Carolina Scagnolari

Respiratory syncytial virus, human bocavirus and rhinovirus bronchiolitis in infants

Objective: To investigate the prevalence of 14 viruses in infants with bronchiolitis and to study demographic and clinical differences in those with respiratory syncytial virus (RSV), human bocavirus (hBoV) and rhinovirus (RV) infection. Methods: 182 infants aged <12 months hospitalised for bronchiolitis were enrolled. Infants underwent nasal washing for the detection of RSV, influenza virus A and B, human coronavirus OC43, 229E, NL-63, HUK1, adenovirus, RV, parainfluenza 1–3, human metapneumovirus and hBoV. Demographic, clinical and laboratory data were obtained from parents and from patient medical files. Main outcome measurements were age, breastfeeding history, family smoking habits, family history for asthma and atopy, blood eosinophil count, chest radiological findings, clinical severity score and number of days of hospitalisation. Results: A virus was detected in 57.2% of the 182 infants. The most frequently detected viruses were RSV (41.2%), hBoV (12.2%) and RV (8.8%). Infants with dual infections (RSV and hBoV) had a higher clinical severity score and more days of hospitalisation than infants with RSV, RV and hBoV bronchiolitis (mean±SD: 4.7+2.4 vs 4.3±2.4 vs 3.0±2.0 vs 2.9±1.7, p<0.05; and 6.0±3.2 vs 5.3±2.4 vs 4.0±1.6 vs 3.9±1.1 days; p<0.05). Infants with RV infection had higher blood eosinophil counts than infants with bronchiolitis from RSV and hBoV (307±436 vs 138±168 vs 89±19 n/mm3; p<0.05). Conclusions: Although the major pathogen responsible for bronchiolitis remains RSV, the infection can also be caused by RV and hBoV. Demographic characteristics and clinical severity of the disease may depend on the number of viruses or on the specific virus detected.

Detection and typing by molecular techniques of respiratory viruses in children hospitalized for acute respiratory infection in Rome, Italy

Detection of a broad number of respiratory viruses is not undertaken currently for the diagnosis of acute respiratory infection due to the large and always increasing list of pathogens involved. A 1‐year study was undertaken on children hospitalized consecutively for acute respiratory infection in a Pediatric Department in Rome to characterize the viruses involved. Two hundred twenty‐seven children were enrolled in the study with a diagnosis of asthma, bronchiolitis, bronchopneumonia, or laringo‐tracheo bronchitis. A molecular approach was adopted using specific reverse transcription (RT)‐PCR assays detecting 13 respiratory viruses including metapneumovirus (hMPV) and the novel coronaviruses NL63 and HKU1; most amplified fragments were sequenced to confirm positive results and differentiate the strain. Viral pathogens were detected in 97 samples (42.7%), with 4.8% of dual infections identified; respiratory syncytial virus (RSV) was detected in 17.2% of children, followed by rhinovirus (9.7%), parainfluenza virus type 3 (PIV3) (7.5%), and influenza type A (4.4%). Interestingly, more than half the patients (9/17) that have rhinovirus as the sole respiratory pathogen had pneumonia. HMPV infected children below 3 years in two peaks in March and June causing bronchiolitis and pneumonia. One case of NL63 infection is described, documenting NL63 circulation in central Italy. In conclusion, the use of a comprehensive number of PCR‐based tests is recommended to define the burden of viral pathogens in patients with respiratory tract infection. J. Med. Virol. 79:463–468, 2007.

Rhinovirus bronchiolitis and recurrent wheezing: 1-year follow-up

The association between bronchiolitis and recurrent wheezing remains controversial. In this prospective study, we assessed risk factors for recurrent wheezing during a 12-month follow-up in 313 infants aged <12 months hospitalised for their first episode of bronchiolitis. Demographic, clinical and laboratory data were obtained with a questionnaire and from medical files. A total of 14 respiratory viruses were concurrently assayed in nasal washings. Parents were interviewed 12 months after hospitalisation to check whether their infants experienced recurrent wheezing. The rate of recurrent wheezing was higher in infants with bronchiolitis than in controls (52.7 versus 10.3%; p<0.001). Multivariate analysis identified rhinovirus (RV) infection (OR 3.3, 95% CI 1.0–11.1) followed by a positive family history for asthma (OR 2.5, 95% CI 1.2–4.9) as major independent risk factors for recurrent wheezing. In conclusion, the virus most likely to be associated with recurrent wheezing at 12 months after initial bronchiolitis is RV, a viral agent that could predict infants prone to the development of recurrent wheezing.

Fate of neutralizing and binding antibodies to IFN beta in MS patients treated with IFN beta for 6 years

An increasing number of evidence is showing that during prolonged treatment of relapsing-remitting multiple sclerosis (RRMS) with interferon (IFN) beta 1a or IFN beta 1b, the patients may develop serum anti-IFN antibody. It has been argued that some of the RRMS patients receiving IFN beta, who developed antibodies to IFN, lose them over time even though the treatment continues. To gain further insights into this issue, we performed a study to establish what happened to binding antibodies (BAB) and neutralizing antibodies (NAB) in 42 RRMS patients treated for 6 years with IFN beta 1a and/or IFN beta 1b. While the data of BAB analysis did not allow to reach definite conclusions, the results on NAB development confirm that the presence of this type of antibodies is transitory; in fact, most of the positive patients reverted to seronegative, although the IFN treatment is still ongoing; the only patients who were positive for NAB at 6 years of treatment are those whose serum contains high concentration of them. The paper also shows that patients lose antibodies to IFN independently on the type of IFN used for the treatment. In conclusion, the data indicate that the disappearance of the anti-IFN antibodies from the serum while the patients are still undergoing IFN treatment depends on the titer of antibodies but not on the type of IFN administered.

Neutralizing and Binding Antibodies to IFN-β: Relative Frequency in Relapsing-Remitting Multiple Sclerosis Patients Treated with Different IFN-β Preparations

The frequencies of anti-interferon-β (IFN-β) antibody development reported to date in patients treated with different IFN-β preparations are not readily comparable mainly because of differences in ...

Differential expression of interferon-induced microRNAs in patients with chronic hepatitis C virus infection treated with pegylated interferon alpha

There have been reports of in-vitro interferon (IFN)-mediated antiviral activity against the hepatitis C virus (HCV) through microRNAs (miRNAs). The main aim of this study was to evaluate the expression of several miRNAs (miR-1, miR-30, miR-128, miR-196, miR-296) in peripheral blood mononuclear cells (PBMCs) from healthy individuals after in vitro IFN-treatment and in PBMCs from patients with chronic hepatitis C (CHC) before and 12 hours after the first injection of pegylated IFN alpha. We demonstrated that expression of these miRNAs could be recorded in PBMCs collected from healthy individuals before and after in-vitro IFN alpha treatment. Our analysis revealed that the levels of expression of all miRNAs investigated in patients with CHC were different to those in healthy individuals. When levels of the miRNAs were measured 12 hours after the first IFN injection, increases in expression levels of IFN-induced miRNAs were observed in 25-50% of patients, depending on the type of miRNA examined. No correlations were observed between HCV viral load, alanine aminotransferase status and expression of miRNA. Together these findings suggest that: (i) IFN alpha in-vitro treatment of PBMCs leads to a transcriptional induction of all miRNAs investigated; (ii) miRNAs can be induced differentially by IFN treatment in patients with HCV. Given the importance of miRNAs in defending the host against virus infections, it is possible that IFN-induced miRNAs may represent an important determinant of the clinical outcome of IFN therapy in HCV infection.

Rapid spread of the novel respiratory syncytial virus a on1 genotype, central Italy, 2011 to 2013

Respiratory infections positive for human respiratory syncytial virus (RSV) subtype A were characterised in children admitted to hospitals in Rome and Ancona (Italy) over the last three epidemic seasons. Different strains of the novel RSV-A genotype ON1, first identified in Ontario (Canada) in December 2010, were detected for the first time in Italy in the following 2011/12 epidemic season. They bear an insertion of 24 amino acids in the G glycoprotein as well as amino acid changes likely to change antigenicity. By early 2013, ON1 strains had spread so efficiently that they had nearly replaced other RSV-A strains. Notably, the RSV peak in the 2012/13 epidemic season occurred earlier and, compared with the previous two seasons, influenza-like illnesses diagnoses were more frequent in younger children; bronchiolitis cases had a less severe clinical course. Nonetheless, the ON1-associated intensive care unit admission rate was similar, if not greater, than that attributable to other RSV-A strains. Improving RSV surveillance would allow timely understanding of the epidemiological and clinicopathological features of the novel RSV-A genotype.

Evaluation of viral load in infants hospitalized with bronchiolitis caused by respiratory syncytial virus

The relationship between viral load, disease severity and antiviral immune activation in infants suffering from respiratory syncytial virus (RSV)-associated bronchiolitis has not been well identified. The main objective of this study was to determine the existence of a correlation between RSV load and disease severity and also between different clinical markers and mRNA levels of the interferon stimulated gene (ISG)56 in infants hospitalized for bronchiolitis. We also evaluated whether viral load tended to be persistent over the course of the RSV infection. The levels of RSV-RNA were quantified in nasopharyngeal washings, collected from 132 infants infected with RSV as a single (90.15%) or as a dual infection with other respiratory viruses (9.85%). Results indicated that viral load was positively related to the clinical severity of bronchiolitis, the length of hospital stay, the levels of glycemia and the relative gene expression of ISG56, whereas an inverse correlation was observed with the levels of hemoglobin. We also found that the RSV load significantly decreased between the first and second nasopharingeal washings sample in most subjects. These results suggest that infants with high RSV load on hospital admission are more likely to have both more severe bronchiolitis and a higher airway activation of antiviral immune response.

Gene Expression of Nucleic Acid-Sensing Pattern Recognition Receptors in Children Hospitalized for Respiratory Syncytial Virus-Associated Acute Bronchiolitis

ABSTRACT Given the critical role of pattern recognition receptors (PRRs) in acid nucleic recognition in the initiation of innate immunity and the orchestration of adaptive immunity, the aim of this study was to determine whether any heterogeneity of PRR expression in the airway tracts of infants with respiratory syncytial virus (RSV) infection might explain the broad clinical spectrum of RSV-associated bronchiolitis in infants. For this purpose, the levels of melanoma differentiation-associated protein-5 (MDA-5), retinoic acid inducible gene-1 (RIG-1), and Toll-like receptor 3 (TLR-3), TLR-7, TLR-8, and TLR-9 mRNAs were evaluated, using TaqMan quantitative reverse transcription-PCR, in cells from nasopharyngeal washes collected from 157 infants suffering from acute bronchiolitis whether or not they were associated with respiratory viruses. High interindividual variability was observed in both virus-positive and -negative infants; however, the relative gene expression levels of MDA-5, RIG-1, TLR-7, and TLR-8 were significantly higher in the virus-infected group, whereas the expression levels of TLR-3 and TLR-9 were not significantly different. The differences in the gene expression of MDA-5, RIG-1, TLR-7, and TLR-8 were more evident in infants with RSV infection than in those with bocavirus or rhinovirus infection. In RSV-infected infants, PRR-mRNA levels also were analyzed in relation to interferon protein levels, viral load, clinical severity, days of hospitalization, age, and body weight. A significant positive correlation was observed only between RSV viral load and RIG-1 mRNA levels. These findings provide the first direct evidence that, in infants with respiratory virus-associated bronchiolitis, especially RSV, there are substantial changes in PRR gene expression; this likely is an important determinant of the clinical outcome of bronchiolitis.

Incidence and predisposing factors for severe disease in previously healthy term infants experiencing their first episode of bronchiolitis.

Aim:  To determine the incidence and predisposing factors for severe bronchiolitis in previously healthy term infants <12 months of age experiencing their first episode of bronchiolitis.