Can an otorhinolaryngological visit induce the suspect of allergic rhinitis in children?

Summary: Allergic rhinitis (AR) is very frequent in childhood. AR is commonly associated with some co-morbidities and typical clinical features. This study aimed to test the hypothesis whether an otorhinolaryngological (ORL) visit could induce the suspect of AR. Globally, 1,002 children (550 males, mean age 5.77 years) were consecutively visited at an ORL clinic. Clinical visit, nasal endoscopy, and skin prick test were performed in all patients. In particular, history investigated atopic familiarity, birth, feeding type, passive smoking, comorbidities, including asthma, respiratory infections, otitis media, respiratory sleep disorder. Endoscopy assessed the tonsil and adenoid volume, turbinate contacts, mucosal color, and nasal discharge. Univariate and multivariate analysis were performed. The study showed that 547 (54.6%) children had AR. Some parameters were predicting factor for suspecting AR: middle turbinate contact (OR = 9.27), familial atopy (OR = 6.24), pale nasal mucosa (OR = 4.95), large adenoid volume (OR = 3.02 for score 4), and asthma co-morbidity (OR = 2.95). In conclusion this real-life study showed that during an ORL visit it is possible to suspect AR in children with turbinate hypertrophy, familial atopy, nasal pale mucosa, adenoid enlargement, and asthma comorbidity.

Differentiation of tonsil-tissue-derived mesenchymal stem cells controlled by surface-functionalized microspheres in PEG-polypeptide thermogels.

Poly(ethylene glycol)-poly(l-alanine) diblock copolymer (PEG-L-PA; molecular weight of each block of 1000-1080 Da) aqueous solutions undergo sol-to-gel transition in a 3.0-8.0 wt % concentration range as the temperature increases. By incorporating the polystyrene microspheres with different functional groups with a size of 100-800 µm in in situ formed PEG-L-PA thermogels, the differentiation of tonsil-tissue-derived mesenchymal stem cells (TMSCs) was investigated. The mRNA expression and immunohistochemical assays suggested that the TMSCs preferentially undergo adipogenesis in the ammonium (-NH3(+))- or thiol (-SH)-functionalized microsphere incorporated thermogels; chondrogenesis in the thiol-, phosphate (PO3(2-))-, or carboxylate (-COO(-))-functionalized microsphere incorporated thermogels; and osteogenesis in the phosphate-, carboxylate-functionalized, or neat polystyrene microsphere incorporated thermogels. This paper provides a new TMSC 3D culture system of a sol-gel reversible matrix and suggests that the surface-functional groups of microspheres in the thermogel can control the preferential differentiation of stem cells into specific cell types during the 3D culture.

Human vascular adhesion protein 1 (VAP-1) is a unique sialoglycoprotein that mediates carbohydrate-dependent binding of lymphocytes to endothelial cells.

The regulated interactions of leukocytes with vascular endothelial cells are crucial in controlling leukocyte traffic between blood and tissues. Vascular adhesion protein-1 (VAP-1) is a novel, human endothelial cell molecule that mediates tissue-selective lymphocyte binding. Two species (90 and 170 kD) of VAP-1 exist in lymphoid tissues. Glycosidase digestions revealed that the mature 170-kD form of VAP-1 expressed on the lumenal surfaces of vessels is a heavily sialylated glycoprotein. The sialic acids are indispensable for the function of VAP-1, since the desialylated form of VAP-1 no longer mediates lymphocyte binding. We also show that L-selectin is not required for binding of activated lymphocytes to VAP-1 under conditions of shear stress. The 90-kD form of VAP-1 was only seen in an organ culture model, and may represent a monomeric or proteolytic form of the larger species. These data indicate that L-selectin negative lymphocytes can bind to tonsillar venules via the VAP- 1-mediated pathway. Moreover, our findings extend the role of carbohydrate-mediated binding in lymphocyte-endothelial cell interactions beyond the known selectins. In conclusion, VAP-1 naturally exists as a 170-kD sialoglycoprotein that uses sialic acid residues to interact with its counter-receptors on lymphocytes under nonstatic conditions.

Bcl-2+ tonsillar plasma cells are rescued from apoptosis by bone marrow fibroblasts.

Plasma cells represent the final stage of B lymphocyte differentiation. Most plasma cells in secondary lymphoid tissues live for a few days, whereas those in the lamina propria of mucosa and in bone marrow live for several weeks. To investigate the regulation of human plasma cell survival, plasma cells were isolated from tonsils according to high CD38 and low CD20 expression. Tonsillar plasma cells express CD9, CD19, CD24, CD37, CD40, CD74, and HLA-DR, but not CD10, HLA-DQ, CD28, CD56, and Fas/CD95. Although plasma cells express intracytoplasmic Bcl-2, they undergo swift apoptosis in vitro and do not respond to CD40 triggering. Bone marrow fibroblasts and rheumatoid synoviocytes, however, prevented plasma cells from undergoing apoptosis in a contact-dependent fashion. These data indicate that fibroblasts may form a microenvironment favorable for plasma cell survival under normal and pathological conditions.

Optimization of tenocyte lineage-related factors from tonsil-derived mesenchymal stem cells using response surface methodology.

BACKGROUND: In order to optimize the tenogenic differentiation of mesenchymal stem cells (MSCs), researchers should consider various factors. However, this requires testing numerous experimental settings, which is costly and time-consuming. We aimed to assess the differential effects of transforming growth factor beta-3 (TGF-ß3) on the tenogenesis of tonsil-derived MSCs (T-MSCs) and bone marrow-derived MSCs (BM-MSCs) using response surface methodology (RSM). METHODS: Bone marrow and tonsillar tissue were collected from four patients; mononuclear cells were separated and treated with 5 or 10 ng/mL of TGF-ß3. A full factorial experimental design with a categorical factor of 0 was employed to study the effect of tension based on T-MSCs. Eighty-four trials were fitted with RSM and then used to obtain mathematical prediction models. RESULTS: Exposure of T-MSCs and BM-MSCs to TGF-ß3 increased the expression of scleraxis (SCX), tenomodulin (TNMD), decorin, collagen I, and tenascin C. Expression of most of these factors reached a maximum after 2-3 days of treatment. The model predicted that the values of the tenocyte lineage-related factors assessed would be significantly increased at 2.5 days of culture with 2.7 ng/mL of TGF-ß3 for T-MSCs and at 2.3 days of culture regardless of TGF-ß3 concentration for BM-MSCs. CONCLUSIONS: This study demonstrated that the RSM prediction of the culture time necessary for the tenogenic differentiation of T-MSCs and BM-MSCs under TGF-ß3 stimulation was similar to the experimentally determined time of peak expression of tenocyte-related mRNAs, suggesting the potential of using the RSM approach for optimization of the culture protocol for tenogenesis of MSCs.

Association Between Galactose-Deficient IgA1 Derived From the Tonsils and Recurrence of IgA Nephropathy in Patients Who Underwent Kidney Transplantation.

Background: Recurrence of IgA nephropathy (IgAN) in the transplanted kidney is associated with graft survival, but no specific treatment is available. Tonsillectomy (TE) reportedly arrests the progression of IgAN in the native kidney. Thus, we conducted a single-center retrospective cohort study to evaluate the effect of TE prior to IgAN recurrence. Methods: Of the 36 patients with biopsy-proven IgAN who underwent kidney transplantation, 27 were included in this study. Nine patients underwent TE at 1 year after kidney transplantation (group 1), and the remaining 18 did not undergo TE (group 2). Results: The rate of histological IgAN recurrence was significantly lower in group 1 than in group 2 (11.1 vs. 55.6%, log-rank p = 0.046). In addition, half of the recurrent patients in group 2 exhibited active lesions, compared to none in group 1. Serum Gd-IgA1 levels decreased after TE in group 1, whereas they remained stable or increased slightly in group 2. In the recurrent cases, IgA and Gd-IgA1 were found in the germinal center in addition to the mantle zone of tonsils. Finally, mesangial IgA and Gd-IgA1 immunoreactivity was reduced after TE in some cases. Conclusion: Our data suggest that TE at 1 year after kidney transplantation might be associated with the reduced rate of histological IgAN recurrence. TE arrested or reduced serum Gd-IgA1 and mesangial Gd-IgA1 immunoreactivity. Therefore, we generated a hypothesis that serum Gd-IgA1 derived from the tonsils may play a pivotal role in the pathogenesis of IgAN. Based on these findings, we need to conduct verification in a prospective randomized controlled trial.

Sialomucin CD34 is the major L-selectin ligand in human tonsil high endothelial venules.

Peripheral node addressin (PNAd) is a complex mixture of glycoproteins with L-selectin ligand activity that functions in lymphocyte homing. We have investigated the contribution of the sialomucin CD34 relative to other components of PNAd in lymphocyte tethering and rolling in in vitro laminar flow assays. PNAd was isolated with MECA-79 mAb-Sepharose from tonsillar stroma, and the CD34 component (PNAd,CD34+) and CD34-negative component (PNAd,CD34-) separated on CD34 mAb-Sepharose. Lymphocytes on the PNAd,CD34- fraction tether less efficiently, roll faster and are less resistant to shear detachment than on PNAd. The PNAd,CD34+ fraction constitutes about half the total functional activity. These studies show that CD34 is a major functional component of PNAd. Ligand activity in both the PNAd,CD34+ and PNAd,CD34- fractions is expressed on mucin-like domains, as shown with O-sialoglycoprotease. The CD34 component of PNAd has about four times higher tethering efficiency than total tonsillar CD34. CD34 from spleen shows no lymphocyte tethering. Although less efficient than the PNAd,CD34+ fraction from tonsil, CD34 from the KG1a hematopoietic cell line is functionally active as an L-selectin ligand despite lack of reactivity with MECA-79 mAb, which binds to a sulfation-dependent epitope. All four forms of CD34 are active in binding to E-selectin. KG1a CD34 but not spleen CD34 are active as L-selectin ligands, yet both lack MECA-79 reactivity and possess E-selectin ligand activity. This suggests that L-selectin ligands and E-selectin ligands differ in more respects than presence of the MECA-79 epitope.

In vitro culture of equine respiratory mucosa explants.

An in vitro model of the upper respiratory tract of the horse was developed to investigate mechanisms of respiratory diseases. Four tissues of the upper respiratory tract of three horses were collected. Explants were maintained in culture at an air-liquid interface for 96h. At 0, 24, 48, 72 and 96h of cultivation, a morphometric analysis was performed using light microscopy, scanning electron microscopy and transmission electron microscopy. The explants were judged on morphometric changes of epithelium, basement membrane and connective tissue. Viability was evaluated using a fluorescent Terminal deoxynucleotidyl transferase-mediated dUTP Nick End Labelling (TUNEL) staining. No significant changes in morphometry and viability of any of the explants were observed during cultivation. Hence, the in vitro model may be useful to study infectious and non-infectious diseases at the level of the equine respiratory tract, with potential application to the development of vaccines and treatments for diseases of the respiratory tract.

Administration of Tonsil-Derived Mesenchymal Stem Cells Improves Glucose Tolerance in High Fat Diet-Induced Diabetic Mice via Insulin-Like Growth Factor-Binding Protein 5-Mediated Endoplasmic Reticulum Stress Modulation.

Type 2 diabetes mellitus (T2DM) is a prevalent chronic metabolic disorder accompanied by high blood glucose, insulin resistance, and relative insulin deficiency. Endoplasmic reticulum (ER) stress induced by high glucose and free fatty acids has been suggested as one of the main causes of ß-cell dysfunction and death in T2DM. Stem cell-derived insulin-secreting cells were recently suggested as a novel therapy for diabetes. In the present study, we demonstrate the therapeutic potential of tonsil-derived mesenchymal stem cells (TMSCs) to treat high-fat diet (HFD)-induced T2DM. To explore whether TMSC administration can alleviate T2DM, TMSCs were intraperitoneally injected in HFD-induced T2DM mice once every 2 weeks. TMSC injection markedly improved glucose tolerance and glucose-stimulated insulin secretion and prevented HFD-induced pancreatic ß-cell hypertrophy and cell death. In addition, TMSC injection relieved the ER-stress response and preserved gene expression related to glucose sensing and insulin secretion. Moreover, administration of TMSC-derived conditioned medium induced similar therapeutic outcomes, suggesting paracrine effects. Finally, proteomic analysis revealed high secretion of insulin-like growth factor-binding protein 5 by TMSCs, and its expression was critical for the protective effects of TMSCs against HFD-induced glucose intolerance and ER-stress response in pancreatic islets. TMSC administration can alleviate HFD-induced-T2DM via preserving pancreatic islets and their function. These results provide novel evidence of TMSCs as an ER-stress modulator that may be a novel, alternative cell therapy for T2DM.

Altering the gag reflex via a palm pressure point.

BACKGROUND: The gag reflex regularly interferes with dental procedures. The authors hypothesize that applying pressure to a specific point on the palm alters the gag reflex and that hypersensitive gag reflexes may be categorized according to oropharyngeal landmarks. METHODS: Thirty-six neurologically intact subjects underwent a series of gag reflex trials (baseline, sham and treatment). The authors developed a hand pressure device for subjects to wear, which provided a consistent force, and they described a gag trigger point index (GTPI) scale. On the basis of the GTPI, they divided subjects into a hypersensitive group and an expected-sensitivity (control) group. RESULTS: The trigger point of the gag reflex moved posteriorly in all subjects as a result of pressure to the palm point. Statistical results from repeated measures analysis of variance support the GTPI baseline data, and group assignments helped predict mean GTPI scores across conditions. The authors noted a significant treatment-group interaction effect, which indicated that the difference in mean GTPI responses between the hypersensitive and expected-sensitivity groups depended on the treatment being used. CONCLUSIONS: The authors introduce a treatment involving the stimulation of a pressure point that consistently altered the gag reflex trigger. The results of the study show the need for a more detailed, systematic approach to studying the hypersensitive gag reflex. CLINICAL IMPLICATIONS: The change in trigger point in the hypersensitive group represented a functional gain. Application of the pressure point during dental procedures would decrease the likelihood of triggering a gag reflex.

Correlation between Brodsky Tonsil Scale and Tonsil Volume in Adult Patients.

PURPOSE: To evaluate the value of Brodsky tonsil scale in predicting the objective tonsil volume and to identify the potential factors that might interfere with the accuracy of prediction. METHODS: A total of 87 adult patients who underwent single tonsillectomy or uvulopalatopharyngoplasty (UPPP) procedure including tonsillectomy in our hospital between Jan 2015 and Dec 2016 were included. The data of Brodsky tonsil scale evaluated preoperatively and objective tonsil volume evaluated postoperatively were collected for analysis. RESULTS: Among the 87 adult patients included, 85 patients underwent bilateral tonsillectomy, while only 2 underwent unilateral procedure. Therefore, a total of 172 tonsils were included. Significant positive correlations were established between Brodsky scale and objective volume for either right (R = 0.647), left (R = 0.664), or overall tonsils (R = 0.654) (all p < 0.001). However, volume overlaps could be found between 2+ and 3+ tonsils. Age [odds ratio (OR) = 4.053, p = 0.003] and body mass index (BMI; OR=1.740, p = 0.044) were found to be independent factors that could influence the consistency between the Brodsky scale and objective volume. As a result, a formula "Index = -1.409+1.399×age+0.554×BMI" was constructed for the evaluation of the consistency. CONCLUSION: Tonsil grading was significantly correlated with tonsil volume; preoperative tonsil grading that reflected the real tonsil volume was regarded as the protocol for the evaluation of the tonsil size. Age and BMI were independent factors that could affect the consistency between tonsil grade and tonsil volume. A mathematical model was estimated to predict the consistency accurately.

Relationships between the obstructive character of the tonsils and the type of ventilation and lip posture.

INTRODUCTION: The role of obstructive tonsils in ventilatory disorders and abnormal lip posture is widely discussed in the literature but remains controversial. The data reported on the probable relationship between obstructive tonsils and an existing breathing disorder or lip incompetence were subjective. The purpose of this study was to evaluate the relationship between the obstructive character of the tonsils and the type of ventilation and lip posture. MATERIALS AND METHODS: This is a cross-sectional study performed in children aged from 6 to 12 years old. The subjects were divided into two groups (A and B) according to the obstructive or non-obstructive character of the palatal tonsils. Type of ventilation and lip posture at rest were recorded for each child. The collected data were analysed using the SPSS 20.0 software (for Windows). A Student's t-test and a Chi2 test were respectively used to compare quantitative and qualitative variables according to the obstructive character of the tonsils for each group. The level of significance is fixed at P=0.05. RESULTS: The subjects in group B with obstructive palatal tonsils were significantly more likely to oral breathing and lip incompetence than the subjects with non-obstructive tonsils (group A). CONCLUSION: The clinical examination of children with ventilatory and postural disorders with lip incompetence must be directed towards the search for associated obstructive palatal tonsils in order to plan an early etiological treatment. This would allow to avoid subsequent problems in the dentofacial structures.

Pulsating Tonsil Due to Medial Displacement of the Internal Carotid Artery.

BACKGROUND The internal carotid artery (ICA) is about 2.5 cm away from the tonsils. It has no branches in the cervical portion. ICA anomalies of the neck zone may result in a massive arterial bleeding during pharynx and neck surgery. Due to these anomalies, the surgeon must be aware of this risk during tonsillectomy, adenoidectomy, and pharyngeal operations.  CASE REPORT A 23-year-old woman who was discovered to have an acute S curling-type anomaly of the ICA in contact with the lateral border of the right tonsil during a work-up for a tonsillectomy. This anomaly was incidentally discovered via computed tomography (CT) with contrast. In re-evaluating the course of treatment, we found a severe S-shape kink on the right side, bringing it close to the right tonsil by approximately 2 mm, and putting it at severe risk of injury during a simple tonsillectomy, possibly exposing the patient to serious bleeding. Partial tonsillectomy was performed for this patient with the aim to preserve and not expose the internal carotid artery. Pulsation of right tonsil was recorded. The patient made an uneventful postoperative recovery. CONCLUSIONS Undetected ICA anomaly variation can lead to fatal bleeding during a simple procedure, like tonsillectomy. We recommend vigilance during tonsillectomy if one is using a hot dissection method versus a cold dissection method, which may allow for detection of a perioperative ICA anomaly. Tonsillectomy performed by a junior resident should be under direct supervision, particularly if the hot dissection method is used.

Predicting the effect of treatment in paediatric OSA by clinical examination and functional respiratory imaging.

OBJECTIVE: The aim of this study was to investigate whether functional respiratory imaging (FRI) or clinical examination could predict treatment outcome for obstructive sleep apnea (OSA) in normal-weight, non-syndromic children. METHODS: Normal weight children diagnosed with OSA by polysomnography were prospectively included. All children got a thorough evaluation and an ultra-low dose computed tomography scan of the upper airway (UA). A 3-D reconstruction was built combined with computational fluid dynamics for FRI. Decisions on the need and type of surgery were based upon findings during drug-induced sleep endoscopy. A second polysomnography was performed 3-12 months after surgery. RESULTS: Ninety-one children were included: 62 boys, 5.0 ± 2.7 years, and BMI z-score of -0.1 ± 1.2. Children with more severe OSA had a smaller volume of the overlap region between the adenoids and tonsils. Nineteen out of 60 patients had persistent OSA (oAHI >2/h). A lower conductance in the UA and a higher tonsil score predicted successful treatment. CONCLUSIONS: A less constricted airway, as characterized by both FRI and a lower tonsil score, was associated with a less favorable response to (adeno) tonsillectomy. Further studies after treatment using FRI and DISE are warranted to further characterize the UA of these subjects.

Therapeutic potential of tonsil-derived mesenchymal stem cells in dextran sulfate sodium-induced experimental murine colitis.

The therapeutic potential of tonsil-derived mesenchymal stem cells (TMSC) prepared from human tonsillar tissue has been studied in animal models for several diseases such as hepatic injury, hypoparathyroidism, diabetes and muscle dystrophy. In this study, we examined the therapeutic effects of TMSC in a dextran sulfate sodium (DSS)-induced colitis model. TMSC were injected in DSS-induced colitis mice via intraperitoneal injection twice (TMSC[x2]) or four times (TMSC[x4]). Control mice were injected with either phosphate-buffered saline or human embryonic kidney 293 cells. Body weight, stool condition and disease activity index (DAI) were examined daily. Colon length, histologic grading, and mRNA expression of pro-inflammatory cytokines, interleukin 1ß (IL-1ß), IL-6, IL-17 and tumor necrosis factor α, and anti-inflammatory cytokines, IL-10, IL-11 and IL-13, were also measured. Our results showed a significant improvement in survival rates and body weight gain in colitis mice injected with TMSC[x2] or TMSC[x4]. Injection with TMSC also significantly decreased DAI scores throughout the experimental period; at the end of experiment, almost complete reversal of DAI scores to normal was found in colitis mice treated with TMSC[x4]. Colon length was also significantly recovered in colitis mice treated with TMSC[x4]. However, histopathological alterations induced by DSS treatment were not apparently improved by injection with TMSC. Finally, treatment with TMSC[x4] significantly reversed the mRNA levels of IL-1ß and IL-6, although expression of all pro-inflammatory cytokines tested was induced in colitis mice. Under our experimental conditions, however, no apparent alterations in the mRNA levels of all the anti-inflammatory cytokines tested were found. In conclusion, our findings demonstrate that multiple injections with TMSC produced a therapeutic effect in a mouse model of DSS-induced colitis.

[Tonsillectomy in 2005]. / L'amygdalectomie en 2005.

During the past years, the number of tonsillectomies (only palatine tonsils are taken off) has decreased, indications for surgery have changed. A multi-disciplinal group of paediatricians tried to elaborate the state of the art in the field. Tonsils are the first line defense of high respiratory tract. The immune functions of their lymphoid tissue are multiple: mucosal antigens capture, presentation to lymphocytes, antigens specific proliferation of lymphocytes T and B, differentiation of lymphocytes in effectors lymphocytes and immune lymphocytes. Epithelial cells on the tonsils' surface express non-specific defense. These facts explain partly tonsils' hypertrophy. Tonsillectomy has no general immune consequences. In 2002, in France, 75,000 tonsillectomies were realized, of which 90% were in children. Tonsil's hypertrophy is the major indication, mandatory when sleep apnoeas exist. The main historical tonsillectomy indication for recurrent tonsillitis should decrease due to a more precise diagnostic (rapid test at bed site), an efficient antibiotics therapy and better care for pain. Other indications are scarce. Surgery, feasible from 9 months of age, requires a brief general anaesthesia and has very few contra-indications. The technique, operator dependent, relies on his experience. The only potentially severe complication is an haemorrhage due to scab fall between the eighth and twelfth days. It requires explanation and a written note given to parents. The possibility of lack of feeding and voice modification, usually transitory, should be known. Multiple consequences of tonsillectomy especially allergy have been alleged. Since the years 1980, it is well established that pre-existing allergy or asthma are not a contraindication. More, its deleterious impact on allergic children has not been demonstrated. Last, a gain of weight post-tonsillectomy is possible and could become a risk if excessive.

Centrocytoid plasma cells of the germinal center.

Germinal centers within the lymph node follicles are T-cell-dependent, antigen-driven B-cell proliferations that develop from the rapid clonal expansion of a few founder cells. The end results of this B-cell expansion are memory B cells or plasma cells. Two morphologic forms of plasma cell can be recognized in the germinal center: classic plasma cells, characterized morphologically by peripherally clumped arrangement of nuclear chromatin, and cells with a nuclear morphology more resembling that of the centrocytes, which the authors have termed "centrocytoid plasma cells." In this study the authors examined the distribution and immunohistochemical characteristics of these two populations of germinal center plasma cells. The centrocytoid plasma cells were arranged in a band stretching from the junction of the dark and light zone to the periphery of the germinal centers, while the classic plasma cells were mainly present at the germinal center periphery. Both marked with CD38, CD138, and VS38c, recognized markers for plasma cells; however, EMA and CD31 were present only in the classic form of plasma cell. The proliferation marker Ki67 was present in less than 1% of the cells labeling with CD138. Others have demonstrated Ki67 in 50% of the cells labeled with Blimp-1, which is consistent with Blimp-1 appearing earlier than CD138 in ontogeny. CD10 is co-expressed with CD138 in about 10% of cells and CD45 with CD138 in about 5% of cells. Their topographic features, together with the progressive acquisition of plasma cell markers, suggest that the centrocytoid plasma cells may be the precursors of the classic plasma cells. Of note, both the forms of plasma cell were absent in follicles of follicular lymphoma, which supports the concept that in this disease, lymphocytes fail to differentiate and mature beyond the centrocyte stage.

Ultrastructure of the human palatine tonsil and its functional significance.

The human palatine tonsils represent a mucosa-associated lymphoid tissue with a significant function in mucosal protection against alimentary and airborne pathogens. The ultrastructure of different morphological compartments in the human palatine tonsil was studied in eighteen tonsils obtained from the patients who had undergone elective tonsillectomy due to chronic tonsillitis. The tonsillar specimens were analyzed by scanning and transmission electron microscopy. The results showed the presence of tight junctions between superficial epithelial cells of the oropharyngeal tonsillar surface. The crypt epithelium is a sponge-like structure infiltrated by non-epithelial cells, mostly lymphocytes, and is characterized by the presence of small pores - microcrypts occupied by large microvillus cells and/or lymphocytes. Antigen-presenting Langerhans cells with typical intracytoplasmic Birbeck granules were also found in the crypt epithelium. The lymphoid follicles are composed of lymphocytes and two types of non-lymphoid follicular cells: small fibroblast-like cells and large cells, morphologically consistent with antigen-bearing follicular dendritic cells or macrophages. The interfollicular areas consisted of a dense network of reticular cells and reticular fibers; many lymphocytes were interspersed between the reticular fibers. In addition to arterioles and high endothelial venules in the interfollicular lymphoid tissue, some fenestrated capillaries were seen intraepithelially and subepithelially. The complex ultrastructure of the human palatine tonsil provides a microenvironment necessary for antigen uptake, antigen processing and immune response.