Characterisation of follicular dendritic cells in labial salivary glands of patients with primary Sjögren syndrome: comparison with tonsillar lymphoid follicles.

OBJECTIVE: To localise and characterise follicular dendritic cells (FDC) present in autoimmune lesions of primary Sjögren syndrome. METHODS: Cryostat sections of labial salivary glands from 15 patients with primary Sjögren syndrome were examined by an indirect immunoperoxidase technique and monoclonal antibodies to a panel of dendritic cell markers. Tonsils from two controls were also examined for the same markers. RESULTS: FDC were localised in the centre of 75% of lymphoid focal structures in labial salivary glands biopsies. FDC in labial salivary glands of patients with primary Sjögren syndrome expressed CD35, CD11c, and CD106 (VCAM-1) in a pattern similar to FDC in tonsils, but they did not express either CD14 or CD11b. This indicates that they may not be of myeloid origin, while FDC in tonsillar lymphoid follicles strongly expressed both CD14 and CD11b. FDC in labial salivary glands of patients also lacked VLA-2 alpha and VLA-3 alpha, which were expressed by FDC in tonsils. CONCLUSIONS: The characteristic phenotype and origin of these cells may be of importance in the immune responses involved in Sjögren syndrome and the retention of infiltrating lymphocytes in the glands.

Expression of selectins (CD62 E,L,P) and cellular adhesion molecules in primary Sjögren's syndrome: questions to immunoregulation.

Adhesion molecules are important signal transmitters of the immune system and may mediate the homing of leukocytes to sites of inflammation. The aim of this work was to examine the presence of selecting and cellular adhesion molecules on epithelial and endothelial cells in labial salivary glands (LSG) in Sjögren's syndrome (SS). LSG biopsies were obtained from patients with primary SS (n = 31) and normal subjects (n = 21). Cryostat sections were examined with indirect immunoperoxidase. Epithelial cells in LSG from both patients and controls expressed LFA-3 (CD58) and Hermes I (CD44). A significantly increased number of acinar and ductal epithelial cells in LSG from patients expressed class I MHC (74%, as mean percentage of ductal epithelial cells) (P < 0.05), HLA-DR (58%) (P < 0.0001), and HLA-DQ (11%) (P < 0.001). To a lesser extent limited ICAM-1 (CD54) epithelial expression (6%) was noted only in a few biopsies from patients but none of the controls. Epithelial cells did not express any of the selectins CD62 E, L, and P and sometimes they expressed sialyl Le(x) (a ligand for selectins). Although the number of endothelial structures expressing ICAM-1 (CD54), HLA-DR, HLA-DQ, and class I MHC (per surface area) was increased in patients (P < 0.05), this may be due to the total increase of number of endothelial structures (P < 0.05) (Von Willebrand factor +ve) as part of the chronic inflammatory process. A smaller proportion of endothelial structures expressed E-selectin (CD62 E) (32%) and to a lesser extent VCAM-1 (CD106) (approximately 7%) as detectable only in some LSG from patients. P-selectin (CD62 P) was demonstrated on about one-third of endothelial structures in LSG from patients. Infiltrating mononuclear cells expressed CD11a (68%), CD18 (73%), CD11b (13%), CD11c (21%), CD58 (13%), CD4 (44%), CD8 (17%), CD62L (L-selectin) (18%), CD49d (38%), CD49e (15%), CD2 (56%), and CD44 (77%). The relatively reduced number of CD62 L +ve lymphocytes may be due to shedding of that molecule after activation. Sialyl Le(x) was not detectable on infiltrating lymphocytes. Although infiltrating mononuclear cells were activated, as evidenced by their expression of HLA-DR (72%) and ICAM-1 (55%), they did not express IL-2Ralpha (CD25, confirmed by two antibodies 2A3 and ACT1) or IL-2Rbeta (CD122), except rarely (< or = 1%). In some biopsies, CD106 and CD11c were localized on lymphocytes at the central areas of periductal lymphoid follicles with the appearance of dendritic cells. We conclude that adhesion molecules probably play a major role in the pathogenesis of SS. The pattern of expression of these molecules demonstrates a regulated altered activation in the glands associated with this disease. The glands may be subject to specific regulatory factors, in addition to proinflammatory cytokines.

Modulation of endothelial cell expression of ICAM-1, E-selectin, and VCAM-1 by beta-estradiol, progesterone, and dexamethasone.

The aim of this study was to examine the effects of beta-estradiol, progesterone, and dexamethasone on cytokine-stimulated endothelial cell expression of adhesion molecules. TNF-alpha (250 U/mL) and IL-1 alpha (50 U/mL) were used to stimulate the endothelial cells for 6 or 23 hr in vitro. Indirect immunofluorescence and flow cytometry were used to quantitate expression of adhesion molecules. After 6 hr stimulation with TNF-alpha increased expression of E-selectin (P < 0.03) was noted with beta-estradiol. Strong suppression of ICAM-1 (P < 0.005) and E-selectin (P < 0.005) expression was evident with dexamethasone, which did not influence VCAM-1 expression. After 6 hr stimulation with IL-1 alpha suppression of E-selectin was observed with progesterone (P < 0.001). Dexamethasone had strong suppressive effects on ICAM-1 (P < 0.001), E-selectin (P < 0.0001), and VCAM-1 (P < 0.0002). After 23 hr stimulation with IL-1 alpha or TNF-alpha none of the examined steroids showed a significant effect on the fluorescence intensity of adhesion molecules, although there was a slight increase of the percentage of ICAM-1 positive cells with high concentrations of beta-estradiol after stimulation with TNF-alpha. Beta-estradiol and progesterone are modulatory factors of E-selectin expression on endothelial cell in vitro. Dexamethasone reduces adhesion molecule expression over endothelial cells after cytokine stimulation. These effects may be important in understanding the role of these steroids in autoimmune diseases.

In vivo and in vitro expression of adhesion molecules by peripheral blood lymphocytes from patients with primary Sjogren's syndrome: culture-associated enhancement of LECAM-1 and CD44.

The interaction of adhesion receptors on lymphocytes with their ligands over endothelial cells provides the mechanism by which lymphocytes infiltrate target tissues in autoimmune diseases. Primary Sjogren's syndrome (SS) is associated with lymphocytic infiltration in exocrine glands. The aim of this study was to examine levels of expression of adhesion molecules by peripheral blood lymphocytes from patients with SS (before and after stimulation). Peripheral blood lymphocytes from 16 patients with primary SS and from 15 controls were stained directly or cultured for 72 h with and without phytohaemagglutinin (PHA). Indirect immunofluorescence with monoclonal antibodies and flow cytometry were used. The following molecules were detected in patients before culture: CD18 (mean percentage 94%), CD11a (94%), CD11b (39%), CD54 (23%), CD58 (62%), CD44 (Hermes-1; 82%), CD49-d (VLA-4; 80%), CD25 (11%) and LECAM-1 (62%). After stimulation with PHA, there was an increase in the levels of CD18 (2.5-fold), CD11a (2.3-fold), CD54 (10.2-fold), CD58 (2.5-fold), CD44 (2.4-fold), CD49d (3.4-fold) and CD25 (62-fold) on lymphocytes from both patients and controls. The number of positive cells and level of expression did not differ from the controls, except in the case of unstimulated, cultured lymphocytes in which the levels of CD44 and LECAM-1 were increased more in patients than in normal controls. The increase in the level of in vitro expression of CD44 (P < 0.05) and LECAM-1 (P < 0.002) on lymphocytes from patients with primary SS reached statistical significance when compared to similarly cultured lymphocytes from controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Pattern of adhesion molecule expression in labial salivary glands from patients with primary Sjögren's syndrome.

The aim of this work was to examine the pattern of distribution of adhesion molecules in minor salivary glands from patients with primary Sjögren's syndrome (SS). Labial salivary gland (LSG) biopsies from 31 patients with primary SS and 21 normal subjects were examined. Cryostat sections were examined with monoclonal antibodies to different adhesion molecules using an indirect immunoperoxidase technique. There was an increased expression of ICAM-1, class IMHC, HLA-DR & DQ (p<0.05) on endothelial cells, lymphocytes, fibroblasts and salivary epithelial cells (HLA-DR far exceeds ICAM-1 (limited) epithelial expression). ELAM-1 and to a lesser extent VCAM-1 were demonstrated over some of the endothelial cells in patients, but not in controls (p<0.01). Many of the endothelial cells expressing ICAM-1, DR, DQ, ELAM-1 were high endothelial venules. CD44 was strongly expressed over epithelial cells, endothelial and infiltrating mononuclear cells, while LFA-3 was present mainly on epithelial cells, and faintly on infiltrating inflammatory cells. There was no difference between patients and controls with regard to CD44 or LFA-3 expression. The ligands for the above mentioned adhesion molecules, namely LFA-1α, LFA-1ß, LECAM-1, VLA-4ß(CD49d), CD44 and CD2 were demonstrated (variably) on the surface of infiltrating lymphocytes. CD11b and CD11c were detected over monocytes/macrophages. A proportion of lymphocytes expressed VCAM-1 and CD11c and may function as antigen presenting cells. In some biopsies these molecules were localized at the center of lymphoid follicles with the appearance of dendritic cells. Although the majority of lymphocytes were activated and strongly expressing DR and ICAM-1, they were IL-2Rα (CD25) negative. We conclude that adhesion molecules are prominent in LSG of patients with primary SS. They may play a major role by mediating the lymphocytic infiltration to the glands, retaining the lymphocytes in the glands and regulating the different immune responses in the local microenvironment of this chronic inflammatory disease.

Phenotypic and functional abnormalities in the peripheral blood T-cells of patients with primary Sjogren's syndrome.

Changes in regulatory T-cell subset (including the recently described CD4 helper inducers or suppressor inducers) balance in the peripheral blood may play a role in the pathogenesis of primary Sjogren's syndrome (SS). Direct immunofluorescence and flow cytometry were used to quantitate and analyse peripheral blood lymphocytes in 15 patients with primary SS and 15 control subjects. A reduction in the percentage of circulating CD4 lymphocytes was observed in patients with SS. There was no quantitative abnormality in the percentage of circulating CD4+ 2H4+ (suppressor inducer), CD4+ 4B4+ (helper inducer), CD2, CD3, CD8, CD8+ 2H4+, CD8+ 4B4+, CD25 (IL-2R), CD19, CD16, CD57 lymphocytes in the patients. Circulating CD8 lymphocytes expressing the activation marker HLA-DR were increased in the patients. The functional status of peripheral blood lymphocytes was assessed by PHA (phytohaemagglutinin) stimulation followed by monitoring their proliferative response by radiolabelled thymidine uptake and expression of CD25 (Interleukin-2 receptor). A reduction in the proliferative response of total, CD4-depleted, and CD8-depleted lymphocytes suspensions to PHA was demonstrated. The level of expression of CD25 (IL-2 receptor) was similar in patients and controls before and after 24 h stimulation with PHA. We conclude that there is a disturbance in the functional properties of peripheral blood T cells that can contribute to the immunopathogenesis of SS. Meanwhile, the quantitative reduction of suppressor/inducer lymphocytes as defined by the CD4 2H4 phenotype can be precluded from a role in the development of such an autoimmune condition.

Vascular endothelium and lymphocyte adhesion molecules in minor salivary glands of patients with Sjogren's syndrome.

The aim of this study was to examine the distribution and types of adhesion molecules expressed over endothelial cells and the ligands present on lymphocytes which infiltrate exocrine glands in patients with Sjogren's syndrome. Minor salivary gland biopsies were examined from twelve patients with Sjogren's syndrome and eight normal subjects for the presence of adhesion molecules using monoclonal antibodies and an Indirect Immunoperoxidase technique. There was an increased expression of intercellular adhesion molecule-1 (ICAM-1, CD54) on endothelial cells, lymphocytes, fibroblasts and salivary gland epithelial cells. In addition we documented the expression of endothelial leukocyte adhesion molecule-1 (ELAM-1) on endothelial cells in salivary glands from patients but not the controls. Many of the endothelial cells expressing these adhesion molecules in patients with Sjogren's syndrome had the morphological appearance of high endothelial venules. V-CAM-1 was shown to be present in some of the salivary biopsies from patients with Sjogren's syndrome. Lymphocytes infiltrating salivary glands strongly express LFA-1 (CD11a/CD18) molecules. Some infiltrating lymphocytes, and most monocytes, expressed C3bi-R (CD11b/CD18) and the p150.95 (CD11c/CD18) antigens on their cell surface. The results of this study reveal the enhanced expression of vascular endothelial and lymphocyte adhesion molecules on the minor salivary glands of patients with Sjogren's syndrome. The presence of such receptors and their putative ligands indicate an important role for these molecules in the pathogenesis of Sjogren's syndrome.