Immunologie Reactivity in the Middle Ear in Otitis Media with Effusion

Clinical significance of T helper-1/T helper-2 cytokines in peripheral blood of children with otitis media with effusion and allergic rhinitis

OBJECTIVE

Otitis media with effusion (OME) is a prevalent and costly disease, especially in children. This article analyzed the expression patterns and clinical significance of T helper-1 (Th1)/Th2 cytokines in the peripheral blood of children with OME and allergic rhinitis (AR).

METHODS

Subjects were assigned to the OME + AR group and the Control group (children with OME), with their clinical baseline data documented. The correlations between Th1/Th2 cytokines and between the total nasal symptom score (TNSS) and Th1/Th2 cytokines were analyzed. The risk factors and the predictive value of Th1/Th2 cytokines for OME + AR were analyzed using logistics multivariate regression analysis and receiver operating characteristic curve.

RESULTS

Significant differences were observed in tympanic pressure/speech frequency/air conduction valve/TNSS score/immunoglobulin E (IgE) level between both groups. The OME + AR children exhibited evidently elevated interleukin-2 (IL-2)/tumor necrosis factor-α (TNF-α)/IL-4/IL-10/IL-6 levels and no significant difference in interferon-γ (IFN-γ) level. Th1/Th2 cytokines were remarkably positively-correlated with the TNSS score. IL-2/TNF-α/IL-4/IL-6 were risk factors for OME with AR. The area under the curves (AUCs) of IL-6/IL-2/IL-4/TNF-α levels in predicting the occurrence of OME + AR were 0.805/0.806/0.775/0.781, with sensitivities of 75.76 %/89.39 %/72.21 %/72.73 % and specificities of 74.29 %/61.34 %/72.86 %/70.00 %, and the cut-off values were 239.600/20.300/29.880/34.800 (pg/mL). The AUC of their combination in predicting OME + AR was 0.955 (93.94 % sensitivity, 85.71 % specificity).

CONCLUSION

Th1/Th2 cytokine levels were imbalanced and obviously positively-correlated with the TNSS score in OME + AR children. IL-2, TNF-α, IL-4, and IL-6 levels had auxiliary predictive value in the occurrence of OME + AR.

Adenoid hypertrophy in children: a narrative review of pathogenesis and clinical relevance

Adenoids (nasopharyngeal tonsils), being part of Waldeyer's ring, are masses of lymphoid tissues located at the junction of the roof and the posterior wall of the nasopharynx. Adenoids play an important role in the development of the immune system and serve as a defence against infections, being the first organs that come into contact with respiratory and digestive antigens. The causes of adenoid hypertrophy are not fully known. They are most likely associated with aberrant immune reactions, infections, environmental exposures and hormonal or genetic factors. The aim of this review is to summarise the current knowledge of adenoid hypertrophy in children and associated diseases. Adenoid hypertrophy has many clinical manifestations that are frequent in the paediatric population and is accompanied by various comorbidities.

Microbiological profile of adenoid hypertrophy correlates to clinical diagnosis in children

Objective. Adenoid hypertrophy is a common condition in childhood, which may be associated with recurring acute otitis media (RAOM), otitis media with effusion (OME), and obstructive sleep apnea syndrome (OSAS). These different clinical characteristics have some clinical overlap; however, they might be explained by distinct immunologic and infectious profiles and result in various histopathologic findings of adenoid specimens. Methods. A total of 59 children with adenoid hypertrophy undergoing adenoidectomy were studied. Three series of identical adenoid specimens were processed to hematoxylin-eosin (H.E.) and Gram staining and to respiratory virus specific real-time PCR, respectively. Results. According to the clinical characteristics, patients were recruited into three groups: RAOM (n = 25), OME (n = 19), and OSAS (n = 15). Bacterial biofilms were detected in 21 cases, while at least one of the studied respiratory viruses was detected in 52 specimens. RAOM cases were significantly associated with biofilm existence (n = 20, P < 0.001). In contrast, OME group was characterized by the absence of bacterial biofilm and by normal mucosa. Showing a statistically significant correlation, all OME cases were positive for human bocavirus (HBoV, P < 0.001). Conclusions. Bacterial biofilms might contribute to the damage of respiratory epithelium and recurring acute infections resulting in RAOM. In OME cases persisting respiratory viruses, mainly HBoV, can cause subsequent lymphoid hyperplasia leading to ventilation disorders and impaired immunoreactivity of the middle ear cleft.

The role of Fas-mediated apoptosis in otitis media: observations in the lpr/lpr mouse

Apoptosis, or programmed cell death, is a critical regulatory mechanism involved in the function, homeostasis and stimulus response of many organ systems. In the middle ear, apoptosis could participate in mucosal remodeling or leukocyte clearance during otitis media (OM). Fas is a death receptor that can contribute to apoptosis in a variety of cell types. To assess the role of Fas signaling in OM, we probed for expression of Fas and Fas ligand (FasL) by polymerase chain reaction (PCR) during bacterial OM in the rat. In addition, we assessed the response of the middle ear to endotoxin, an inflammatory bacterial product that has been used as a model for otitis media in the mouse, in normal and Fas deficient mice. We saw evidence of increased expression of Fas and Fas ligand during bacterial OM. Moreover, the intensity of the mucosal response to endotoxin was significantly greater and the resolution of the response was prolonged in Fas deficient mice. Prolonged resolution of mucosal hyperplasia may reflect reduced apoptosis of the hyperplastic mucosal cells. Elucidation of the pathways that regulate the mucosal hyperplastic response during otitis media brings us closer to manipulating them in the interest of reducing the chronic complications of this disease.

Dynamics of interleukin-1 production in middle ear fluid during acute otitis media treated with antibiotics

In an ongoing prospective study, IL-1 concentrations were measured in 78 children (aged 3-36 months) with acute otitis media receiving antibiotics. Middle ear fluid IL-1 concentrations were determined using ELISA kits. Ninety-eight middle ear fluid samples were obtained by tympanocentesis at enrollment (day 1) and 43 samples were collected on days 4-5. Ninety-two pathogens were isolated in 77/98 samples obtained on day 1: 55 Haemophilus influenzae, 34 Streptococcus pneumoniae, 2 Moraxella catarrhalis and 1 Streptococcus pyogenes. Among 37 paired samples initially culture-positive, eradication of the pathogen was achieved on day 4-5 in 20 while pathogens were still present in 17. On day 1, IL-1 was detected in 61/77 (79%) culture-positive samples vs 9/21 (43%) culture-negative ones (P = 0.003). The mean +/- SD middle ear fluid concentration of IL-1 on day 1 was significantly higher in culture-positive (316 +/- 508 pg/ml) than in culture-negative samples (111 +/- 245 pg/ml) (P = 0.01). When paired samples were evaluated, IL-1 decreased on days 4-5 in 13/20 (65%) ears where bacterial eradication was achieved, but also in 11/19 (58%) with persistent or new infection. The mean IL-1 concentrations decreased on days 4-5 in the 20 samples from ears where bacterial eradication was achieved (330 +/- 460 vs 118 +/- 294 pg/ml, P = 0.1) but also in the 17 samples where it was not (465 +/- 660 vs 232 +/- 289 pg/ml, P = 0.02). No significant differences were found between day 1 and days 4-5 in the mean IL-1 concentrations measured in patients with H. influenzae vs S. pneumoniae or concomitant H. influenzae and S. pneumoniae. It was concluded that: 1) IL-1 was detected in the middle ear fluid of most patients with acute otitis media; 2) significantly higher IL-1 concentrations were found in patients with culture-positive than in those with culture-negative acute otits media; 3) IL-1 concentrations decreased on days 4-5 of antibiotic therapy, whether the pathogen was eradicated or not.

Killed whole bacterial cells, a mucosal delivery system for the induction of immunity in the respiratory tract and middle ear: an overview

Infectious diseases remain a leading cause of morbidity and mortality worldwide with mucosal membranes being the most frequent portals of entry of pathogenic micro-organisms. This has prompted studies aimed at the development of vaccination protocols that would lead to an increased protection of mucosae through an understanding of the common mucosal immune system as an immune communication network between mucosal sites. Recent studies have suggested that preferential sub-networks exist within the system and these studies have exploited the gut-associated lymphoid tissue (GALT)-lung sub-network in the development of oral vaccine strategies for infections of the respiratory tract and middle ear. Mucosal immunization with whole formalin killed Pseudomonas aeruginosa (Pa), Branhamella catarrhalis, nontypable Haemophilus influenzae (NTHi) or Streptococcus pneumoniae (Spn) results in enhanced homologous bacterial clearance from the lung of immune animals challenged with live bacteria. These studies have been extended to the middle ear where similar results have been observed for NTHi and Spn. Mechanisms responsible for inducing enhanced bacterial clearance from the airways include opsonising antibody, antigen specific CD4+ T helper cells, cytokine responses and recruitment of activated polymophonuclear neutrophils. The mechanisms induced by immunization which stimulates the immune system to rapidly mobilise both innate and specific immune responses during infection are the subject of ongoing research.

Immunologic and histologic observations in reovirus-induced otitis media in the mouse

The goals of this study were to develop a mouse model for virally induced otitis media, and to study the immune response to infection. Intranasal inoculation of mice by reovirus was used to induce otitis media. Immunohistochemical evidence for the presence of reovirus in the nasopharynx, eustachian tubes, and middle ears and the amount of infiltrating B-cells and T-cells in those sites were serially evaluated by painlessly sacrificing animals over a 21 -day period. Reovirus antigen was detected in the middle ear mucosa by day 4 in 75% of infected animals, and histologic evidence for otitis media was found in 54% of all infected animals. A significant increase in B-cells in the nasopharynx and eustachian tubes was noted 7 to 10 days following infection. The number of infiltrating T-cells did not vary significantly from that in the control animals at any of the sites. These results provide a basis for further investigations of the immune response in otitis media.

Eustachian Tube Function and Otitis Media in Children

Recent findings from studies of populations of children with and without otitis media show that a poor ability to equalize negative pressure is a fundamental deficit of eustachian tube function. Not only was active function found to be poor in children with otitis media with effusion, it was also impaired in healthy children, as compared to adults. However, the deficit improved with age and time.

The active rather than the passive tubal function seems to be of critical importance with respect to proneness to recurrent acute otitis media and secretory otitis media. This suggests the involvement of primarily a eustachian tube opening dysfunction or muscular opening hypofunction in children, which is considered to be a primary endogenous etiologic factor.

In a subgroup of children with recurrent acute otitis media or secretory otitis media, habitual sniffing in combination with closing failure and poor active function may be a possible mechanism for the development of otitis media.

Chronic secretory otitis media: negative bacteriology

There is disagreement on the role of bacteria in the genesis and maintenance of chronic secretory otitis media (CSOM). Extensive studies from other countries report up to 40% of middle ear cultures with bacterial growth. For the present study, material was collected from 94 ears of children with both clinical and tympanometric diagnoses of CSOM. The samples were sent for bacteriological analysis, in there it was stained according to Gram's method and put into growing media: MacConkey (for gram-negative bacteria) and blood agar (for gram-positive bacteria) for 24 h, at 37 degrees C. If germs were identified by Gram's method, antibiograms would be carried out as well, with the Mueller Hington medium. No cultures were made for anaerobes. Only one ear had grown bacteria (Staphylococcus epidermidis), which was deemed contamination. No other ear studied bore bacteria. The possible causes for this disagreement between our study and the literature are discussed.

Immunological aspects of otitis media: present views on possibilities of immunoprophylaxis of acute otitis media in infants and children

The article reviews, based on current knowledge of immunological events affecting the middle ear, the possibilities and prospects for the prevention of otitis media (OM) by immunologic measures. While pneumococcal capsular polysaccharide vaccines proved not to be effective against infant acute otitis media (AOM), pneumococcal conjugate vaccines provide good immunogenicity even in infants, and call for trials with better prospects of clinical efficacy. The other future approaches currently under development are vaccines against nontypable Haemophilus influenzae and Branhamella catarrhalis, anti-viral immunoprophylaxis, combinations of the above alternatives, or passive immunization. Also, the use of new routes or ways of immunization are under study. Furthermore, the ways to modify the present treatment practices of AOM to favour good immunologic responses in infants and children must be studied.

Neutrophil elastase-alpha 1-antitrypsin in middle ear fluid in chronic otitis media with effusion

Neutrophil elastase-alpha 1-antitrypsin was quantified in samples taken from middle ear effusions collected at operation from 17 children attending for elective myringotomy and grommet insertion. At the time of surgery the effusion was classified as serous or mucoid. Children with a recent history of infection or antimicrobial therapy were excluded. The quantification of immunoreactive neutrophil elastase was by means of enzyme-linked immunosorbant assay (ELISA). The mean value of neutrophil elastase-alpha 1-antitrypsin was 50.6 +/- 38.3 (SD) micrograms/ml in mucoid effusions, which was significantly higher (P < 0.05) than that in serous effusions (5.3 +/- 4.8 micrograms/ml). These results indicate that a mucoid effusion may reflect a more severe inflammatory response and that persistence of neutrophil activity in the middle ear mucosa may contribute to the persistence of at least one group of middle ear effusions.