Immune complexes in the middle ear fluid and adenoid tissue in chronic secretory otitis media

Microbiology of healthy and diseased adenoids

OBJECTIVE

To determine the qualitative and quantitative microbiology of core adenoid tissue obtained from four groups of 15 children each, with recurrent otitis media (ROM), recurrent adenotonsillitis (RAT), obstructive adenoid hypertrophy (OAH), and occlusion or speech abnormalities (controls).

METHODS

Core cultures of surgically removed diseased adenoids and of healthy controls were cultured for aerobic and anaerobic bacteria.

RESULTS

Polymicrobial aerobic-anaerobic flora were present in all instances. Ninety-four organisms were isolated from control specimens, and 148 from ROM, 142 from RAT, and 149 from OAH specimens. The predominant aerobes in all groups were alpha-hemolytic and gamma-hemolytic streptococci, Haemophilus influenzae, Staphylococcus aureus, group A beta-hemolytic streptococci, and Moraxella catarrhalis. The prominent anaerobes were Peptostreptococcus, Prevotella, and Fusobacterium species. The number, concentration and distribution of types of most organisms did not vary among the three groups of diseased adenoids. However, the number of those that are potential pathogens and those that produced beta-lactamase was lower in the control than the diseased adenoids (P < .001).

CONCLUSION

The study highlights the importance of the bacterial load in the adenoids in contributing to the etiology of ROM, RAT, and OAH.

The aetiology of otitis media with effusion: a review

Otitis media with effusion (OME) is the most common cause of deafness in children in the developed world. In this article we aim to present an overview of current research developments on the aetiology of OME and the resulting implications for treatment. In the model we describe, the primary event is inflammation of the middle ear mucosa, usually due to the presence of bacteria. This leads to the release of inflammatory mediators, which cause secretion of a mucin-rich effusion by up-regulating mucin genes. Prolonged stimulation of the inflammatory response and poor mucociliary clearance lead to persistence of the middle ear fluid, giving rise to the clinical presentation of OME. We describe OME in the following sequence: the initial production of the effusion, the composition of the effusion produced, and factors impairing clearance of the effusion.

Adenoid bacteriology and sinonasal symptoms in children

OBJECTIVE

To study the correlation between sinonasal symptoms in children and the prevalence of bacterial pathogens in the adenoid core.

DESIGN

Prospective cross-sectional survey.

SETTING

Tertiary referral center.

PATIENTS

Consecutive sample of 84 children, aged 2 to 12 years, scheduled for adenoidectomy between July 1995 and November 1995. A blocked recruitment scheme was used to ensure a balanced distribution of sinonasal symptoms in the study sample.

METHODS

A caregiver-completed quality-of-life survey was used to measure the frequency and severity of baseline sinonasal, ear, obstructive, and behavioral symptoms. Standard microbiologic techniques were used for qualitative and quantitative adenoid bacteriology.

OUTCOME MEASURES

Pathogenic and nonpathogenic bacteria isolated, percentage of specimens with no growth, colony-forming units of pathogens per gram of adenoid tissue, dominant bacterial organism, and number of pathogenic species per adenoid with concentration greater than 10(5) colony-forming units.

RESULTS

One or more bacterial pathogens were recovered from core samples of all adenoids, with a concentration greater than 10(5) colony-forming units in 31 specimens (26%). Haemophilus influenzae, group A beta-hemolytic streptococcus, and Staphylococcus aureus were encountered most often. Multivariate analysis revealed a significant correlation of sinonasal infection symptom scores with colony-forming units of adenoid core pathogens (R2 = 0.48, p < 0.0001), adjusted for the confounding effects of nasal obstructive symptoms and adenoid size (specimen weight).

CONCLUSIONS

Sinonasal infectious symptoms explain 48% of the variability in quantitative bacteriology of the adenoid core, independent of adenoid size. Although longitudinal studies are required, our results support a potential role for adenoidectomy in the management of refractory pediatric sinusitis.

Interleukin-8 in otitis media with effusion

Interleukin-8 induces chemotaxis of neutrophils, basophils and T-lymphocytes, releases intracellular enzymes from neutrophils and histamine from basophils, and regulates the adhesion of neutrophils. In this study, using an enzyme-linked immunosorbent assay, we evaluated 33 middle ear effusions (MEEs) for levels of IL-8. The mean level of IL-8 in MEEs from children with OME was 616.7 +/- 211.0 pg/mgTP, while that of adults was 197.4 +/- 66.7 pg/mgTP. With respect to MEE types, the mean level of IL-8 in serous effusion was lower than that in two other types of MEEs (mucoserous and serous). These results suggest that inflammatory reaction in the middle ear cavity of children with OME is different from that of adults and that the pathogenesis of OME in children may differ from that in adults. Determination of IL-8 concentration in MEEs may help to illuminate the pathogenesis of OME.

Detection of Haemophilus influenzae in middle ear of otitis media with effusion by polymerase chain reaction

Otitis media with effusion (OME) is one of the major causes of hearing loss in childhood. The pathogenesis still remains unclear, though it is closely related to acute otitis media with bacterial infections. It is known that Haemophilus influenzae is one of the most common bacteria isolated from middle ear effusions (MEEs). Recently, in vitro DNA amplification by polymerase chain reaction (PCR) is a new technology that has considerable implication for diagnosis of viral and bacterial infections because of its potentially precise specificity and sensitivity. In the present experiment polymerase chain reaction (PCR) was applied to the detection of DNA genome of H. influenzae contained in middle ear effusions. By Southern blot hybridization, two characteristic bands for H. influenzae DNA were detected at 273 b.p. and 550 b.p. position in 15 of 27 MEEs. However, no organism was cultured by conventional methods. Our results indicate the PCR technique is more specific and sensitive in detection of bacteria in middle ear effusion of OME, compared with conventional methods. It strongly suggests more involvement of the bacteria, especially H. influenzae, in OME onset.

Nasopharyngeal flora in otitis media with effusion. A comparative semiquantitative analysis

An inflammatory process in the middle ear caused by bacteria or bacterial products emanating from the nasopharynx is one etiological factor considered in the unknown pathogenesis of otitis media with effusion (OME). The nasopharyngeal prevalence of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella (Branhamella) catarrhalis and Streptococcus pyogenes was studied in 191 children with defined OME and in 53 age-matched children without middle ear disease. Duplicate sampling and semiquantitative analysis were performed to assess even minor differences in the distribution of pathogens between the two groups of children. Pathogens were recovered in 91% of OME children. A significantly higher number of pathogen species/patient (1.66 vs. 1.15, p less than 0.01) as well as pathogen colonies/patient was found in OME children compared to control children. Chronic OME in children is associated with an increased pathogen load in the nasopharynx, suggesting a role of these pathogens in the etiology of OME.

Endotoxin and lysosomal protease activity in acute and chronic otitis media with effusion

Endotoxin levels and lysosomal protease (collagenase, cathepsin B, and lysozyme) activity were measured in 104 middle ear effusions (MEEs) from patients with otitis media with effusion (OME). The MEE samples were classified into four groups: pediatric serous, mucoid, and acute, and adult serous. Endotoxin levels and lysosomal protease activity in MEEs were significantly different in the following order: adult less than serous less than mucoid less than acute groups, indicating that both endotoxin and lysosomal proteases are more closely related to the pathogenesis of pediatric chronic OME than to adult OME. In pediatric serous and mucoid effusions, endotoxin level had a significant correlation with activity of the lysosomal proteases. In conclusion, endotoxin enhances leukocyte infiltration into the middle ear, and lysosomal proteases released from leukocytes damage the middle ear mucosa and thereby prolong mucosal inflammation, which may be responsible for delayed recovery from acute OME.

Nasopharyngeal culture with quantitative analysis of pathogenes in chronic otitis media with effusion. Effects on pathogen yield of different swabs and transport methods

The influence of different swabs and transport media on nasopharyngeal culture pathogen recovery has been studied in patients with chronic otitis media with effusion. Transport times of less than two hours have been used. Protecting the cotton wire swab with a polyethylene shealth to prevent contamination by nasal flora did not have any significant influence either on the recovery of potential pathogens or on the contaminating nasal flora. Facilitating a quantitative analysis of the nasopharyngeal culture by transporting the specimen in empty tubes gave a pathogen recovery rate similar to that with transport in Stuart medium, whereas an attempt at transporting in sodium chloride or prereduced PY broth led to significantly lower yields of Branhamella catarrhalis (p less than 0.01) and in PY broth on Haemophilus influenzae as well (p less than 0.01).

Adenoids and otitis media with effusion: nasopharyngeal flora

In order to clarify the role of the microflora of the nasopharynx and adenoids as causative factors of otitis media with effusion (OME), bacteriologic species in middle ear effusions (MEEs), nasopharyngeal smears, and adenoid tissues of children with OME were cultured. The change in the microflora of the nasopharynx after adenoidectomy, and the degree of bacterial agreement between the microflora of the nasopharynx and adenoid tissue were investigated. Nasopharyngeal bacterial flora were investigated in 259 children with OME from November 1984 to November 1987. The patients were divided into two groups: group A (43 patients) underwent adenoidectomy, and group B (216 patients) had no adenoidectomy. Hemophilus influenzae, Streptococcus pneumoniae, Branhamella catarrhalis, and Staphylococcus aureus were cultured in 66.7% of nasopharyngeal smears from group B, and in 46.5% from group A. Adenoid specimens for bacteriologic investigation were obtained from 38 adenoidectomy patients at surgery. Of these, H influenzae were cultured from adenoid specimens taken from 16 of the 26 patients with OME (group C), while only three of the 12 adenoidectomy patients without OME (group D) were found to have H influenzae in their adenoid specimens. The findings of this study suggest that adenoid vegetation plays an important role in the etiology of OME.

Pneumococcal antigens and endotoxin in effusions from patients with secretory otitis media

Counterimmunoelectrophoresis revealed pneumococcus capsular polysaccharide antigen in 16% of 108 effusions from chronic secretory otitis media (SOM). Pneumococci were cultured from the effusion in only 1%. In an additional series of 23 SOM ears, only 4.3% were antigen-positive. Tests by means of pneumococcal coagglutination and C-polysaccharide detection gave identical results. Endotoxin was detected in 76% of the specimens. Control tests with aggregated NHS, IgG and IgA diluted 1: 10 were invariably positive. It appears that endotoxin positivity in SOM fluids results from the presence of activated immunoglobulins, most probably dimeric IgA, in the secretion, and so allows no conclusions as to the bacterial etiology of SOM.

Characterization of human middle ear mucus glycoprotein in chronic secretory otitis media (CSOM)

Middle ear effusion was obtained from children with chronic secretory otitis media undergoing myringotomy. The effusions contained about 120 mg/ml non-dialysable solids, of which 18-31% was mucus glycoprotein. The purified mucus glycoprotein had a composition characteristic of other mucus glycoproteins. Amino acid analysis of the glycoprotein indicates a protein core consisting of glycosylated regions resistant to proteolysis and non-glycosylated regions susceptible to proteolysis. Analysis of the mucus glycoprotein by gel filtration on Sepharose 2B showed that reduction caused a decrease in hydrodynamic size and proteolysis caused a further decrease. The difference was confirmed by sedimentation coefficient and viscosity measurements. The reduced glycoprotein had an intrinsic viscosity of 0.113 ml/mg and an S0(20) of 15.2S compared to a value of 0.018 ml/mg and 9.6S for the proteolytically digested glycoprotein. These results suggest a model for this middle ear mucus glycoprotein, in which the native glycoprotein is a large molecular mass polymer maintained by disulphide bridges. These disulphide linked glycoprotein units are broken down into smaller units by proteolysis. The mucus glycoprotein could not be purified completely free from low molecular mass components. A glycoprotein, susceptible to proteolysis Mr 28,000-33,000 co-fractionates with the major high molecular mass mucus glycoprotein.

The effect of tonsillectomy and adenoidectomy on the intra-tympanic pressure

A group of 67 children were studied (mean age 7 years, 2 months) who underwent adenoidectomy and/or tonsillectomy because of either recurrent otitis media or upper respiratory tract infection. The mean pre-operative intratympanic pressure was -67.3 mmH2O (SD 65.1); three months post-operatively it was -21.9 mmH2O (SD 32.4), a highly significant improvement (p less than 0.001). The size of the adenoids had a nearly significant effect on the pre-operative intratympanic pressure (p less than 0.05). In children with large vs small adenoids the difference was highly significant (p less than 0.001). In a group of five children, tonsillectomy alone (adenoidectomy performed earlier) did not have any effect on the intratympanic pressure. No change in intratympanic pressure was seen in children with nasal allergy as compared with non-allergic children after adenoidectomy.

Experimentally induced otitis media with effusion following inoculation with the outer cell wall of nontypable Haemophilus influenzae

Previously, we extracted lipopolysaccaride endotoxin (LPS) from an axenic culture of Haemophilus influenzae and inoculated it into the middle ears of guinea pigs, inducing temporary serous effusions. In the present study, we tried to clarify whether the immunological mechanism responsible for producing the otitis media following outer cell wall inoculation was persistent. We extracted the outer cell wall from nontypable H. influenzae, using Zollinger's method, and inoculated extracts into the middle ears of guinea pigs that had previously received three injections of nonviable H. influenzae in Freund's complete adjuvant. Histological evaluations were performed from day 2 to day 24. Effusions and mucosal changes persisted for a longer time than in the LPS-inoculated model. Hypertrophied mucosae and increased numbers of goblet cells with hypersecretion were visible in the specimens on days 23-24. The condition seemed to show a greater similarity to chronic otitis media with effusion in children than did the LPS-inoculated model. We concluded that both the biological activity of the outer cell wall and immunological mechanisms might induce prolonged otitis media. We speculate that not only single middle ear infection but also general infections and repetitive middle ear infections may contribute to prolonged otitis media.

Prognosis and endotoxin contents in middle ear effusions in cases after acute otitis media

We analysed the endotoxin content of middle ear effusion (MEE) from patients after acute otitis media, by a Limulus assay. Endotoxin was positive in 70% of the cases treated with antibiotics at an acute event for more than 5 days, while the incidence of bacteria was only 22%. One month after the sample collection, cases with a high concentration of endotoxin in MEE still tended to have effusion. These results suggest that endotoxin in MEE cannot be easily inactivated and may be involved in the development of acute otitis media into chronic otitis media with effusions.

Effect of erythromycin on adenoid bacteria

Seventy-eight patients with secretory otitis media were given erythromycin ethylsuccinate 50 mg/kg/day, divided into 2 doses, for 7-8 days before undergoing adenoidectomy and tympanostomy. Nasopharyngeal swabs for bacterial culture were obtained before medication and at surgery and the adenoid homogenate was also studied for bacteria. Pneumococci and Branhamella strains became significantly reduced, while Hemophilus influenzae showed no change. Pneumococcus and Branhamella strains partially returned one month after surgery and in part were found in patients who had not had these strains before antimicrobial therapy. Erythromycin ethylsuccinate can sterilize neither the adenoids nor the middle ear space if the causative agent is Hemophilus influenzae.

Pneumococcal immune complexes and clinical course of secretory otitis media

One-hundred-and-six children (182 ears) with secretory otitis media (SOM) were included in a follow-up study to determine whether presence of immune complexes to pneumococcal capsular polysaccharides in the middle ear fluid or adenoid suspension was related to the clinical course of SOM. The patients with immune complexes did not differ significantly from those without demonstrable immune complexes as to length of healing period or chronicity. The presence of immune complexes must be seen as evidence of the infectious etiology of SOM (pneumococcal in at least 25%), the immune complexes forming part of the immunological defense system. Poor immune response to serotype 6 can explain why this serotype plays a dominant role in the pneumococcal immune complexes in SOM fluid and adenoid suspension.

Endotoxin in middle ear effusions tested with Limulus assay

Endotoxin in middle ear effusion (MEE) from both children and adult patients with otitis media with effusion (OME) was assayed with the Limulus amoebocyte lysate test, in parallel with the detection of microorganisms. Whereas only 17% of MEE from adults, diluted 1:10 showed the presence of endotoxin, endotoxin was found in 69% of MEE from recent and recurrent cases in children, although microorganisms were isolated from only one-quarter of the samples. 83% of mucoid MEE from children contained endotoxin, compared with 41% of serous MEE. In older children, endotoxin was less frequently detected in accordance with the fact that the incidence of OME decreases with age. It is concluded that endotoxin may be one of the important factors in the pathogenesis of onset of, as well as in delayed recovery from OME in children.

Histopathological changes of the eustachian tube in OME animal models

To determine whether or not stimulations of various inflammatory irritants such as endotoxin and/or immune complexes (IC) play a role in the pathogenesis of otitis media with effusion (OME), experimental animal models were examined under light and electron microscopy. Horseradish peroxidase (HRP) was chosen as an antigen and anti-HRP sera were obtained from the animals immunized by emulsions of HRP and Freund's complete adjuvant. Seventy-three albino guinea pigs and 41 chinchillas were used in this experiments. One hundred and fourteen animals were divided into three groups: forty in the active Arthus (AA) group, 61 in the passive Arthus (PA) group and 13 in the control group. According to the chronological changes of the tympanograms, it was confirmed that the pathological changes in the middle ear cleft of the OME animals persisted for at least 10-14 days after the injection, whereas those in the control animals recovered within 3-4 days. Histological examinations of both PA- and AA-group animals revealed that electron-dense HRP-positive cells, most of which were non-ciliated, were widely dispersed in the epithelium. Many inflammatory cells such as polymorphonuclear leukocyte (PMN), macrophage and plasma cells were seen in the lamina propria and some PMNs were attached to the basal lamina. Intra-epithelial infiltration of PMNs and epithelial cell degeneration associated with the disrupted basal lamina were also observed. Most conspicuous changes were found in the Eustachian tube.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunohistochemical identification of inflammatory cells in secretory and chronic otitis media and cholesteatoma using monoclonal antibodies

Monoclonal antibodies (OKT 3,4,6,8 and OKIa) were used in conjunction with the avidin-biotin-peroxidase complex method to classify inflammatory cells in 6 biopsies of the middle ear mucosa in patients with secretory otitis media (SOM) and in 19 middle ear or mastoidal biopsies in patients with chronic otitis media (COM). Mononuclear cell infiltrates under the mucosal epithelium were found to consist mainly of T4 positive (helper-inducer) T-lymphocytes (50-60%). T8 positive (suppressor-cytotoxic) T-lymphocytes accounted for 20-30% of the cells. T4 positive cells were confined to the round cell infiltrates, whereas T8 positive cells were also located under the mucosal epithelium and seemed to penetrate it. There were no differences between SOM or COM with regard to the distribution or localization of T4 and T8 cells. T6 and Ia positive Langerhans cells were found in the ingrowing tympanic membrane squamous epithelium and in the cavity skin. The number and distribution of these T6 positive cells were similar to those observed in the skin. In the thick cholesteatoma epithelium these cells were somewhat unevenly distributed but were more numerous than in other sites studied. The results are indicative of a normal cell-mediated mucosal response to infection.

Antibiotic treatment of secretory otitis media

There is increasing evidence for an infectious etiology of secretory otitis media (SOM). Respiratory pathogens (S. pneumoniae, H. influenzae, B. catarrhalis and group A streptococci) have been found in cases of long-standing SOM, with a frequency of 18% in the middle ear and 79% in the nasopharynx. Erythromycin has been shown to penetrate into the middle ear effusion of SOM and into adenoid tissue. The concentrations surpassed the MIC's of most respiratory pathogens, with the exception of certain strains of H. influenzae. In agreement with this, a ten day course of erythromycin in children with SOM eradicated practically all nasopharyngeal strains of S. pneumoniae and B. catarrhalis, while there was no significant decrease in the number of strains of H. influenzae. The present study consisted of 119 children with SOM lasting three months or more. One group of 47 consecutive children was treated with erythromycin (Abboticin), given orally twice a day, in a dose of 40-60 mg/kg/24 hours, for ten days. The rate of resolution in this test group was 45% (21/47 cases). Another group of 72 consecutive children with SOM of a similar duration received no antibiotics. The cure rate in this control group was 15% (11/72 cases). The difference between the two groups is statistically significant (chi 2 = 11054; df = 1; p less than 0.001). The results suggest that a ten day course of erythromycin could reduce the need for surgical treatment in children with long-standing SOM.

Pneumococcal polysaccharide capsular antigens in chronic secretory otitis media

In a series of 163 ears with chronic, mucoid effusion, free or immune complex bound pneumococcal capsular polysaccharide antigens were demonstrated with Omniserum and counterimmunoelectrophoresis (CIEP) in 37 ears (23%). In crushed adenoid tissue this figure was 39% (42/107). Using type- or group-specific sera pneumococcus type 6 was found to be most frequent (56%) followed by type 19 (17%). A similar trend was also seen in adenoid suspensions. The results suggest that development of secretory otitis media is much more linked with the pneumococcal serotypes than has been thought hitherto, and that type 6 occurs significantly more often bound in immune complexes than any other subtype.