Differential impact of respiratory syncytial virus and parainfluenza virus on the frequency of acute otitis media is explained by lower adaptive and innate immune responses in otitis-prone children

Variability of vaccine responsiveness in early life

Vaccinations in early life elicit variable antibody and cellular immune responses, sometimes leaving fully vaccinated children unprotected against life-threatening infectious diseases. Specific immune cell populations and immune networks may have a critical period of development and calibration in a window of opportunity occurring during the first 100 days of early life. Among the early life determinants of vaccine responses, this review will focus on modifiable factors involving development of the infant microbiota and metabolome: antibiotic exposure, breast versus formula feeding, and Caesarian section versus vaginal delivery of newborns. How microbiota may serve as natural adjuvants for vaccine responses and how microbiota-derived metabolites influence vaccine responses are also reviewed. Early life poor vaccine responsiveness can be linked to increased infection susceptibility because both phenotypes share similar immunity dysregulation profiles. An early life pre-vaccination endotype, when interventions have the highest potential for success, should be sought that predicts vaccine response trajectories.

Postmortem Nasopharyngeal Microbiome Analysis of Zambian Infants With and Without Respiratory Syncytial Virus Disease: A Nested Case Control Study

BACKGROUND

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis and lower respiratory tract infections in children in their first year of life, disproportionately affecting infants in developing countries. Previous studies have found that the nasopharyngeal (NP) microbiome of infants with RSV infection has specific characteristics that correlate with disease severity, including lower biodiversity, perturbations of the microbiota and differences in relative abundance. These studies have focused on infants seen in clinical or hospital settings, predominantly in developed countries.

METHODS

We conducted a nested case control study within a random sample of 50 deceased RSV+ infants with age at death ranging from 4 days to 6 months and 50 matched deceased RSV- infants who were all previously enrolled in the Zambia Pertussis and RSV Infant Mortality Estimation (ZPRIME) study. All infants died within the community or within 48 hours of facility admittance. As part of the ZPRIME study procedures, all decedents underwent one-time, postmortem NP sampling. The current analysis explored the differences between the NP microbiome profiles of RSV+ and RSV- decedents using the 16S ribosomal DNA sequencing.

RESULTS

We found that Moraxella was more abundant in the NP microbiome of RSV+ decedents than in the RSV- decedents. Additionally, Gemella and Staphylococcus were less abundant in RSV+ decedents than in the RSV- decedents.

CONCLUSIONS

These results support previously reported findings of the association between the NP microbiome and RSV and suggest that changes in the abundance of these microbes are likely specific to RSV and may correlate with mortality associated with the disease.

Immunological profiles of children with recurrent otitis media with or without spontaneous tympanic membrane perforation and of children with recurrent respiratory infections

OBJECTIVES

The primary aim of this study was to compare the immunological profiles of children affected by recurrent acute otitis media (rAOM) with and without spontaneous tympanic membrane perforation (STMP). The secondary aim was to compare immunological features of children without parameters outside the normal range and affected by either rAOM or recurrent respiratory tract infections (rRTI).

METHODS

In this study, otherwise healthy children (<10 years of age) with rAOM or rRTI were included. Data on perinatal history, vaccination status, presence of risk factors for rAOM or rRTI (including personal or family history of allergy) and number of infectious episodes in the previous 12 months were retrospectively obtained. Furthermore, data on immunological profile (blood cell count, circulating IgA, IgG, IgM and total IgE, IgG subclasses and lymphocyte subpopulations) were collected. The immune profile of children affected by rAOM with and without STMP were compared. Among children with parameters within normal range, we compared the levels of the immunological parameters of children affected by rAOM (with and without STMP) and rRTI.

RESULTS

The study involved a total of 751 children: 566 (75.3%) with rAOM and 185 (24.7%) with rRTI. Among the 566 children with rAOM, 39.7% had uncomplicated rAOM and 60.3% had rAOM with STMP. The mean age of the study population was 34.9 (SD 20.5) months. The frequency of children with parameters outside the normal range was similar among children with rAOM with (4.9%) and without STMP (6.1%). Among subjects without parameters outside the normal range, children with uncomplicated rAOM had significantly lower serum IgG, lymphocyte CD8⁺ and CD19⁺ and significantly higher IgG2 levels than children affected by rAOM with STMP. Finally, children with rAOM had lower levels of IgA, IgM and IgG2 and higher levels of IgG, lymphocyte CD19⁺ and CD16/56+ compared to children with rRTI.

CONCLUSIONS

A low (<6.5%) percentage of children with rAOM with or without STMP present parameters outside the normal range. Among subjects without parameters outside the normal range, children with uncomplicated rAOM have a different immune profile as compared to those with STMP and rRTI. New prospective studies are needed to further explore the immune features of children affected by rAOM with and without STMP.

Interleukin-33 and thymic stromal lymphopoietin are primary cytokines involved in the Th1/Th2 inflammatory response in chronic secretory otitis media

Background:

T-helper (Th)1/Th2 inflammatory responses are responsible for secretory otitis media (SOM) development. However, the mechanisms underlying these immune responses remain unknown. This study aims to identify the primary cytokines that play essential roles in chronic SOM.

Methods:

Two groups were established for the present study: chronic SOM group ( n = 21) and control group ( n = 10). The middle ear effusion and serum samples of the expression cytokines (interleukin IL-2, IL-4, IL-5, IL-13, IL-17, IL-25, IL-33, interferon [IFN]-γ, thymic stromal lymphopoietin [TSLP], immunoglobulin IgE, and pepsins) were analyzed by enzyme-linked immunosorbent assay.

Results:

The levels of IL-4, IL-5, IL-13, IL-17, IL-25, IFN-γ, TLSP, pepsins, IL-2, and IL-33 (all, p < 0.001) were higher in middle ear effusion, when compared to those in serum, in chronic SOM group (non-paired sample). However, there was no significant difference in serum expression for those cytokines compared chronic SOM group and control group. The paired sample expression for IL-33 and TLSP (both, p = 0.046) were higher compared the effusion and serum in chronic SOM group.

Conclusions:

IL-33 produces inflammatory cytokines, such as IL-1b, IL-6, TNF-α, IL-10, IL-4, and TGF-β, which through nucleus into cytoplasm causing inflammatory responses. The present study revealed that IL-33 also produce IL-17, IL-4, IL-5, and IL-13 inflammatory factors, triggering an inflammatory response. Study reported that the combined stimulation of TSLP and IL-33 elicits an approximately 10-fold increase in cytokine production, when compared to the stimulation of IL-33 alone. This suggests that IL-33 and TLSP may be the primary cytokines involved in Th1/Th2 inflammatory responses in chronic SOM.

Immunohistochemical and qPCR Detection of SARS-CoV-2 in the Human Middle Ear Versus the Nasal Cavity: Case Series

Viral infections have already been implicated with otitis media and sudden sensorineural hearing loss. However, the pathophysiology of COVID-19 as it relates to otologic disorders is not well-defined. With the spread of SARS-CoV-2, it is important to evaluate its colonization of middle ear mucosa. Middle ear and nasal tissue samples for quantitative RT-PCR and histologic evaluations were obtained from post-mortem COVID-19 patients and non-diseased control patients. Here we present evidence that SARS-CoV-2 colonizes the middle ear epithelium and co-localizes with the primary viral receptor, angiotensin-converting enzyme 2 (ACE2). Both middle ear and nasal epithelial cells show relatively high expression of ACE2, required for SARS-CoV-2 entry. The epithelial cell adhesion molecule (EpCAM) was use as a biomarker of epithelia. Furthermore, we found that the viral load in the middle ear is lower than that present in the nasal cavity.

Prevention of antimicrobial prescribing among infants following maternal vaccination against respiratory syncytial virus

Strategies to reduce consumption of antimicrobial drugs are needed to contain the growing burden of antimicrobial resistance. Respiratory syncytial virus (RSV) is a prominent cause of upper and lower respiratory tract infections, as a single agent and in conjunction with bacterial pathogens, and may thus contribute to the burden of both inappropriately treated viral infections and appropriately treated polymicrobial infections involving bacteria. In a double-blind, randomized, placebo-controlled trial, administering an RSV vaccine to pregnant mothers reduced antimicrobial prescribing among their infants by 12.9% over the first 3 mo of life. Our findings implicate RSV as an important contributor to antimicrobial exposure among infants and demonstrate that this exposure is preventable by use of effective maternal vaccines against RSV.

Reductions in antimicrobial consumption are needed to mitigate the burden of antimicrobial resistance. Vaccines may have an important role to play in reducing antimicrobial consumption by preventing infections for which treatment is often prescribed, whether appropriately or inappropriately. However, limited understanding of the volume of antimicrobial treatment attributable to specific pathogens—and to viruses, in particular—presently hinders efforts to prioritize vaccines with the greatest potential to reduce antimicrobial consumption. In a double-blind trial undertaken across 11 countries, infants born to mothers who were randomized to receive an experimental vaccine against respiratory syncytial virus (RSV) experienced 12.9% (95% CI: 1.3 to 23.1%) lower incidence of antimicrobial prescribing over the first 3 mo of life than infants whose mothers were randomized to receive placebo. Vaccine efficacy against antimicrobial prescriptions associated with acute lower respiratory tract infections (LRTIs) was 16.9% (95% CI: 1.4 to 29.4%). Over the first 3 mo of life, maternal vaccination prevented 3.6 antimicrobial prescription courses for every 100 infants born in high-income countries and 5.1 courses per 100 infants in low- and middle-income countries, representing 20.2 and 10.9% of all antimicrobial prescribing in these settings, respectively. While LRTI episodes accounted for 69 to 73% of all antimicrobial prescribing prevented by maternal vaccination, striking vaccine efficacy (71.3% [95% CI: 28.1 to 88.6%]) was also observed against acute otitis media–associated antimicrobial prescription among infants in high-income countries. Our findings implicate RSV as a cause of substantial volumes of antimicrobial prescribing among young infants and demonstrate the potential for prevention of such prescribing through use of maternal vaccines against RSV.

Pneumonia, Sinusitis, Influenza and Other Respiratory Illnesses in Acute Otitis Media-Prone Children

BACKGROUND

Recurrent acute otitis media in the first years of life can be explained by immune dysfunction. Consequently, it would be expected that otitis-prone (OP) children would be more susceptible to other infectious diseases, especially respiratory infections, since a component of the immune problem involves nasopharyngeal innate immunity.

DESIGN

Cohort study with prospective identification of all physician-diagnosed, medically attended respiratory illness visits in children 6 months to 5 years of age to determine the incidence of pneumonia, acute sinusitis, influenza and other bacterial and viral infections among OP compared with non-OP (NOP) children. Tympanocentesis to microbiologically confirm acute otitis media disease.

RESULTS

Two hundred eighty-five children were studied. Thirty-nine met a standard definition of stringently defined OP (sOP) determined by tympanocentesis and 246 were NOP. sOP children had increased frequency of presumptive respiratory infections, pneumonia (6-fold higher, P < 0.001), sinusitis (2.1-fold higher, P = 0.026) and influenza (2.9-fold higher, P = 0.002), compared with NOP children. Demographic and risk factor covariate-adjusted fold difference between sOP and NOP children for all respiratory infection illness visits was 2.4-fold (P < 0.00001) at 6-18 months of age, 2.2-fold (P < 0.00001) at 18-30 months of age and at age and 2.4-fold (P = 0.035) higher at 30 to 42 months. For both sOP and NOP children, more frequent medically attended respiratory infection illness visits from 6-18 months of age predicted more frequent visits experienced from 18-60 months of age.

CONCLUSIONS

Clinicians should be aware of a significant increased likelihood of bacterial and viral respiratory infection proneness among OP children.

Respiratory syntycial virus: Current treatment strategies and vaccine approaches

Respiratory Syncytial Virus is a yearly respiratory virus that causes significant frequencies of morbidities, particularly in the young and elderly populations. However, preventive vaccines and/or treatment therapies are generally lacking, although much attention is now being placed on this virus. Moreover, there are now multiple strategies currently being explored in a race to the first licensed vaccine. While vaccines are being developed, multiple treatment strategies are being explored to attenuate the severity of infection and thus reduce hospitalization rates in vulnerable populations. This review outlines current strategies to prevent or treat this virus in the hopes of reducing significant human morbidity and mortality that occurs yearly with this seasonal virus.

Streptococcus pneumoniae serotype 22F infection in respiratory syncytial virus infected neonatal lambs enhances morbidity

Respiratory syncytial virus (RSV) is the primary cause of viral bronchiolitis resulting in hospitalization and a frequent cause of secondary respiratory bacterial infection, especially by Streptococcus pneumoniae (Spn) in infants. While murine studies have demonstrated enhanced morbidity during a viral/bacterial co-infection, human meta-studies have conflicting results. Moreover, little knowledge about the pathogenesis of emerging Spn serotype 22F, especially the co-pathologies between RSV and Spn, is known. Here, colostrum-deprived neonate lambs were divided into four groups. Two of the groups were nebulized with RSV M37, and the other two groups were mock nebulized. At day three post-RSV infection, one RSV group (RSV/Spn) and one mock-nebulized group (Spn only) were inoculated with Spn intratracheally. At day six post-RSV infection, bacterial/viral loads were assessed along with histopathology and correlated with clinical symptoms. Lambs dually infected with RSV/Spn trended with higher RSV titers, but lower Spn. Additionally, lung lesions were observed to be more frequent in the RSV/Spn group characterized by increased interalveolar wall thickness accompanied by neutrophil and lymphocyte infiltration and higher myeloperoxidase. Despite lower Spn in lungs, co-infected lambs had more significant morbidity and histopathology, which correlated with a different cytokine response. Thus, enhanced disease severity during dual infection may be due to lesion development and altered immune responses rather than bacterial counts.

Impaired Proinflammatory Response in Stringently Defined Otitis-prone Children During Viral Upper Respiratory Infections

BACKGROUND

Viral upper respiratory infections (URIs) are common and often precipitate acute otitis media (AOM), caused by bacterial otopathogens, in young children. Acute inflammatory responses initiated in the early phase of viral URI contribute to preventing the development of AOM. Stringently-defined otitis-prone (sOP) children are susceptible to recurrent AOM.

METHODS

We assessed proinflammatory cytokine and chemokine levels in the nasopharynxes during viral URIs, and examined the different nasopharyngeal responses between viral URI events and the following AOM episodes in both sOP and non-otitis-prone (NOP) children.

RESULTS

The sOP children exhibited significantly more AOM episodes per child (8.86-fold higher), viral URIs (P < .0001), and viral URIs followed by AOMs (P < .0001) than the NOP children. The sOP children had lower nasal proinflammatory levels of interleukin (IL)-6 (P = .05), IL-10 (P = .001), tumor necrosis factor (TNF)-α (P = .004), and regulated on activation, normal T-cell-expressed and -secreted (RANTES; P = .002) than NOP children during viral URIs. NOP children had higher levels of IL-6 (P = .02), IL-10 (P = .02), interferon-γ (P = .003), TNF-α (P = .006), IL-1β (P = .022), monocyte chemoattractant protein 1 (P = .028), RANTES (P = .005), IL-2 (P = .002), and IL-17 (P = .007) during viral URIs versus AOMs following the URIs, when compared to sOP children.

CONCLUSIONS

We conclude that sOP children have more frequent viral URIs than NOP children, due to deficient antiviral nasopharyngeal proinflammatory cytokine and chemokine responses.

Respiratory Syncytial Virus's Non-structural Proteins: Masters of Interference

Respiratory Syncytial Virus (RSV) is a highly prevalent virus that affects the majority of the population. The virus can cause severe disease in vulnerable populations leading to high hospitalization rates from bronchiolitis or secondary bacterial infections leading to pneumonia. Two early and non-structural proteins (Ns1 and Ns2), strongly over-ride the antiviral innate system but also diminish the adaptive response as well. This review will cover interactions of Ns1 and Ns2 with the host antiviral response with a focus on alterations to signaling pathways, cytokine gene expression, and effects of the Ns proteins on mitochondria.

Immunologic dysfunction contributes to the otitis prone condition

Acute Otitis Media (AOM) is a multifactorial disease occurring mostly in young children who are immunologically naïve to AOM pathogens. This review focuses on work from Rochester NY, USA over the past 12 years among young children who had AOM infections microbiologically-confirmed by tympanocentesis, so called "stringently-defined". Among stringently-defined otitis prone children deficiencies in fundamental immune defense mechanisms have been identified that contribute to the propensity of young children to experience recurrent AOM. Dysfunction in innate immune responses that cause an immunopathological impact in the nasopharynx have been discovered including inadequate proinflammatory cytokine response and poor epithelial cell repair. Adaptive immunity defects in B cell function and immunologic memory resulting in low levels of antibody to otopathogen-specific antigens allows repeated infections. CD4+ and CD8+ T cell function and memory defects significantly contribute. The immune profile of an otitis prone child resembles that of a neonate through the first year of life. Immunologic deficits in otitis prone children cause them to be unusually vulnerable to viral upper respiratory infections and respond inadequately to routine pediatric vaccines.

Influence of Immunological Maturity on Respiratory Syncytial Virus-Induced Morbidity in Young Children

Respiratory syncytial virus (RSV) is a very frequent viral respiratory pathogen of the young (<5 years old) with a significant portion of young toddlers having been infected before 2 years of age. Although we understand that some of the morbidity associated with RSV in neonates is due to immunological maturation that favors immunosuppression over antiviral innate and/or adaptive immune responses, the rapid development of the immune system right after birth suggests that each age group (newborn, early infant, older infant, toddler, and older) may respond to the virus in different ways. In this study, we summarize the morbidity associated with infection in young children in the context of immunological maturation of monocytes/macrophages and the ramifications for poor innate control of viral pathogenesis. We also summarize key mechanisms that contribute to the diminished antiviral innate immune responses of these young children.

Role of Inflammatory Risk Factors in the Pathogenesis of Streptococcus pneumoniae

Streptococcus pneumoniae (Spn) is a colonizer of the human nasopharynx (NP), causing a variety of infections in humans including otitis media, pneumonia, sepsis, and meningitis. The NP is an immune permissive site which allows for the persistence of commensal bacteria. Acute or chronic respiratory airway inflammation constitutes a significant risk factor for the manifestation of Spn infections. The inflammatory conditions caused by an upper respiratory viral infection or respiratory conditions such as allergic asthma and chronic obstructive pulmonary disorders (COPDs) are implicated in the dysregulation of airway inflammation and tissue damage, which compromise the respiratory barrier integrity. These immune events promote bacterial outgrowth leading to Spn dissemination and invasion into the bloodstream. Therefore, suppression of inflammation and restoration of respiratory barrier integrity could contain Spn infections manifesting in the backdrop of an inflammatory disease condition. The gained knowledge could be harnessed in the design of novel therapeutic interventions to circumvent Spn bacterial infections.

Pneumococcal whole-cell and protein-based vaccines: changing the paradigm

INTRODUCTION

Epidemiologic evaluations of Streptococcus pneumoniae nasopharyngeal (NP) colonization and pneumococcal disease suggest that newer serotypes in future formulations of pneumococcal conjugate vaccines (PCVs) are needed and there may need to be continued reformulations because there are many new emerging serotypes expressed by pneumococci. Areas covered: Mechanisms of protection by next-generation whole-cell vaccine (WCV) and/or multi-component pneumococcal purified protein vaccines (PPVs) in development for prevention of pneumococcal infections. Expert commentary: A long-term strategy for prevention of pneumococcal disease will likely include WCV and PPVs. However these vaccines will impact disease pathogenesis in a different manner than PCVs. Prevention of pneumococcal NP colonization should not be expected, nor is it desirable because risks for NP colonization by other replacement organisms into the ecological niche vacated by all pneumococci may have consequences. The expression biology of capsule and surface protein antigens are phase dependent. Therefore, the immune response will be different and the mechanism of protection divergent. WCVs and PPVs may be alternative strategies in low income developing countries to protect against invasive disease and reduce NP carriage load.

Differences in innate immune response gene regulation in the middle ear of children who are otitis prone and in those not otitis prone

OBJECTIVE

Acute otitis media (AOM) causes an inflammatory response in the middle ear. We assessed differences in innate immune responses involved in bacterial defense at onset of AOM in children who were stringently defined as otitis prone (sOP) and children not otitis prone (NOP).

STUDY DESIGN

Innate immune genes analysis from middle ear fluid (MEF) samples of children.

METHODS

Genes of toll-like receptors (TLR), nod-like and retinoic acid-inducible gene-I-like receptors, downstream effectors important for inflammation and apoptosis, including cytokines and chemokines, were studied from MEF samples by using a real-time polymerase chain reaction array. Protein levels of differentially regulated genes were measured by Luminex.

RESULTS

Gene expression in MEF among children who were sOP was significantly different in upregulation of interleukin 8, secretory leukocyte peptidase inhibitor, and chemokine (C-C motif) ligand 3, and in downregulation of interferon regulatory factor 7 and its related signaling molecules interferon alpha, Toll-like receptor adaptor molecule 2, chemokine (C-C motif) ligand 5, and mitogen-activated protein kinase 8 compared with children who were NOP. Differences in innate gene regulation were similar when AOM was caused by Streptococcus pneumoniae or nontypeable Haemophilus influenzae.

CONCLUSION

Innate-immune response genes are differentially regulated in children who were sOP compared with children with NOP.

Panel 5: Immunology

Objective

To perform a state-of-the-art review of the literature from January 2012 through May 2015 on studies that advanced our knowledge of the innate and adaptive immunology related to otitis media. This review also proposes future directions for research in this area.

Data Sources

PubMed database of the National Library of Medicine.

Review Methods

Three subpanels comprising experts in the field focused on sections relevant to cytokines, innate immunity, and adaptive immunity. The review focused on animal, cell line, and human studies and was critical in relation to the recommendations from the previous publication and for determination of the proposed goals and priorities. The panel met at the 18th International Symposium on Recent Advances in Otitis Media in June 2015 to consolidate its prior search results and discuss, plan, and refine the review. The panel approved the final draft.

Conclusion

From 2012 to 2014, tremendous progresses in immunology of otitis media were established—especially in the areas of innate immunity associated with the pathogenesis of otitis media.

Implications for Practice

The advances of the past 4 years formed the basis for a series of short- and long-term research goals in an effort to guide the field. Accomplishing these goals will provide opportunities for the development of novel interventions, including new ways to better treat and prevent otitis media, especially for recurrent otitis media.

Ten-Year Study of the Stringently Defined Otitis-prone Child in Rochester, NY

This review summarizes a prospective, longitudinal 10-year study in Rochester, NY, with virtually every clinically diagnosed acute otitis media (AOM) confirmed by bacterial culture of middle ear fluid. Children experiencing 3 episodes within 6 months or 4 episodes in 12 months were considered stringently defined otitis prone (sOP). We found stringent diagnosis compared with clinical diagnosis reduced the frequency of children meeting the OP definition from 27% to 6% resulting in 14.8% and 2.4% receiving tympanostomy tubes, respectively. Significantly more often respiratory syncytial virus infection led to AOM in sOP than non-otitis-prone children that correlated with diminished total respiratory syncytial virus-specific serum IgG. sOP children produced low levels of antibody to Streptococcus pneumoniae and Haemophilus influenzae candidate vaccine protein antigens and to routine pediatric vaccines. sOP children generated significantly fewer memory B cells, functional and memory T cells to otopathogens following nasopharyngeal colonization and AOM than non-otitis-prone children and they had defects in antigen-presenting cells.

Developing a vaccine to prevent otitis media caused by nontypeable Haemophilus influenzae

Nontypeable Haemophilus influenzae (NTHi) is a predominant organism of the upper respiratory nasopharyngeal microbiota. Its disease spectrum includes otitis media, sinusitis, non-bacteremic pneumonia and invasive infections. Protein-based vaccines to prevent NTHi infections are needed to alleviate these infections in children and vulnerable populations such as the elderly and those with chronic obstructive pulmonary disease (COPD). One NTHi protein is included in a pneumococcal conjugate vaccine and has been shown to provide efficacy. Our lab has been interested in understanding the immunogenicity of NTHi vaccine candidates P6, protein D and OMP26 for preventing acute otitis media in young children. We expect that continued investigation and progress in the development of an efficacious protein based vaccine against NTHi infections is achievable in the near future.

Peripheral blood antigen presenting cell responses in otitis-prone and non-otitis-prone infants

Stringently defined otitis-prone (sOP) children represent a new classification of the otitis-prone condition. Previous studies showed dysfunction in Ab, B-cell memory and T-cell memory responses. We sought to determine whether there are defects in numbers, phenotype and/or function of professional APC in the peripheral blood of sOP infants. APC phenotypic counts, MHC II expression and intracellular cytokine levels were determined in response to TLR7/8 (R848) stimulation by flow cytometry. Innate immune mRNA expression was measured using RT-PCR and cytokines were measured using Luminex technology. Significant (P < 0.05) increases in the phenotypic counts of monocytes and conventional dendritic cells but not plasmacytoid DCs were observed in sOP compared with non-otitis-prone (NOP) age-matched infants. No significant differences in APC activation or function were observed. Expression of various TLRs, intracellular signaling molecules and downstream cytokines was also not found to be significantly different between sOP and NOP infants. Higher numbers of APCs in sOP infants suggest the possibility of a persistent mucosal inflammatory status. Transcriptional and cytokine profiles of PBMCs among sOP infants suggest their systemic innate responses are not different compared to NOP infants.

The Role of Viruses in the Clinical Presentation of Chronic Rhinosinusitis

Background

The role of viruses in chronic rhinosinusitis (CRS) is poorly understood. In part, this is secondary to difficulty in isolating viruses. Although traditional detection methods for respiratory viruses have had little clinical utility, modern viral screening techniques that use molecular sequencing are now both rapid and feasible, which makes analysis of the paranasal sinus microbiome more accessible.

Objective

To detect respiratory viruses in the paranasal sinuses of patients with CRS and of healthy controls as well as to correlate clinical and radiographic measures of CRS with viral presence.

Methods

In this prospective study, 13 patients with CRS with nasal polyposis (CRSwNP) and 8 patients without nasal polyposis (CRSsNP) were enrolled and compared with 14 healthy controls. Samples were obtained from the paranasal sinuses and were screened for viral DNA with polymerase chain reaction—based sequencing techniques. Typical symptoms of CRS, the Sinonasal Questionnaire, and objective measures, including the modified Lund-Mackay and modified Lund-Kennedy scores were obtained.

Results

Eighty percent of the positive screens (4/5) were found in patients with CRSsNP, whereas 20% of the positive tests (1/5) were in the CRSwNP group, and none of the controls tested positive (p = 0.0029). Coronavirus was the most common virus detected. Sinonasal Questionnaire scores of the patients with CRS who tested positive for viruses were higher but not statistically different than those without a positive screen (p = 0.31). Radiographic and endoscopic measures of disease were not significantly different in the setting of a positive viral screen (p = 0.12 and 0.11 respectively).

Conclusion

Although traditionally difficult, advances in molecular sequencing enhance detection of viruses in the sinonasal tract. In this study, respiratory viruses were more commonly isolated from patients with CRS compared with healthy controls. Moreover, viral infection may play a greater role in symptom exacerbation in CRSsNP than in CRSwNP. These findings warrant further investigation into the role of the viral microbiome in CRS.

Poor memory B cell generation contributes to non-protective responses to DTaP vaccine antigens in otitis-prone children

We recently identified a cohort of children with recurrent episodes of acute otitis media (AOM) who fail to generate protective antibody titres to otopathogens and several vaccine antigens. In this study we determined the antibody levels against DTaP vaccine antigens, diphtheria toxoid (DT), tetanus toxoid (TT) and acellular pertussis toxoid (PT) in sera from 15 stringently defined otitis-prone (sOP) children and 20 non-otitis-prone (NOP) children. We found significantly lower concentrations of immunoglobulin (Ig)G antibodies against vaccine antigens in the serum of sOP children compared to age-matched NOP children. To elucidate immunological cellular responses to the vaccines in these children, we investigated memory B cell responses to DTaP vaccination. We used fluorescently conjugated vaccine antigens to label antigen receptors on the surface of memory B cells and examined the frequency of antigen-specific CD19(+) CD27(+) memory B cells in the peripheral blood. sOP children showed a significantly lower percentage of antigen-specific CD19(+) CD27(+) memory B cells than NOP children. We also found a linear correlation between the frequencies of memory B cells and circulating IgG titres for DT, TT and PT proteins. To our knowledge, this is the first study to show significant differences in memory B cell responses to DTaP vaccine antigens and their correlation with the circulating antibodies in young children with recurrent AOM.

Importance of viruses in acute otitis media

PURPOSE OF REVIEW

Acute otitis media occurs as a complication of viral upper respiratory tract infection. Bacterial otopathogens and respiratory viruses interact and play important roles in acute otitis media development. A better understanding of viral and bacterial interactions may lead to innovative ways to lessen the burden of this common childhood disease.

RECENT FINDINGS

There has been increasing evidence that acute otitis media occurs during upper respiratory infection, even in the absence of nasopharyngeal bacterial colonization. Among the types of viruses associated with acute otitis media, respiratory syncytial virus continues to be the most commonly detected. It is still unclear whether viral load plays an important role in acute otitis media development, but symptomatic upper respiratory tract infection (as opposed to asymptomatic viral infection) is crucial. Widespread use of bacterial and viral vaccines in young children, including pneumococcal conjugate and influenza vaccines, has led to the reduction in otitis media-related healthcare use between 2001 and 2011. There has been no new vaccine against respiratory viruses other than influenza.

SUMMARY

Progress has been made toward the reduction of the burden of acute otitis media in the last decade. Success in reducing acute otitis media incidence will rely mainly on prevention of nasopharyngeal otopathogen colonization, as well as reduction in the incidence of viral upper respiratory tract infection.