Role of Macrophage Migration Inhibitory Factor in Otitis Media with Effusion in Adults

Otitis media with effusion (OME) is one of the most common ear diseases. Bacterial endotoxins and several inflammatory cytokines appear to be involved in the pathogenesis of OME in children; however, little is known of the immunological aspects of the onset of OME in adults. We sought to determine the presence of macrophage migration inhibitory factor (MIF) as well as interleukin 1β (IL-1β), tumor necrosis factor alpha (TNF-α), RANTES (regulated upon activation, normal T-cell expressed and presumably secreted), and endotoxin in middle ear effusions (MEEs) from adult patients with OME. In addition, the levels of MIF in MEEs from adults and children were compared. MEE was obtained from 95 adults and 11 children. The levels of MIF, IL-1β, TNF-α, and RANTES were determined by enzyme-linked immunosorbent assay, and the concentrations of endotoxin and total protein were determined by the Endospec assay and bicinchoninic acid assay, respectively. MIF was detected in 97.9% of the MEEs from adults, while endotoxin, IL-1β, TNF-α, and RANTES were detected in 96.8, 12.6, 5.3, and 43.9%, respectively. In addition, the level of MIF was significantly higher than those of endotoxin, IL-1β, and TNF-α. A positive correlation between the levels of MIF and endotoxin was observed. MIF and endotoxin were detected in 81.8 and 72.7%, respectively, of the MEEs from the children. The level of MIF was significantly higher in the children, and conversely that of endotoxin was significantly higher in the adults. These results suggest that the interaction between MIF and endotoxin may promote fluid collection in the middle ear, particularly in adults.     

RANTES in otitis media with effusion: presence, role and correlation with cytokines and microbiology

Various inflammatory cells and cytokines have been identified in otitis media with effusion (OME). The presence of neutrophils has been linked to interleukin-8, but no chemotactic factor has as yet been identified for monocytes. The chemokine RANTES (Regulated upon Activation, Normal T Expressed and Secreted) attracts and activates primarily monocytes and may contribute to the pathogenesis of middle ear inflammation. We investigated the presence of RANTES by: 1) ELISA measurement in 114 middle ear effusions from children suffering from OME, 2) immunohistochemical localisation in experimental OME rabbit middle ear mucosa, and 3) expression in cultured rabbit middle ear epithelium in response to proinflammatory stimuli. RANTES was detectable in 94 (82%) of 114 effusions with a median concentration of 79.7 pg/mg total protein content. The concentration of RANTES was positively correlated with the endotoxin content. Immunohistochemically, RANTES was localized to the epithelial layer in experimental OME. In vitro, RANTES was expressed in middle ear epithelium in response to proinflammatory stimuli (TNF-alpha) in a dose-dependent manner. The expression of RANTES may explain the recruitment of monocytes in OME, possibly as a result of TNF-alpha-mediated endotoxin stimulation.     

Cytokines in nasopharyngeal secretions; evidence for defective IL-1 beta production in children with recurrent episodes of acute otitis media.

The host-parasite relationship in the nasopharynx of young children with bacterial colonization and antigen uptake in the mucosa and lymphatic tissue provides an opportunity to investigate infectious/inflammatory processes and responses. IL-1 beta, IL-6 and tumour necrosis factor-alpha (TNF-alpha) were analysed in nasopharyngeal secretions and serum from children with or without recurrent episodes of acute otitis media, from healthy adults and adults with or without recurrent episodes of acute otitis media, from healthy adults and adults with hypogammaglobulinaemia or selective deficiency of IgG3. Nasopharyngeal secretions generally contained substantial amounts of IL-1 beta, IL-6 and TNF-alpha. In contrast, IL-1 beta, IL-6 and TNF-alpha were not detectable in sera on the same occasion. Children were found to have higher levels of IL-1 beta, IL-6 and TNF-alpha than healthy adults and than adults with immunodeficiency. High levels of IL-1 beta were associated with low or undetectable levels of IL-6 and TNF-alpha, whereas the opposite pattern was seen in association with low levels of IL-1 beta. This was especially true for children with recurrent episodes of acute otitis media (RAOM). In children with nasopharyngeal colonization with Haemophilus influenzae, significantly higher levels of IL-1 beta, IL-6 and TNF-alpha (P = 0.0001, respectively) were found compared with non-colonized children. Notably, the RAOM children exhibited significantly lower levels of IL-1 beta, IL-6, and TNF-alpha in nasopharyngeal secretions (P = 0.0001, 0.01 and 0.0001, respectively) than healthy children. These results demonstrate local production of inflammatory cytokines in nasopharynx, related to bacterial colonization, and suggest that children with RAOM are poor nasopharyngeal cytokine producers.     

Multiplex analysis of cytokines in the blood of cynomolgus macaques naturally infected with Ebola virus (Reston serotype)

Ebola virus (EBO) causes the most severe form of viral hemorrhagic fever in humans and nonhuman primates with up to 90% of infections culminating in death. The requirement of maximum containment laboratories for Ebola virus research has limited opportunities to study the pathogenesis of EBO infections. While tissue damage does occur, often it would appear not to be sufficient to explain death, indicating that soluble mediators play an important role in disease progression. In previous studies, fatal human infections with the Zaire subtype of Ebola (EBO-Z) were associated with an increase in the levels of inflammatory cytokines. In this investigation, a new multiplex assay was developed and used to measure circulating levels of cytokines and chemokines in cynomolgus macaques infected with the Reston subtype of EBO (EBO-R). Increased levels of IL-6, TNF-alpha, IFN-gamma, IL-2, IL-4, IL-8, IL-10, and GM-CSF were detected in infected animals, and the increase in circulating cytokines correlated with an increase in circulating viral antigen. Blood samples from animals showing high levels of cytokines were also tested for the chemokines: MCP-1, IL-1beta, MIP-1alpha, MIP-1beta, IP-10, and RANTES. High levels of MCP-1 and MIP-1beta, and RANTES were found in infected primates and, while levels were more variable, IL-1beta was detected only in infected animals.     

Endotoxin in middle-ear effusions from patients with chronic otitis media with effusion

Endotoxin concentrations were determined in middle-ear effusions (MEEs) from 89 children with chronic otitis media by using the Limulu's amoebocyte lysate assay. Mean concentrations of endotoxin in Haemophilus influenzae-positive and Streptococcus pneumoniae-positive MEEs were 157 and 21.8 ng/ml, respectively, and were significantly different (P less than 0.01). Endotoxin was also found in Gram stain-positive, culture-negative and Gram stain-negative, culture-negative MEEs, but the levels were not significantly different (P greater than 0.05). However, the endotoxin concentrations in both groups of culture-negative MEEs significantly lower than those found in MEEs that grew either H. influenzae or S. pneumoniae (P less than 0.05). These results show that endotoxin is present in a high percentage of human MEEs, including those that are culture negative, and may contribute to the pathogenesis of otitis media with effusion.     

Interleukin (IL)-8 and growth related oncogene-alpha in severe endotoxemia and the effects of a tumor necrosis factor-alpha/IL-1beta inhibitor on these chemokines

FR167653 inhibits the production of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta, powerful inducers of CXC chemokines IL-8 and growth related oncogene (GRO)-alpha. The production of IL-8 and GRO-alpha was investigated and the effects of FR167653 were examined in a rabbit model of endotoxin shock. Male New Zealand rabbits were given endotoxin at a dose sufficient to induce DIC. Three groups of rabbits received FR167653 at different doses. TNF-alpha, IL-1beta, IL-8, and GRO-alpha levels were measured, several pathologic features were evaluated, and the results were compared with those obtained in control rabbits, which received only endotoxin. Endotoxin increased serum levels of IL-8 and GRO-alpha, which were associated with hypotension, renal dysfunction, and mortality, peaking at 4 h. FR167653 improved mortality, an event that was associated with decreased levels of not only TNF-alpha and IL-1beta but also IL-8 and GRO-alpha. TNF-alpha peaked at 2 h, at a time point before IL-8 and GRO-alpha reached their peak, and the TNF-alpha level was tightly correlated with that of IL-8 and GRO-alpha. Altogether, these data suggest the possible involvement of IL-8 and GRO-alpha in endotoxin shock, and FR167653 may foster a beneficial outcome in part by modulating the chemokines level by inhibiting TNF-alpha and IL-1beta.     

Trauma patients with positive cultures have higher levels of circulating macrophage migration inhibitory factor (MIF)

Macrophage migration inhibitory factor (MIF) is a pituitary "stress" hormone that plays a critical role in the host immune response. The aims of the study were to determine whether MIF was detectable in the circulation of trauma patients, to assess whether MIF levels were associated with injury severity, days post injury, infection, and to examine concentrations of other pro-inflammatory cytokines in circulation. We collected plasma samples from 35 trauma (multiple injury) patients and 18 healthy controls. Concentrations of MIF, TNF-alpha, IL-1beta, and IL-6 were measured by ELISA. Average MIF concentration in plasma of trauma patients was 14 fold higher than that of healthy controls (19,439+/-2,615 pg/ml in trauma vs 1,337+/-286 pg/ml in control; p=0.0002). There was no correlation between MIF values and injury severity score or days post injury. Average level of IL-6 in trauma patients was 587+/-85 pg/ml but was not correlated with MIF concentration. TNF-alpha and IL-1beta were not detectable in trauma patients or healthy controls. Higher MIF levels were associated with positive cultures (blood, urine, sputum, wound). These data suggest that MIF may be a possible indicator of infection in trauma patients.     

Effect of clarithromycin on cytokines and chemokines in children with an acute exacerbation of recurrent wheezing: a double-blind, randomized, placebo-controlled trial.

BACKGROUND: Clarithromycin is postulated to possess immunomodulatory properties in addition to its antimicrobial activity. OBJECTIVE: To evaluate the effect of clarithromycin on serum and nasopharyngeal cytokine and chemokine concentrations in children with an acute exacerbation of recurrent wheezing. METHODS: Children with a history of recurrent wheezing or asthma and who presented with an acute exacerbation of wheezing were enrolled in a double-blind, randomized trial of clarithromycin vs placebo. Concentrations of tumor necrosis factor alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta), IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, RANTES, eotaxin, macrophage inflammatory protein 1alpha, macrophage inflammatory protein 1beta, and monocyte chemoattractant protein 1 were measured in serum and/or nasopharyngeal aspirates before, during, and after therapy. Mycoplasma pneumoniae and Chlamydophila pneumoniae infection were evaluated for by polymerase chain reaction and serologic testing. RESULTS: Nasopharyngeal concentrations of TNF-alpha, IL-1beta, and IL-10 were significantly and persistently lower in children treated with clarithromycin compared with placebo. There tended to be a greater effect of clarithromycin on nasopharyngeal cytokine concentrations in patients with evidence of M. pneumoniae or C. pneumoniae infection. No significant differences were detected in serum cytokines for children treated with clarithromycin compared with placebo. CONCLUSION: Clarithromycin therapy reduces mucosal TNF-alpha, IL-1beta, and IL-10 concentrations in children with an acute exacerbation of recurrent wheezing.     

Cytolytic complement activity in otitis media with effusion

Otitis media with effusion (OME) is a chronic inflammation persisting in the middle ear cavity of at least 8 weeks duration. Middle ear effusion (MEE; n = 38), samples from children suffering from OME were investigated for their direct cytolytic activity or an ability to enhance complement lysis of unsensitized bystander cells. Thirteen of the 38 MEEs had direct endogenous haemolytic activity and 27 samples had an ability to enhance serum-initiated lysis. Using an enzyme immunoassay, high levels of terminal complement complexes (TCC) were detected in the MEE samples (mean 34.1 microg/ml, range 5--89 microg/ml). This indicated strong local complement activation that had progressed to the terminal stage. As one potential factor promoting complement activation we identified both monomeric and trimeric properdin in MEE by Western blotting. By stabilizing C3 and C5 convertases properdin accelerates the alternative and terminal pathways of complement. On the other hand, the membrane attack complex (MAC) inhibitor CD59, which was found to be extensively shed into the MEE in a functionally active form, may control excessive cytotoxicity of the MEE. In conclusion, intense complement activation, up to the terminal level, maintains ongoing inflammation in the middle ear cavity and can pose a threat to the local epithelium.     

Middle ear fluid cytokine and inflammatory cell kinetics in the chinchilla otitis media model

Streptococcus pneumoniae is the most frequent microbe causing middle ear infection. The pathophysiology of pneumococcal otitis media has been characterized by measurement of local inflammatory mediators such as inflammatory cells, lysozyme, oxidative metabolic products, and inflammatory cytokines. The role of cytokines in bacterial infection has been elucidated with animal models, and interleukin (IL)-1beta, IL-6, and IL-8 and tumor necrosis factor alpha (TNF-alpha) are recognized as being important local mediators in acute inflammation. We characterized middle ear inflammatory responses in the chinchilla otitis media model after injecting a very small number of viable pneumococci into the middle ear, similar to the natural course of infection. Middle ear fluid (MEF) concentrations of IL-1beta, IL-6, IL-8, and TNF-alpha were measured by using anti-human cytokine enzyme-linked immunosorbent assay reagents. IL-1beta showed the earliest peak, at 6 h after inoculation, whereas IL-6, IL-8, and TNF-alpha concentrations were increasing 72 h after pneumococcal inoculation. IL-6, IL-8, and TNF-alpha but not IL-1beta concentrations correlated significantly with total inflammatory cell numbers in MEF, and all four cytokines correlated significantly with MEF neutrophil concentration. Several intercytokine correlations were significant. Cytokines, therefore, participate in the early middle ear inflammatory response to S. pneumoniae.     

Chemokines,osteopontin, ICAM-1 gene expression in cultured rat mesangial cells.

To investigate whether MCP-1, CINC, RANTES, osteopontin and ICAM-1 mRNA could be induced in cultured rat mesangial cells by interleukin-1beta(IL-1beta), tumor necrosis factor-alpha (TNF-alpha) and lipopolysaccharide (LPS), and whether MCP-1 and CINC gene expression could be modulated by dexamethasone, Northern blot assays were performed. IL-1beta induced MCP-1, CINC, RANTES and ICAM-1 gene expression in a time dependent manner. IL-1beta-induced MCP-1, CINC and ICAM-1 mRNA amount were maximal at 3 hours exposure around 14.5, 15.7, 2.2 folds increase and IL-1beta-induced RANTES mRNA at 24 hours around 2.0 folds. TNF-alpha and LPS also induced MCP-1 and ICAM-1 gene expression. TNF-alpha also induced RANTES gene expression but LPS did not. On the other hand, IL-1beta, TNF-alpha and LPS had little effect on osteopontin gene expression but fetal calf serum could increase osteopontin mRNA. Dexamethasone suppressed the IL-1beta-induced MCP-1 and CINC mRNA. These results suggest that, through these gene expressions, mesangial cells are able to communicate directly or indirectly with macrophages or neutrophils, which may lead to glomerulosclerosis.     

Mycobacterium avium subsp. paratuberculosis infection causes suppression of RANTES, monocyte chemoattractant protein 1, and tumor necrosis factor alpha expression in peripheral blood of experimentally infected cattle

Blood from cattle with subclinical Mycobacterium avium subsp. paratuberculosis infection was stimulated with M. avium subsp. paratuberculosis antigens, and expression of interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), RANTES, monocyte chemoattractant protein 1 (MCP-1), and IL-8 was measured. Expression of TNF-alpha, RANTES, and MCP-1 was lower in infected than in uninfected cattle. The reduced response may weaken protective immunity and perpetuate infection.     

Keratinocytes from patients with atopic dermatitis and psoriasis show a distinct chemokine production profile in response to T cell-derived cytokines

BACKGROUND: Atopic dermatitis (AD) and psoriasis are genetically determined inflammatory skin disorders. Keratinocytes actively participate in cutaneous inflammatory responses by elaborating various chemokines. OBJECTIVE: We investigated the capacity of IL-4, IFN-gamma, and TNF-alpha to modulate the expression of CCL and CXCL chemokines in cultured keratinocytes from patients and healthy individuals, as well as chemokine expression in situ. METHODS: Keratinocyte cultures were established from normal-looking skin of adult patients with AD or psoriasis vulgaris and from healthy subjects. Monocyte chemoattractant protein 1 (MCP-1)/CCL2, RANTES/CCL5, IL-8/CXCL8, and IFN-gamma-induced protein of 10 kd (IP-10)/CXCL10 production was evaluated at the mRNA and protein levels by using RNase protection assay and ELISA, respectively. The expression of the same chemokines was studied in chronic lesional skin by means of immunohistochemistry or in situ hybridization. RESULTS: Only IL-8 mRNA was detected in unstimulated ke-ratinocyte cultures. MCP-1 and IP-10 were potently induced by IFN-gamma, whereas IL-8 and RANTES were preferentially upregulated by TNF-alpha and, to a lesser extent, by IFN-gamma. IL-4 weakly induced IP-10, RANTES, and IL-8 but not MCP-1. Keratinocytes of patients with AD invariably responded with significantly earlier and higher RANTES expression. By contrast, keratinocytes of patients with psoriasis displayed much higher levels of both constitutive and induced IL-8 and a stronger induction of MCP-1 and IP-10. RANTES and MCP-1 mRNA(+) keratinocytes were detected in the basal layer of lesions of patients with AD and psoriasis. IP-10 and IL-8 were consistently upregulated in the epidermis of patients with psoriasis but not in lesions of patients with AD. CONCLUSIONS: Keratinocytes of patients with AD and psoriasis show an intrinsically abnormal and different chemokine production profile and may thus favor the recruitment of distinct leukocyte subsets into the skin.     

Porphyromonas gingivalis-induced inflammatory mediator profile in an ex vivo human whole blood model

Periodontitis is characterized by an accumulation of inflammatory cells in periodontal tissue and subgingival sites. Leukocytes play a major role in the host response to Porphyromonas gingivalis, a major aetiological agent of chronic periodontitis. Secretion of high levels of inflammatory mediators, including cytokines and prostaglandins, by leucocytes is believed to contribute to periodontal tissue destruction. The aim of this study was to investigate the inflammatory response of an ex vivo whole blood model to P. gingivalis stimulation. The production of interleukin-1 beta (IL-1beta), IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-13, tumour necrosis factor alpha (TNF-alpha), interferon gamma (IFN-gamma), IFN-gamma-inducible protein 10 (IP-10), monocyte chemoattractant protein-1 (MCP-1), Regulated on Activation Normal T cell Expressed and Secreted (RANTES) and prostaglandin E2 (PGE2) were quantified by enzyme-linked immunosorbent assays. P. gingivalis induced the secretion of the pro-inflammatory cytokines IL-1beta, TNF-alpha, IL-6 and IFN-gamma, the chemokines IL-8, RANTES and MCP-1 and the inflammatory mediator PGE2 in an ex vivo human whole blood model. The secretion levels were dependent on the strain and the infectious dose used. While the mediator profiles were comparable between six healthy subjects, a high interindividual variability in the levels of secreted mediators was observed. This study supports the view that P. gingivalis, by inducing high levels of inflammatory mediators from a mixed leucocyte population, can contribute to the progression of periodontitis.     

Intranasal immunization enhances clearance of nontypeable Haemophilus influenzae and reduces stimulation of tumor necrosis factor alpha production in the murine model of otitis media

Nontypeable Haemophilus influenzae (NTHi) is a major pathogen causing otitis media (OM). One of the outer membrane proteins of NTHi, P6, is a common antigen to all strains and is considered a candidate for mucosal vaccine. We have previously reported that intranasal immunization with P6 and cholera toxin (CT) could induce P6-specific immunoglobulin A (IgA) antibodies in the middle ear. In the present study, we assessed the effect of intranasal immunization for the protection against NTHi-induced OM. Mice were immunized intranasally with P6 and CT as an adjuvant on days 0, 7, and 14. Control mice were given phosphate-buffered saline (PBS) without antigen. One week after the final immunization, a suspension of live NTHi (10(7) CFU) was injected into the tympanic cavity to induce experimental OM. On days 3 and 7 after bacterial challenge, mice were killed and middle ear effusions (MEEs) were collected. All immunized mice showed elevated titers of P6-specific antibodies in MEEs. The rank order of specific antibody included, from highest to lowest levels, IgG, IgA, and IgM. In addition, immunized mice showed enhanced clearance of NTHi from the middle ear and the number of NTHi in MEEs of immunized mice was reduced by 97% on day 3 and by 92% on day 7 after bacterial challenge relative the number in the MEEs of control mice. The protective effect of intranasal immunization on the incidence of NTHi-induced experimental OM was evident on day 7 after challenge. By day 7, the number of MEEs in immunized mice was 64% less than that in control mice and the incidence of NTHi culture-positive MEEs in immunized mice was 56% less than that in control mice. Less stimulation of tumor necrosis factor alpha (TNF-alpha) production in the middle ear was evident on day 3 after challenge. Immunized mice showed lower concentrations of TNF-alpha in MEEs. These results indicate that intranasal immunization affords protection against experimental OM as evidenced by enhanced clearance of NTHi and less stimulation of TNF-alpha production in the middle ear. These findings suggest that a nasal vaccine might be useful for preventing OM.