Nasopharyngeal tonsil's provision of the surface secretions with immunocytes, a property additional to antigen processing

Effects of tonsillectomy and adenoidectomy on the immune system

Surgical removal of the tonsils and adenoids, important immune organs, is a frequent and recurrent class of surgery, and currently, there is no consensus on the effects these surgical procedures may have on the immune system. Here, we examine individual studies on tonsillectomy, adenoidectomy, and adenotonsillectomy, discuss their postoperative humoral and cellular immune changes, and explore their effects on the incidence of related diseases. There is evidence that these three surgeries have no negative effects on humoral immunity; however, there has been contrary results. Furthermore, these procedures seem to have no significant effects on cellular immunity, although tonsil and adenoid removal can cause an increased incidence of certain illnesses, especially infectious diseases. Based on this comprehensive review, we conclude that the removal of tonsils and adenoids does not negatively affect cellular and humoral immunity. However, surgery may lead to an increased incidence of related infectious diseases. This finding may inform the surgeon's decision to perform the procedure in a clinical setting.

M cells and associated lymphoid tissue of the equine nasopharyngeal tonsil

The aim of this study was to characterise the morphological and histochemical features of equine nasopharyngeal tonsillar tissue. Nasal and oropharyngeal tonsillar tissue has been described as the gatekeeper to mucosal immunity because of its strategic location at the entrance to the respiratory and alimentary tracts. A combination of light, scanning and transmission electron microscopy has revealed the presence of follicle-associated epithelium (FAE) overlying lymphoid tissue of the equine nasopharyngeal tonsil caudal to the pharyngeal opening of the guttural pouch. Membranous microvillus (M) cells were identified in the FAE on the basis of short microvilli, an intimate association with lymphocytes, cytoplasmic vimentin filaments and epitopes on the apical surface reactive with lectin GS I-B4 specific for alpha-linked galactose. CD4-positive lymphocytes were scattered throughout the lamina propria mucosae as well as forming dense aggregates in the subepithelial part. The central follicular area was heavily populated with B lymphocytes and the dome and parafollicular areas contained both CD4- and CD8-positive lymphocytes. CD8-positive lymphocytes were also present in the epithelium and, together with B lymphocytes, in small numbers in the lamina propria mucosae. These observations indicate that the nasopharyngeal tonsil is potentially an important mucosal immune induction site in the horse and an appropriate target for intranasally administered vaccines.

Adenoid as a source of lymphocytes in the surface secretions of nasopharynx

OBJECTIVE

The significance and protective efficacy of surface secretions on mucosal membranes in the upper airways are well recognized. The aim of our study was to reveal the role of the adenoids as a source of cellular components in the mucosal secretion.

METHODS

The adenoid removed because of its hypertrophy and the samples of surface secretions taken by "imprint method" described by Ebenfelt et al. from the group of 38 children were examined by flow cytometry. The lymphocyte subsets with following antigens: CD3, CD4, CD8, CD19, CD23, CD16+56, CD45RA, CD45RO, HLA-DR were analyzed. Two groups were studied: (1) AH, children with adenoid hyperplasia without otitis media; (2) OME, children with adenoid hyperplasia and persistent otitis media with effusion. Age-related changes in percentages of lymphocyte subpopulations were analyzed.

RESULTS

The percentage of lymphocyte subsets in adenoid and secretion were similar, however, in the surface secretion there was higher proportion of lymphocytes B and NK and lower of T. There was no correlation between percentages of lymphocyte in adenoid and surface secretion except for lymphocytes Th with memory phenotype and lymphocytes B with marker CD23(+). In adenoid the percentage of T and Th lymphocytes increased with age and the percentage of B lymphocytes decreased. In the secretion age-related changes were less pronounced and only the percentage of lymphocytes B CD23(+) showed positive correlation with age. In cases of otitis media with effusion there was higher proportion of lymphocytes B (CD19(+) and CD19(+)CD23(+)) and lower of lymphocytes Ts and Th with naive phenotype in the secretion. In adenoid however, the cases of OME revealed lower percentage of lymphocytes B and higher of lymphocytes Ts.

CONCLUSIONS

Similar proportions of lymphocyte subpopulations in surface secretion and in adenoid imply that adenoid is the source of those cells. However, lack of correlation between the percentages of lymphocytes in secretion and in adenoid suggest that the process of lymphocyte migration has active and selective character.

Cytokines produced by T cells in adenoid surface secretion are mainly downregulatory or of Th1 type

CONCLUSIONS

T cells in adenoid surface secretion (AdSS) possess the property of cytokine production and are mainly downregulatory or of Th1 type. These results strengthen the hypothesis of an active immunological defense in AdSS.

OBJECTIVES

Recently, we demonstrated the presence of activated T cells in AdSS. The aims of this study were to elucidate the ability of these T cells to produce cytokines and to reveal their cytokine profile.

MATERIAL AND METHODS

Eight children subjected to adenoidectomy were enrolled. Samples of AdSS, adenoid tissue and peripheral blood were obtained, as well as a nasopharyngeal culture. T cells obtained from AdSS, adenoid tissue and peripheral blood were then cultured and stimulated with anti-CD3 and -CD28 for 5 days. The production of interferon (IFN)-gamma, tumor necrosis factor (TNF)-a and IL-2, -4, -5 and -10 was then analyzed using flow cytometry.

RESULTS

All children had T cells in AdSS capable of cytokine production. T cells in AdSS, adenoid tissue and peripheral blood samples from all children produced IFN-gamma. Of the cytokines analyzed, IFN-gamma was produced in the highest concentrations. In 6/8 children, T cells in AdSS also produced TNF-a and IL-10.

Antibody production directed against pneumococci by immunocytes in the adenoid surface secretion

OBJECTIVE

In previous studies of the adenoid surface secretion we revealed the presence of activated T cells, granulocytes engaged in phagocytosis and immunocytes that produce IgG, IgA and IgM. In the present study the objective was to assess the ability of these immunocytes to produce antibodies directed at S. pneumoniae.

METHOD

Nine children subjected to adenoidectomy due to adenoid hypertrophy, secretory otitis media or recurrent otitis media were enrolled in the study. Samples of adenoid surface secretion were obtained by an imprint method and for comparison samples of adenoid tissue and peripheral blood were also obtained as well as a nasopharyngeal culture. Double-colour enzyme-linked immunospot (ELISPOT) assays were performed to detect total and pneumococci-specific IgG- and IgA-antibody secreting cells (ASC). In the adenoid tissue, the presence of H. influenzae type b specific ASC was also examined.

RESULTS

ASC were present in all nine samples of adenoid surface secretion with a dominance of IgG-ASC as compared to IgA-ASC. The proportion of ASC relative to the total number of lymphocytes was always greater in the secretion than in the corresponding adenoid tissue. The adenoid surface secretion samples from three of nine children contained IgG-ASC directed against S. pneumoniae. IgG-ASC directed against S. pneumoniae were detected in six of eight adenoids and IgA-ASC directed against S. pneumoniae were detected in two of eight adenoids. IgA-ASC directed against H. influenzae type b (Hib) were detected in one of seven adenoids.

CONCLUSION

The immunocytes in the adenoid surface secretion and the adenoid tissue itself hold the property to produce antibodies specific for known pathogens of the upper airways. These ASC are probably engaged in the immunologic defence of the nasopharyngeal mucosa and further studies are therefore called upon.

Activated T cells in the surface secretion on the adenoid--a flow cytometric study

We previously demonstrated the presence of leucocytes in the adenoid surface secretion with the ability of immunoglobulin A (IgA), IgM and IgG production as well as production of cells with phagocytic capacity. In the present study, we investigated the presence of activated T cells in the secretion. Adenoid surface secretion from 12 children subjected to adenoidectomy was obtained with an imprint method. From six children, peripheral blood was also obtained. By flow cytometry, the number of lymphocytes, granulocytes, epithelial cells and red blood cells was analysed as well as the expression on lymphocyte subsets of the following antigens: CD3, CD4, CD8, CD19, CD25, CD38, CD45RO, CD45RA, HLA-DR, TcRgd, CD161 and l-selectin. The majority of T cells were activated and to a significantly higher degree were CD45RO+, CD161+ and l-selectin-, as compared with the corresponding peripheral blood. The median percentage of B cells and T cells in the secretion were 81 and 13%, respectively. In conclusion, the proportion of B and T cells in the adenoid surface secretion is significantly different as compared with the peripheral blood. The T cells in the adenoid surface secretion are to a high degree activated. The results suggest that the leucocytes in the surface secretion are part of the mucosal defence.

HHV-8 infection: a model for reactivation and transmission

The rapid pace of knowledge about HHV-8 since its discovery has been one of the most exciting aspects of medical virology in the last decade. As outlined in this review, the discovery by Drs Chang and Moore of this virus has opened up a broad field of biology with interesting contrasts between current epidemiological data for Kaposi's sarcoma and the cell biology of this gamma herpesvirus. In particular, we summarise the paucity of virological data supporting genital sites of replication and emphasise detection of HHV-8 in the oropharynx. Hopefully continued study will address many of the critical questions that exist today regarding how this infection is transmitted and acquired.