Adenoidectomy and nasopharyngeal carriage of Streptococcus pneumoniae in young children

A dynamic relationship between mucosal T helper type 17 and regulatory T-cell populations in nasopharynx evolves with age and associates with the clearance of pneumococcal carriage in humans

Pneumococcal carriage is common in young children, which may account for the high incidence of disease in this age group. Host factors determining the clearance of carriage in humans remain unclear. We aimed to study the relationships between T helper type 17 (Th17) and Foxp3(+) regulatory T (Treg) cells in nasopharynx-associated lymphoid tissue (NALT) and carriage in children and adults. Frequencies of Th17 and Treg cells in NALT were analysed by flow cytometry in association with age and pneumococcal carriage status. Cytokine responses following pneumococcal stimulation were analysed by cytometric beads array. The frequencies of Th17 and Treg cells in NALT were inversely correlated (R -0.60). Whereas Treg cell frequency decreased with age (R -0.63), both Th17 and the Th17: Treg ratio increased with age (R 0.62 and R 0.64, respectively). Also, the Th17: Treg ratio was higher in carriage-negative than in carriage-positive children (p <0.01). Pneumococcal stimulation of tonsillar cells increased both Th17 and Treg cell numbers, but the Th17: Treg ratio and pattern of cytokine responses differed between carriage-negative and carriage-positive children. The former showed markedly higher Th17: Treg and interleukin-17A: interleukin-10 ratios than in the latter (p <0.01). Pneumococcal stimulation also induces Th17, although the capacity of this Th17 differentiation from naive T cells of young children was low, but increased with age. We demonstrated a dynamic relationship between Th17 and Treg cells in human nasopharynx that evolves with age. The balance between Th17 and Treg cells in NALT appears to be a major host factor closely associated with the clearance of Streptococcus pneumoniae from the nasopharynx.

Endoscopic Adenoidectomy in Children With Otitis Media With Effusion and Mild Hearing Loss

Objectives

Surgical management of children with chronic otitis media with effusion (OME) includes tympanostomy tube insertion or adenoidectomy, alone or with myringotomy and tube insertion. The aim of this study was to compare the effectiveness of transoral microdebrider endoscopic-assisted adenoidectomy (TOMEA) and traditional adenoidectomy in the management of children with mild hearing loss due to OME and chronic adenoiditis.

Methods

This prospective, double-blind and controlled study involved 120 consecutive patients aged 4–12 years, who were randomised 1:1 to undergo TOMEA or traditional adenoidectomy under general anesthesia. All the patients underwent a complete otolaryngological examination, including nasopharyngeal fibre endoscopy (NFE), pneumatic otoscopy, otomicroscopy, tympanometry and supraliminar tonal audiometry, upon enrolment, and three and nine months postoperatively.

Results

There were no statistically significant differences in age or gender distribution between the TOMEA group (mean age, 4.9±1.1 years; 53.3% males) and the traditional adenoidectomy group (mean age, 5.3±0.9 years; 56.7% males). Both procedures led to a significant improvement in choanal patency (P<0.01) and all of the otological and audiological parameters (P<0.01) 3 and 9 months postoperatively, although postoperative NFE showed that the mean percentage of residual choanal obstruction was significantly less in the TOMEA group (P=0.02). There was no significant between-group difference in the percentage of children with tympanic membrane changes, but the postoperative prevalence of children with a type B tympanogram was significantly lower in the TOMEA group after 3 (15.0% vs. 31.7%, P=0.05) and 9 months (18.3% vs. 38.3%, P=0.02), as was the percentage of children with mild conductive hearing loss (3.3% vs. 23.3%, P<0.01; and 8.3% vs. 28.3%, P<0.01).

Conclusion

Although both TOMEA and traditional adenoidectomy are effective in treating children with mild hearing loss due to adenoidal hypertrophy and OME, the former achieves the greater reduction in residual adenoidal hypertrophy and better audiological outcomes.

Activation of memory Th17 cells by domain 4 pneumolysin in human nasopharynx-associated lymphoid tissue and its association with pneumococcal carriage

Pneumococcal carriage is common in children that may account for the high incidence of disease in this age group. Recent studies in animals suggest an important role for CD4+ T cells, T helper type 17 (Th17) cells in particular, in pneumococcal clearance. Whether this Th17-mediated mechanism operates in humans and what pneumococcal components activate Th17 are unknown. We investigated the ability of domain 4 pneumolysin (D4Ply) to activate CD4+ T cells including Th17 in human nasopharynx-associated lymphoid tissue (NALT) and peripheral blood. We show that D4Ply elicited a prominent CD4+ T-cell proliferative response. More importantly, D4Ply elicited a significant memory Th17 response in NALT, and a moderate response in peripheral blood mononuclear cells (PBMCs). This D4Ply-elicited memory Th17 response was more marked in carriage- than in carriage+ children in both NALT and PBMCs. In contrast, no difference was shown in D4Ply-induced Th1 response between the two groups. We also show D4Ply activated human monocytes and murine macrophages that was in part dependent on Toll-like receptor 4 (TLR-4). Our results support a protective role of Th17 against pneumococcal carriage in human nasopharynx, and identify a novel property of D4Ply to activate Th17 in NALT that may offer an attractive vaccine candidate in intranasal immunization against pneumococcal infection.

Otitis media and ear tubes

The placement of myringotomy tubes remains an effective treatment of recurrent acute otitis media and chronic otitis media with effusion. Infants and young children are prone to these entities because of their immature anatomy and immunology. Several host, pathogenic, and environmental factors contribute to the development of these conditions. The identification and modification of some these factors can preclude the need for intervention. The procedure continues to be one of the most common outpatient pediatric procedures. Close vigilance and identification of potential complications is of utmost importance in the ongoing management of the child with middle ear disease.

Panel 7: Treatment and comparative effectiveness research

BACKGROUND AND OBJECTIVES

Otitis media (OM) is one of the most common reasons for antibiotic treatment in children. Controversies regarding antibiotic treatment for OM have accumulated in the past decade, and there seem to be more dilemmas than certainties. The objectives of this article are to provide the state-of-the art review on achievements in treatment of all different stages of OM, including acute otitis media (AOM), otitis media with effusion (OME), and chronic suppurative otitis media, and to outline the future research areas.

DATA SOURCES

PubMed, Ovid Medline, the Cochrane Database, and Clinical Evidence (BMJ Publishing).

REVIEW METHODS

All types of articles related to OM treatment published in English between January 2007 and June 2011 were identified. A total of 286 articles related to OM treatment were reviewed by the panel members; 114 relevant quality articles were identified and summarized.

RESULTS

New evidence emerged on beneficial results of antibiotic treatment, compared with observation of AOM in young children who were diagnosed based on stringent criteria. In OME, the main results were related to a nonsignificant benefit of adenoidectomy versus tympanostomy tube placement alone in the treatment of chronic OME in younger children. Other modalities of OM treatment were studied and described herein.

CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

Significant progress has been made in advancing the knowledge on the treatment of OM. Areas of potential future research have been identified and outlined.

Adenoidectomy in young children and serum IgG antibodies to pneumococcal surface protein A and choline binding protein A

OBJECTIVE

We have previously reported that surgical removal of the nasopharyngeal adenoid in young children resulted in increased risk of nasopharyngeal colonization by pneumococci. We now investigated whether adenoidectomy influences the development of serum IgG antibodies to pneumococcal choline-binding protein A (CbpA) and pneumococcal surface protein A (PspA).

METHODS

Altogether 217 children aged 12-48 months who had recurrent or persistent otitis media were randomized to undergo or not to undergo adenoidectomy. All the children underwent insertion of tympanostomy tubes. 166 children were followed-up for 3 years. The main outcome measures were concentrations of serum IgG antibodies to CbpA and PspA three years after randomization. Nasopharyngeal colonization by pneumococci was assessed 1, 2, and 3 years after randomization.

RESULTS

Adenoidectomy decreased concentrations of CbpA antibodies by ca. 25% independently of the observed increase in pneumococcal carriage (OR of log(10) transformed concentrations 0.74, 95% CI 0.58-0.94, P=0.016). Concentrations of PspA antibodies were lower and they seemed not to be influenced by adenoidectomy.

CONCLUSIONS

Adenoidectomy in young children causes a small but detectable impairment in the development of serum IgG antibodies to pneumococcal CbpA. The adenoid seems to have a role in augmenting systemic immunity against pneumococci.

Human nasal challenge with Streptococcus pneumoniae is immunising in the absence of carriage

Infectious challenge of the human nasal mucosa elicits immune responses that determine the fate of the host-bacterial interaction; leading either to clearance, colonisation and/or disease. Persistent antigenic exposure from pneumococcal colonisation can induce both humoral and cellular defences that are protective against carriage and disease. We challenged healthy adults intra-nasally with live 23F or 6B Streptococcus pneumoniae in two sequential cohorts and collected nasal wash, bronchoalveolar lavage (BAL) and blood before and 6 weeks after challenge. We hypothesised that both cohorts would successfully become colonised but this did not occur except for one volunteer. The effect of bacterial challenge without colonisation in healthy adults has not been previously assessed. We measured the antigen-specific humoral and cellular immune responses in challenged but not colonised volunteers by ELISA and Flow Cytometry. Antigen-specific responses were seen in each compartment both before and after bacterial challenge for both cohorts. Antigen-specific IgG and IgA levels were significantly elevated in nasal wash 6 weeks after challenge compared to baseline. Immunoglobulin responses to pneumococci were directed towards various protein targets but not capsular polysaccharide. 23F but not 6B challenge elevated IgG anti-PspA in BAL. Serum immunoglobulins did not increase in response to challenge. In neither challenge cohort was there any alteration in the frequencies of TNF, IL-17 or IFNγ producing CD4 T cells before or after challenge in BAL or blood. We show that simple, low dose mucosal exposure with pneumococci may immunise mucosal surfaces by augmenting anti-protein immunoglobulin responses; but not capsular or cellular responses. We hypothesise that mucosal exposure alone may not replicate the systemic immunising effect of experimental or natural carriage in humans.

Exposure to respiratory pathogens such as Streptococcus pneumoniae (pneumococcus) is a frequent event that can result in immediate clearance, nasal colonisation or disease for the host. Human and mouse studies have shown that natural colonisation is an immunising event. Colonisation is prevalent in children but rare in human adults (<10%), suggesting that despite high pneumococcal exposure adult mucosal defences are sufficient to prevent colonisation. We exposed healthy adults to pneumococci in the nose in order to achieve colonisation and mimic a natural colonisation event. In most volunteers, however, we were not able to obtain colonisation using this protocol. In exposed but not colonised volunteers we measured antibody and cellular responses in nose, lung and blood samples. The mucosal defences elicited during acute pneumococcal exposure are poorly described but these data will shed light on the mechanisms that prevent colonisation in healthy adults and inform future vaccine design. Live bacterial exposure increases specific antibody and innate responses at mucosal surfaces such as the nose and lung. Systemic responses were not increased. These data suggest that acute bacterial exposure per se augments mucosal but not systemic defences. Natural or experimental colonisation may be required for systemic immunisation.

Role of adenoidectomy in otitis media and respiratory function

Adenoidectomy is among the most frequent surgical procedures performed on children. The rationale for adenoidectomy is to remove a chronically infected or enlarged and obstructing adenoid. Adenoidectomies are performed on children who have recurrent or chronic otitis media with effusion, on children with chronic rhinosinusitis, and on children with nasopharyngeal obstruction causing sleep disturbances and continuous mouth breathing. Various underlying factors that lead to adenoidectomy are also associated with asthma. Asthma is associated with recurrent respiratory tract infections predisposing individuals to recurrent or chronic otitis media and chronic rhinosinusitis. Children with asthma also have an increased risk of sleep-disordered breathing that is treated with adenoidectomy in the presence of nasopharyngeal obstruction. In nonasthmatic children, adenoidectomy does not influence the development of IgE-mediated allergy, bronchial hyperreactivity, or exhaled nitric oxide concentrations, all of which are surrogate asthma markers. Adenoidectomy in selected asthmatic children may relieve comorbidities associated with asthma.