The surface epithelium of recurrent infected palatine tonsils is rich in gammadelta T cells

Selected Immunohistochemical Assessment and Clinical Examinations in the Diagnosis of Palatine Tonsil Diseases

INTRODUCTION

The palatine tonsils are secondary lymphoid organs where immune processes occur, influencing the development of a targeted cellular and humoral response. The diseased tonsils are subject to immunological imbalances, including the activity of pro-inflammatory and anti-inflammatory factors. This leads to the development of palatine tonsil diseases, such as palatine tonsillitis and palatine tonsillar hypertrophy.

AIM

The main aim of the study was to evaluate the similarities and differences in the clinical and pathomorphological pictures of patients qualified for surgical treatment due to hypertrophy or inflammation of the palatine tonsils. The aim was achieved by demonstrating the relationship between the patient's medical history and physical examination and histopathological diagnosis of a given tonsillar disease, evaluating the usefulness of basic blood tests (leukocytosis, ASO, ESR, and CRP) in differential diagnosis, and assessing the immunohistochemical assessment of palatine tonsil tissue.

MATERIAL AND METHODS

The tonsils were stained with the following antibodies: IL-1, IL-2, IL-6, IL-8 IL-10, and IL-37 and CD25, CD40, and CD69, taking into account the histological division of the studied lymphatic tissue (epithelial, subepithelial, follicular, follicular center, and interfollicular). Patients aged between 19 and 70 years with tonsillitis or clinical signs of tonsillar hypertrophy were qualified for tonsillectomy/UPPP. Seventy-two males (68.6%) and thirty-three females (31.4%) were enrolled in the study. Histopathological and immunohistochemical assessment was performed on 105 palatine tonsils.

RESULTS

The diagnostic value of blood tests, including determination of ASO, ESR, CRP, and leukocyte level, proved to be a significant predictor of tonsil disease. In the pathomorphological assessment, 75% of the subjects who had simultaneously elevated ESR (>4.73) and leukocytosis (>6.96) and reduced ASO (<161.03) and CRP (<0.31) belonged to the tonsillitis group. The immunohistochemical assessment revealed a diverse profile of the markers tested depending on the diagnosed disease of the tonsils. The follicular center proved to be the region of palatine tonsil tissue for which the most statistically significant differences between the markers were found. Responses to CD-40 and IL-1 were observed in this region. The tissue of epithelial, follicular, and interfollicular regions each showed one statistically significant value for the studied chemokines and lymphokines. However, the lack of significant statistical differences for p < 0.05 between the study groups was only noted in the subepithelial region. It should be emphasized that for the data as a whole (calculated on the basis of the data for all regions together), no statistically significant differences were observed.

CONCLUSION

In conclusion, the results obtained are indicative of the presence of a specific immunohistochemical profile for palatine tonsil diseases. Significant discrepancies have been found in the clinical and pathomorphological assessment of tonsils qualified for tonsillectomy. Therefore, these methods should be considered complementary. The patient's medical history and physical examination, depending on the adopted clinical or histopathological classification, show a variation in the distribution of features that are the basis for allocation to a particular group.

Age-related changes of the innate immune system of the palatine tonsil in a healthy cohort

Although tonsillectomy is performed frequently, the role of palatine tonsils in life long immune protection or tolerance is still debated and the consequences of their removal for the immune system are of general interest. We analysed the tonsillar myeloid compartment in healthy subjects across a wide range of age (64% male; age range: 3 - 85 years) and compared its composition to the peripheral blood. We could observe a strong accumulation of all granulocyte subsets in the aging tonsil, which was most pronounced for basophils and mast cells. On functional level, an increase of CD163 and CD206 expression among monocytes and an increase of neutrophils expressing the inhibitory FcγRIIb correlated with increasing age. While the age-related shift of the leukocyte composition towards monocytes in blood is not reflected in tonsils, the increasing immunoregulatory phenotype of tonsilar monocytes is potentially counteracting the phenomenon of inflammaging at higher age.

Increased levels of S100A8/A9, IL-1ß and IL-18 as a novel biomarker for recurrent tonsillitis

Background

Acute tonsillitis represents one of the most frequent reasons patients seek primary medical care and otorhinolaryngology consultation. Therefore, recurrent episodes of acute tonsillitis (RAT), also called chronic tonsillitis, exhaust a substantial amount of medical and financial resources. Diagnosis of tonsillitis depends on a physical examination, which therefore does not allow for a reliable differentiation between viral and bacterial infection. However, the frequency of bacterial infections during the previous three years is currently being used as the major deciding factor in patient selection for tonsillectomy. The aim of the present study was to determine an objective biomarker to help in the identification of patients suffering from recurrent tonsillitis.

Results

By analyzing a panel of cytokines and chemokines in serum and saliva of patients with RAT compared to healthy controls, increased levels of IL-1ß (153.7 ± 48.5 pg/ml vs 23.3 ± 6.6 pg/ml, p = 0.021), IL-18 (120.2 ± 16.5 vs 50.6 ± 9.3 pg/ml, p = 0.007) and/or S100A8/A9 (996 ± 102 ng/ml vs 546 ± 86 ng/ml, p = 0.042) could be observed in patients suffering from RAT. Cut-off values of these parameters were determined and combined to a new RAT-score allowing for reliable identification of patients suffering from recurrent tonsillitis with a sensitivity of 95% and a specificity of 88%.

Conclusion

The RAT-score represents the first objective criterion as a tool for the diagnosis of recurrent tonsillitis and it also improves patient selection for tonsillectomy.

TRAIL-Receptor 4 Modulates γδ T Cell-Cytotoxicity Toward Cancer Cells

Acquired immune evasion is one of the mechanisms that contributes to the dismal prognosis of cancer. Recently, we observed that different γδ T cell subsets as well as CD8⁺ αβ T cells infiltrate the pancreatic tissue. Interestingly, the abundance of γδ T cells was reported to have a positive prognostic impact on survival of cancer patients. Since γδ T cells utilize TNF-related apoptosis inducing ligand (TRAIL) for killing of tumor cells in addition to granzyme B and perforin, we investigated the role of the TRAIL-/TRAIL-R system in γδ T cell-cytotoxicity toward pancreatic ductal adenocarcinoma (PDAC) and other cancer cells. Coculture of the different cancer cells with γδ T cells resulted in a moderate lysis of tumor cells. The lysis of PDAC Colo357 cells was independent of TRAIL as it was not inhibited by the addition of neutralizing anti-TRAIL antibodies or TRAIL-R2-Fc fusion protein. In accordance, knockdown (KD) of death receptors TRAIL-R1 or TRAIL-R2 in Colo357 cells had no effect on γδ T cell-mediated cytotoxicity. However, KD of decoy receptor TRAIL-R4, which robustly enhanced TRAIL-induced apoptosis, interestingly, almost completely abolished the γδ T cell-mediated lysis of these tumor cells. This effect was associated with a reduced secretion of granzyme B by γδ T cells and enhanced PGE2 production as a result of increased expression level of synthetase cyclooxygenase (COX)-2 by TRAIL-R4-KD cells. In contrast, knockin of TRAIL-R4 decreased COX-2 expression. Importantly, reduced release of granzyme B by γδ T cells cocultured with TRAIL-R4-KD cells was partially reverted by bispecific antibody [HER2xCD3] and led in consequence to enhanced lysis of tumor cells. Likewise, inhibition of COX-1 and/or COX-2 partially enhanced γδ T cell-mediated lysis of TRAIL-R4-KD cells. The combination of bispecific antibody and COX-inhibitor completely restored the lysis of TRAIL-R4-KD cells by γδ T cells. In conclusion, we uncovered an unexpected novel role of TRAIL-R4 in tumor cells. In contrast to its known pro-tumoral, anti-apoptotic function, TRAIL-R4 augments the anti-tumoral cytotoxic activity of γδ T cells.

Functional characterization of T-cells from palatine tonsils in patients with chronic tonsillitis

The palatine tonsils, localized in the oropharynx, are easily accessible secondary lymphoid tissue in humans. Inflammation of the palatine tonsils, local and chronic in case of chronic tonsillitis (CT) or acute in the presence of a peritonsillar abscess (PTA), ranks among the most common diseases in otolaryngology. However, the functionality of tonsillar immune cells, notably T-cells, in the context of these immune pathologies is poorly understood. We have examined the functional status of human tonsillar T-cells in CT and compared it to the acute inflammatory setting of a PTA. Patients presenting with CT (n = 10) or unilateral PTA (n = 7) underwent bilateral tonsillectomy and a subgroup of 8 patients underwent additional blood sampling. T-cells were purified via automated magnetic selection and subjected to flow cytometry-based immunophenotyping. In addition, the response to T-cell receptor (TCR) stimulation was assessed at the level of proximal signaling, activation marker expression and proliferation. We observed no difference between the percentage of T helper (CD4(+)) cells from tonsil tissue in CT and PTA, but observed a trend towards a higher percentage of T helper cells in the blood of patients with PTA versus CT, probably reflecting an acute, systemic bacterial infection in the former cohort. Tonsils from CT harbored more PD-1(+) CD4(+) T-cells, pointing to T-cell exhaustion due to chronic infection. This notion was supported by functional studies that showed a tendency to weaker TCR responses of tonsillar T-cells from CT. Intriguingly, tonsillar T-cells recurrently featured a dampened response to T-cell receptor stimulation at the level of receptor proximal signaling steps compared to peripheral T-cells. In sum, our study documents distinct differences in tonsillar T-cell class distribution and function between the various pathological conditions. Our observations are consistent with the concept that tonsillar T-cells react to infections by eliciting specific immunological responses in chronic versus acute settings of inflammation.

Oral Mucosal Immunity and HIV/SIV Infection

Human Immunodeficiency Virus (HIV) transmission through genital and rectal mucosa has led to intensive study of mucosal immune responses to HIV and to the development of a vaccine administered locally. However, HIV transmission through the oral mucosa is a rare event. The oral mucosa represents a physical barrier and contains immunological elements to prevent the invasion of pathogenic organisms. This particular defense differs between micro-compartments represented by the salivary glands, oral mucosa, and palatine tonsils. Secretory immunity of the salivary glands, unique features of cellular structure in the oral mucosa and palatine tonsils, the high rate of oral blood flow, and innate factors in saliva may all contribute to the resistance to HIV/Simian Immunodeficiency Virus (SIV) oral mucosal infection. In the early stage of HIV infection, humoral and cellular immunity and innate immune functions in oral mucosa are maintained. However, these particular immune responses may all be impaired as a result of chronic HIV infection. A better understanding of oral mucosal immune mechanisms should lead to improved prevention of viral and bacterial infections, particularly in immunocompromised persons with Acquired Immune Deficiency Syndrome (AIDS), and to the development of a novel strategy for a mucosal AIDS vaccine, as well as vaccines to combat other oral diseases, such as dental caries and periodontal diseases.

Bispecific T-cells expressing polyclonal repertoire of endogenous γδ T-cell receptors and introduced CD19-specific chimeric antigen receptor

Even though other γδ T-cell subsets exhibit antitumor activity, adoptive transfer of γδ Tcells is currently limited to one subset (expressing Vγ9Vδ2 T-cell receptor (TCR)) due to dependence on aminobisphosphonates as the only clinically appealing reagent for propagating γδ T cells. Therefore, we developed an approach to propagate polyclonal γδ T cells and rendered them bispecific through expression of a CD19-specific chimeric antigen receptor (CAR). Peripheral blood mononuclear cells (PBMC) were electroporated with Sleeping Beauty (SB) transposon and transposase to enforce expression of CAR in multiple γδ T-cell subsets. CAR(+)γδ T cells were expanded on CD19(+) artificial antigen-presenting cells (aAPC), which resulted in >10(9) CAR(+)γδ T cells from <10(6) total cells. Digital multiplex assay detected TCR mRNA coding for Vδ1, Vδ2, and Vδ3 with Vγ2, Vγ7, Vγ8, Vγ9, and Vγ10 alleles. Polyclonal CAR(+)γδ T cells were functional when TCRγδ and CAR were stimulated and displayed enhanced killing of CD19(+) tumor cell lines compared with CAR(neg)γδ T cells. CD19(+) leukemia xenografts in mice were reduced with CAR(+)γδ T cells compared with control mice. Since CAR, SB, and aAPC have been adapted for human application, clinical trials can now focus on the therapeutic potential of polyclonal γδ T cells.

Questionable relevance of gamma delta T lymphocytes in renal cell carcinoma

Adoptive gammadelta T cell immunotherapy has moved briskly into clinical trials prompted by several small studies suggesting abundant accumulation of gammadelta T cells within renal cell carcinoma (RCC). In this study, we re-examined levels of gammadelta T cells within RCC tumors and correlated levels of these cells with pathologic features and outcome associated with this form of cancer. Tissues from 248 consecutive clear cell RCC tumors obtained from 2000 to 2003 were stained and quantified for total CD3+ and gammadelta T cells per mm2. Wilcoxon rank sum and Kruskal-Wallis tests were used to evaluate associations between T cell amounts and prognostic factors (age, gender, tumor size, stage, grade, tumor necrosis). Cox models were used to assess associations with RCC-specific death. Median numbers of total CD3+ and gammadelta T cells were 281/mm2 (interquartile range (IQR): 149-536) and 2.6/mm2 (IQR: 1.3-4.6), respectively. The median percentage of CD3+ T cells that were gammadelta T cells was 1.0% (IQR: 0.4-1.9). This low percentage of intratumoral gammadelta T cells was diluted even further with rising CD3+ T cell infiltration. Percentages of gammadelta T cells were not associated with even one single clinicopathologic feature examined. Median follow-up for this study was 3.1 years (48 patients died of RCC) and Cox analysis failed to demonstrate that gammadelta T cells (hazard ratio=1.02, p=0.25) were predictive of RCC-specific death. gammadelta T cells are rare and not recruited nor expanded within RCC tumors. Percentages of gammadelta T cells fail to correlate with any prognostic features of RCC nor specific death. As such, the role of gammadelta T cells in RCC immunobiology remains questionable.

The Role of Mucosal Immunity: An Update

There is considerable evidence that the mucosa associated lymphoid tissues (MALT) of the body play an active part in triggering off and conducting the immune system's response to both viral and bacterial pathogens. Effectors are capable of intercepting the micro-organisms and rendering them harmless before they penetrate through the mucous membranes, or of expelling and inactivating them after they have penetrated. The system is consequently useful both in the prevention of infection and in the humoral or cellulo-mediated immune response. These operations, whose principal protagonists are Immunoglobulins A and dendritic cells, are made possible by the high degree of functional interconnection which binds the effectors of the system and the anatomical structures located in the mucosae. The data provided in literature consequently infer that appropriate stimulation of mucosal immunity, which takes into account the new acquisitions in the field of immunology, can enable oral vaccination to overcome the obstacles encountered up till now in terms of insufficient protection against diseases.

Macroscopic oropharyngeal signs indicating impaired defensive function of palatine tonsils in adults suffering from recurrent tonsillitis

The present study explored in adults suffering from recurrent tonsillitis the association between macroscopic oropharyngeal signs of recurrent inflammation, immunomorphology of palatine tonsils (counts of neutrophils by CD4 and macrophages by CD68 monoclonal antibodies in tonsillar microcompartments) and the occurrence of post-tonsillectomy bacteremia. The study involved 50 adults (31 females and 19 males) with recurrent tonsillitis. According to predominance of either inflammatory changes or evidence of sclerotic process in palatine tonsils and surrounding tissue macroscopic at oropharyngeal examination, the patients were divided into groups with 'inflammatory-type' and 'sclerotic-type' tonsils. Biochemically detected mean collagen content was significantly higher in 'sclerotic-type' tonsils than in 'inflammatory-type' tonsils (p=0.001). Post-tonsillectomy bacteremia was found in 22 patients (44%). A noteworthy finding was the higher recovery of anaerobes from blood cultures than in previous studies. A logistic regression analysis revealed that the post-tonsillectomy bacteremia was strongly associated with 'sclerotic-type' tonsils (p=0.0015) and with low counts of neutrophils in tonsillar tissue (p=0.047). We conclude that macroscopic oropharyngeal signs of sclerotic process in palatine tonsils indicate impaired tonsillar defense, in terms of lowered counts of neutrophils, increasing the risk of post-tonsillectomy bacteremia.

In search of the origin of the thymus: the thymus and GALT may be evolutionarily related

The thymus is the major primary immune tissue for the production of functional T lymphocytes in vertebrates. However, its evolutionary origin is unknown. It has recently been shown that the generation of local T cells also occurs in gut-associated lymphoid tissues (GALT). This suggests that the thymus and GALT have similar functions and that they might be evolutionarily related. We discuss the possibility that the thymus may have evolved from mucosa-associated lymphoid tissues (MALT) located in the gill region in early vertebrates. Various facts supporting this proposal are summarized.

Lymphocyte subsets in porcine tonsillar crypt epithelium

The palatine tonsils are part of the mucosa-associated lymphoid tissue (MALT), strategically located in the oropharynx at the entrance of respiratory and gastrointestinal tracts, and are recognized portals of entry and sites of multiplication and persistence of several pathogens in pigs. As the tonsillar crypt epithelium is in close contact with external environment and the underlying lymphoid tissue, the characterization of the intra-epithelial lymphocyte subpopulations is essential for the understanding of initial steps of pathogenesis of several diseases. In this work we investigated specific lymphocyte subsets in the tonsillar crypt epithelium of 10 adult healthy pigs, using monoclonal antibodies against lymphocyte markers CD3, CD4, CD8, gammadelta T cell receptor and immunoglobulin light-chain in an avidin-biotin immunoperoxidase technique. The crypt epithelium was usually extensively infiltrated by a diverse population of T cells and by B cells. The degree of infiltration of each subset was variable among animals and within individual animals. In the T cell population CD4 cells and gammadelta TCR cells predominated over CD8 cells. These data suggest that the crypt lymphoepithelium is capable of participating in both cellular and humoral immune responses and that gammadelta T cells may play an important role in the defense of this mucosa.

Human uvula: characterization of resident leukocytes and local cytokine production

Upper airway infections often lead to macroscopic changes in the architecture of the uvula. Using immunomorphometric analysis, we investigated the frequency and distribution of immune cells and of cytokine-producing cells in uvular samples. Tissue macrophages, alphabeta T cells, gammadelta T cells, and B cells were, in declining order, the main cell populations. Gammadelta T cells and B cells exhibited reciprocal localization, with almost all gammadelta T cells residing in the vicinity of the epithelium, and all B cells in the glandular area. The presence of cells expressing the suppressor phenotype CD8+CD28- alphabeta T cells is suggested. Fifteen to twenty-five percent of the immune cells expressed the down-regulatory cytokine tumor growth factor beta. Most macrophages were located subepithelially, in the vicinity of the basal lamina. The composition and cytokine profile of leukocytes in the tissue suggest that the uvula may be a site, additional to the jejunal mucosa, for induction of mucosal tolerance to inhaled and ingested antigens. Concomitantly, the uvula appears to be protected from invasion of microbial pathogens by a subepithelial barrier of macrophages and gammadelta T cells.

Lymphocyte populations and adhesion molecule expression in bovine tonsils

Bovine tonsils are mucosal-associated lymphoid tissue (MALT) located at the entry of the pharynx where both inhaled and ingested antigens can induce an immune response. This study was conducted to determine the lymphocyte populations and adhesion molecule expression in the palatine tonsil (PT) and pharyngeal tonsil (PhT) of adult cattle and compare them with typical MALT (discrete Peyer's patches, PP) and a peripheral lymph node (parotid lymph node, PLN). The distribution of various lymphocyte subsets was determined in situ by immunofluorescence, and their proportions were determined by multicolor flow cytometry. The tonsils were similar to PP in the proportions of B- and T-cells (25-32% T-cells, 39-45% B-cells), and T cell subpopulations (CD4, CD8, and gammadelta). The PP contained the highest proportion of memory T-helper cells with beta7 integrin (30.3%+/-5.4), the tonsils intermediate (PT: 19.8%+/-4.4 and PhT: 19.7%+/-4.9), and the PLN had the lowest proportion (15.4%+/-3.1). The opposite relationship was observed with CD62L on naïve T- helper cells as PP had the lowest proportion (14.2%+/-6.4), the tonsils intermediate (PT: 17.4%+/-2.5 and PhT: 24.3%+/-7.3), and the PLN the highest proportion (45.3%+/-6.5). MAdCAM-1 was highly expressed in the high endothelial venules (HEV) of PP, with variable and weak expression in the tonsils and PLN. PNAd, on the other hand, was highly expressed in HEV of tonsils and PLN, and weakly expressed in the PP. These results indicate that the bovine tonsils share characteristics with both PP and PLN. The alpha4beta7/MadCAM-land CD62L/PNAd interaction may be involved in lymphocyte migration to the tonsils, but it is likely that other adhesion molecules participate as well. Similarities between the human and bovine tonsils suggest that cattle may provide a good model to study the role of the tonsil in the respiratory immune response.