributed throughout cells of the alveolar wall and the bronchiolar epithelium. The virus grew to highest titer in the lungs on the fourth to sixth day after inoculation; up to 10(8) pfu/gram of tissue were detected. The cebus monkey represents the first experimental host to develop extensive pulmonary lesions during infection with respiratory syncytial virus.     

Evidence for transfer of cellular and humoral immunity to cytomegalovirus from donor to recipient in allogeneic bone marrow transplantation.

In order to study the importance of the immune status of the donor in the development of immunity after allogeneic bone marrow transplantation (BMT), we monitored 23 cytomegalovirus (CMV) antibody-positive BMT recipients for humoral and cellular immunity to CMV, of whom 12 had a CMV antibody-positive and 11 a CMV antibody-negative marrow donor. Lymphocyte proliferation to CMV recovered significantly earlier after BMT in recipients of marrow from a CMV+ donor (10.4 weeks after BMT) compared with the recipients of marrow from CMV- donors (16.7 weeks after BMT, P less than 0.05). This seemed to be specific, as lymphocyte proliferation to phytohaemagglutinin and Candida were not different between the to groups. IgM responses after active infection were seen in both groups, but initial IgG rises without IgM were seen only in recipients of marrow from CMV+ donors (P less than 0.05). Lymphocyte proliferative or humoral immune responses to CMV were not detected in any of the patients in a control group consisting of nine CMV- recipients. These results indicate that T cell memory to CMV is transferred with donor marrow from CMV+ donors, leading in most patients to direct IgG anti-CMV responses and to quicker recovery of cellular immunity to CMV.     

Genetic predisposition to wheeze following respiratory syncytial virus bronchiolitis

BACKGROUND: The nature of the association between severe respiratory syncytial virus (RSV) bronchiolitis and subsequent wheezing remains unknown. In a previous study, we showed that genetic variation in the IL-8-promoter region is associated with susceptibility to severe bronchiolitis. OBJECTIVE: The purpose of this study was to assess the association between wheezing post-bronchiolitis and the genetic variant of IL-8 gene. METHODS: We collected data from 134 children who had suffered from bronchiolitis, enrolled in our previous study. The occurrence of wheezing post-bronchiolitis was recorded from a questionnaire sent by post. The association between the genotype and wheezing phenotype was assessed by family-based and case-control approaches. RESULTS: Family-based association showed that the IL-8 variant was transmitted significantly more often than expected in the children who wheezed after the episode of bronchiolitis (transmission=56%, P=0.02). This effect was not observed in the group of children who had bronchiolitis but did not go on to wheeze. Moreover, the variant was significantly more frequent in post-bronchiolitis wheezers compared with the general population (odds ratio=1.6, 95% confidence interval 1.0-2.6). CONCLUSION: These preliminary results suggest that there is a genetic predisposition to wheeze following severe RSV bronchiolitis.     

Decreased bacterial clearance from the lungs of mice following primary respiratory syncytial virus infection

Virus respiratory infections often precede bacterial pneumonia in healthy individuals. In order to determine the potential role of respiratory syncytial virus (RSV) in bacterial secondary infections, a mouse sequential pulmonary infection model was developed. Mice were exposed to RSV then challenged with Streptococcus pneumoniae (StPn). Exposure of BALB/c mice to 10(6)-10(7) plaque forming units (pfu) of virus of RSV significantly decreased StPn clearance 1-7 days following RSV exposure. This finding was not restricted to StPn alone: exposure to RSV followed by Staphylococcus aureus (SA) or Pseudomonas aeruginosa(PA) resulted in similar decreases in bacterial clearance. Both bronchoalveolar lavage (BAL) cell counts and pulmonary histopathology demonstrated that RSV-StPn exposed mice had increased lung cellular inflammation compared to mice receiving StPn or RSV alone. The effect of RSV infection on bacterial clearance was dependent on the mouse genetic background: C57BL/6J mice (relatively resistant to RSV infection) demonstrated a modest change in StPn clearance following RSV exposure, whereas FVBN/J mice (similar to the BALB/cJ mice in RSV susceptibility) demonstrated a similar degree of RSV-associated decrease in StPn clearance 7 days following RSV exposure. Neutrophils from the RSV-StPn sequentially exposed BALB/cJ mice were functionally altered-produced greater levels of peroxide production but less myeloperoxidase (MPO) compared to mice receiving StPn alone. These data demonstrate that RSV infection decreases bacterial clearance, potentially predisposing to secondary bacterial pneumonia despite increased lung cellular inflammation, and suggest that functional changes occur in the recruited neutrophils that may contribute to the decreased bacterial clearance.     

Primary respiratory syncytial virus infection in mice

A mouse model of respiratory syncytial virus (RSV) infection is described. A high-titered, large-volume inoculum results in replication of RSV to a high titer in lungs of BALB/c mice. Mice older than 15 weeks of age are more susceptible to RSV infection. Titers up to 10(6.9) plaque-forming units (pfu)/gram lung can be attained in 32-week-old mice. Older mice experience a clinical illness manifested by ruffled fur, reduced activity, and weight loss. Lung histology of older mice infected with RSV shows bronchiolitis and increased number of lymphocytes and macrophages in alveolar spaces compared with that of mice less than 8 weeks old. This model will serve as the basis for investigating immunodeterminants of recovery and protection from RSV infection.     

The potential usefulness of interleukin-2 activated bone marrow cells as an active therapeutic tool against cytomegalovirus infection in a bone marrow transplantation setting

Bone marrow transplantation (BMT) has been used in recent years for the treatment of immunodeficiency disease, aplastic anemia, and leukemia. However, there are a number of serious problems and limitations associated with autologous or allogeneic BMT. One of these is an increase in opportunistic infections, of which cytomegalovirus (CMV) infection is one of the most important. Cytomegalovirus has been associated with more frequent deaths than any other single agent, with no reproducibly successful or therapy currently available. Recently usage of interleukin-2 or immunomodulation has been suggested as a powerful modality to combat infectious disease. In this study we showed that bone marrow activated in interleukin-2 for 2 days has the ability to lyse spleen cells infected for 3 days with murine CMV (acute infection model) or salivary gland cells infected for 7 days (chronic infection model), while nonactivated bone marrow or natural killer (NK) cells showed no such lysis. The majority of activated cells involved in lysis were antiasialo GM ₁ ^– , Thy-1^±, indicating a population of cells other than the natural killer-cell population involved.     

新生儿呼吸道合胞病毒肺炎的临床特征及干扰素的干预效果

目的 研究新生儿呼吸道合胞病毒(RSV)肺炎的临床特征及干扰素的干预效果.方法 将我院儿科2014年5月至2015年7月收治的96例RSV肺炎新生患儿纳入研究对象.经随机数字法分为观察组和对照组,每组48例.对照组入院后进行常规治疗,观察组在此基础上增加重组人干扰素α1b的使用.比较观察组与对照组肺部哕音消失时间、吸氧天数、住院时间,并于治疗1周后评估两组临床疗效,治疗期间观察药物不良反应.另随机抽取医院同期出生的RSV检查阴性新生儿90例为阴性对照组,比较RSV阳性患儿与RSV阴性新生儿的一般资料、临床特征差异.结果 RSV阳性组纯母乳喂养率为35.42％,明显低于RSV阴性组53.33％ (P ＜0.05),咳嗽、鼻塞、细湿鸣音、哮鸣音发生率分别为76.04％、71.88％、54.17％、30.21％,均明显高于RSV阴性组(P＜0.05);观察组肺部哕音消失时间、吸氧天数及住院时间分别为(6.44 ±2.13)d、(5.67±1.75)d、(9.28±2.89)d,均明显少于对照组(7.58±3.29)d、(6.83±2.02)d、(10.85±3.60) d(P ＜0.05);观察组治疗1周后有效率为81.25％,较对照组明显升高(P＜0.05).结论 咳嗽、鼻塞、细湿鸣音、哮鸣音、纯母乳喂养率低为新生儿RSV肺炎的主要特征,以干扰素治疗该病,可有效改善治疗效果,促进肺部功能恢复,是值得推广的治疗方式.     

Differentiation and immune function of human dendritic cells following infection by respiratory syncytial virus

RSV causes annual epidemics of bronchiolitis in winter months resulting in the hospitalization of many infants and the elderly. Dendritic cells (DCs) play a pivotal role in coordinating immune responses to infection and some viruses skew, or subvert, the immune functions of DCs. RSV infection of DCs could alter their function and this could explain why protection after natural RSV infection is incomplete and of short duration. In this study, this interaction between DCs and RSV was investigated using a human primary culture model. DCs were generated from purified healthy adult volunteer peripheral blood monocytes. Effects of RSV upon DC phenotype with RSV primed DCs was measured using flow cytometry. Changes to viability and proliferation of cocultured DCs and T-cells were determined using microscopy with fluorescent dyes (Hoechst 33342 and propidium iodide). DC maturation was not prevented by the RSV challenge. RSV infected a fraction of DCs (10-30%) but the virus replicated slowly in these cells with only small reduction to cell viability. DCs challenged with RSV stimulated T-cell proliferation less well than lipopolysaccharide. This is the first study to demonstrate RSV infection of human monocyte derived DCs and suggests that the virus does not significantly interfere with the function of these cells and potentially may promote cellular rather than humoral responses.     

Role of complement in neutralization of respiratory syncytial virus

Serum neutralizing antibody titers to respiratory syncytial virus (RSV) are higher when assayed with guinea pig complement. A number of different mechanisms have been suggested for enhancement of neutralization by complement. The most straightforward is that complement-antibody complexes present a greater steric hindrance to viral entry than with antibody alone. To define the implications of measuring serum neutralizing antibody with and without complement, sera from adults, young children, infants, and cord bloods were run in plaque neutralization assays with representative viruses of the RSV A and B subgroups. Although titers of neutralizing antibody were higher in the presence of complement, the addition of complement did not increase the ability to detect antibody rises after natural infection. Some of the complement effect may be attributable to an inhibition of RSV replication by complement alone. While these observations do not address the role for complement in the pathogenesis of RSV infection, they suggest that neutralization assays performed without complement may be most reflective of physiologic conditions in the respiratory tract.     

Cell-mediated immunity in respiratory syncytial virus disease

Systemic cell-mediated responses to respiratory syncytial (RS) virus were detected, using a whole blood transformation assay, in 10 of 28 infants and children with RS virus infections during the period 1–14 days postadmission. Cell-mediated responses were unrelated to the age of the patient or the severity of illness. No correlation was found between cellular responses and fourfold or greater rises in antibody titre to RS virus, as determined by a membrane immunofluorescence technique. Patients under 6 months of age had significantly lower levels of IgA and IgG antibody to RS virus compared to older patients, although cell-mediated responses were similar in both groups. The presence of cell-mediated reactivity to RS virus was also demonstrated in 5 of 95 samples of cord blood examined, and cellular responses failed to correlate with the levels of IgG antibody to RS virus.     

Experimental respiratory syncytial virus infection of four species of primates.

Four species of nonhuman primates were inoculated intranasally with 10(3.1) to 10(3.7) plaque forming units (pfu) of respiratory syncytial (RS) virus. Adults squirrel monkeys and newborn rhesus monkeys became infected and shed small quantities (peak titer 10(2.0) pfu/ml of nasopharyngeal swab specimen) of virus, but illness did not develop. Infant cebus monkeys aged 2 months became infected, shed 10(2.3) to 10(3.8) pfu/ml of nasopharyngeal swab specimen, but did not become ill. Chimpanzees aged 15 to 18 months shed a large quantity of virus, up to 10(6.0) pfu/ml of nasopharyngeal swab specimen and developed an upper respiratory illness. Chimpanzees are proposed as a possible animal model for future study of the immunopathology of RS virus disease and for in vivo evaluation of attenuated live virus vaccine candidates.     

Improvement of respiratory syncytial virus replication in actively growing HEp-2 cells

The growth of respiratory syncytial (RS) and parainfluenza type III (PI3) viruses has been studied in actively growing versus relatively stationary HEp-2 cells. There was no effect on PI3 virus growth. RS virus synthesis was stimulated from 20- to 60-fold by growth in actively growing cultures when the cell density was approximately $\text{1}\text{3}$ that of a confluent culture. This stimulation was manifested by a greater yield of virus per cell, more virus-specific mRNA produced per cell, and a 50% decrease in the time before cytopathic changes appeared.     

静脉注射用丙种球蛋白对呼吸道合胞病毒治疗的作用

目的:研究静脉注射用丙种球蛋白(IVγG)体内外抗呼吸道合胞病毒(RSV)的作用。方法:①采用微量细胞病变抑制法试验(MCIA),检测不同浓度的IVγG抑制RSV的作用。②建立RSV感染的BALB/c小鼠模型,将40只感染RSV的小鼠分为4组,即IVγG治疗组、病毒唑治疗组、Palivizumab治疗组、生理盐水对照组,及10只未感染RSV的小鼠作为正常对照组,每组10只。于治疗后第5及第7天,分2批处死小鼠,分离病毒并观察肺组织的病理积分。结果:①IVγG具有抑制RSV的作用,其治疗指数(TI)为275,较病毒唑高6倍,较Palivizumab低2倍。②IVγG治疗组小鼠肺组织的病理积分较生理盐水对照组明显减低(P<0.01),但其5d的治疗作用低于Palivizumab治疗组(P<0.05)。结论:IVγG在体内外均有一定的抗RSV的作用,但效果均低于Palivizumab。     

Modified immunoprecipitation procedure for the identification of human respiratory syncytial virus polypeptides

When analysed by polyacrylamide gel electrophoresis, human respiratory syncytial virus harvested after a one step growth cycle and purified through a continuous sucrose density gradient was shown to be composed of nine structural proteins of 90, 68, 49, 42, 34, 28, 25, 19 an 13 kd. The 90, 49 and 19 kd polypeptides were identified as glycopolypeptides by glucosamine incorporation. A modified immunoprecipitation procedure confirmed the viral specificity of the 49, 42, 28, 25 and 19 kd polypeptides.     

Molecular epidemiology of respiratory syncytial virus

Respiratory syncytial virus (RSV) is a major cause of viral acute respiratory tract infections in young children. The virus is characterised by distinct seasonality that is dependent upon the latitude and its ability to cause reinfection. Respiratory syncytial virus demonstrates a complex molecular epidemiology pattern as multiple strains and/or genotypes cocirculate during a single epidemic. Previous studies have investigated the relationship between RSV genetic diversity, reinfection, and clinical features. Here, we review the evidence behind this relationship together with the impact that the advancement of whole genome sequencing will have upon our understanding and the need for reconsidering the classification of RSV genotypes.     

Molecular epidemiology of respiratory syncytial virus in Kilifi district, Kenya

Respiratory syncytial virus (RSV) causes significant burden of disease during infancy and childhood. This study examined the genetic relatedness of RSV positive samples from child inpatients and outpatients and a birth cohort from a rural coastal district of Kenya and also the distribution of strains between these three groups. Clinical samples were collected over a 4-year period in Kilifi District, Kenya from community and hospital surveillance. Three hundred ninety seven of 1,044 nasal specimens from children (under 5 years old) attending Kilifi District Hospital, and from community-monitored infants, were positive for RSV by multiplex RT-PCR. Of these, 376 samples were analysed further by restriction fragment length polymorphisms (RFLP) of the nucleocapsid (N) and attachment (G) protein genes. The G gene was sequenced for 109 samples and phylogenetic analysis carried out. The group A samples from Kilifi fell into two clusters based on G gene sequences, while only one group B cluster was observed. One RSV-B sample from 2003 demonstrated the presence of a 60-nucleotide duplication within the G gene, clustering with similar isolates from Buenos Aries from 1999. All had similar sequences to isolates from the UK, USA, Spain, or Uruguay. The Kilifi District samples showed greater than 97% homology to isolates from South Africa and Mozambique and 91-94% homology to isolates from The Gambia. Samples from different sources, clearly differing in disease severity, did not differ in genotype characteristics, suggesting that disease causing variants are a general reflection of infections within this community.     

呼吸道合胞病毒F蛋白研究进展

人呼吸道合胞病毒（RSV）融合蛋白（F蛋白）为病毒表面结构蛋白,可以刺激机体产生保护性抗体和细胞免疫反应。因此对F蛋白的深入研究将有助于了解病毒感染的机理,从而为研究RSV的免疫机理、研制特定部位的亚单位或多肽疫苗提供帮助。     

Resolution of peanut allergy following bone marrow transplantation for primary immunodeficiency

Peanut allergy is a severe and life-threatening form of food allergy. Treatments are being developed but the mainstays of current management remain avoidance of peanut and appropriate use of rescue medication. We report the case of a boy with peanut allergy who required a bone marrow transplant (BMT) for combined immunodeficiency. A food challenge, 2 years after transplant, showed that his peanut allergy had resolved. Allergic disorders constitute a form of immune deviation and while we do not advocate BMT as a treatment for peanut allergy, we believe this case provides an insight into the basic mechanisms involved in food allergy.