Structural and immunological characteristics of chronically inflamed adenotonsillar tissue in childhood

Adenoid Hypertrophy and Endoscopic Adenoidectomy in Adults: Our Experience

Adenoid tissue is considered as first line immunological defence mechanism in childhood. Adenoid hypertrophy in children is a common cause of nasal obstruction. It usually gets atrophied by puberty. Adenoid hypertrophy persisting in adults is a cause of nasal obstruction. A randomized prospective study was conducted on adult patients aged above 20 years of age presenting with bilateral nasal obstruction at a tertiary care hospital, for duration of 20 months from January 2018 to August 2019.The differential diagnosis of adenoid hypertrophy was evaluated and role of endoscopic adenoidectomy was studied. The various associated causes of adenoid hypertrophy in adults showed previous history of adeno-tonsillectomy, allergy, deviated nasal septum and smoking. In all cases endoscopic assisted adenoidectomy was performed. Post adenoidectomy patients were asymptomatic in 21 cases, partial improvement in 6 cases and failure in 3 cases. Enlarged adenoid in adults should be considered in the differential diagnosis of cases suffering from bilateral nasal obstruction, or presenting as a nasopharyngeal mass with aural problems. Endoscopic adenoidectomy is safe and reliable. The nasal endoscope aids in removal of adenoid completely with good haemostasis, without any injury to Eustachian tube.

Role of Tonsillar Chronic Inflammation and Commensal Bacteria in the Pathogenesis of Pediatric OSA

Immune responses at the boundary between the host and the world beyond are complex and mucosal tissue homeostasis relies on them. Obstructive sleep apnea (OSA) is a syndrome suffered by children with hypertrophied tonsils. We have previously demonstrated that these tonsils present a defective regulatory B cell (Breg) compartment. Here, we extend those findings by uncovering the crucial role of resident pro-inflammatory B and T cells in sustaining tonsillar hypertrophy and hyperplasia by producing TNFα and IL17, respectively, in ex vivo cultures. Additionally, we detected prominent levels of expression of CD1d by tonsillar stratified as well as reticular epithelium, which have not previously been reported. Furthermore, we evidenced the hypertrophy of germinal centers (GC) and the general hyperplasia of B lymphocytes within the tissue and the lumen of the crypts. Of note, such B cells resulted mainly (IgG/IgM)⁺ cells, with some IgA⁺ cells located marginally in the follicles. Finally, by combining bacterial culture from the tonsillar core and subsequent identification of the respective isolates, we determined the most prevalent species within the cohort of OSA patients. Although the isolated species are considered normal oropharyngeal commensals in children, we confirmed their capacity to breach the epithelial barrier. Our work sheds light on the pathological mechanism underlying OSA, highlighting the relevance taken by the host immune system when defining infection versus colonization, and opening alternatives of treatment.

Comparative clinicopathological aspects of chronic tonsillitis and adenoiditis in children

Chronic palatal and nasopharyngeal inflammations are common lesions in pediatric pathology, with major effects on children’s development. The study included 34 cases of chronic tonsillitis and adenoiditis for which we quantified immunohistochemically and analyzed the distribution of inflammatory elements in the follicular, extrafollicular and epithelial compartments, in relation to the composite histological scores and the clinico-epidemiological profile of the lesions. The cases were more frequent under the age of 10, in female patients, coming from urban areas, with the diagnosis of tonsillitis. B-lymphocytes have been associated with follicular areas in tonsillitis and epithelial areas in adenoiditis. In all compartments, T-lymphocytes were more frequently associated with tonsillitis and plasma cells associated with adenoiditis. Macrophages and dendritic cells had a relatively uniform distribution for the three compartments in all cases. The results obtained indicate different inflammatory phenotypes for chronic tonsillitis and adenoiditis, an aspect that may be useful for stratifying patients for optimal therapy.

Selected cytokines in hypertrophic adenoids in children suffering from otitis media with effusion

OBJECTIVES

The aim of the current study was to assess the levels of MMP-8, MMP-9 and TIMP-1 in the group of children with adenoids who suffered from exudative otitis media.

METHODS

The study included 20 patients (10 females and 10 males) with adenoid hypertrophy coexisting with otitis media with effusion. The reference group included 24 patients (10 females and 14 males) with adenoid hypertrophy without otitis media. The levels of MMP-8, MMP-9 and TIMP-1 were determined in supernatants obtained from phytohemagglutinin (PHA)-stimulated cell cultures of the tonsils, using commercial enzyme-linked immunosorbent assay kits (R@D Systems, USA).

RESULTS

The median MMP-8, MMP-9 and TIMP-1 concentrations (220.8 ng/mL, 311.1 ng/mL, 53.5 ng/mL, respectively) in the study group were significantly higher (p = 0.000, p = 0.000, p = 0.048, respectively) than those in the reference group (93.5 ng/mL, 112.5 ng/mL, 36.95 ng/mL, respectively). ROC analysis revealed that the area under a curve (AUC) for both metalloproteinases MMP-8 and MMP-9 was 1 with a diagnostic sensitivity of 100% and diagnostic specificity of 95.8%, as compared to 0.690 for TIMP-1. Significant differences were found between the AUC for MMP-8 and TIMP-1 and MMP-9 and TIMP-1 (p < 0.001 for both comparisons).

CONCLUSIONS

The changes in the concentrations of MMP-8, MMP-9 and TIMP-1 may indicate an increased remodeling of the extracellular matrix in children with adenoid hypertrophy and otitis media with effusion. The findings can have clinical as well as diagnostic utility. Determination of MMP-8 and MMP-9 may help qualify a child for adenoidectomy and differentiate pediatric patients affected by adenoid hypertrophy with and without otitis media.

Impact of adenotonsillectomy on the evolution of inflammatory markers

BACKGROUND

Tonsils are first-line host defence organs against pathogenic agents and participate in local and systemic immunity. Persistent increases in systemic inflammatory responses may contribute to associated morbidity. The aim of this study was to verify the short- and long-term impact of adenotonsillectomy on the evolution of inflammatory markers in 3- to 9-year-old children.

METHODS

A prospective and longitudinal study was conducted over 1 year in 29 children who underwent tonsillectomy due to either chronic tonsillitis or adenotonsillar hypertrophy. Measurements of high-sensitivity C-reactive protein (hs-CRP) levels were taken. Levels of Th1-type cytokines [interleukin-1, interferon-γ, and tumor necrosis factor-α (TNF-α)] and anti-inflammatory Th2-type cytokines [interleukin-4, -5, -6, -10 and -13] were measured. Levels of transforming growth factor-beta (TGF-β) and intercellular adhesion molecule-1 (ICAM-1) were also determined. The results were compared to those of 29 control children.

RESULTS

At baseline, children with surgery indications presented with higher levels of hs-CRP, interleukin-1 and -10, interferon-γ, TNF-α and ICAM-1, whereas values of interleukin-4 were significantly lower than in control children. Children with severe tonsillar obstruction had higher values of interleukin-1, -4, and -5 and lower values of interleukin-10 compared with children with recurrent tonsillitis. One year after surgery, the levels except IL-4 did not show a significant difference from those obtained in the control group. The levels of hs-CRP and TNF-α decreased significantly in the first month.

CONCLUSION

Children with chronic tonsillitis and/or adenotonsillar hypertrophy have significantly elevated levels of proinflammatory cytokines. Adenotonsillectomy restores the normal values of these parameters 1 year after surgery.

Tonsil-derived stem cells as a new source of adult stem cells

Located near the oropharynx, the tonsils are the primary mucosal immune organ. Tonsil tissue is a promising alternative source for the high-yield isolation of adult stem cells, and recent studies have reported the identification and isolation of tonsil-derived stem cells (T-SCs) from waste surgical tissue following tonsillectomies in relatively young donors (i.e., under 10 years old). As such, T-SCs offer several advantages, including superior proliferation and a shorter doubling time compared to bone marrow-derived mesenchymal stem cells (MSCs). T-SCs also exhibit multi-lineage differentiation, including mesodermal, endodermal (e.g., hepatocytes and parathyroid-like cells), and even ectodermal cells (e.g., Schwann cells). To this end, numbers of researchers have evaluated the practical use of T-SCs as an alternative source of autologous or allogenic MSCs. In this review, we summarize the details of T-SC isolation and identification and provide an overview of their application in cell therapy and regenerative medicine.

Glutathione S-transferase enzyme activity and protein expression in patients with recurrent tonsillitis and idiopathic tonsillar hypertrophy

OBJECTIVES

The palatine tonsil is a significant part of the secondary immune system. Tonsillitis and idiopathic tonsillar hypertrophy (ITH) are the most common pathologies of this component. Although there are studies on their pathogenesis, there is insufficient study of the role of antioxidant agents. Glutathione S-transferase (GST) isozymes contribute to the antioxidation reactions in the tissue via the glutathione pathway. The purpose in this study was to reveal the levels of the GST enzyme activity and protein expression of GSTP1 and GSTA1 isozymes in patients with tonsillitis and tonsil hypertrophy, and to investigate their role in the pathogenesis of these diseases.

MATERIALS AND METHODS

Sixteen patients with recurrent tonsillitis and 5 patients with ITH and were included in the study. Cytosolic extracts were prepared from post-tonsillectomy tissues of both patient groups and GST enzyme activities were measured.

RESULTS

The expression of GSTP1 was found to be significantly higher than GSTA1 in tissue samples of patients with ITH and recurrent tonsillitis (P<0.001). Increased GST activity and GSTP1 isozyme expression were shown in patients with recurrent tonsillitis compared to the idiopathic tonsillar hypertrophy study group. There was a positive correlation between the expressions of GSTP1 (P=0.040; r=0.47).

CONCLUSION

Increased GST activity and GSTP1 isozymes were demonstrated histologically in the pathogenesis of ITH and recurrent tonsillitis. We believe that the data of changes in antioxidant capacity, obtained from studies with more extensive and larger samples, would support our findings.

[Proinflammatory cytokine content in the saliva of children suffering from chronic tonsillitis]

INTRODUCTION

We have examined 92 children aged between 6 and 15, suffering from chronic tonsillitis (CT). Tumor necrosis factor (TNF-α) and interleukin 1β and 6 (IL-1β and IL-6) contents have been defined in saliva. The control set comprised 17 healthy children. Cytokine content was defined with the enzyme multiplied immunoassay sets (Vektor Best Ltd., Russia) by enzyme-linked immunosorbent assay. The statistic analysis and data processing were carried out with statistic analysis programs (version 3.2, R Foundation for Statistical Computing, Vienna, Austria).

RESULTS

The content of cytokines TNF-α, IL-1, IL-6 in CT children's saliva was high against the healthy children, yet the statistically significant differences were only noted for IL-6. In the CT group the median value of this factor (12.5) was significantly higher than in the control set (6.72) (p=0.01 in Mann-Whitney assessment). IL-6 was chosen as the basic factor for the mathematic model; its combinations in the form of a multi-factor logistic regression were given consideration. From out of the three possible models there was just one that had all the coefficients statistically significantly different from zero (TNF-α - IL-6). It was chosen as the basic diagnostic model for chronic tonsillitis. The created model's sensitivity is 80.4%, while its specificity is 82.4%.

DISCUSSION

The revealed IL-6 dominance in saliva at CT can be is attributable to permanent antigenic challenge characteristic of the toxic allergic CT since, as previously shown, there are living proliferating microorganisms in the palatal tonsil tissues and their blood- and lymph vessels at CT.

CONCLUSION

The conducted ROC-analysis has demonstrated high sensitivity and specificity of the mathematical model, which enabled us to recommend determination of IL-6 in the saliva of the children suffering from CT as an additional diagnostic criterion.

Paediatric obstructive sleep apnoea syndrome (OSAS) is associated with tonsil colonisation by Streptococcus pyogenes

The involvement of pathogenic bacteria in obstructive sleep apnoea syndrome (OSAS) has yet to be elucidated. We investigated the possible role of group A streptococcus (GAS) in OSAS pathogenesis. In 40 tonsillectomized patients affected by OSAS and 80 healthy controls, significant (p < 0.0001) association of GAS with paediatric OSAS was found. Supernatant from streptolysin O (SLO)-producing GAS induced production of cysteinyl leukotrienes (CysLTs) in tonsil mononuclear cells (TMCs). CysLTs-treated TMCs showed significant (p < 0.05) proliferation of CD4+ T, CD19+ and CD19+CD27+CD38+ B lymphocytes. We discovered a SLO-dependent activation of CysLTs production through a pathway involving TOLL-like receptor 4 (TLR4), TIR-domain-containing adapter-inducing interferon-β (TRIF), Myeloid differentiation primary response gene 88 (MyD88), and p38 MAP Kinase. In conclusion, we hypothesise that GAS may contribute to paediatric tonsillar hyperplasia through CysLTs production induced by SLO, and this might explain its association with OSAS.

Quantification of cells expressing markers of proliferation and apoptosis in chronic tonsilitis

During chronic tonsillitis, the relationship between proliferation and apoptosis of lymphocytes in tonsillar follicles can be disturbed, which gives rise to attenuation of tonsil immunocompetence and diminishing its contribution in systemic immunity. In this study, we have quantified the cells expressing the markers of proliferation and apoptosis in the follicles of the palatine tonsil. Six tonsils from patients aged 10-29 years with hypertrophic tonsillitis and five tonsils from patients aged 18-22 years with recurrent tonsillitis were studied. The sections of paraffin blocks of tonsillar tissue were stained by the immunohistochemical LSAB/HRP method with the utilisation of antibodies for: Ki-67 antigen-cell marker of proliferation; Bcl-2 and survivin anti-apoptotic factors and Fas/CD95, caspase-3 and Bax pro-apoptotic factors. The size of lymphoid follicles, i.e. mean follicle area and number of lymphoid follicle immunopositive cells per mm2 of a slice area, i.e. numerical areal density were determined by the quantitative image analysis. The localisation of Ki-67, Bcl-2, survivin, Fas/CD95, caspase-3 and Bax- immunopositive cells inside the palatine tonsil was similar in both types of tonsillitis. The number of Ki-67 immunopositive cells was significantly (p < 0.01) larger in the tonsils with hypertrophic tonsillitis (14681.4 ± 1460.5) in comparison to those with recurrent tonsillitis (12491.4 ± 2321.6), although the number of survivin and caspase-3 immunopositive cells was significantly (p < 0.05) larger in recurrent tonsillitis (survivin, 406.9 ± 98.4; caspase-3, 350.4 ± 119.4) when compared to those with hypertrophic tonsillitis (survivin, 117.4 ± 14.5; caspase-3, 210 ± 24). Our results show that the rate of the proliferation and apoptosis of follicular lymphocytes is different in various types of tonsillitis. This suggests that the immunological potential of the palatine tonsil varies in patients with hypertrophic and recurrent tonsillitis, which in practice poses a dilemma over the choice of conservative or surgical treatment.

Immunoregulatory cytokines and chronic tonsillitis

The purposes of the present study were to determine the distribution of cells producing cytokines: tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) in different morphological sections of tonsils in patients with tonsillar hypertrophy (TH) and recurrent tonsillitis (RT), to analyze the level of production of these cytokines in TH and RT and evaluate the potential of peripheral blood lymphocytes for production of interferon-γ (IFN-γ) and interleukin 4 (IL-4). Analyzed materials consisted of the tonsils after tonsillectomy and blood taken from patients right before tonsillectomy (study group) and blood taken from healthy donors (control group).We used histological and immunohistochemical method, morphometric methods for the quantification of TNF-α and IL- 6 producing cells and immunological methods for determining the concentration of IFN-γ and IL-4. Most of TNF-α producing cells are settled in the subepithelial region (55%). Numerical density of TNF-α producing cells in the crypt epithelium, subepithelial and interfollicular region was significantly higher in RT compared with TH. The concentration of IFN-γ is three times higher in RT then in TH. After the stimulation of peripheral blood lymphocytes in culture there was no significant increase in concentrations of IL- 4. The index of stimulation of IFN-γ was the highest in the RT, and of IL- 4 in TH. The production of Th1-type cytokines (TNF-α and IFN-γ) is higher in RT compared with TH. In both forms of tonsillitis, production of Th1-type cytokines is higher in relation to the production of Th2-type cytokines (IL-6 and IL-4).

A pro-inflammatory role for nuclear factor kappa B in childhood obstructive sleep apnea syndrome

STUDY OBJECTIVES

Childhood obstructive sleep apnea syndrome (OSAS) is associated with an elevation of inflammatory markers such as C-reactive protein (CRP) that correlates with specific morbidities and subsides following intervention. In adults, OSAS is associated with activation of the transcription factor nuclear factor kappa B (NF-kB). We explored the mechanisms underlying NF-kB activation, based on the hypothesis that specific NF-kB signaling is activated in children with OSAS.

DESIGN

Adenoid and tonsillar tissues from children with OSAS and matched controls were immunostained against NF-kB classical (p65 and p50) and alternative (RelB and p52) pathway subunits, and NF-kB-dependent cytokines: interleukin (IL)- 1α, IL-1β, tumor necrosis factor-α, and IL-8). Serum CRP levels were measured in all subjects. NF-kB induction was evaluated by a luciferase-NF-kB reporter assay in L428 cells constitutively expressing NF-kB and in Jurkat cells with inducible NF-kB expression. p65 translocation to the nucleus, reflecting NF-kB activation, was measured in cells expressing fluorescent NF-kB-p65-GFP (green fluorescent protein).

SETTING

Sleep research laboratory.

PATIENTS OR PARTICIPANTS

Twenty-five children with OSAS and 24 without OSAS.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Higher expression of IL-1α and classical NF-kB subunits p65 and p50 was observed in adenoids and tonsils of children with OSAS. Patient serum induced NF-kB activity, as measured by a luciferase-NF-kB reporter assay and by induction of p65 nuclear translocation in cells permanently transfected with GFP-p65 plasmid. IL-1β showed increased epithelial expression in OSAS tissues.

CONCLUSIONS

Nuclear factor kappa B is locally and systemically activated in children with obstructive sleep apnea syndrome. This observation may motivate the search for new anti-inflammatory strategies for controlling nuclear factor kappa B activation in obstructive sleep apnea syndrome.

The role of matrix metalloproteinases in recurrent tonsillitis

OBJECTIVE

The aim of this study was to investigate the status of matrix metalloproteinases (MMP-2, MMP-7, MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) due to dysregulated turnover of connective tissue matrices in children with recurrent tonsillitis (RT).

METHODS

Forty-four patients with RT were enrolled in the study. All patients with RT were graded according to the hypertrophy degree of the tonsillar tissue from grade I to grade IV. Patients with grade I tonsillar hypertrophy and grade II tonsillar hypertrophy were accepted as group A, patients with grade III tonsillar hypertrophy and grade IV tonsillar hypertrophy were accepted as group B Tonsillectomy was performed via the usual dissection-snare method. Tonsillar specimens of superficial and core region were evaluated for MMP-2, MMP-7, MMP-9 and TIMP-1 analysis.

RESULTS

There was no statistical significance according to the MMP-2, MMP-7, MMP-9 and TIMP-1 activity of superficial part and core regions in both groups individually, MMP-9 level of both the superficial and core regions in group B had statistical significant higher results than group A (p=0.026, p=0.06 respectively). MMP-7 level of the superficial part in group B patients also had statistical significant higher results than group A (p=0.025). However, there was no statistical difference found between superficial and core region MMP-2 and TIMP-1 levels of group A and group B. Related to this, balance between MMP-7-9 and TIMP-1 activities tended to slip MMP-7 and MMP-9 sides with increased tonsillar grade.

CONCLUSIONS

Results from this study suggest that the presence of MMPs in tonsil tissue consolidates the involvement of degraded extracellular matrix proteins in the pathophysiology of chronic tonsillitis. MMPs activity showed diffuse dissemination in the tonsillar tissue and especially MMP-9 and MMP-7 are the main promoters of the extracellular matrix that responded to inflammatory changes in the tonsillar tissue. Further studies are needed concerning the possible efficiency of selective MMP inhibitors on tonsillar tissue.

Enzymatic study of tonsil tissue alkaline and acid phosphatase in children with recurrent tonsillitis and tonsil hypertrophy

OBJECTIVE

Indications for tonsillectomy in recurrent tonsillitis are defined according to the number of episodes of acute bacterial infections in a year. However, little is known about the tonsil immune competence status in patients presenting with recurrent tonsillitis with either hypertrophied or atrophied tonsils, or in patients presenting with obstructive sleep apnoea. In this study we examined the tonsil immune status in children with 3-5 acute recurrent infections a year and in children with obstructive sleep apnoea by comparing the activity of tonsil and adenoid tissue nonspecific alkaline and acid phosphatase.

METHODS

Specific activity of tonsil and adenoid tissue nonspecific alkaline and acid phosphatase was investigated in children who underwent tonsillectomy and adenoidectomy for recurrent infection (72 children) and for obstructive sleep apnoea (10 children). Tissue enzyme activities were measured using p-nitrophenylphosphate as a substrate. Tissue samples were examined by the haematoxylin-eosin histological technique. Statistical analyses were performed using SPSS v. 16 software.

RESULTS

The tissue nonspecific alkaline phosphatase activity was similar in hypertrophied tonsils in the recurrent infection group and in the obstructive sleep apnoea group (3.437+/-1.226 and 3.978+/-0.762 U/mg of protein, respectively). The enzyme activity in both hypertrophied tonsil groups was significantly higher as compared to atrophied tonsils in the recurrent tonsillitis group, p=0.021 and p=0.006, respectively. The enzyme activity was significantly higher in the adenoids compared to the tonsils from all three groups. Contrary to this, no significant differences were noticed for tonsil and adenoid acid phosphatase activities among the groups.

CONCLUSION

Similar acid phosphatase activity in all three groups implies that all three groups have preserved antigen presenting cell activity. In patients with hypertrophied tonsils similar tissue nonspecific alkaline phosphatase activity suggests preserved B cell tonsil immune activity, regardless of the pathology. Patients with atrophied tonsils had significantly lower alkaline phosphatase activity, indicating relative tonsil B cell immune deficiency. Thus, different immunological status in patients presenting with hypertrophied vs. atrophied tonsils could point to a different underlying pathophysiologic mechanism of the disease.

A mixed cell culture model for assessment of proliferation in tonsillar tissues from children with obstructive sleep apnea or recurrent tonsillitis

BACKGROUND

Recurrent infective tonsillitis (RI) and obstructive sleep apnea (OSA) are the major indications for adenotonsillectomy (T&A) in children. However, little is known on the determinants of lymphadenoid tissue proliferation in the pediatric upper airway.

OBJECTIVES

To develop an in vitro culture system allowing for assessment of tonsillar or adenoidal proliferation under basal or stimulated conditions.

METHODS

Tonsils surgically removed from pediatric patients with obstructive sleep apnea and recurrent tonsillitis during T&A, were dissociated using standard methods. Whole cell tonsillar cultures were either maintained in normal medium or stimulated with lipopolysaccharide (25 microg/mL) and concanavalin A (10 microg/mL) for 24 hours (stimulated conditions [STIM]). Cellular proliferation was evaluated by [3H]thymidine incorporation. In parallel, supernatants were collected after 48 hours, and concentration of cytokines was measured using standard enzyme-linked immunosorbent assay procedures.

RESULTS

Basal proliferative rates were increased in the OSA group (305.2 +/- 40.6 cpm; n = 31) compared to RI group (232.8 +/- 31.9 cpm; n = 26; P < .001). No significant differences in proliferative rates emerged after STIM between OSA and RI. Furthermore, basal TNF-alpha, IL-6, and IL-8 concentrations in the supernatant were increased in OSA-derived cultures compared to RI, but IL-8 was higher after STIM in RI, while IL-6 remained increased in OSA.

CONCLUSIONS

The proliferative rates and concentrations of inflammatory mediators in tonsillar cell cultures from children with OSA and RI suggest that lymphadenoid tissue proliferation in these two conditions may be regulated by different mechanisms. This novel method may allow for future development of specific therapeutic interventions aimed at curtailing and reversing tonsillar and adenoidal hypertrophy in children in a disease-specific manner.

Human palatine tonsil: a new potential tissue source of multipotent mesenchymal progenitor cells

INTRODUCTION

Mesenchymal progenitor cells (MPCs) are multipotent progenitor cells in adult tissues, for example, bone marrow (BM). Current challenges of clinical application of BM-derived MPCs include donor site morbidity and pain as well as low cell yields associated with an age-related decrease in cell number and differentiation potential, underscoring the need to identify alternative sources of MPCs. Recently, MPC sources have diversified; examples include adipose, placenta, umbilicus, trabecular bone, cartilage, and synovial tissue. In the present work, we report the presence of MPCs in human tonsillar tissue.

METHODS

We performed comparative and quantitative analyses of BM-MPCs with a subpopulation of adherent cells isolated from this lymphoid tissue, termed tonsil-derived MPCs (T-MPCs). The expression of surface markers was assessed by fluorescent-activated cell sorting analysis. Differentiation potential of T-MPCs was analyzed histochemically and by reverse transcription-polymerase chain reaction for the expression of lineage-related marker genes. The immunosuppressive properties of MPCs were determined in vitro in mixed lymphocyte reactions.

RESULTS

Surface epitope analysis revealed that T-MPCs were negative for CD14, CD31, CD34, and CD45 expression and positive for CD29, CD44, CD90, and CD105 expression, a characteristic phenotype of BM-MPCs. Similar to BM-MPCs, T-MPCs could be induced to undergo adipogenic differentiation and, to a lesser extent, osteogenic and chondrogenic differentiation. T-MPCs did not express class II major histocompatibility (MHC) antigens, and in a similar but less pronounced manner compared with BM-MPCs, T-MPCs were immunosuppressive, inhibiting the proliferation of T cells stimulated by allogeneic T cells or by non-specific mitogenic stimuli via an indoleamine 2,3-dioxygenase-dependent mechanism.

CONCLUSION

Human palatine T-MPCs represent a new source of progenitor cells, potentially applicable for cell-based therapies.

Adenoid hypertrophy in adults: clinical and morphological characteristics

This study compared the aetiology and pathological characteristics of adult and childhood adenoid hypertrophy (AH). Clinical and morphological features and accompanying otolaryngological pathologies were recorded in 40 adults and 23 children undergoing adenoidectomy for obstructive AH. Both AH forms were similar in terms of symptomatology and associated inflammations. There were, however, significant differences in otitis media rate, with effusion and dullness, and retraction in the eardrum both more prevalent in childhood AH. Adult AH was associated with nasal septum deviation in 25.0% of patients. Histopathological features of adenoidal lymphoid tissue were dissimilar in the two groups: numerous lymph follicles with prominent germinal centres was the chief finding in childhood adenoids, whereas adult adenoids showed chronic inflammatory cell infiltration and secondary changes (e.g. squamous metaplasia). These results underline the importance of considering AH as a cause or contributing factor in nasal obstruction and related pathologies in adults and supports the theory that it represents a long-standing inflammatory process rather than being a novel clinical entity.

Tonsillotomy or tonsillectomy?—a prospective study comparing histological and immunological findings in recurrent tonsillitis and tonsillar hyperplasia

We evaluated the differences in histological and immunological findings in children with recurrent tonsillitis and tonsillar hyperplasia and assessed the risk for relapsing tonsillar hyperplasia or recurrent tonsillitis after tonsillotomy in a prospective clinical study. Sixty-four children with recurrent tonsillitis underwent traditional (total) blunt dissection tonsillectomy between October 2003 and July 2004. Partial tonsillectomy (tonsillotomy) using CO(2)-laser technique was performed on 49 children with tonsillar hyperplasia and no history of recurrent tonsillitis between August 2003 and March 2005. The present study compares preoperative serum anti-streptolysin-O antibody and immunoglobulin levels (IgG, IgA and IgM), C-reactive protein levels (CRP) and blood leukocyte counts of the two study groups. Additionally the tonsillar tissue removed by tonsillotomy or tonsillectomy was histologically examined in order to determine the grade of hyperplasia, chronic inflammation and fibrosis. Furthermore, the grade of fresh inflammation within the tonsillar crypts of the specimens was analysed. The parents of 40 patients treated by laser tonsillotomy were surveyed in average 16 months. There was no statistically significant difference in preoperative serum anti-streptolysin-O antibody and immunoglobulin levels, C-reactive protein levels and blood leukocyte counts between the two study groups. All specimens showed the histological picture of hyperplasia. There was no statistically significant difference in the grades of hyperplasia between the two study groups. Signs of fresh but mild inflammation within the tonsillar crypts could be found in over 70% of both study groups. Fibrosis only occurred in children with recurrent tonsillitis (9%). In all specimens signs of chronic inflammation could be detected. The histological examinations of specimens from children with repeated throat infections more frequently showed a moderate chronic inflammation of the tonsillar tissue. Two of forty patients treated by tonsillotomy required a subsequent tonsillectomy due to a recurrence of tonsillar hyperplasia but no recurrent tonsillitis occurred. Tonsillotomy with CO(2)-laser technique is an effective surgical procedure with a long-lasting effect in patients with tonsillar hyperplasia. The benefits over conventional tonsillectomy are a lower risk for postoperative haemorrhage, reduced postoperative morbidity and accelerated recovery. Even in children with no history of recurrent tonsillitis signs of chronic inflammation histologically can be found in specimens after tonsillotomy. The occurrence of recurrent tonsillitis after tonsillotomy is rare, however. A low incidence of relapsing tonsillar hyperplasia after tonsillotomy should be expected. Preoperative laboratory investigations show few differences in patients with tonsillar hyperplasia and recurrent tonsillitis. Components of the antimicrobial defense system are also produced by chronically infected tonsils. Therefore tonsillotomy with CO(2)-laser could also be an option in some patients with mild symptoms of recurrent tonsillitis.

Toll-like receptor expression in the human nasopharyngeal tonsil (adenoid) and palantine tonsils: a preliminary report

OBJECTIVE

The Waldeyer's ring, comprised of the nasopharyngeal tonsil (adenoid), the paired tubal tonsils, the paired palantine tonsils, and the lingual tonsil, is arranged in a circular orientation around the wall of the throat. This orientation allows direct contact between the tissues of the Waldeyer's ring and inhaled or ingested material, which may contain potential antigenic substances. Previous studies involving the tissues of the Waldeyer's ring have been focused on the adaptive immune system, with little consideration toward the innate immune system. Since studies have demonstrated that the adenoids and tonsils are capable of producing proinflammatory cytokines, we postulate that toll-like receptors (TLRs), which recognize components of pathogenic organisms, may be involved in the immune response in these tissues. TLRs are innate pattern recognition receptors, which produce proinflammatory cytokines and chemokines upon ligation. In this pilot study, we address expression of TLRs, which are vital components of the innate immune system, in adenoid and tonsil tissue.

METHODS

To determine whether TLRs are expressed in the human adenoid and palantine tonsils, we utilized endpoint RT-PCR and real time RT-PCR. Endpoint PCR was performed on all tissue obtained from adenotonsillectomy patients. Real time RT-PCR was performed only on adenoid tissue.

RESULTS

All of the ten TLRs examined are expressed in the adenoid and tonsil tissue with varying band intensities. TLR3, TLR7, TLR8, and TLR9 expression is highly variable between patients.

CONCLUSIONS

TLRs are expressed in human adenoid and tonsil tissue, and may play a vital role in the immunological outcomes of these tissues.