Eosinophil cationic protein and chemokines in nasopharyngeal secretions of infants with respiratory syncytial virus (RSV) bronchiolitis and non-RSV bronchiolitis

Reshaping Our Knowledge: Advancements in Understanding the Immune Response to Human Respiratory Syncytial Virus

Human respiratory syncytial virus (hRSV) is a significant cause of respiratory tract infections, particularly in young children and older adults. In this review, we aimed to comprehensively summarize what is known about the immune response to hRSV infection. We described the innate and adaptive immune components involved, including the recognition of RSV, the inflammatory response, the role of natural killer (NK) cells, antigen presentation, T cell response, and antibody production. Understanding the complex immune response to hRSV infection is crucial for developing effective interventions against this significant respiratory pathogen. Further investigations into the immune memory generated by hRSV infection and the development of strategies to enhance immune responses may hold promise for the prevention and management of hRSV-associated diseases.

CAF08 adjuvant enables single dose protection against respiratory syncytial virus infection in murine newborns

Respiratory syncytial virus is a leading cause of morbidity and mortality in children, due in part to their distinct immune system, characterized by impaired induction of Th 1 immunity. Here we show application of cationic adjuvant formulation CAF08, a liposomal vaccine formulation tailored to induce Th 1 immunity in early life via synergistic engagement of Toll-like Receptor 7/8 and the C-type lectin receptor Mincle. We apply quantitative phosphoproteomics to human dendritic cells and reveal a role for Protein Kinase C-δ for enhanced Th1 cytokine production in neonatal dendritic cells and identify signaling events resulting in antigen cross-presentation. In a murine in vivo model a single immunization at birth with CAF08-adjuvanted RSV pre-fusion antigen protects newborn mice from RSV infection by induction of antigen-specific CD8+ T-cells and Th1 cells. Overall, we describe a pediatric adjuvant formulation and characterize its mechanism of action providing a promising avenue for development of early life vaccines against RSV and other respiratory viral pathogens.

Innate Immune Components that Regulate the Pathogenesis and Resolution of hRSV and hMPV Infections

The human respiratory syncytial virus (hRSV) and human Metapneumovirus (hMPV) are two of the leading etiological agents of acute lower respiratory tract infections, which constitute the main cause of mortality in infants. However, there are currently approved vaccines for neither hRSV nor hMPV. Moreover, despite the similarity between the pathology caused by both viruses, the immune response elicited by the host is different in each case. In this review, we discuss how dendritic cells, alveolar macrophages, neutrophils, eosinophils, natural killer cells, innate lymphoid cells, and the complement system regulate both pathogenesis and the resolution of hRSV and hMPV infections. The roles that these cells play during infections by either of these viruses will help us to better understand the illnesses they cause. We also discuss several controversial findings, relative to some of these innate immune components. To better understand the inflammation in the lungs, the role of the respiratory epithelium in the recruitment of innate immune cells is briefly discussed. Finally, we review the main prophylactic strategies and current vaccine candidates against both hRSV and hMPV.

The Human Immune Response to Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) is an important etiological agent of respiratory infections, particularly in children. Much information regarding the immune response to RSV comes from animal models and in vitro studies. Here, we provide a comprehensive description of the human immune response to RSV infection, based on a systematic literature review of research on infected humans. There is an initial strong neutrophil response to RSV infection in humans, which is positively correlated with disease severity and mediated by interleukin-8 (IL-8). Dendritic cells migrate to the lungs as the primary antigen-presenting cell. An initial systemic T-cell lymphopenia is followed by a pulmonary CD8+ T-cell response, mediating viral clearance. Humoral immunity to reinfection is incomplete, but RSV IgG and IgA are protective. B-cell-stimulating factors derived from airway epithelium play a major role in protective antibody generation. Gamma interferon (IFN-γ) has a strongly protective role, and a Th2-biased response may be deleterious. Other cytokines (particularly IL-17A), chemokines (particularly CCL-5 and CCL-3), and local innate immune factors (including cathelicidins and IFN-λ) contribute to pathogenesis. In summary, neutrophilic inflammation is incriminated as a harmful response, whereas CD8+ T cells and IFN-γ have protective roles. These may represent important therapeutic targets to modulate the immunopathogenesis of RSV infection.

Endobiogeny: a global approach to systems biology (part 2 of 2)

ENDOBIOGENY AND THE BIOLOGY OF FUNCTIONS ARE BASED ON FOUR SCIENTIFIC CONCEPTS THAT ARE KNOWN AND GENERALLY ACCEPTED: (1) human physiology is complex and multifactorial and exhibits the properties of a system; (2) the endocrine system manages metabolism, which is the basis of the continuity of life; (3) the metabolic activity managed by the endocrine system results in the output of biomarkers that reflect the functional achievement of specific aspects of metabolism; and (4) when biomarkers are related to each other in ratios, it contextualizes one type of function relative to another to which is it linked anatomically, sequentially, chronologically, biochemically, etc.

Indirect ultrasound guidance increased accuracy of the glenohumeral injection using the superior approach: a cadaveric study of injection accuracy

Objective

To investigate whether or not indirect ultrasound guidance could increase the accuracy of the glenohumeral joint injection using the superior approach.

Methods

Twelve shoulders from 7 adult cadavers were anatomically dissected after a dye injection had been performed, while the cadavers were in the supine position. Before the injection, a clinician determined the injection point using the ultrasound and the more internal axial arm rotation was compared to how it was positioned in a previous study. Injection confidence scores and injection accuracy scores were rated.

Results

The clinician's confidence score was high in 92% (11 of 12 shoulders) and the injection accuracy scores were 100% (12 of 12 shoulders). The long heads of the biceps tendons were not penetrated.

Conclusion

Indirect ultrasound guidance and positioning shoulder adducted at 10° and internally rotated at 60°-70° during the superior glenohumeral joint injection would be an effective method to avoid damage to the long head of biceps tendons and to produce a highly accurate injection.

Leukocyte chemotactic cytokine and leukocyte subset responses during ultra-marathon running

PURPOSE

The aim of this study was to assess leukocyte chemotactic cytokine and leukocyte subset responses during ultra-marathon running. Leukocyte chemokines such as interleukin (IL)-8, interferon gamma-induced protein-10 (IP-10), regulated upon activation, normal T-cell expressed and secreted (RANTES), and eotaxin are involved in leukocyte recruitment.

METHODS

Among 60 male amateur endurance runner volunteers, 18 finished the course (a 308 km continuous race from Kanghwado to Kangneung, South Korea). Their average age, height, and body mass were 52.8 ± 5.0 years, 167.6 ± 5.2 cm, and 64.5 ± 1.2 kg, respectively. Blood samples were collected at 0, 100, 200, and 308 km during the race for analysis of white blood cells and serum concentrations of IL-8, IP-10, RANTES, eotaxin, IL-6, creatine kinase (CK), and C-reactive protein (CRP).

RESULTS

Muscle and liver damage indicators (IL-6, CK, and CRP) were maximally elevated as a result of marathon running. Total leukocytes, neutrophils, and monocytes increased significantly during the event (leukocytosis, neutrophilia, and monocytosis, respectively). However, lymphocytes and eosinophils decreased significantly during the event (lymphopenia and eosinopenia, respectively). Serum levels of the neutrophil chemokine IL-8 increased maximally at 100 km and were maintained. Monocyte-lymphocyte chemokine IP-10 concentration decreased during the latter part of the race. The eosinophil chemokine eotaxin decreased gradually during the race, and no difference was observed in eosinophil chemokine RANTES levels.

CONCLUSION

These observations indicate that prolonged endurance ultra-marathon running was associated with significant systemic inflammation and perturbation in leukocyte subsets. Leukocyte chemotactic cytokines such as IL-8, IP-10, eotaxin showed similar patterns of responses in related leukocyte subsets, but RANTES did not.

Inflammatory responses to respiratory syncytial virus (RSV) infection and the development of immunomodulatory pharmacotherapeutics

Respiratory syncytial virus (RSV; Family Paramyxoviridae, Genus Pneumovirus) is a major respiratory pathogen of infants and children and an emerging pathogen of the elderly. Current management of RSV disease includes monoclonal antibody prophylaxis for infants identified as high risk and supportive care for those with active infection; there is no vaccine, although several are under study. In this manuscript, we review published findings from human autopsy studies, as well as experiments that focus on human clinical samples and mouse models of acute pneumovirus infection that elucidate basic principles of disease pathogenesis. Consideration of these data suggests that the inflammatory responses to RSV and related pneumoviral pathogens can be strong, persistent, and beyond the control of conventional antiviral and anti-inflammatory therapies, and can have profound negative consequences to the host. From this perspective, we consider the case for specific immunomodulatory strategies that may have the potential to alleviate some of the more serious sequelae of this disease.

Pattern recognition receptors for respiratory syncytial virus infection and design of vaccines

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract illness in infants and young children. Host immune response has been implicated in both the protection and immunopathological mechanisms. Pattern recognition receptors (PRRs) expressed on innate immune cells during RSV infection recognize the RSV-associated molecular patterns and activate innate immune cells as well as mediate airway inflammation, protective immune response, and pulmonary immunopathology. The resident and recruited innate immune cells play important roles in the protection and pathogenesis of an RSV disease by expressing these PRRs. Agonist-binding PRRs are the basis of many adjuvants that are essential for most vaccines. In the present review, we highlight recent advances in the innate immune recognition of and responses to RSV through PRRs, including toll-like receptors (TLRs), retinoic acid-inducible gene (RIG)-I-like receptors (RLRs), and nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs). We also describe the role of PRRs in the design of RSV vaccines.

The infectious march: the complex interaction between microbes and the immune system in asthma

There has been significant progress in our knowledge about the relationship between infectious disease and the immune system in relation to asthma, but many unanswered questions still remain. Respiratory tract infections such as those caused by respiratory syncytial virus and rhinovirus during the first 2 years of life are still clearly associated with later wheezing and asthma, but the mechanism has not been completely worked out. Is there an "infectious march" triggered by infection in infancy that progresses to disease pathology or are infants who contract respiratory infections predisposed to developing asthma? This review focuses on the common themes in the interaction between microbes and the immune system, and presents a critical appraisal of the evidence to date. The various mechanisms whereby microbes alter the immune response and how this might influence asthma are discussed along with new and promising clinical practices for prevention and therapy. Recent advances in using sensitive polymerase chain reaction detection methods have allowed more rigorous testing of the causality hypothesis of virus infection leading to asthma, but the evidence is still equivocal. Various exceptions and inconsistencies in the clinical trials are discussed in light of new guidelines for subject inclusion/exclusion in hopes of providing some standardization. Despite past failures in vaccination and disappointing results of some clinical trials, the new strategies for prophylaxis including RNA interference and targeted delivery of microbicides offer a large dose of hope to a world suffering from an increasing incidence of asthma as well as a huge burden of health care cost and loss of quality of life.

Presence of eosinophils in nasal secretion during acute respiratory tract infection in young children predicts subsequent wheezing within two months

BACKGROUND

In young children with wheezing or bronchiolitis, especially with respiratory syncitial virus, blood eosinophilia and a high eosinophil cationic protein level in nasal secretions predicts subsequent wheezing in later childhood. However, whether eosinophil activation results from virus-induced inflammation or local eosinophilia per se precedes the onset of wheezing remains unknown. In the present study, we examined the association between the presence of nasal eosinophils during respiratory tract infection (RTI) and subsequent wheezing in young children.

METHODS

A total of 35 young children less than 3 years of age who visited our outpatient clinic with rhinorrhea between April and July 2004 were enrolled in this prospective cohort study. Subjects who were given diagnoses of allergic rhinitis were excluded. In all the subjects, the presence of eosinophils in nasal secretions was determined. The subjects were followed, and the cumulative incidences of wheezing during the subsequent 2- and 12-month periods were examined.

RESULTS

According to a logistic regression analysis adjusted for age, sex, family history, allergies, and wheezing at entry, young children with nasal eosinophil infiltration during acute RTI had a significantly higher risk of wheezing during the subsequent 2 months, compared with those without nasal eosinophil infiltration (adjusted odds ratio, 27.618, p = 0.016).

CONCLUSIONS

Our findings not only suggest that nasal eosinophil testing may serve as a convenient clinical marker for identifying young children at risk for subsequent wheezing, but also shed new light on the role of eosinophils in the onset of wheezing in young children.

The role of eosinophil cationic protein in patients with Mycoplasma pneumoniae infection

BACKGROUND

To study the role played by eosinophil cationic protein (ECP) in patients with Mycoplasma pneumonia infection.

METHODS

Pediatric patients aged 4 to 14 years old were divided into 3 groups, each consisting of 30 patients. Group 1 comprised patients with known M. pneumoniae infection. Group 2 comprised patients with asthma who were in a stable condition with no infection, acute asthma exacerbation or steroid use in the last 2 months. Group 3 consisted of healthy children and was designated the control group. The level of ECP in patients' serum was measured by an ECP radioimmunoassay kit.

RESULTS

There were 90 children enrolled in this study; 59 (65.56%) were boys and 31 (34.44%) were girls. Mean serum ECP levels between males and females was not significantly different (p = 0.544). The variance of serum ECP levels decreased as patient age increased, but there was no relationship between serum ECP level and patient age (gamma = 0.118, p = 0.267). Serum ECP levels were similar in both the M. pneumoniae-infected and asthma groups; serum ECP levels in the control group were less than the levels seen in the other 2 groups. The difference in serum ECP levels among the 3 groups was statistically significant (p < 0.001).

CONCLUSION

Both the children who had M. pneumoniae infection and the children with asthma had significantly increased serum ECP levels compared to normal healthy children. The elevated ECP levels found in the serum of patients with M. pneumoniae infection may be associated with damage to the respiratory epithelium and accelerated hypersensitivity in the respiratory system. Decreasing the serum level of ECP may potentially be a method of relieving symptoms in patients with M. pneumoniae infection. Additional studies are warranted to further validate this conclusion.