Connexin Expression in Human Minor Salivary Glands: An Immunohistochemical Microscopy Study

Connexins (Cxs) are transmembrane proteins involved in the formation of hemichannels and gap junctions (GJs). GJs are involved in various physiological functions, including secretion in glandular tissue. It has been demonstrated that Cx26, Cx32, and Cx43 are mainly expressed in glands, but no data are available in human salivary glands to date. The aim of our study was to investigate the presence and the localization of Cxs in human minor labial salivary glands. Immunofluorescence and immunoelectron microscopy were employed to evaluate the Cx26, Cx32, and Cx43 protein in human labial salivary gland biopsies (hLSGBs). RT-PCR was also used to detect their mRNA expression. Cx expression was found at both the mRNA and protein levels in all hLSGBs analysed. Cxs were observed at the level of the duct and acinar cells, as well as in myoepithelial cells. The localization of the three Cx types was very similar, suggesting colocalization of these Cxs in the same connexons. These results demonstrated the presence of Cxs in human salivary glands for the first time. Moreover, the few samples with primary Sjögren’s Syndrome analysed only by immunofluorescence showed an alteration of the Cx expression, indicating that these proteins could be involved in salivary gland dysfunctions.

Characterization of Lipids in Saliva, Tears and Minor Salivary Glands of Sjögren's Syndrome Patients Using an HPLC/MS-Based Approach

The diagnostic work-up of primary Sjögren’s syndrome (pSS) includes quantifying saliva and tear production, evaluation of autoantibodies in serum and histopathological analysis of minor salivary glands. Thus, the potential for further utilizing these fluids and tissues in the quest to find better diagnostic and therapeutic tools should be fully explored. Ten samples of saliva and tears from female patients diagnosed with pSS and ten samples of saliva and tears from healthy females were included for lipidomic analysis of tears and whole saliva using high-performance liquid chromatography coupled to time-of-flight mass spectrometry. In addition, lipidomic analysis was performed on minor salivary gland biopsies from three pSS and three non-SS females. We found significant differences in the lipidomic profiles of saliva and tears in pSS patients compared to healthy controls. Moreover, there were differences in individual lipid species in stimulated saliva that were comparable to those of glandular biopsies, representing an intriguing avenue for further research. We believe a comprehensive elucidation of the changes in lipid composition in saliva, tears and minor salivary glands in pSS patients may be the key to detecting pSS-related dry mouth and dry eyes at an early stage. The identified differences may illuminate the path towards future innovative diagnostic methodologies and treatment modalities for alleviating pSS-related sicca symptoms.

[Clinicopathologic and molecular genetic analysis of secretory carcinoma of salivary gland]

Objective: To investigate the clinicopathologic and molecular genetic features of secretory carcinoma of salivary gland (SCSG). Methods: Six cases of SCSG were collected from Zhejiang Provincial People's Hospital from January 2011 to March 2018. The clinical, histopathological and immunohistochemical features were analyzed and fluorescence in situ hybridization (FISH) was used to detect ETV6 gene rearrangement. Results: Four out of 6 tumors originated in the parotid gland and one of each in the minor salivary glands of soft palate and the buccal mucosa. Grossly, 4 cases were solid and 2 were partially cystic with maximum diameter ranging from 1.0 to 4.0 cm. Microscopically, 5 tumors showed typical features of low grade SCSG with tumor divided by thin fibrous septa into lobules composed of solid acinar, microcystic, follicular and papillary structures with abundant extracellular mucinous secretions. The tumor cells had cuolated or hobnail cytoplasm with low-grade nuclei and scarce mitoses. Perineural invasion was present in 1 case. The remaining tumor showed about 30% of the tumor areas with high-grade transformation characterized by proliferation of a distinct population of anaplastic cells arranged in irregular glandular, small nested and single cell patterns that were surrounded by desmoplastic stroma and invaded into surface mucosa with ulceration. Immunohistochemistry showed that all 6 tumors had diffuse and strong reactivities to S100 protein and cytokeratin 7, and 4 cases showed focal reactivity to gross cystic disease fluid protein 15 (GCDFP15), all were negative for discovered on gist 1 (DOG1), cytokeratin 20, p63 and calponin. High grade transformation cases were analysed, the high grade SCSG components showed a significantly increased Ki-67 index and cyclin D1 positive tumor cells compared to the conventional SCSG components. FISH analyses showed that 4 cases had ETV6 gene rearrangement. Eleven to seventy one months' follow-up showed no evidence of tumor recurrence nor metastasis. Conclusions: SCSG harbors characteristic genetic abnormalities with ETV6 gene rearrangement and typically shows a low grade morphology with occasionally, high grade transformation can be present.

Immunolocalization of Surfactant Proteins SP-A, SP-B, SP-C, and SP-D in Infantile Labial Glands and Mucosa

Surfactant proteins in different glandular structures of the oral cavity display antimicrobial activity for protection of invading microorganisms. Moreover, they are involved in lowering liquid tension in fluids and facilitate secretion flows. Numerous investigations for studying the occurrence of surfactant proteins in glandular tissues were performed using different methods. In the oral cavity, minor salivary glands secrete saliva continuously for the maintenance of a healthy oral environment. For the first time, we could show that infantile labial glands show expression of the surfactant proteins (SP) SP-A, SP-B, SP-C, and SP-D in acinar cells and the duct system in different intensities. The stratified squamous epithelium of the oral mucosa revealed positive staining for SPs in various cell layers.

Predictive significance of CCL21 and CXCL13 levels in the minor salivary glands of patients with Sjögren's syndrome

OBJECTIVES

To investigate whether CCL21 and CXCL13 expression levels in the minor salivary gland are associated with the laboratory and clinical manifestations of Sjögren's syndrome (SS).

METHODS

Sociodemographic data on 106 SS patients were obtained and the glandular and extraglandular manifestations of the disease were documented. In addition, minor salivary gland biopsies were performed and the patients' laboratory findings were analysed. European League Against Rheumatism SS disease activity index (ESSDAI) values of SS disease activity at the time of biopsy and the SS disease damage index (SSDDI) values were also recorded. An immunohistochemical approach was used to semiquantitatively measure the CCL21 and CXCL13 expression in the minor salivary glands.

RESULTS

The minor salivary glands of SS patients stained positively for CCL21 and CXCL13 in 46.2% (49/106) and 70.7% (75/106) of all cases, respectively. Higher-level expression of CCL21 and CXCL13 was associated with increases in ESR, IgG and rheumatoid factor levels, as well as anti-SS-A and -SS-B titers. A higher focus score and ESSDAI value at the time of biopsy were also associated with these chemokines. In patients with extraglandular manifestations of SS, the prevalence of lymphadenopathy increased with increasing CCL21 levels.

CONCLUSIONS

The expression levels of CCL21 and CXCL13 within the lymphocytic infiltrates of SS patients were associated with several laboratory features of the disease as well as lymphadenopathy and the extent of clinical disease activity. CCL21 and CXCL13 levels can therefore serve as useful markers to predict the disease activity and prognosis of patients with SS.

Cholera toxin B subunit-binding and ganglioside GM1 immuno-expression are not necessarily correlated in human salivary glands

OBJECTIVE

To determine and compare the presence and in situ localization of the glycosphingolipid ganglioside GM1 in human salivary glands using the biomarkers for GM1: cholera toxin and antibodies against GM1.

MATERIALS AND METHODS

Immunohistochemical analyses were performed on sections of adult human submandibular, parotid and palatinal glands using cholera toxin sub-unit B and two polyclonal antibodies against ganglioside GM1 as biomarkers.

RESULTS

Immunofluorescence microscopy showed that the toxin and antibodies were co-localized in some acini but not in others. The cholera toxin mainly reacted with the cell membranes of the mucous acini in the submandibular gland, while incubation with the antibody against GM1 gave rise to a staining of the cytoplasm. The cytoplasm in some secretory acinar cells in the parotid gland was stained by the cholera toxin, whereas only small spots on the plasma membranes reacted with anti-GM1. The plasma membranes in the parotid excretory ducts appeared to react to anti-GM1, but not to cholera toxin.

CONCLUSIONS

Cholera toxin induces the expression of ion channels and carriers in the small intestine and increases the production of secretory mucins. Although their mutual immunohistochemical localization may differ, both cholera toxin and ganglioside GM1 are present in the mucin-producing acini from salivary glands. This could point to a relationship between ganglioside expression and production of salivary mucins.

Ultrastructural localization of salivary mucins MUC5B and MUC7 in human labial glands

As a result of their presence throughout the mouth in the submucosa or between muscle fibers, minor salivary glands secrete directly and continuously into the oral cavity, providing mucosal surfaces with highly glycosylated proteins that are active in bacterial aggregation and in oral tissue lubrication. In this study, we investigated the ultrastructural localization of the MUC5B and MUC7 mucins in human labial glands by means of a postembedding immunogold technique. Thin sections of normal human labial glands, obtained during surgery, were incubated with polyclonal antibodies to human salivary mucins MUC5B and MUC7, and then with gold-labeled secondary antibodies. Specific MUC5B reactivity was found in the secretory granules of mucous cells of all glands examined, and was associated with the luminal membrane of duct cells. MUC7 labeling was observed in the granules of both mucous and seromucous secretory cells of the glandular parenchyma. Quantitative analyses demonstrated that seromucous granules have higher immunogold labeling densities for MUC7 than mucous granules. Our immunohistochemical data extend the results of previous light microscopic studies of MUC5B and MUC7 localizations, pointing out the significant contribution of human labial glands in the secretion process of these two mucins.

Intraductal carcinoma is the precursor of carcinoma ex pleomorphic adenoma and is often associated with dysfunctional p53

AIMS

Although intraductal carcinoma has been demonstrated in intracapsular carcinoma ex pleomorphic adenoma (CEPA), the morphological and genetic stages of transformation of pleomorphic adenoma (PA) to CEPA are not fully understood. The aim of this study was to investigate the morphology of intracapsular CEPA.

METHODS AND RESULTS

The largest series of intracapsular CEPA studied was subject to immunohistochemical double-staining to detect p53 protein and cellular proliferation in different types of cell combined with mutational analysis of the p53 gene in laser-microdissected material. Intraductal carcinoma with high-grade cellular atypia and frequent accumulation of p53 protein was found in 15/19 cases. Purely intraductal carcinoma was found in eight cases. Mutation of p53 was found in 7/19 cases, of which it was found in intraductal carcinoma in 5/15 cases.

CONCLUSIONS

The frequent demonstration of intraductal carcinoma indicates that this preinvasive lesion is likely to be a constant feature in the malignant transformation of PA to CEPA. It appears to be a feature of CEPA developing from both primary and recurrent PA. The combined immunohistochemical and genetic data show that 14/19 cases of CEPA and 11/15 cases with intraductal carcinoma showed genetic or morphological evidence of dysfunctional p53, indicating that this is an early event in malignant transformation.

Clear cell carcinoma arising from pleomorphic adenoma of a minor salivary gland: Report of a case with fine needle aspiration, histologic and immunohistochemical findings

BACKGROUND

Malignant changes in pleomorphic adenoma (PA) of the salivary gland (carcinoma ex pleomorphic adenoma) are not common. Clear cell carcinoma is a rare form of salivary gland tumor and involves mostly minor salivary glands, especially those of the palate. Only 3 cases of clear cell carcinoma arising in PA have been reported, 2 in submandibular glands and 1 in a minor salivary gland of the palate.

CASE

A 53-year-old man presented with an enlarged mass on the left side of the palate. He had a history of palate mass about 30 years earlier; it was excised and reported as PA. Since then the tumor had recurred twice in the same place; it had been excised and was diagnosed as PA again. A few years later the mass showed rapid growth over a few months. Fine needle aspiration of the mass showed epithelial clusters with bland nuclear features and myxohyaline material typical of PA. Also noted were large and small papillary, trabecular and well-circumscribed clusters of neoplastic cells with a moderate amount offoamy, vacuolated cytoplasm with distinct borders. Glandlike and acinar structures with hyaline globule material resembling cannonballs were also noted. The cytology was suspicious for malignancy. Incisional biopsy was reported as PA. Due to the suspicion of malignancy, the whole mass was excised up to the floor of the orbit. The final diagnosis was clear cell carcinoma expleomorphic adenoma.

CONCLUSION

Due to nonspecific cytologic findings in clear cell carcinoma and a mixture of elements of PA in this case, we did not consider clear cell carcinoma as the malignant component.

Inverted ductal papilloma of minor salivary gland: Case report with immunohistochemical study and literature review

Inverted ductal papilloma (IDP) is a type of ductal papilloma arising in ducts of minor salivary glands. Very few cases, and no cases in Japan, have been reported. Reported herein is a case of IDP with a review of the literature. The patient was a 49-year-old man presenting with a lump in the right buccal mucosa of the premolar area of the mandible. The tumor was excised en bloc after a biopsy diagnosis of IDP. On the surface of the covering epithelium, an opening was seen to be filled with mucinous material. On cut surface the opening led to the tumor cavity. The major portion of the tumor parenchyma was made up of papillary proliferation of basaloid squamous cells. Some crypts, microcysts, and mucous cells were seen. There were no findings suggestive of a malignant tumor. The patient's postoperative course was uneventful and there has been no recurrence after 1 year's follow up. Immunohistochemical analysis of the present case supports the hypothesis that IDP originates from squamous metaplasia and proliferation of minor salivary gland duct cells.

Basal cell adenocarcinoma arising from the minor salivary gland in the soft palate: A case report

Basal cell adenocarcinomas (BCACs) of the oral minor salivary gland are very rare neoplasms. We report on an 86-year-old woman with BCAC arising from the minor salivary gland in the soft palate. Histologically, the tumor was located in the submucosa and showed microinvasion into the adjacent soft tissue without encapsulation. It contained tiny tumor islands with solid and tubular patterns, as well as myxoid stroma. The neoplastic cells were basaloid cells and were composed of large pale cells and small dark cells. They were positive for alpha-smooth muscle actin, cytokeratin 14, and vimentin in the periphery of the tumor island, showing a myoepithelial differentiation. The myxoid stroma was positive for alcian blue and colloidal iron. Apical membranes of the neoplastic cells were positive for MUC1 and CEA. The present case is the 14th documented case of oral BCAC (the fifth case of palatal BCAC).

Localisation of epidermal growth factor receptor in mucous cells of human salivary glands

EGFR activation has been related to an increase in synthesis and secretion of mucins in epithelial cells, so that the use of EGFR tyrosine kinase inhibitors has been proposed in the therapy of mucin hypersecretory diseases. In this paper, we describe the ultrastructural localisation of EGFR in the mucous elements of human major and minor salivary glands and relate it to mucin distribution. A post-embedding immunogold staining method has been applied to normal surgical samples of human submandibular, sublingual, and labial glands, using a mouse monoclonal antibody specific for the intracellular domain of human EGFR. In mucous cells of all the glands examined, specific reactivity was detected in the cytoplasmic basolateral portions and near the mucous droplets, but not on cell surfaces. Since this pattern of labelling must be related to the internalisation process of the ligand-GFR complex, our results support the hypothesis that EGFR activation takes place in mucous cells and affects mucin production in human salivary glands.

Sialadenoma papilliferum: immunohistochemical study

Sialadenoma papilliferum (SP) is a rare benign tumour of salivary gland origin, which has been included among the ductal papillomas in the latest classification of tumours by the World Health Organisation. Two SP from the minor salivary gland of the palate of middle age patients were presented and studied by immunohistochemical. Our results showed presence of cytokeratins (CKs) 13, 14, 7, 8, 19 and absence of vimentin and smooth muscle actin. This immunoprofile is similar to the excretory duct of salivary gland.

Comparative immunoprofile of polymorphous low-grade adenocarcinoma and canalicular adenoma

Immunohistochemistry is an important tool when dealing with salivary gland neoplasms. Canalicular adenoma and polymorphous low-grade adenocarcinoma may share some histologic characteristics that can cause difficulties in their separation. In the present study, cases of polymorphous low-grade adenocarcinoma and canalicular adenoma were submitted to a panel of antibodies to evaluate the differences in their immunoprofiles. The results obtained showed that, while vimentin is only expressed by polymorphous low-grade adenocarcinoma, CK7 and CK8 are present in both neoplasms. Therefore, vimentin is the best marker to differentiate between these tumors.

Age-related histochemical and immunohistochemical changes in human labial salivary glands

We here in determined the histochemical and immunological changes that salivary glands experience as a result of the ageing process. Samples from the inferior lip of children, youngsters and young adults were analyzed by histochemical techniques, Periodic-acid-Schiff, (PAS) Alcian blue (AB) (pHs 1.0 and 2.5) and Toluidine blue for mucosubstances and immunohistochemical staining of S 100 protein and cytokeratin 20, avidin-biotin system (DAB). In children, the techniques used evidenced various reaction degrees in the acinar cells, even within a single acinous. They displayed a slight metachromasia and were alcianophilic at pH 2.5. In youngsters, and especially in adults, glands showed a notable PAS positivity and alcianophilia at both pH levels, and an intense metachromasia. PS 100 was positive in the basal area of the acini and serous demilunes of all groups, the reactivity being higher in adults. Cytokeratin 20 was better observed in ductal cells from children glands. These findings suggest modifications at cytological level and in the chemical composition of the secretory granules, indicating possible functional variations in lip salivary glands related to the ageing process.

Sialadenoma papilliferum of the hard palate: report of 2 cases and immunohistochemical evaluation

This study reports on the clinical and histologic features of 2 previously unreported cases of sialadenoma papilliferum. Immunohistochemical analysis of one of the cases demonstrated that the ductal cell component shows both epithelial and myoepithelial differentiation.

Prognostic significance of p27 and Ki-67 expression in mucoepidermoid carcinoma of the intraoral minor salivary gland

p27 and Ki-67, a universal cyclin-dependent kinase inhibitor and a proliferative cell marker, respectively, have been useful in predicting clinical aggressiveness in various human tumors. We studied clinicopathologic significance of these molecules in mucoepidermoid carcinoma of the intraoral minor salivary gland. Expression of p27 and Ki-67 was assessed immunohistochemically in primary mucoepidermoid carcinomas from 31 patients without distant metastasis at surgery. Correlation each of p27 and Ki-67 expression was analyzed with various clinicopathologic parameters including age, sex, primary tumor site, tumor size, nodal metastasis, clinical stage, and histologic grade. The latter was evaluated using a point-scoring scheme of Auclair et al. that consists of five histologic factors (intracystic component, neural invasion, necrosis, mitosis, and anaplasia). p27 expression was correlated inversely with histologic grade (P =.007), but with none of other factors. When the correlation of p27 expression was further examined with each of the histologic factors, it was correlated significantly with intracystic component, but not with neural invasion, necrosis, mitosis, or anaplasia. Ki-67 expression was correlated significantly with histologic grade only in the clinicopathologic factors (P <.0001), and in the histologic factors, with necrosis, mitosis, and anaplasia. Multivariate prognostic analyses were performed to identify independent risk factors for both disease-free and overall survivals. Large tumor size (P =.031, relative risk = 5.5) and low p27 expression (P =.012, relative risk = 5.2) were risk factors for worse disease-free survival. Low p27 expression (P =.015, relative risk = 15.2) was selected as a risk factor for worse overall survival. Other factors including age, sex, tumor site, nodal status, clinical stage, histologic grade, and Ki-67 did not emerge as independent risk factors in either prognostic analysis. These data suggest that p27 may be useful in estimating prognosis of the patients who have mucoepidermoid carcinoma of the intraoral minor salivary gland.

Cytokine profile in minor salivary glands from patients with bronchial asthma

BACKGROUND

T lymphocytes are important components of the bronchial inflammatory cell infiltrate in asthma. Because lymphocytes activated in the respiratory tract recirculate to remote glandular and mucosal sites, we previously studied the histologic features of minor salivary glands (MSGs) in bronchial asthma and found an airway-like inflammation with T-lymphocyte infiltration, the presence of mast cells that were often degranulated, and basement membrane thickening but no eosinophil infiltration.

OBJECTIVE

We sought to investigate the cellular infiltration and cytokine profile in MSGs from untreated asthmatic subjects, steroid-treated asthmatic subjects, and control subjects and to compare these values with those found in bronchial biopsy specimens.

METHODS

The cellular infiltration was studied by using immunohistochemistry. Cytokine messenger (m)RNA expression for IL-4, IL-5, and IFN-gamma was determined by using in situ hybridization and cytokine immunoreactivity with immunohistochemistry.

RESULTS

A significant increase in CD4 and IL-4 mRNA(+) cells was observed in MSGs from asthmatic patients (both untreated and steroid-treated subjects) when compared with control subjects, which correlated with the clinical severity of asthma (FEV(1) and Aas score). In contrast to the bronchi, no IL-5 mRNA expression was observed in MSGs, and no difference was observed for MSG IFN-gamma mRNA between the groups. At the level of MSG protein expression, the 3 cytokines were seen, with a significant increase in IL-4 protein expression in steroid-treated asthmatic subjects compared with untreated asthmatic subjects and control subjects, but there were no differences between the groups in IL-5 and IFN-gamma protein expression.

CONCLUSION

The cytokine mRNA expression pattern observed in the MSGs of asthmatic subjects was different from that found in the bronchi, suggesting a different local immune regulation.

Expression of the antimicrobial peptide, human beta-defensin 1, in duct cells of minor salivary glands and detection in saliva

The oral cavity is exposed to a variety of environmental insults. Salivary secretions play a critical role in maintaining oral health via innate host defense mechanisms and secretion of secretory IgA. Human beta-defensins (hBD) are antimicrobial peptides that are a component of the innate immune response; they are expressed in epithelia and are proposed to have a role in mucosal defense. hBD-1 mRNA is constitutively expressed in numerous mucosal tissues, including human gingiva and submandibular and parotid glands. Our objective was to detect the expression and localization of hBD-1 peptide in human salivary glands and in saliva. Minor salivary gland tissue was obtained from biopsies of patients with mucoceles (n = 20). hBD-1 peptide was detected by immunohistochemistry; expression was localized to the ductal cells and not the acinar cells of these glands. The peptide was located apically, toward the lumen in the duct cells. Further evaluation showed stronger hBD-1 expression in ducts with periductal inflammation, as indicated by the immunostaining of serial sections with anti-CD45 specific for B- and T-lymphocytes. Statistical analysis showed a strong correlation of hBD-1 staining and inflammation. Results of immunolocalization suggest that hBD-1 functions to protect salivary glands from retrograde infection, that expression of the peptide is enhanced in inflamed sites, and that post-transcriptional regulatory mechanisms may be involved in hBD-1 peptide expression. Western immunoblot analysis also detected hBD-1 peptide in unstimulated, whole, acidified saliva from normal volunteers. However, hBD-1 peptide associated with salivary mucin resulted in loss of the detection in a dot-immunoblot assay. Association of hBD-1 with salivary mucin may facilitate peptide distribution and adherence to oral surfaces and aid its function within the oral cavity.

Myoepithelioma arising from the buccal gland: histopathological and immunohistochemical studies

A rare case of myoepithelioma of the buccal gland in a 54-year-old Japanese woman is reported. As the swelling exhibited a normal mucosal color and was relatively well defined, showing no ulcers, a benign salivary gland tumor was suspected upon clinical inspection. Microscopically, the parenchyma of the present case mainly consisted of plasmacytoid cells with round nuclei and eosinophilic cytoplasm, and partial spindle cells with eccentric nuclei. The stroma was composed of fibro-hyalinized or myxoid connective tissue that separated from the parenchyma. Immunohistochemically, the cytoplasm of the plasmacytoid and spindle cells was moderately positive for vimentin and GFAP, whereas the buccal gland adjacent to the tumor was negative for these antibodies. S-100 protein reactivity is strong for both types tumor cells. Actin reactivity was negative for both types of tumor cells, notwithstanding the fact that myoepithelial cells of the buccal gland were positively stained. Anti-cytokeratin reactivity was weak for both types of tumor cells in portions of the plexiform and solid areas; nevertheless, the buccal glands were moderately positive. These results suggest that neoplasmic myoepithelial cells exhibit abnormal differentiation and modification. There have been only two published reports of myoepithelioma arising from the buccal gland in the literature to date.

Phenotypes in canalicular adenoma of human minor salivary glands reflect the interplay of altered secretory product, absent neuro-effector relationships and the diversity of the microenvironment

AIMS

Uncertainty about the factors influencing phenotypes in salivary canalicular adenoma prompted the present investigation.

METHODS AND RESULTS

Specimens of canalicular adenoma from 15 patients were examined with the use of histology, histochemistry for protein, mucosubstances and pigments, nerve staining and immunocytochemistry for cytoskeleton components. The tumours consisted largely of simple cells lining tubules that were occasionally cystic or branching and budding, and were set in loose, vascular and often haemorrhagic stroma. Other phenotypes recognized were mucous cells, apocrine-like cells, pigmented cells, microliths and stromal macrophages, detected in 26.6%, 20%, 33.3%, 20% and 53. 3% of the patients, respectively. Simple cells showed moderate levels of -SH groups and strong immunoreactivity for 'simple' epithelial phenotype cytokeratin. The simple cells lining cystic tubules showed additional immunoreactivity for 'stratified' epithelial phenotype cytokeratin, possibly an adaptation to mechanical pressure. Lumina showed variable levels of neutral and carboxylated glycoproteins, and chondroitin sulphate. Stroma showed high levels of chondroitin sulphate and hyaluronic acid. Mucous cells showed high levels of -SS- groups and nonsulphated glycoproteins. Apocrine-like cells contained lipofuscin. Pigmented cells contained haemosiderin, possibly a consequence of localized iron overload. Microliths contained mucosubstances. Macrophages often contained lipofuscin. No nerves were found in relation to the tumours.

CONCLUSIONS

The results suggest that, contrary to popular belief, phenotypes in canalicular adenoma do not reflect histogenetic concepts but rather may derive from the interplay between an altered secretory product, consisting of glycosaminoglycan and an immature form of glycoprotein, the lack of neuro-effector relationships and the different microenvironments throughout the tumour.

Lectin histochemistry of dog major and minor salivary glands

The distribution of different carbohydrates in dog major and minor salivary glands was investigated using a peroxidase-labelled avidin-biotin method to demonstrate binding of six lectins (Canavalia ensiformis agglutinin [Con A], Dolichos biflorus agglutinin [DBA], Arachis hypogaea (peanut) agglutinin [PNA], Glycine max agglutinin [SBA], Tetragonolobus purpurea agglutinin [TGP] and wheat germ agglutinin [WGA]). With PNA, there was only weak staining in serous acini of parotid glands. Other lectins bound, to different degrees, to different components of the salivary glands; differences could be detected between glands and between binding of different lectins to serous and mucous acinar cells and to the epithelial cell cytoplasm, luminal surface and contents of ducts. These results provide a basis for the comparison of possible changes in carbohydrates which may occur in salivary gland diseases.

Sialic acid residues in the labial salivary glands from Sjögren's syndrome patients

OBJECTIVE

To investigate the composition and expression of sialic acid in the labial salivary glands (LSG) in Sjögren's syndrome (SS).

METHODS

LSG of 19 patients with primary SS (n = 11) or secondary SS (n = 8) were studied. Specimens from 7 healthy women served as controls. Computer-assisted microscopy was employed to quantitatively determine the percentage of positive structures, the staining intensity and the heterogeneity for the 4 biotinylated plant lectins Tritricum vulgaris L. (WGA), Maackia amurensis (MAA), Sambucus nigra (SNA) and Canavalia ensiformis L. (Con A).

RESULTS

In the acini there was a significant decrease in the staining heterogeneity of WGA in SS compared to controls; the same was observed with respect to MAA staining in the connective tissue and extralobular ducts. In the intralobular ducts, primary SS differed from normal and secondary SS mainly in terms of a decrease in the percentage of positively labeled MAA tissue. In addition, Con A stained acinar cells were significantly more numerous in secondary SS compared with primary SS.

CONCLUSION

Differences in the degree of glycoconjugate sialylation were found in SS labial salivary glands, and may play a role in the disease process.

Intravascular tumour in intra-oral pleomorphic adenomas: a diagnostic and therapeutic dilemma

AIMS

Intravascular tumour has been described very rarely in pleomorphic adenomas. The aim of this study was to establish the frequency of intravascular tumour in pleomorphic adenomas arising in minor salivary glands and to determine the biological significance of this phenomenon.

METHODS AND RESULTS

Representative sections of 67 widely excised pleomorphic adenomas were examined for the presence of intravascular tumour. Sixty-two cases were derived from the palate while the remaining five were from the cheeks and lips. In instances where intravascular tumour was identified, multiple serial sections were assessed and immunohistochemical stains were performed. None of these cases showed cytological evidence of malignancy. Solid cords of intravascular tumour were present in six palatal tumours (8.9%) and consisted of plasmacytoid myoepithelial cells permeating muscular walled blood vessels and capillaries both within the tumour and capsule. Immunoperoxidase staining confirmed that the intravascular cells were phenotypically identical to those of the tumour being S100- and smooth muscle actin (SMA) positive. There is some evidence that this phenomenon represents true vascular invasion although artefactual spillage cannot be excluded.

CONCLUSIONS

Although the biological significance of intravascular tumour in pleomorphic adenomas of minor salivary glands remains unknown, the occurrence of metastatic disease has not been demonstrated nor have aggressive behaviour or recurrences.

Localization of prostate-specific antigen-like immunoreactivity in human salivary gland and salivary gland tumors

Immunoreactivity of prostate-specific antigen (PSA), a kallikrein-like enzyme present in the seminal plasma, was demonstrated by indirect immunoperoxidase staining using a PSA antiserum in the apical cytoplasm along the luminal border of small-sized duct epithelial cells of the major salivary (parotid and submandibular) gland of both sexes (56/56, 100%). No PSA-like immunoreactivity was seen in large-sized duct epithelial cells and acinar cells. Minor salivary gland ducts were negative. When inflammatory and atrophic changes were observed, ductal expression of PSA-like immunoreactivity was decreased (12/37, 32%) and the site of intracellular localization often became diffusely cytoplasmic. The immunoreactivity was absorbed by human seminal plasma. Immunoreactivities of prostatic acid phosphatase and sex hormone receptors were undetectable in the salivary gland. Twenty-nine (34%) of 86 salivary gland tumors with ductal differentiation were immunoreactive for PSA mainly in the cytoplasm. A PSA monoclonal antibody ER-PR8 detected immunoreactivity in the prostate but not in the salivary glands or their tumors. Prostate-specific antigen-like immunoreactivity in small-sized (intercalated) duct epithelial cells of the major salivary gland and their tumors may be due to cross-reactivity of the antiserum with kallikrein-like substances.

Histochemical study of magellanic penguin (Spheniscus magellanicus) minor salivary glands during postnatal growth

The histological and histochemical features of the minor salivary glands during postnatal development have been generally associated with the type of food ingested. However, recent studies support the fact that these salivary glands develop independently of the diet; in fact, minor salivary glands have similar morphological and histochemical characteristics in adult individuals of species with different diet regimens. Thus, the aim of this study was to characterize the developmental morphology of the penguin minor salivary glands and to contrast them with minor salivary glands of other species. The tongue, palatine, and mouth cavity (bottom) minor salivary glands of newborn, 1- to 20-day-old, and adult magellanic penguins were studied with hematoxylin-eosin, periodic acid-Schiff, alcian blue, toluidine blue, and lectin histochemistry. Minor salivary glands were present at all ages, although they were only moderately developed in animals less than 15 days old. After this age, glands were abundant in all age groups; in addition, cells from the glandular epithelium were functionally mature and secreted mucins. Nevertheless, in newborn to 15-day-old penguins, mucins were located only at the apical cytoplasm of mucous cells. In all ages, mucous cells displayed periodic acid-Schiff-positive, alcianophilic, and metachromatic reactions; among mucous cells, other orthochromatic cells appeared interspersed. From 15 days on, histochemical reactions became more intense until adulthood, and the cytoplasm of secretory cells was filled with glycoproteins and sulfomucins. Moreover, lectins bound to different oligosaccharides in mucous cells, depending on the stage of maturation of the glands. In conclusion, penguin minor salivary glands are already present at birth, and show progressive and quantitative increases in mucous secretion during postnatal development. These changes are necessary not only for nutrient ingestion, but also for nonimmune protection of the buccal cavity.

Labial salivary gland biopsy for diagnosis of amyloid polyneuropathy

Biopsies of peroneal nerve and labial salivary gland (LSG) were performed in 32 patients with polyneuropathy of unknown origin. Amyloid deposits were detected in 7 LSG (transthyretin=5; amyloid, light chain derived=2) and 6 nerve biopsies. Familial amyloid and light chain amyloid polyneuropathies were subsequently confirmed by relevant tests. We propose that LSG biopsy, a minimally invasive test that may document both sicca syndrome and amyloidosis, should be systematically performed in the investigation of patients with axonal polyneuropathies.

Atypical plasmacytoid monomorphic adenoma of salivary glands of the tongue: cytologic, histologic, immunohistochemical, and ultrastructural findings

We describe the case of an 11-yr-old boy with a 2.5-cm-diameter soft tumor superficially located at the dorsal aspect of the tongue. Fine-needle aspiration cytology smears showed plump epithelioid cells with round to mildly oval nuclei and open chromatin. One or two nucleoli of intermediate size were noticed in each nucleus. These cells appeared singly or in small groups. The findings were interpreted as containing plasmacytoid cells coming from an adenoma of salivary gland origin. The histologic examination of the surgical specimen revealed noncohesive, pleomorphic polygonal cells combining plasmacytoid/rhabdoid cytoplasmic features, with mild to moderate nuclear pleomorphism. One mitotic figure was observed per 10 high-power fields. Immunoreactivity was strongly positive for vimentin and S-100 protein, less intense for the cytokeratins, and negative for smooth muscle actin, muscle-specific actin, myoglobin, and GFAP. No ultrastructural evidences of myogenous differentiation were found. We propose that this case represents an unusual atypical variant of plasmacytoid monomorphic adenoma.

Hyaluronan and CD44 expression in minor salivary gland tumors

OBJECTIVES

Hyaluronan (HA) and CD44 are most likely associated with tumor invasion and metastasis. Malignancies with different degrees of aggressiveness may express different levels and patterns of HA and CD44. The aim of this project was to examine the distribution of HA and CD44 in minor salivary gland tumors to determine if staining could be correlated with biologic behavior or tumor type.

MATERIALS AND METHODS

Biotinylated hyaluronan binding protein as a probe for HA and monoclonal antibodies specific for CD44 were used to stain classic examples of the five most commonly encountered minor salivary gland tumors: monomorphic adenomas, pleomorphic adenomas, polymorphous low grade adenocarcinomas, mucoepidermoid carcinomas, and adenoid cystic carcinomas.

RESULTS

Tumor cells of monomorphic adenomas were negative for both HA and CD44, and tumor capsules were intensely HA-positive. Pleomorphic adenomas exhibited HA and CD44 positivity in both mesenchymal and epithelial components, and HA in capsular tissues. All malignant salivary gland tumors expressed similar intense HA in tumor stroma. HA staining was more intense in stroma than in parenchymal cells. Tumor cells of most adenoid cystic carcinomas were HA-positive, while most polymorphous low grade adenocarcinomas were HA-negative. HA was uniformly distributed throughout supporting stroma of high and low grade malignancies, except for two polymorphous low grade adenocarcinomas (PLGAs) in which HA was more intense at the invading edge of the tumors. CD44 expression was seen only in tumor cells (not stroma) of malignancies, and was of similar intensity in both low and high grade tumors.

CONCLUSIONS

Differences in the expression of HA and CD44 among different types of salivary gland tumors were noted. These findings, however, could not be correlated with known biologic behaviors of the tumor groups studied. Immunohistochemical staining of salivary gland tumors for HA and CD44 may be useful in separating monomorphic adenoma, polymorphous low grade adenocarcinoma and adenoid cystic carcinoma, lesions that may be difficult to distinguish with routine light microscopy.

Polymorphous low-grade adenocarcinoma of minor salivary glands: a study of 17 cases with emphasis on cell differentiation

AIMS

The diagnosis of polymorphous low-grade adenocarcinoma (PLGA) of salivary glands remains difficult for general surgical pathologists. In an effort to understand the morphological heterogeneity of these neoplasms and facilitate their recognition we reviewed the architectural patterns, cell differentiation and immunohistochemical features of 17 case of PLGA.

METHODS AND RESULTS

There were 11 females and six males with a mean age of 58 years. Twelve tumours were located in the palate, two in the posterior third of the tongue, and one each in the upper lip, buccal mucosa and retromolar triangle. Two patients presented with neck metastases. The mean tumour size was 20 mm (range 6-50 mm). The tumour cells were arranged in five architectural patterns: tubules and small duct-like structures; cords and trabeculae; solid nests; cribriform areas and papillae. Twelve (71%) cases were composed of a combination of tubules and small duct-like structures, cords and trabeculae, and solid nests. Cribriform areas with pseudoluminal spaces were seen in six (35%) cases. A focal papillary pattern was evident in three cases and constituted 40% of the tumour in one. Perineural invasion was seen in 13 cases (76%). All cases studied were positive for CAM5.2, 34BE12, vimentin and S100 protein and showed overexpression of bcl-2 protein. Rb protein was present in 13 cases whereas p53 expression was absent in all cases. The average proliferation index (PI) was 7% (range 1-17%). Three patients developed local recurrences with cervical lymph node metastases but no patient died as result of tumour. No morphological features were found to be prognostic for the development of local recurrences or lymph nodes metastases.

CONCLUSIONS

PLGA is a distinctive neoplasm of salivary glands formed by luminal and nonluminal tumour cells with limited patterns of architectural differentiation. The relative proportion of these cells seems to play a significant role in the morphogenesis of these tumours. The overexpression of the bcl-2 protein and the low PI suggest that inhibition of programmed cell death may be involved in the oncogenesis of PLGA.

Complement regulatory proteins in the salivary glands and saliva of Sjögren's syndrome patients and healthy subjects

OBJECTIVE

The aim of this study was to examine the presence of the complement regulatory proteins protectin (CD59), decay accelerating factor (CD55), membrane cofactor protein (CD46) and clusterin (SP-40,40) in connection with the autoimmune exocrinopathy in Sjögren's syndrome (SS).

METHODS

Labial salivary gland biopsy specimens and saliva samples were obtained from SS patients and healthy subjects. The tissue expression of these proteins was assessed by ABC immunoperoxidase techniques. Saliva was analysed by immunoblotting methods.

RESULTS

Tissues from healthy subjects expressed CD59 and CD46 on the apical/luminal surfaces of acinar and ductal epithelial cells. CD59, CD55, and SP-40,40 were expressed in interstitial tissues. In SS tissues, the expression of CD55, CD59, CD46 and SP-40,40 was up-regulated, following the same patterns of tissue localization as the controls. CD46 and SP-40,40 exhibited a much higher staining intensity in SS patients compared to controls. CD55, CD59 and SP-40,40 were present at high concentrations in saliva from SS patients.

CONCLUSION

The presence of complement regulators in our SS patients' saliva and the high expression of these proteins in inflamed salivary gland tissue followed the inflammatory reaction. These regulators may be involved in protecting the exocrine glands from complement mediated injury.

Polymorphous low-grade adenocarcinoma: glial fibrillary acidic protein staining in the differential diagnosis with cellular mixed tumors

Polymorphous low-grade adenocarcinoma is a recently recognized salivary gland carcinoma arising primarily within the oral cavity. Most of these tumors are readily diagnosed; occasionally, however, they may be confused histologically with cellular mixed tumors. The difficulty stems from the bland cytologic nature of cellular mixed tumors and their organizational diversity, together with the irregular pushing growth at their interface with adjacent soft tissues, on histologic examination. Because of this diagnostic problem, we evaluated the use of glial fibrillary acidic protein localization in the differential diagnosis of polymorphous low-grade adenocarcinoma and cellular mixed tumor. Twelve oral polymorphous low-grade adenocarcinomas (polymorphous low-grade adenocarcinoma) and twelve cellular mixed tumors were selected and stained for glial fibrillary acidic protein (glial fibrillary acidic protein) using a strept-avidin-biotin system and examined independently by each investigator. In addition, five tumors with limited material (three cellular mixed tumors and two polymorphous low-grade adenocarcinoma) from the consultation service of one author were evaluated using the same techniques. Two polymorphous low-grade adenocarcinoma stained positive in very focal areas and only in the epithelial component; staining did not occur in the stroma. Fourteen of fifteen mixed tumors focally to diffusely expressed glial fibrillary acidic protein. Only one tumor did not express glial fibrillary acidic protein. In mixed tumors with only focal staining, the most helpful differential diagnostic feature was positive staining of the mesenchyme-like cells adjacent to epithelial nests. We did not find this latter staining pattern in any of the polymorphous low-grade adenocarcinoma.

Sialadenoma papilliferum: an immunohistochemical study of five cases

Sialadenoma papilliferum (SP) is a rare, benign, salivary gland tumor which most commonly arises in the palate. It has a typical biphasic gross and microscopic appearance which distinguishes this tumor from other papillary-like tumors of the oral cavity. This study reports the clinico-pathologic features of 5 new cases and analyzes the morphologic and immunophenotypic features of their cell components. Adluminal epithelial cells of duct-like structures appeared immunoreactive to cytokeratin 19 and to S-100 protein antibodies; two subsets of basally-located cells were identified by means of immunohistochemistry. One cell subset expressed cytokeratin 14, S-100 protein, GFAP, vimentin and smooth muscle actin immunoreactivity; this antigenic profile is consistent with myoepithelial differentiation. The second subset of basal cells expressed cytokeratins 13 and 14 reactivity but it was negative to all other antibodies. Anti-CD 1a and anti-S-100 protein antibodies revealed distinct cells with dendritic processes which resembled Langerhans cells. The extralobular location of SP, the continuity between neoplastic duct-like structures and the surface epithelium along with the presence, within the excretory ducts adjacent to the tumour, of lesions which possibly precede the development of SP give further strength to the hypothesis of an origin from the excretory ducts of this tumor. Langerhans cells seem to be present in sialadenoma papilliferum but their role in this tumor is still unclear.

Myoepithelial tumors of salivary glands: a clinicopathologic, immunohistochemical, ultrastructural, and flow-cytometric study

Myoepitheliomas of the salivary glands remain a controversial entity. To contribute to the knowledge of this entity, 16 myoepithelial tumors of the salivary glands were studied: 12 benign myoepitheliomas (BME) and 4 malignant myoepitheliomas (MME). The clinical and the histologic findings of each case were studied Immunohistochemistry and flow-cytometry analysis were performed from the paraffin-embedded material in 15 cases. An electron-microscopy study was performed in 8 cases. The myoepithelial tumors affected patients of both sexes equally. The mean age of the patients with BME was 54 years, and the mean age of patients with MME was 62 years. Eight cases of BME originated in the parotid gland and 4 cases originated in the minor salivary glands. All the MME developed from a benign preexistent tumor: two developed from a pleomorphic adenoma in the parotid gland, and the other two MME developed in the minor salivary gland from a BME. The myoepithelial tumors were composed of epithelioid, plasmacytoid, spindle, or clear cell types, and they showed a solid or a myxoid pattern of growth. Immunohistochemical studies revealed marked and diffuse positivity to cytokeratins, vimentin, and S-100 protein in all cases. Glial fibrillary acidic protein was positive in 8 cases (53%), and muscle-specific actin and smooth-muscle actin were positive in only 3 cases (20%); they were all cases of BME. Desmin was negative in all tumors. Ultrastructural studies showed the presence of basal membrane, tight junctions, intermediate filaments, and microvilli as well as actin-like filaments lacking focal densities in all cases. But actin-like filaments with focal densities were not identified. Flow cytometry determined that all BME were diploid with a mean proliferative index of 7.73%. Two of the MME were diploid and the other two MME were aneuploid. The mean proliferative index of MME was 11.93%. In conclusion, BME and MME originated in major and minor salivary glands can display different histologic patterns and cellular features. Some immunohistochemical and ultrastructural characteristics have been found in all these neoplasms, which supports the idea that myoepitheliomas are composed by neoplastic modified myoepithelial cells, not fully differentiated. These techniques can be useful for the diagnosis of these tumors.

Sialic acids in the chicken anterior lingual glands detected by lectins combined with enzymatic degradation and oxidizing agents

The chicken anterior lingual glands contain a large amount of sialoglycoconjugates. This study is aimed at discriminating between them, on the basis of the degree of acetylation and the acceptor sugars, by means of lectins combined with neuraminidase digestion and treatment with oxidizing and deacetylating agents. In the anteromedial part of lingual glands, only low concentrations of periodate-labile sialic acid having alpha 2-3,6-galactose and alpha 2-6-N-acetylgalactosamine acceptor sugars were present. Mostly, C7 and/or C8 acetylated sialic acids occurred, while C9 acetylated sialic acid linked alpha 2-3-galactose and alpha 2-6-N-acetylgalactosamine were restricted to some cells. In the anterolateral part, sialic acid linked alpha 2-6-N-acetylgalactosamine was not acetylated, while sialoderivatives alpha 2-3 linked to galactose were mainly C9 acetylated.

Anion exchanger immunoreactivity in human salivary glands in health and Sjögren's syndrome

Salivary gland ducts play a relevant role in saliva secretion through transport processes. Na(+)-independent chloride-bicarbonate anion exchangers (AE) may be involved in these processes by generating ion fluxes into the salivary secretion. In Sjögren's syndrome, a disorder with gland dysfunction, there might be an impaired expression of AE proteins. Here we study AE immunoreactivities in human salivary glands, both in health and in Sjögren's syndrome. Immunohistochemistry was carried out on salivary glands from normal subjects and patients with Sjögren's syndrome, using two monoclonal antibodies against AE1 and AE2. Normal salivary glands showed AE2 immunoreactivity, which was restricted to the epithelium of the ducts, with no staining at the acini. A strong positivity was seen in the basolateral portion of the striated ducts, while interlobular duct cells showed a discrete positivity at their apical pole. In salivary glands from most of the patients with Sjögren's syndrome, AE2 immunoreactivity was absent in the ducts as well as in the acini. In both normal and diseased salivary glands, AE1 immunoreactivity was only located at the erythrocyte membrane. The recently reported AE0 was discarded because no AE0 message was found in salivary glands by reverse transcription polymerase chain reaction. In conclusion, AE2 immunoreactivity is observed in the ducts of normal salivary glands, particularly in the striated ducts. AE2 immunoreactivity is virtually absent in salivary glands from patients with Sjögren's syndrome, which may reflect either a loss of AE2 after inflammatory atrophy, or a primary defect occurring in the disease.

A lectin histochemical study of gustatory (von Ebner's) glands of the horse tongue

In the present work, gustatory glands (von Ebner's glands) of the horse tongue were examined by means of five peroxidase-conjugated lectins (PNA, DBA, SBA, UEA I, WGA), with and without prior sialidase digestion, in order to investigate the presence and distribution of carbohydrate residues in secretory cells and duct cells. The most intense staining of secretory cells was observed with PNA after pre-treatment with neuraminidase. This indicates that the terminal trisaccharide sequence sialic acid- (alpha 2-->3, 6) galactosyl (beta 1-->3) N-acetylgalactosamine is the most frequent oligosaccharide chain present in glycoproteins secreted by horse gustatory glands. Secretory cells also contained oligosaccharides with terminal alpha-N-acetylgalactosamine and N-acetylglucosamine, whereas fucose was found in only a few glandular cells. The apical cytoplasm of duct lining cells reacted with all the lectins except WGA.

E-selectin expression in salivary endothelial cells and sera from patients with systemic sclerosis. Role of resident mast cell-derived tumor necrosis factor alpha

OBJECTIVE

To assess endothelial cell activation in patients with systemic sclerosis (SSc).

METHODS

Concomitant study of salivary gland biopsy tissues and sera for expression of E-selectin and its potent activator tumor necrosis factor alpha (TNF alpha), using immunostaining and enzyme-linked immunosorbent essay.

RESULTS

E-selectin was overexpressed in SSc patients, but not in controls. TNF alpha was detected in mast cells.

CONCLUSION

Mast cell-derived TNF alpha may contribute to endothelial cell activation in SSc.

Immunohistochemical analysis of salivary gland canalicular adenoma

Canalicular adenoma is a newly recognized salivary gland adenoma that may be confused with malignant salivary gland tumors. To better characterize this neoplasm, six examples were investigated with a panel of immunohistochemistry antibodies including anti-keratin (AE1/AE3), anti-epithelial membrane antigen, anti-carcinoembryonic antigen, anti-vimentin, anti-S-100, anti-muscle specific actin, and anti-glial fibrillary acid protein. All canalicular adenomas stained in a similar fashion showing positive staining with anti-keratin, anti-vimentin, and anti-S-100 (6 of 6 cases each). Rare focal staining with anti-epithelial membrane antigen and anti-glial fibrillary acid protein was noted (1 of 6 cases each). This immunohistochemistry staining pattern was compared with those of ameloblastoma, polymorphous low-grade adenocarcinoma, and adenoid cystic carcinoma. Immunohistochemistry may be useful in the distinction of canalicular adenoma from other salivary gland tumors.

Glycoconjugates in the mandibular salivary gland of adult dogs revealed by lectin histochemistry

The glycosidic residues in the mandibular glands of five adult dogs were studied by using seven different lectin-horseradish peroxidase conjugates. In some cases a treatment with sialidase preceded the lectin staining. The mucous acinar cells contained oligosaccharides with alpha- and beta-N-acetylgalactosamine, N-acetylglucosamine and fucose residues, whereas the demilunar cells contained glycoconjugates rich in sialic acid linked to the penultimate disaccharide galactosyl-(beta 1-->3) N-acetylgalactosamine.

Ultrastructure and histochemistry of human anterior lingual salivary glands (glands of Blandin and Nuhn)

BACKGROUND

Specimens of human anterior lingual salivary glands obtained by surgery and by dissection of cadavers were studied ultrastructurally and histochemically.

METHODS

Specimens were obtained by surgery for ultrastructural study. Other specimens for histochemistry were obtained by dissection of fresh cadavers. Tissues for electron microscopy were fixed and processed by conventional means. Formalin-fixed cadaver specimens were subjected to a battery of tests for glycoconjugates.

RESULTS

The anterior lingual salivary glands are composed predominantly of mucous tubules (which come in two distinct sizes: large and small), seromucous demilunes, and rare seromucous acini. Regardless of tubule size, mucous cells are typical in appearance and, like mucous cells in other human salivary glands, contain filamentous bodies. Histochemically, the larger tubules contain neutral glycoproteins, low concentrations of sialoglycoproteins, and large amounts of sulfated glycoproteins. The small mucous tubules contain neutral glycoproteins, much sialoglycoprotein, and relatively small amounts of sulfated glycoprotein. The seromucous cells, whether demilunar or acinar, are identical. They contain numerous secretory granules, which show a spectrum of internal patterns from one individual to another. These cells have considerable concentrations of neutral- and sialoglycoproteins and lower concentrations of sulfated glycoproteins. Contrary to previously published reports, we could find no differences in the ratio of mucous to seromucous cells along the anterior-posterior lingual axis: there was no gradient of seromucous cells in our specimens. The ducts in the anterior lingual salivary glands are not precise counterparts of those in the major salivary glands, since the former have no capsules, hence lack lobulation. Without these familiar structural landmarks, the only duct that can be identified with certainty is the intercalated duct, and then only if it is in continuity with or lies close to a secretory endpiece. Such ducts consist of simple cuboidal epithelium of prosaic appearance. The ductular epithelium gradually thickens and gives rise to what appear to be excretory ducts consisting of columnar cells with few mitochondria. Scattered within the walls of the larger ducts are patches of typical striated ducts wherein the taller cells display basal striations resulting from highly folded basal plasma membranes and numerous, vertically oriented, virgulate mitochondria. In other atypical regions of the excretory duct, basal cells may have a primary cilium that juts into the intercellular space.

CONCLUSIONS

There is a high degree of structural variability in human anterior lingual salivary glands. Because of the technical difficulties in collecting pristine saliva from these glands, the precise function(s) of these organs remains unknown.

Simple mucin-type carbohydrate antigens in major salivary glands

Simple mucin-type carbohydrate antigens Tn, sialosyl-Tn and T are often markers of neoplastic transformation and have very limited expression in normal tissues. We performed an immunohistological study of simple mucin-type carbohydrate antigens, including H and A variants, with well-defined monoclonal antibodies (MAb) on frozen and paraffin-embedded normal salivary gland tissue from 22 parotid, 14 submandibular, six sublingual, and 13 labial glands to elucidate the simple mucin-type glycosylation pattern in relation to cyto- and histodifferentiation. The investigated carbohydrate structures were predominantly observed in the cell cytoplasm, most often in the supranuclear area, suggesting localization to the Golgi region, whereas ductal contents were unstained. Mucous acinar cells expressed Tn, sialosyl-Tn, and H and A antigens, regardless of glandular location. Serous acinar cells, on the other hand, expressed A, H, and inconstantly sialosyl-T, Tn, and sialosyl-Tn antigens in major salivary glands, whereas serous cells of minor (labial) salivary glands expressed H exclusively, Tn and sialosyl-T antigens inconstantly, but never sialosyl-Tn and A antigens. The difference may be related to a more simple cytodifferentiation of serous cells of minor (labial) salivary glands as compared with major salivary glands. Duct cells in major salivary glands expressed A, H, and inconstantly T, sialosyl-T, and Tn antigens, whereas minor (labial) salivary glands ducts exclusively expressed H, T and sialosyl-T antigens, differences that may be related to dissimilarities in the duct system. Myoepithelial cells and basal cells exclusively expressed T and sialosyl-T antigens, which may prove useful in studies of salivary gland tumors, since these cells are known to play a key role in the histological characteristics of some salivary gland tumors. The results indicate a similar glycosylation pattern in the different major salivary glands, whereas minor (labial) salivary gland differ slightly in serous and duct cells. The limited and exclusive intracellular expression of the immature Tn, sialosyl-Tn, and T antigens indicates that these structures may be of value as markers of salivary gland tumors.

Early detection of lymphomas in Sjögren's syndrome by in situ hybridisation for kappa and lambda light chain mRNA in labial salivary glands

Sjögren's syndrome (SS) is an autoimmune disease characterised by a generalised lymphoproliferation. Patients have an increased risk of developing lymphomas which are usually of the type associated with mucosa-associated lymphoid tissue (MALT). Histological examination of the minor salivary glands of the lower lip is a common and useful diagnostic test for SS but has not been able to provide information with regard to potential malignant change. In this study, a sensitive in situ hybridisation technique for the detection of kappa and lambda immunoglobulin light-chain mRNA was applied to labial salivary glands of 14 patients with SS. 7 cases showed light chain restriction, in 5 cases this was kappa(kappa:lambda ratio > 8.0) and in 2 it was lambda(kappa:lambda ratio < 0.6). Of these 7, 5 developed lymphomas--4 were low grade lymphomas of MALT type and the fifth patient died of disseminated lymphoma. The finding of light chain restriction in lip minor salivary glands is strong evidence of a monoclonal population of B-cells at this site. It is concluded that in patients with SS who develop lymphomas, dissemination of malignant cells may result in detectable disease in the minor salivary glands. Determination of kappa:lambda ratios in labial minor salivary glands may thus provide important prognostic information.

Fibrinolysis-resistant fibrin deposits in minor labial salivary glands of patients with Sjögren's syndrome

Minor labial salivary glands obtained at biopsy from 12 patients with Sjögren's syndrome were investigated by immunomorphological methods for the presence of fibrinolysis-resistant fibrin deposition. Fibrin could be found in extracellular localization between individual inflammatory cells infiltrating minor salivary glands. In the areas surrounding mononuclear infiltrations the labeling for fibrin showed an essentially fibrillar pattern. Staining for factor XIII A was observed over fibrin deposits and in large, stellate cells not showing reaction for fibrin. Here it is demonstrated that factor XIII A+ tissue macrophages are in an intimate relationship with fibrin deposits. The authors suggest that tissue macrophages may play a regulatory role in fibrin accumulation in association with autoimmune inflammation and consequently in demarcation of the inflamed tissue.

[Morphology of the minor salivary glands in Sjogren's disease]

Histochemical, immunohistochemical and histomorphometrical changes in sialadenitis have been studied on 33 biopsies of labial salivary glands (LSG) from patients with primary Sjogren's syndrome. The control group consisted of 10 biopsies from persons without oral cavity inflammatory diseases. A direct relation was established between xerostomia stage and the degree of LSG parenchyma substitution for the inflammatory cell infiltrate. Dependence of LSG tissue damage on local immunopathologic reaction was detected. With a highly active inflammatory reaction the changes were characterized by cellular hypersensitivity including inflammatory cell infiltrate (T-lymphocytes, macrophages, neutrophils), increased vascular permeability, destructive and proliferative changes of the intralobular ductuli and acini. Reduction in inflammatory activity was accompanied by a decrease in the number of macrophages and neutrophils, an increase in the number of plasma cells and mast cells, higher compensatory hypertrophy of the serous cells of semicircular mixed acini, secretion products status, as well as intralobular sclerosis and lipomatosis.

Estrogen receptor assay in polymorphous low-grade adenocarcinoma and adenoid cystic carcinoma of salivary gland origin. An immunohistochemical study

An apparent relationship between breast cancer and salivary gland cancer has been observed, and there is one report in the literature that describes estrogen receptors in normal salivary gland and salivary gland cancers. With the use of a monoclonal antibody against estrogen receptor protein and the avidin-biotin immunoperoxidase procedure, we were unable to demonstrate estrogen receptors in formalin-fixed paraffin-embedded sections of either polymorphous low-grade adenocarcinoma or adenoid cystic carcinoma of salivary gland origin.

EGF and EGF-r immunoexpression in Sjögren's syndrome secondary to rheumatoid arthritis. Correlation with EBV expression?

Minor labial salivary gland biopsies from 25 patients with secondary Sjögren's syndrome (SS) suffering from rheumatoid arthritis and from 11 patients complaining of ocular dryness associated with rheumatoid arthritis without proven SS, were studied for the immunohistochemical expression of Epidermal Growth Factor (EGF) and its receptor (EGF-r). Minor labial salivary glands from 11 healthy individuals were used as the control. Furthermore, the results were correlated with data retrieved from a previous study on EBV expression by the in situ hybridization method in the same specimens. In 16/25 cases of secondary SS the epithelial duct cells expressed both EGF and EGF-r, particularly in the areas of lymphoepithelial lesion and tissue destruction. Eleven of these cases expressed a positive EBV hybridization signal. In contrast, only 3/11 patients with ocular dryness and 2/11 cases from the group of healthy individuals showed immunoreactivity for EGF/EGF-r. A positive EBV signal was detected in 3/11 and 1/11 of these cases, respectively. These results indicate that EGF and EGF-r may play a crucial role in the evolution of the disease under the constant influence of EBV, which seems to up-regulate the expression of the EGF/EGF-r system.