Complement and C1q binding substances in otitis media

Bactericidal activity of middle ear effusion on a single isolate of non-typable Haemophilus influenzae

Bactericidal activity of middle ear effusion (MEE) from children with otitis media with effusion (OME) on one strain of non-typable Haemophilus influenzae was measured and was compared with that of normal human serum. H. influenzae culture negative MEEs had a bactericidal activity on one strain of non-typable H. influenzae (P less than 0.01), and the activity of serous effusions was significantly stronger than that of mucoid ones (P less than 0.01). The bactericidal activity of 20% pooled MEE was almost equal to that of 4% normal human serum. Heat treatment (56 degrees C, 30 min) abolished this activity of both pooled MEE and normal human serum. Addition of fresh guinea pig serum (GPS) as a complement source to the heat-treated pooled MEE restored this activity, while its addition to the heat-treated normal human serum failed to do so. These results suggest that complement factor is important in the bactericidal activity of MEE.

Current concepts of pathogenesis of otitis media: a review

A number of important factors singly or in combination contribute to the pathogenesis of otitis media. These are poor tubal function, upper respiratory viral infection, bacterial adherence and nasopharyngeal flora, and immune status of the host. One of the important functions of the tubotympanum is to protect the middle ear from invading microbes. The host has available a number of strategies for this function including mucociliary protection, antibacterial secretory products, and specific immunodefenses. The microbes also possess the capability of escaping host defenses by enhancing their ability to adhere to mucosal surfaces, impairing mucociliary function and evading phagocytosis. Once microbes gain entrance to the middle ear, the microbes must overcome phagocytosis and immunodefense of the host, leading to otitis media. Recent data further indicate that specific qualitative and quantitative deficiencies in the immune system of children may predispose certain children to develop otitis media. These deficiencies appear to be in part due to a lack of maturity of the child's developing immune system as well as functional defects that are attributable to genetic or other unknown factors.

Components of the alternative pathway of complement in otitis media with effusion

An evaluation of the alternative pathway of complement was undertaken in patients with otitis media with effusion (OME). Middle ear fluid (MEF) and serum specimens were obtained from 34 patients at the time of elective myringotomy for OME. Bacterial, viral, and mycoplasma cultures were made for all specimens of the fluids. Immunochemical determinations by radial immunodiffusion were performed for C3, C5, factor B, properdin, factor H, factor I, and albumin. Each patient's recent clinical course and past history were reviewed. The results of all viral and mycoplasma cultures were negative. Three of 55 bacterial cultures were positive for type B Haemophilus influenzae. All components of the alternative pathway measured were found to be present in varying amounts in MEF. When the levels of the complement components were compared to the clinical factors studied, there were no observable differences. These data suggest that components of the alternative pathway of complement are present in OME and are not useful in predicting the clinical course or outcome of this disorder.

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.

Experimental immune complex otitis media: localization of IgG by protein A-gold technique

Immune complex (IC) was made of bovine serum albumin (BSA) and anti-BSA guinea pig serum, and instilled into the tubotympanic cavity of untreated guinea pigs. The location of IgG was determined by using the protein A-gold technique to trace IC in the tubotympanic mucosa of the otitis media with effusion (OME) caused by the instillation. IgG was found on the effusion, degenerated ciliated cells and on granules of goblet cells. There was no evidence of intense accumulation of IgG on the basement membrane of the mucosal epithelium or the capillaries. It is likely that IC activates complements in the tubotympanic cavity to cause OME.

Acute otitis media. An animal experimental study

This paper describes an investigation performed to study the middle ear events ensuing from Staphylococcus aureus induced infection in the middle ear cavity of the rat. To obtain an evaluation at both the cell and the tissue level, scanning electron microscopy, transmission electron microscopy and histology were used. Staphylococcus aureus infection appears to be characterized by five major events: (i) cellular response, (ii) humoral response, (iii) mucociliary response, (iv) fibroblastic response, (v) bony response. Since these occurrences correspond to the events witnessed in the human middle ear affected by acute otitis media, S. aureus achieved infection might prove a useful tool for the further study of this disease, by means of animal experiments.