Functions of tonsils in the mucosal immune system of the upper respiratory tract using a novel animal model, Suncus murinus.

CONCLUSION: The human palatine tonsils and the nasopharyngeal tonsil were considered the defense mechanism against ingested or inhaled foreign pathogens. The current findings suggest that the tubal tonsils possess abilities of active transportation of foreign antigens, and will act as inductive and effector sites in the mucosal immune system. Our results also indicated a significant difference in roles of immune responses among individual tonsillar organs, suggesting functional sub-compartmentalization. OBJECTIVES: To address the function of tonsils in inducing local immune responses, we evaluated the antigen uptake of tubal tonsils and the induction of specific immune responses in a small laboratory animal with both tubal and palatine tonsils, i.e. Suncus murinus. MATERIALS AND METHODS: S. murinus were injected with 2 x 10(6) CFU of FITC-labeled Staphylococcus aureus via the right tympanic cavity. The distribution of the FITC-labeled S. aureus was examined under a fluorescent microscope. S. murinus were also immunized with 100 microg of ovalbumin (OVA) mixed with 2 microg of cholera toxin (CT) via the right external ear meatus every 2 days for 2 weeks. One week after the final immunization, sera, pairs of tubal and palatine tonsils, and the neck lymph nodes were obtained to evaluate the induction of specific immune responses. RESULTS: The FITC-labeled S. aureus particles were detected in tubal tonsils and also in cervical lymph nodes. Total IgA-producing cells and OVA-specific antibody-producing cells were identified in the immunized tubal tonsils. Trans-external ear meatus immunization of tubal tonsils also evoked systemic antibody responses.

Tonsillitis index: an objective tool for quantifying the indications for tonsillectomy for recurrent acute tonsillitis.

This report is a preliminary exploration of the concept of a "Tonsillectomy Index" (TI) as an objective tool for quantifying the indications for tonsillectomy for recurrent acute tonsillitis (AT). The TI is derived by multiplying the number of episodes of AT by the number of years during which the episodes of AT occurred. Our objective in this study was to investigate whether there is a relationship between the natural history of AT, the immunological functions of tonsils and our proposed TI. For the natural history of AT, we medically followed 11 children with a history of AT for 5 years. When TI was equal to or greater than 8 (TI> or =8), the children suffered a significantly greater number of episodes of AT. For the immunological portion of our study, we enrolled 36 children and 46 adults undergoing tonsillectomy for either AT (study group) or tonsillar hypertrophy (control group, CG). We analyzed the co-stimulatory signals, CD80 and CD86 on tonsillar B-lymphocytes. The expression rates of CD80 and CD86 in the AT group with TI> or =8 were significantly decreased compared to those with TI was less than 8 (TI<8), as well as with those in control (tonsillar hypertrophy) group. Our preliminary findings suggest that when the TI> or =8, the tonsils have deteriorated immunologically and spontaneous resolution of recurrent AT is less likely to occur, hence tonsillectomy is appropriate. TI may be a useful tool for surgical decision making.

Macrolide-resistant genes of Streptococcus pyogenes isolated from the upper respiratory tract by polymerase chain reaction.

The growing number of macrolide-resistant strains of Streptococcus pyogenes is an increasing problem worldwide. This study evaluated 300 clinical isolates obtained from the upper respiratory tract. Minimal inhibitory concentrations (MICs) of erythromycin (EM), azithromycin (AZM), and clindamycin (CLDM), serotypes, and macrolide resistance genes of mefA, ermB, and ermTR were determined. The genetic relationship of EM-resistant and susceptible strains were also analyzed by pulsed-field gel electrophoresis (PFGE). Twenty-nine (9.7%) EM-resistant S. pyogenes were identified. Of the 29 strains showing resistance to EM, 22 isolates (7.3%, MIC 3.13-12.5 microg/ml) expressed the mefA gene. The predominant serotypes among the mefA-positive isolates were T12, emm9 or T25, emm75-1. The two isolates (0.1%) that possessed the ermB gene were highly resistant to EM (MIC > 100 microg/ml). The remaining five strains (1.6%) possessed the ermTR gene (MIC 3.13-100 microg/ml). Restriction fragment polymorphism analyzed by pulsed-field gel electrophoresis (PFGE) by SmaI and ApaI digestions showed several clones among the mefA-positive S. pyogenes. Our findings suggest that the mefA gene is the predominant mechanism for macrolide resistance and that this gene is horizontally transmitted among M phenotype strains of S. pyogenes. Consequently, macrolides would not be the first drug of choice for treatment of tonsillitis and other S. pyogenes-related diseases. Physicians and researchers need to take into consideration the macrolide resistance of some strains of S. pyogenes.

Immunity of tonsil and IgA nephropathy--relationship between IgA nephropathy and tonsillitis.

Our study hypothesized that cytokines or chemokines induced in tonsils by infectious stimulations play an important role on the exacerbation of the glomerular injuries in patients with IgA nephropathy (IgAN). Tonsils from six patients with IgAN diagnosed by renal biopsy were studied after getting their written informed consents Tonsils from six patients with tonsil disorders with non-renal disorders were examined as controls. Tonsillar mononuclear cells (TMCs) were isolated and resuspended with RPMI 1640 with 10% FCS. These cells were incubated for 48 h with staphlococcus enterotoxin-B (SEB) or lipopolysaccaride (LPS). The levels of IL-6, IL-8, IL-12 and MCP-1 in the supernatants were measured by solid-phase enzyme-linked immunosorbent assay (ELISA) kits. The actual cytokine concentrations were calculated by determining the standard curves. The experiments were performed in duplicate, and the mean value was calculated. We found that tonsillar mononuclear cells of IgA nephropathy produced mesangial proliferative chemokines (MCP-1, IL-8) in higher amounts compared to tonsils from non-IgA nephropathy. This result suggests that upper respiratory tract infections such as tonsillitis may be one of the risk factors of the aggravation in patients with IgA nephropathy.

[Roles of beta-catenin overexpression and adenomatous polyposis coli mutation in head and neck cancer].

Beta-catenin is an undercoat protein of cadherin, a cellular adhesion molecule. Beta-catenin also functions as a transcriptional activator downstream of the Wnt signaling pathway. Intracellular beta-catenin is regulated by the formation of a complex with APC (adenomatous polyposis coli) protein. The activation of this pathway by stabilization with beta-catenin has been shown to be an important step in the development of colorectal carcinoma, which is mainly caused by inactivating mutations in the APC tumor suppressor gene or by activating mutations in exon 3 of the beta-catenin gene. This study was conducted to clarify the contribution of beta-catenin accumulation and the mutation of the beta-catenin gene to the carcinogenesis of head and neck cancer. Beta-catenin accumulation was examined immunohistochemically in 49 frozen or formalin-fixed, paraffin-embedded samples of head and neck tumors. We also performed a direct sequence analysis of APC and beta-catenin to examine the cause of beta-catenin accumulation. Genomic DNA was extracted and purified from fresh tissue samples of head and neck cancers. We examined the APC mutation cluster region in 15 samples and analyzed beta-catenin exon 3 mutations in 31 cases. Twelve out of 49 (24.5%) cases exhibited beta-catenin accumulation in our histochemical study. The 5 year survival rate was 0% in the beta-catenin accumulation group, compared to 50% in the non-accumulation group, (p < 0.01). This finding strongly suggests that beta-catenin may play an important role in the carcinogenesis or progression of head and neck cancer. One of the 15 cases exhibited an APC missense mutation that led to the replacement of amino acids; this case died in 12 months. Regarding the beta-catein mutation, non of the 31 samples exhibited a gene mutation in beta-catenin exon 3. Thus, the rate of APC and beta-catenin mutation in head and neck cancer may be very low.

Nasopharyngeal carriage of drug-resistant Streptococcus pneumoniae in children with acute otitis media evaluated by polymerase chain reaction-based genotyping of penicillin-binding proteins.

A polymerase chain reaction (PCR)-based genotyping of the penicillin-binding protein (PBP) genes pbp1a, pbp2x and pbp2b was used to characterize Streptococcus pneumoniae isolated from the nasopharynx of children with acute otitis media (AOM). Mutations were observed in pbp1a, pbp2x and pbp2b genes in 36.5% of the strains. Decreased susceptibility to beta-lactam antibiotics was closely associated with the frequency of mutations in the three PBP genes. Of penicillin-intermediately-resistant S. pneumoniae strains, 54.5% appeared to be genetically similar to penicillin-resistant S. pneumoniae strains. Of penicillin-susceptible S. pneumoniae strains, 33.3% had mutations in the pbp2x gene and showed relatively high MICs to cephalosporins. Strains with mutations in the three PBP genes were often isolated from children < or = 2 years old. Evaluation of mutations in PBP genes using PCR will prove useful for studying the epidemiology of antibiotic resistance.