Primary malignant lymphoma of the salivary gland: a tumor of mucosa-associated lymphoid tissue

The clinical, morphologic and immunohistochemical features of 10 cases of the low-grade mucosa-associated lymphoid tissue (MALT) lymphoma of salivary glands are described. Although the initial histologic diagnosis in nine of these cases was myoepithelial sialadenitis, the diagnosis of primary salivary gland MALT lymphoma was based on the demonstration of light chain restriction and on morphologic characteristics. Histologic study showed a characteristic cytology, which included centrocytoid cells (composed of small centrocytes and monocytoid B cells) and a varying degree of plasma cell differentiation; the occurrence of epithelial or acinar invasion by neoplastic centrocytoid cells; and the presence of reactive lymph follicles among the neoplastic cells. Furthermore, multinucleate giant cells resembling Warthin-Finkeldey cells were detected in seven cases. In the light of these findings, cases previously diagnosed as myoepithelial sialadenitis require careful assessment and nine out of 32 cases are, in reality, examples of primary salivary gland MALT lymphomas. Immunohistochemical analysis of paraffin sections revealed the following characteristic immunophenotype of MALT lymphoma: L26, KiB3 and LN2 positive, and a monotypic immunoglobulin pattern (predominantly IgM/kappa). It was of interest that salivary gland parenchyma, infiltrated by neoplastic centrocytoid cells, reacted with LN3 for cells expressing human leukocyte antigen-DR (HLA-DR) antigens. Whereas salivary gland epithelia devoid of a neoplastic invasion were invariably negative for LN3. This suggests a lymphocyte-mediated role in salivary epithelial HLA-DR expression. It appears that HLA-DR expression is an inducible phenomenon in MALT lymphomas of salivary gland.     

Cell population changes during atrophy and regeneration of rat parotid gland

Limited data exist regarding the changes in number and location of myoepithelial cells during salivary gland atrophy and regeneration. Through the use of double immunohistochemical labeling for muscle-specific actin and amylase coupled with morphometric analysis, this study investigated the changes in distribution and proportion of cell types during salivary gland atrophy/regeneration phases in a model previously used to study proliferation in rat parotid gland. The double immunohistochemical labeling clearly showed the changes in proportion of cell types in the atrophying and regenerating glands. The morphometric analysis showed that the relative myoepithelial area increased (as did the intercalated duct and striated duct areas) as the gland atrophied. Myoepithelial cells occupied 19.0% of the total epithelial area by day 7 of atrophy, up from 2.7% in the resting gland. Regeneration of acinar cells was obvious 1 day after duct release. The myoepithelial cell area decreased to 4.3% of the total epithelial area by day 14 of regeneration; this value was higher than the percentage of area in the resting gland (p = 0.02). The relative areas of acinar, striated duct, and intercalated duct cells returned to resting levels after 14 days of regeneration. The morphometric and histologic results of this study show that the parotid gland is capable of regenerating to essentially normal anatomic condition after 7 days of gland atrophy and then 14 days of regeneration. Each type of cell, however, responded to the atrophy and regeneration differently. Atrophy of salivary glands from radiation therapy, Sjögren's syndrome, or sialadenitis is an important clinical problem. Study of the salivary gland response to atrophy and regeneration may provide a framework for designing strategies for the radioprotection of salivary glands or methods by which to treat or reverse the effects of gland atrophy.     

Immunohistochemical study of palatal salivary glands of denture wearing patients

The binding pattern of antibodies against different cytokeratin (CK) polypeptides, tissue polypeptide antigen (TPA), carcinoembryonic antigen (CEA), lactoferrin (Lf), lysozyme (Ly) and secretory component (SC) in palatal glands (PSG) of long-term denture wearing patients has been studied to investigate immunohistochemically the localization of these marker proteins in normal PSG and in denture-induced sialadenitis of PSG. The study included palatal gland biopsies from 28 patients (15 f, 13 m; mean age 59 years), 17 of them with normal PSGs, 8 with focal obstructive sialadenitis, and 3 with diffuse sialadenitis. Presence of CK and TPA was found in all intra- and extraglandular salivary ducts, in the basophilic portions of acini, in some mucous acini, and in all atrophic acini. Increased expression of CEA and Lf was observed in inflammed areas of PSG which, on the other site, were devoid of Ly and SC. In the mucous acini of healthy PSG considerable basal Ly immunoreactivity was seen. SC was localized in almost all ductal cells and in some acinar cells. Appearance of Lf in the ductal cells of PSG indicates an early sign of palatal sialadenitis. Some distinctions in the expression pattern of the marker proteins between the mucous acini of major salivary glands and PSG point to differences in the functional activities of either group of salivary glands.     

Immunohistochemical study of palatal salivary glands of denture wearing patients

The binding pattern of antibodies against different cytokeratin (CK) polypeptides, tissue polypeptide antigen (TPA), carcinoembryonic antigen (CEA), lactoferrin (Lf), lysozyme (Ly) and secretory component (SC) in palatal glands (PSG) of long-term denture wearing patients has been studied to investigate immunohistochemically the localization of these marker proteins in normal PSG and in denture-induced sialadenitis of PSG. The study included palatal gland biopsies from 28 patients (15 f, 13 m; mean age 59 years), 17 of them with normal PSGs, 8 with focal obstructive sialadenitis, and 3 with diffuse sialadenitis. Presence of CK and TPA was found in all intra- and extraglandular salivary ducts, in the basophilic portions of acini, in some mucous acini, and in all atrophic acini. Increased expression of CEA and Lf was observed in inflammed areas of PSG which, on the other site, were devoid of Ly and SC. In the mucous acini of healthy PSG considerable basal Ly immunoreactivity was seen. SC was localized in almost all ductal cells and in some acinar cells. Appearance of Lf in the ductal cells of PSG indicates an early sign of palatal sialadenitis. Some distinctions in the expression pattern of the marker proteins between the mucous acini of major salivary glands and PSG point to differences in the functional activities of either group of salivary glands.     

Characterization of lymphoid infiltrates in chronic obstructive sialadenitis associated with sialolithiasis

BACKGROUND: Chronic obstructive sialadenitis is characterized by acinar atrophy, lymphocytic infiltrates and progressive fibrosis. The immunological mechanisms involved in the pathogenesis of this disease are, for the most part, unknown. The aim of the present study was to characterize the lymphocytic infiltrates in chronic obstructive sialadenitis associated with sialolithiasis. METHODS: Paraffin-embedded tissue samples from 23 affected submandibular glands were immunostained for T-cells (CD3, CD4, CD8), cytotoxic T-cells (granzyme B), B-cells (CD20), plasma cells (CD38) and macrophages (Ki-M1P). RESULTS: CD4-positive subsets were the predominant cells, and they were located mainly periductally. Isolated intraepithelial CD8-positive cytotoxic T-cells associated with ductal epithelial cell destruction were observed in all cases. B lymphocytes were restricted to lymphoid follicles located periductally and around intralobular ducts. In early stages of the disease, a large number of CD38-positive plasma cells were distributed diffusely in the periacinar area. With progression of the disease, conspicuous clusters of plasma cells were located especially between atrophic acini adjacent to fibrotic tissue. An intimate relation between the lymphocytic infiltrates and the ductal epithelium, the target of the inflammatory process, was observed. CONCLUSION: The composition and distribution of inflammatory cells suggest that intraepithelial infectious agents may be the cause of the inflammatory reaction and the progressive fibrosis in this disease.     

HLA-DR antigens in normal, inflammatory, and neoplastic salivary glands

A monoclonal antibody to HLA-DR antigens that is reactive in formalin-fixed tissues was used with the immunoperoxidase method to evaluate 212 salivary gland lesions (normal, nonspecific, and autoimmune inflammatory, benign, and malignant tumors). Results of immunostaining showed that (1) intercalated ducts, myoepithelial cells, and acinous cells of normal salivary glands express HLA-DR antigens, (2) autoimmune salivary gland disease results in greater HLA-DR expression than that seen in nonspecific inflammatory lesions or normal glands, (3) stromal cells associated with benign and malignant salivary gland tumors express HLA-DR antigens, and (4) numerous benign and malignant salivary gland tumors express HLA-DR antigens. It was of interest that lymphocyte-rich Warthin's tumors displayed epithelial immunoreactivity, whereas oncocytomas devoid of a lymphocytic component were invariably negative. This suggests a lymphocyte-mediated role in salivary epithelial HLA-DR expression. It appears that HLA-DR expression is both a normal and an inducible phenomenon in salivary glands, salivary gland neoplasia, and the desmoplastic host response. There is no discriminatory role in the immunologic detection of HLA-DR for differential diagnosis of salivary gland tumors.     

Phenotyping of immunocompetent cells in normal labial and palatal salivary glands and in non-autoimmune sialadenitis

Different types of inflammatory cells in healthy major and minor salivary glands (SG), including those in labial and palatal non-autoimmune sialadenitis, were quantified immunohistochemically. Plasma cells, mainly IgA type predominated in all SG types, with the smallest number seen in the palatal glands. The numbers of common leukocyte antigen (CLA) reactive lymphocytes were greater in major SGs than in minor ones and were predominantly UCHL1 positive T cell type. Macrophages and neutrophils were absent in palatal glands, rarely present in labial ones and usually present in major SGs. Increases in the number of IgG and IgM plasma cells and lymphocytes (CLA+) which include both UCHL1+ T and L26+ B cell types, were found in non-autoimmune labial and palatal sialadenitis. There was no significant correlation between the number of the inflammatory cells and the degree of glandular atrophy in both labial and palatal non-autoimmune sialadenitis. Increase in their number represents a protective response of these glands in contrast to the inflammatory cells in major autoimmune sialadenitis playing there a pathogenetic role.     

Lipofuscin in salivary glands in health and disease.

Lipofuscin granules were observed in normal salivary glands (parotid, submandibular, and minor salivary glands). The pigment was confined mainly to the epithelial cells of the intralobular ducts, but isolated granules were also found in acinar cells and myoepithelial cells. In chronic sialadenitis pigment granules were found in the intralobular epithelial cells and in macrophages in the surrounding ionnective tissue. In benign epithelial tumors pigment granules were observed within neoplastic epithelial cells and in macrophages in the stroma, while malignant tumors displayed pigmented granules only in macrophages in the stroma.     

Production of microliths and sialadenitis in rats by a short combined course of isoprenaline and calcium gluconate.

The relationship between microliths and sialadenitis in man is unclear, so an attempt was made to investigate it experimentally in rats with the use of isoprenaline and calcium gluconate either alone or combined. The acini of the submandibular and parotid glands of rats that were given isoprenaline were enlarged, and degenerate acinar cells were seen, with extravasated secretions in the submandibular gland. Similar changes were seen in the submandibular and parotid glands of rats that were given isoprenaline combined with calcium gluconate; in addition, ductal microliths with regions of atrophic sialadenitis were observed. The results suggest that there is temporary obstruction to the salivary flow after isoprenaline is injected, and in the rats that were also given calcium gluconate some of the stagnant saliva calcified to form microliths, which produced a lasting obstruction and obstructive sialadenitis. This supports the possibility that microliths, which are present in normal salivary glands of man, are a primary etiologic factor in sialadenitis.     

Ultrastructural localization of microliths in salivary glands of cat

Although microliths occur in normal human salivary glands and may be an aetiological factor of sialadenitis, little is known of their natural history. In an attempt to remedy this, we investigated a large archival collection of normal and experimental feline parotid, submandibular and sublingual salivary glands. In submandibular and sublingual glands, microliths were detected ultrastructurally in: all types of acinar secretory cells; myoepithelial cells; ductal cells; lumina; intercellular spaces; basement membrane; stroma; macrophages; multinuclear giant cells; and neutrophils. Microliths were not detected ultrastructurally in parotid glands. Microliths appear to form in acinar cells during autophagy and in stagnant secretory material in lumina. Microliths appear to be removed by secretion in the saliva, discharge from cells laterally and basally, and engulfment by macrophages. There appears to be a turnover of microliths, which possibly is upset by secretory inactivity with a resulting accumulation that leads to localized obstruction and sialadenitis.     

Immunoreaction of keratin, actin, S-100 protein and rat-EGF in ductligated rat salivary glands

Duct-ligated submandibular and sublingual glands of rats were evaluated immunohistochemically for changes in keratin (MoAb 1164), actin, S-100 protein and rat-EGF (rEGF). Normal salivary glands were reactive for keratin, S-100 protein and rEGF in the granular convoluted tubule (GCT) and duct cells, and for actin in the myoepithelium. Submandibular glands showed a marked reduction of S-100 protein and rEGF staining following duct ligation, and no increased staining of proliferating epithelial cells of the late stage in duct ligated glands. Sublingual glands revealed no marked changes for actin staining in myoepithelial cells, irrespective of atrophic changes occurring in acinar and duct cells after duct ligation. Immunohistochemical patterns differed for each type of gland; changes associated with the obstructive lesion were more prominent in the submandibular gland.     

大鼠颌下腺腺病毒介导荧光素酶基因转导及组织学变化

目的 观察大白鼠颌下腺腺病毒介导的荧光素酶基因转导及其组织学变化。方法 将40只Wistar大鼠随机分为5组，经颌下腺导管转导腺病毒介导荧光素酶基因重组体即AdCMVLuc,3d及1、2、4、8周后观察其基因表达及病理变化。结果 颌下腺转基因表达3d时最高，以后逐渐下降，至4周、8周时仍可测到表达。组织病理学变化：3d-1周时可见腺泡受挤压、腺导管扩张；2周时部分腺泡轻度萎缩，腺泡间距离加大；小叶内及小叶间导管周围淋巴细胞呈灶状浸润；4周时可见有腺泡及腺泡腔结构变清晰；8周时腺泡、导管基本恢复正常，炎症不明显。超微结构变化；注入基因后3d，腺泡和导管细胞内可见大量粗面内质网，粘液腺泡中粘液滴增多，融合成片；1周后，导管腔的微绒毛突起减少，胞质内可见线粒体显著增多；2周及4周，腺泡腔可见少量的微绒毛突起及细丝网状物，粘液腺泡中可见粘液滴。基底部可见粗面内质网，基底膜增厚。结论 本研究报道了腺病毒介导的大鼠颌下腺基因转导后的超微结构变化，提示腺体蛋白合成体系功能活跃，大鼠涎腺基因转导能产生生物活性蛋白，腺体有明显炎症反应。     

Plasticity in Differentiation of Salivary Glands: The Signaling Pathway That Induces Dedifferentiation of Parotid Acinar Cells

Sjögren's syndrome and therapeutic radiation for head and neck cancers result in atrophy of the salivary glands and consequent xerostomia (dry mouth). To clarify the mechanisms of salivary gland dysfunction, we have established a system for the primary culture of parotid acinar cells. We found that the expression patterns of claudins are remarkably changed during culture. These changes are considered a process of dedifferentiation since the expression levels of other differentiation markers also alter. Acinar markers, such as amylase and aquaporin-5, are decreased and, in contrast, duct markers such as claudin-4 and cytokeratin-14 are increased. In the late phase of culture, mesenchymal markers begin to be expressed. These results suggest that acinar cells transiently change to duct-like cells during epithelial mesenchymal transition. Inhibitors of Src and p38 MAP kinases suppress these changes and simultaneously increase the expression of acinar marker proteins. Activation of p38 MAP kinase occurs during cell isolation from the parotid glands, which is suppressed by Src kinase inhibitors. Therefore, cellular stresses caused by cell isolation trigger the signal that induces the transition to duct-like cells and dedifferentiation. There is a possibility that salivary acinar cells have differentiation plasticity, which is regulated by the Src-p38 MAP kinase signaling pathway.     

P-glycoprotein expression in human major and minor salivary glands

Sodium pump and carbonic anhydrase activity have been described in the salivary glands. However, it remains to be elucidated whether these energy sources are used for secretion, excretion or both. In addition, the differences in the function of excretion and the role of the excretory duct cells are currently unknown in salivary glands. Expression of P-glycoprotein (P-gp), which is an ATPase-binding efflux pump, was tested in normal major and minor salivary glands from humans. P-gp was distributed on the basolateral membrane of serous acinar cells in the major salivary glands and the minor salivary glands. In particular, it was found to be present on the basolateral membrane and cytoplasm of acinar demilunar cells in the anterior lingual gland. Intense expression was identified in the basolateral membrane of the striated duct cells of the major salivary glands. P-gp was distinctly positive in the basolateral and/or luminal membranes of the initial part and in the luminal membrane of the terminal part of the excretory duct cells of the major salivary glands, whereas it was positive in the luminal membranes of both the initial part and the terminal part of the excretory duct cells of the minor salivary glands. These disparate distributions between the major and the minor salivary glands suggest different physiological excretions in the striated duct. P-gp may be physiologically involved in an important part of the transporter system, not only in the acinar serous cells and the striated duct cells, but also in the excretory duct cells in the salivary glands.     

A comparative study of the role of atresia and stenosis of the outflow duct of a salivary gland in the pathogenesis of dystrophic and inflammatory changes]

Experiments were carried out with submandibular salivary glands of 20 dogs. Complete obturation of the submandibular duct (in 10 animals) was achieved by binding this duct. Partial impairment of the saliva flow from the gland was induced in 10 animals by fixing a metal ring on the duct. The experiment has demonstrated that both complete and partial obturation of the salivary duct result in the development of chronic sialadenitis. Partial obturation of salivary outflow from the gland did not result in an acute inflammation but in a flaccid process, slowly developing dystrophic changes in acinar cells, gradually developing sclerosis of the glandular parenchyma and stroma. These data indicate a direct relationship between the intensity of dystrophic changes in the salivary gland and the severity of impairment of salivary discharge.     

Effects of tobacco and diuretics on human palatal salivary glands

The prevalence of macrophotographically documented sialadenitis in the palatal mucosa of 184 probands, aged 23 yr or older, was studied in the Koster Health project. A total of 75 (mean age 58.9) revealed inflammatory changes around the duct orifices of the palatal glands. In 10, biopsies were performed for histomorphologic analyses to confirm the diagnosis of sialadenitis. Statistics with matched pairs showed a significantly higher ratio of tobacco use among individuals with sialadenitis than among those with clinically unchanged palatal gland orifices. A relationship between the use of diuretics and sialadenitis was also statistically significant. It can be concluded that tobacco use and diuretics may induce inflammatory changes in the palatal glands and that macrophotography of the palatal mucosa may serve as a valuable, non-invasive method for scoring sialadenitis.     

Binding of wheat-germ agglutinin to glycoconjugates in the salivary glands of reserpinized rats

Salivary glands from adult rats that had received reserpine for 1, 3 or 7 days and from saline-treated controls were treated with rhodamine-labelled wheat-germ agglutinin conjugates (WGA-TRITC) to localize and characterize the distribution of glycoconjugates. Fluorescent and morphometric analysis of the parotid, submandibular and sublingual glands indicated that each gland responded differently to reserpine treatment. Parotid gland acinar cells and ducts showed no change in pattern or intensity of WGA-TRITC staining after reserpine. Mucous acinar cells of the submandibular gland had increased WGA binding and an accumulation of WGA-positive material in duct lumina after 3-7 days of reserpine. Morphometric analysis showed that the maximal increase in submandibular acinar-cell size occurred after 1 day of reserpine treatment. In sublingual glands, there was no detectable increase in mucous acinar-cell staining, but progressive accumulation of WGA-positive material was seen in duct lumina after 7 days of reserpine. As WGA binds to N-acetyl-glucosamine and N-acetyl-neuraminic acid residues, it may be that the eventual blockage of the duct system is related to increased production and secretion of glycoconjugates that contain these carbohydrates.     

Immunohistochemical localization of lectins in normal salivary glands and mucoepidermoid carcinoma

5 kinds of Lectins (ConA, PNA, RCA, SBA and WGA) were used to observe the immunochemical localization of lectins in the cells of normal salivary glands and mucoepidermoid carcinoma. The result shows that in normal salivary glands ConA staining was found only in duct cells and serous acinar cells. Intercalated duct cells and striated duct cells of parotid and submandibular gland displayed RCA and WGA staining. The duct cells of sublingual gland and palatine gland did not react with lectin RCA. The ductal and acinar cells of normal salivary gland were not stained by PNA. Serous acinar cells of sublingual gland could be stained by SBA but mucous cells were negative. In tumor cells, ConA, RCA, WGA showed extensive staining which suggests the tumor cells contain similar glycoproteins as the normal duct cells. PNA was found in squamous epithelial cells but not in glandular epithelium. Its presence in tumor cells may indicate the degree of differentiation of these cells. Epidermoid and mucous cells of the tumor were also stained by 54 Kd antikeratin antibody. The results suggest this tumor may originate from the ductal cells of salivary gland.     

Extracellular matrix molecules in chronic obstructive sialadenitis: an immunocytochemical and Western blot investigation

The exact pathomechanism of inflammation progress and fibrosis in chronic sialadenitis is unknown. Connective tissue growth factor (CTGF), matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) have been implicated in the pathogenesis of various fibrotic conditions. These factors are thought to be essential in the regulation of extracellular matrix turnover and the development of tissue fibrosis. In the present study, the expression of CTGF, MMP-2, -3, -9, -13 and TIMP-3 was examined in chronic obstructive sialadenitis. Tissue samples of 13 patients with chronic sialadenitis of the submandibular gland associated with sialolithiasis and 4 normal tissue samples of the submandibular gland were analyzed immunohistochemically and by Western blot analysis. An intense CTGF immunoreactivity was observed in the ductal system of inflamed salivary glands, whereas in normal glands no reactivity or a very low CTGF immunoreactivity was present. Immunohistochemical studies revealed a low to strong reactivity of MMP-2, -3, -9, -13, and TIMP-3 in the ductal system, in acinar cells and in lymphomonocytic infiltrates in normal and inflamed tissues. The expression of MMP-2, -3, -9, -13, and TIMP-3 was confirmed by Western blotting in all cases. Over-expression of CTGF in chronic obstructive sialadenitis suggests that this factor may play a role in glandular fibrosis. However, the physiological role of MMP-2, -3, -9, -13, and TIMP-3 in normal glands, as well as their possible role in inflammation progress and fibrosis in chronic obstructive sialadenitis, remains to be elucidated.