Relationship between respiratory syncytial virus infection and acute otitis media in children

BACKGROUND: Respiratory syncytial virus (RSV) is among the major causes of respiratory tract infection in infants and young children, and concomitant acute otitis media (AOM) often develops. However, there are only a few reports about AOM associated with RSV infection. METHODS: Two hundred and thirty children who were diagnosed as having RSV infection were studied by enzyme immunoassay (Testpack RSV) at the Department of Pediatrics of Tohoku Rosai Hospital from 1 November 2001 to 31 October 2002. In the patients with AOM, bacterial culture and detection of RSV antigen in the middle ear fluid (MEF) by enzyme immunoassay were performed, and the outcome was investigated. RESULTS: Among the 230 children, 120 (52.2%) were found to have AOM. In children under 2 years of age, the incidence of AOM was significantly higher (73.1%) than in the older children (29.7%). RSV antigen was positive in the MEF of 36 out of 52 patients with AOM (69.2%). In 24 of the 46 patients in whom both RSV antigen detection and bacterial culture of MEF were performed, RSV antigen was detected and bacterial culture was negative. Although the outcome of the first episode of AOM following RSV infection was favorable, relapse was observed in 31% of the patients. CONCLUSION: These results confirm that patients with RSV infection have a high risk of AOM, especially children younger than 2 years of age, and suggest that RSV may be a direct cause of AOM at least in the early stage of infection with this virus. The necessity of performing careful follow-up of AOM after resolution of symptoms is suggested because relapse is common.     

HLA-DR and ICAM-1 expression and modulation in epithelial cells from nasal polyps

OBJECTIVE/HYPOTHESIS: Through human leukocyte antigen-DR (HLA-DR) and intercellular adhesion molecule-1 (ICAM-1) expression, nasal epithelial cells could actively participate in the chronic inflammation and eosinophil infiltration observed in nasal polyps. The objective of the study was to evaluate HLA-DR and ICAM-1 expression in polyp epithelium and in a culture model of polyp epithelial cells allowing ciliated and secretory differentiation. STUDY DESIGN: Prospective non-randomized controlled in vitro study. METHODS: The in vitro HLA-DR and ICAM-1 expression was studied under basal conditions or after exposure to interferon-gamma, transforming growth factor-beta1, lipopolysaccharide, dexamethasone, or cetirizine. HLA-DR and ICAM-1 expression was investigated in situ by immunohistochemical staining of polyps and in vitro by immunofluorescent staining of cell cultures. HLA-DR and ICAM-1 were localized in cultured cells by confocal microscopy. Cultured cells expressing HLA-DR and ICAM-1 were quantified by flow cytometry. RESULTS: Both HLA-DR and ICAM-1 showed significant immunostaining of nasal polyp epithelium. In nasal polyp epithelial cell cultures, less than 5% of cells were positive for HLA-DR whereas 40% were positive for ICAM-1 at day 3. In vitro, HLA-DR was mainly located in the cytoplasm and ICAM-1 predominated on the apicolateral cytoplasmic membrane. Comparison of in situ and in vitro results showed that well-differentiated and poorly differentiated cells predominantly expressed HLA-DR and ICAM-1, respectively. Interferon-gamma significantly increased HLA-DR and ICAM-1 expression, whereas transforming growth factor-beta1 significantly decreased HLA-DR expression and lipopolysaccharide significantly increased ICAM-1 expression. CONCLUSION: HLA-DR and ICAM-1 epithelial expression in nasal polyps in situ and in vitro and their in vitro modulation reinforce the active role of epithelial cells in chronic inflammatory diseases of the upper airways.     

Cytokine expression in experimental chronic otitis media with effusion in mice

OBJECTIVES: Although otitis media with effusion (OME) is still a common disease in children and adults, the pathogenesis is not yet fully understood. We studied the effects of intratympanic injection with endotoxin purified from nontypeable Haemophilus influenzae on the characteristics of middle ear effusion (MEE). METHODS: Murine model of OME was developed by eustachian tube (ET) blockage followed by intratympanic inoculation with endotoxin (endotoxin group) or saline (control group). The mice were decapitated and histological changes and the production of inflammatory cytokines in MEEs were examined 3 days, 2 weeks, and 2 months after injection. RESULTS: All mice showed OME until 2 months after ET blockage. Most MEEs in the control group were serous, and mucoid or pultaceous MEEs were found only in the endotoxin group. Subepithelial space of middle ear mucosa was severely thickened with the infiltration of a large number of mononuclear cells in the endotoxin group. The levels of tumor necrosis factor-alpha (TNF-alpha) in MEEs were significantly higher in the endotoxin group than in the control group at all time points. Further, in situ hybridization showed that TNF-alpha messenger RNA was expressed not only by leukocytes and macrophages in MEEs but mononuclear cells present in the subepithelial space of middle ear mucosa. CONCLUSIONS: These results indicate that ET blockage is essential for the induction of serous MEE and additional administration of endotoxin is associated with the production of mucoid MEE accompanied by histological changes with inflammatory cell infiltration and cytokine production in the tympanic cavity.     

Effects of alpha-toxin of Staphylococcus aureus on the ciliary activity and ultrastructure of human nasal ciliated epithelial cells

OBJECTIVE: The in vitro effects of staphylococcal alpha-toxin on ciliary activity were investigated at different concentrations and exposure times. STUDY DESIGN: Ciliated epithelial cells of the sphenoid sinus were taken from patients operated on for pituitary tumors. Video-computerized analysis technique and transmission electron microscopy were used to analyze the effects of the toxin on ciliary activity. METHODS: Ciliary beat frequency (CBF) was measured in four different concentrations of alpha-toxin including 0.1, 1, 10, and 50 microg/mL. CBF was measured at 2, 4, 6, 12, 24, and 48 hours after administration of the toxin. To observe reversibility of the reduced ciliary activity, after 24-hour incubation in the media containing 10 microg/mL of alpha-toxin, the media were replaced with alpha-toxin-free media. The tissues were also processed for transmission electron microscopy to observe ultrastructural changes of the epithelial cells. RESULTS: CBF increased significantly at 2-hour incubation and then decreased significantly after 12-hour incubation in 10 microg/mL of alpha-toxin (P< .05, repeated-measures ANOVA). The transmission electron microscopic findings showed mitochondrial swelling and a slight protrusion of the plasma membrane of the cilia. In toxin-free media, loss of ciliary activity was not recovered. CONCLUSIONS: CBF increased at first, but with increasing incubation time ciliary movements decreased gradually and stopped eventually. This loss of CBF may be an irreversible change associated with ultrastructural changes in the mitochondria and the plasma membrane of the cilia.     

Regulation of immunoglobulin secretion by plasma cells infiltrating nasal polyps

OBJECTIVE/HYPOTHESIS: To learn more about the role of plasma cells infiltrating nasal polyps in the pathogenesis of nasal polyposis, we examined their function by analyzing immunoglobulin (Ig) production and the factors implicated in the secretion. STUDY DESIGN: A series of 19 consecutive nasal polyp tissue samples and, as a control, peripheral blood samples from the same patients, were studied by histopathological and immunological examination. METHODS: Hematoxylin-eosin and immunohistochemical staining was carried out to identify plasma cells infiltrating nasal polyps. Nasal polyp mononuclear cells (NPMNCs) were purified from nasal polyp tissue samples, and Ig-secreting cells were identified in cytospin preparations stained with fluorescein isothiocyanate-conjugated antibodies against IgA, IgG, IgM, and IgE. Purified NPMNCs were cultured in basal conditions and after the addition of several stimuli. Ig secreted into the culture supernatants was evaluated by an enzyme-linked immunosorbent assay. RESULTS: Plasma cells accounted for an important fraction of the inflammatory infiltrate. The main Ig isotype synthesized by these cells was IgA, whereas little IgE was detected. In vitro cultures demonstrated that the plasma cells actively secreted Ig for a short period. When cytokine dependence was analyzed, interleukin-10 (IL-10) and tumor necrosis factor-alpha (TNF-alpha) were shown to be partially responsible for the Ig production. Dependence on CD95-mediated apoptosis was not observed. CONCLUSIONS: Nasal polyp-infiltrating plasma cells are mainly IgA-secreting cells, the latter property being related to the mucosal immune system. The IgA production is partly dependent on IL-10 and TNF-alpha. The absence of IgE-secreting cells in most of the samples suggests that a type I hypersensitivity reaction is not essential for the development of nasal polyp.     

Effects of beta-toxin of Staphylococcus aureus on ciliary activity of nasal epithelial cells

OBJECTIVES: To investigate the in vitro effects of staphylococcal beta-toxin on ciliary activity and the in vivo effects on sinusitis induction. STUDY DESIGN: The in vitro effects of staphylococcal beta-toxin on ciliary activity were investigated at different concentrations and exposure times. Experimental sinusitis was induced in rabbits with application of beta-toxin and confirmed 7 days later. METHODS: Ciliated epithelial cells were taken from the maxillary sinus mucosa of 10 rabbits. Five culture dishes from each rabbit were used for the experimental group, and one culture dish from each rabbit was used for the control group. In the experimental group, ciliary beat frequency (CBF) was measured at concentrations of 0.1, 1, 2, 5 and 10 U/mL of beta-toxin using a video-computerized analysis technique, while in the control group, culture medium containing no toxin was used. CBF was measured 1, 2, 4, 6, 8, 12, 24, and 48 hours after administration of beta-toxin. To induce experimental sinusitis, 2 U/mL of beta-toxin was percutaneously applied to the maxillary sinus of 10 rabbits without occlusion of the natural ostium, while normal saline was percutaneously applied to the right-side maxillary sinus of 4 rabbits in the control group. At 7 days, mucosal membranes were taken from the inferomedial wall of the maxillary sinus for light microscopic study. RESULTS: CBF dropped significantly after an 8-hour incubation at 2, 5, and 10 U/mL of beta-toxin. No ciliary activity was observed after a 24-hour incubation at 2 and 5 U/mL and a 12-hour incubation at 10 U/mL of beta-toxin. Mucoid, purulent discharge was observed in the maxillary sinuses of the beta-toxin-applied group. Prominent epithelial disruption and infiltration of inflammatory cells into the epithelium and lamina propria were observed in the beta-toxin-applied group. CONCLUSIONS: Staphylococcal beta-toxin may reduce ciliary activity and induce sinusitis without occlusion of the natural ostium of the maxillary sinus in rabbits This study provides another animal model of sinusitis for understanding the pathogenesis of sinusitis induced by bacterial exotoxins.     

Epstein-Barr virus infection in cultured non-malignant epithelial cells from human nasopharyngeal mucosa

Summary Epstein-Barr virus infected cultured epithelial cells from the human nasopharyngeal mucosa only, when the cells were maintained under conditions preventing terminal differentiation. The infection of these cells resulted in a marked cytopathology resembling that morphology induced in cell cultures by other members of the herpesvirus group.     

Effects of benzalkonium chloride on innate immunity physiology of the human nasal mucosa in vivo

OBJECTIVE: Benzalkonium chloride (BC) is a preservative commonly used in nasal decongestant sprays. It has been suggested that BC may be harmful to the nasal mucosa. The present study, involving healthy volunteers, examines effects of BC on nasal mucosal end-organ functions. METHODS: Isotonic saline and BC (0.1 mg/mL) were administered acutely to the nasal mucosa using a nasal pool device. Nasal symptoms were determined. Nasal lavage fluid levels of alpha2-macroglobulin and fucose were measured as indices of plasma exudation and glandular secretion, respectively. In addition, BC (0.1 mg/mL) was given as single actuations of 100 microL per nasal cavity three times daily for 10 days. The ability of histamine (0.4 mg/mL) to evoke nasal symptoms and plasma exudation responses was determined before and after the repeated BC administration series. RESULTS: BC produced immediate nasal smart or pain (P < .05), but tolerance to this response developed by repeated administrations. BC increased nasal mucosal output of fucose (P < .05), whereas nasal lavage fluid levels of alpha2-macroglobulin were unaffected. Histamine produced significant symptoms and mucosal exudation of alpha2-macroglobulin (P values < .01), equally before and after the 10 days of BC exposure. CONCLUSIONS: BC in dosages commonly used as preservative in nasal decongestant sprays produced short-term glandular secretion and nasal smart or pain. However, 10 days' frequent exposure to BC was not associated with untoward symptomatic effects, nor was a sensitive mucosal variable such as histamine-induced exudative responsiveness affected by this repeated exposure 1 BC.     

地塞米松对人鼻黏膜上皮细胞前炎性因子表达的抑制作用

目的观察地塞米松对脂多糖(lipopolysac-charide,LPS)诱导的人鼻黏膜上皮细胞缺氧诱导因子-1(hypoxic inducible factor-1,HIF-1)及血管内皮生长因子(vascular endothelial growth factor,VEGF)表达抑制情况及意义。方法无血清原代培养人鼻息肉和下鼻甲黏膜上皮细胞,以LPS100ng/ml,白细胞介素-1β(interleukin-1β,IL-1β)20ng/ml,LPS100ng/ml加地塞米松13ng/ml,IL-1β20ng/ml加地塞米松13ng/ml作用于对数生长期的上皮细胞3、6、9小时后,采用免疫细胞化学和原位杂交方法检测HIF-1α和VEGF蛋白及mRNA的表达情况。结果①LPS和IL-1β作用于上皮细胞时,HIF-1α及VEGF表达增加具有时间依赖性,以LPS100ng/ml6小时组最明显(P<0.05),且鼻息肉中的表达明显高于下鼻甲(P<0.05);②LPS100ng/ml加地塞米松13ng/ml组和IL-1β20ng/ml加地塞米松13ng/ml组表达强度分别较LPS100ng/ml组和IL-1β20ng/ml组弱(P<0.05)。两抑制组间表达无显著性差异。结论炎性因子及感染性因子可以诱导人鼻黏膜上皮细胞大量表达HIF-1α及VEGF,而地塞米松对其表达有很强的抑制作用。     

mRNA for genes associated with antigen presentation are expressed by human middle meatal epithelial cells in culture

OBJECTIVES/HYPOTHESIS: Although the mechanisms underlying the initiation and maintenance of inflammation in chronic rhinosinusitis are poorly understood, the activation of memory T cells within the nasal mucosa is thought to play an important role. T-cell activation requires specialized antigen processing and presentation of antigen by immunocompetent cells in the context of cell surface immune molecules. The purpose of this study was to investigate the expression of such molecules by human sinonasal epithelial cells grown in culture at the air-liquid interface (ALI). METHODS: Middle meatal epithelium was obtained from six patients undergoing endoscopic sinus surgery. Dissociated epithelial cells were grown to confluence in serum-free, defined medium and transferred to filter inserts for culture at the ALI. Cells were harvested at 2 and 21 days of growth at the ALI and processed for real-time polymerase chain reaction (PCR). The presence and relative abundance of constitutively expressed mRNA for human leukocyte antigen (HLA)-B, HLA-DR, B7 to 1, B7 to 2, B7-H2, B7-H3, and cathepsin D were assessed. RESULTS: After 2 days at the ALI, middle meatal epithelial cells demonstrated expression of genes for each of the antigen processing associated genes tested. The expression of HLA-B and HLA-DR increased significantly with cellular maturation at the ALI. Expression of HLA-DR and B7 to 1 increased with cytokine stimulation. CONCLUSIONS: Primary human epithelial cells obtained from the middle meatus express genes associated with antigen presentation function. The pattern of gene expression is modulated by cytokine stimulation and changes as the cells differentiate at the ALI. These findings suggest that mature middle meatal epithelial cells have the cellular machinery to interact with T cells and therefore may be direct participants in the modulation of T-cell activity in chronic sinusitis.     

Epstein-Barr virus (EBV) latent membrane protein 1 induces interleukin-8 through the nuclear factor-kappa B signaling pathway in EBV-infected nasopharyngeal carcinoma cell line

BACKGROUND/OBJECTIVES: Nasopharyngeal carcinoma (NPC) is a highly invasive and metastatic malignant tumor and is associated with Epstein-Barr virus (EBV) infection that exhibits type II latency. Angiogenesis is essential for tumor growth, invasion, and metastasis. Our previous studies have indicated that interleukin (IL)-8 was over-expressed in many NPC tissues and was found to be significantly correlated with angiogenesis by immunohistochemistry. STUDY DESIGN: In vitro design. METHODS: The influence of the EBV genome for IL-8 gene expression was studied using the EBV-genome-positive and -negative epithelial/NPC hybrid cell line NPC-KT. The EBV-positive and -negative clones were selected by polymerase chain reaction and in situ hybridization. RESULTS: EBV-positive clones expressed abundant IL-8 mRNA compared with EBV-negative clones. This result indicated that over-expression of IL-8 depended on the presence of EBV genomes in NPC-KT cells. Two encoded genes, latent membrane protein (LMP)1 and EBV-encoded small RNAs (EBERs), expressed in NPC were transfected in EBV-negative NPC-KT cells. LMP1 transactivated the IL-8 promoter, whereas EBERs did not. Moreover, the nuclear factor (NF)-kappa B binding site in the IL-8 promoter was essential for the response to LMP1, and the activator protein (AP)-1 binding site played only a partial role. CONCLUSIONS: LMP1 induces IL-8 mainly through the activation of NF-kappa B and partly through AP-1 in NPC model cell lines, NPC-KT, and this suggests that LMP1 plays an important role in the angiogenesis of NPC.