Telocytes in minor salivary glands of primary Sjogren’s syndrome: association with the extent of inflammation and ectopic lymphoid neogenesis

It has been recently reported that telocytes, a stromal (interstitial) cell subset involved in the control of local tissue homeostasis, are hampered in the target organs of inflammatory/autoimmune disorders. Since no data concerning telocytes in minor salivary glands (MSGs) are currently available, aim of the study was to evaluate telocyte distribution in MSGs with normal architecture, non-specific chronic sialadenitis (NSCS) and primary Sjögren’s syndrome (pSS)-focal lymphocytic sialadenitis. Twelve patients with pSS and 16 sicca non-pSS subjects were enrolled in the study. MSGs were evaluated by haematoxylin and eosin staining and immunofluorescence for CD3/CD20 and CD21 to assess focus score, Tarpley biopsy score, T/B cell segregation and germinal center (GC)-like structures. Telocytes were identified by immunoperoxidase-based immunohistochemistry for CD34 and CD34/platelet-derived growth factor receptor α double immunofluorescence. Telocytes were numerous in the stromal compartment of normal MSGs, where their long cytoplasmic processes surrounded vessels and encircled both the excretory ducts and the secretory units. In NSCS, despite the presence of a certain degree of inflammation, telocytes were normally represented. Conversely, telocytes were markedly reduced in MSGs from pSS patients compared to normal and NSCS MSGs. Such a decrease was associated with both worsening of glandular inflammation and progression of ectopic lymphoid neogenesis, periductal telocytes being reduced in the presence of smaller inflammatory foci and completely absent in the presence of GC-like structures. Our findings suggest that a loss of MSG telocytes might have important pathophysiological implications in pSS. The specific pro-inflammatory cytokine milieu of pSS MSGs might be one of the causes of telocyte loss

Altered Immunoregulation in Rheumatoid Arthritis: The Role of Regulatory T Cells and Proinflammatory Th17 Cells and Therapeutic Implications

In recent years several studies investigated the role of T lymphocyte subpopulations in the pathogenesis of rheumatoid arthritis (RA). Pathogenic Th17 cells mediate pannus growth, osteoclastogenesis, and synovial neoangiogenesis; hence they are key players in the development of the disease. On the other hand, regulatory T (Treg) cells are a T cell subset whose peculiar function is to suppress autoreactive lymphocytes. The imbalance between Th17 and Treg cells has been identified as a crucial event in the pathogenesis of RA. In addition, the effects of currently employed RA therapeutic strategies on these lymphocyte subpopulations have been extensively investigated. This review article aims to discuss current knowledge on Treg and Th17 cells in RA and possible implications of their therapeutic targeting in this disorder

IL-17-producing double-negative T cells are expanded in the peripheral blood, infiltrate the salivary gland and are partially resistant to corticosteroid therapy in patients with Sjögren's syndrome

A small CD3+ T-cell population, that lacks both CD4 and CD8 molecules, defined as double negative (DN), is expanded in the peripheral blood of patients with systemic lupus erythematosus, produces IL-17 and accumulates in the kidney during lupus nephritis. Since IL-17 production is enhanced in salivary gland infiltrates of patients with primary Sjögren's syndrome (pSS), we aimed to investigate whether DN T cells may be involved in the pathogenesis of salivary gland damage. Fifteen patients with SS and 15 normal controls (NC) were enrolled. Peripheral blood mononuclear cells were stimulated with anti-CD3 antibody and cultured in presence or absence of dexamethasone (Dex). Phenotypic characterization was performed by flow cytometry in freshly isolated cells and after culture. Minor salivary glands (MSG) from pSS were processed for immunofluorescence staining. Total circulating DN T cells were increased in pSS compared to NC (4.7±0.4% vs 2.6±0.4%). NC and pSS freshly isolated DN T cells produce consistent amounts of IL-17 (67.7±5.6 in NC vs 69.2±3.3 in pSS). Notably, DN T cells were found in the pSS-MSG infiltrate. Dex was able to down-regulate IL-17 in vitro production in NC (29±2.6% vs 15.2±1.9% vs 13±1.6%) and pSS (49±4.8% vs 16±3.8% vs 10.2±0.8%) conventional Th17 cells and in DN T cells of NC (80±2.8% vs 3.8±2.1% vs 4.2±1.8%), but not of pSS (81±1.5% vs 85.4±0.8% vs 86.2±1.7%). DN T cells are expanded in pSS PB, produce IL-17 and infiltrate pSS MSG. In pSS, conventional Th17 cells are inhibited by Dex, but DN T cells appear to be resistant to this effect. Taken together, these data suggest a key role of this T-cell subset in the perpetuation of chronic sialoadenitis and eventually in pSS prognosis

Is minor salivary gland biopsy more than a diagnostic tool in primary Sjorgren's syndrome? Association between clinical, histopathological, and molecular features: A retrospective study

Objectives: Several histological scoring systems, including the focus score, performed in minor salivary glands (MSGs) by hematoxylin-eosin (H&E) staining, have been employed in clinical practice to assess the inflammatory infiltrate and provide the diagnosis of primary Sjorgren's syndrome (pSS). Aims of this study were to integrate different scoring systems and identify potential differences in the molecular profile of lymphoid cytokines related to germinal center (GC) formation and clinical subsets in pSS. Methods: Overall, 104 pSS patients and 40 subjects with sicca non-pSS were retrospectively evaluated. MSG biopsies were evaluated by H&E and immunofluorescence to assess histological pattern, Chisholm and Mason grading system, Tarpley score, a grading for the severity of inflammatory infiltrate, T-/B-cell segregation, and the presence of GC. MSGs from 50 pSS patients and 30 sicca non-pSS patients were processed by real-time PCR to assess LTα, LTβ, BAFF, CXCR4, CXCL12, CXCR5, CXCL13, CCR7, CCL19, and CCL21. Results: GCs presence was associated with anti-Ro/SSA and anti-La/SSB antibodies, hypergammaglobulinemia, salivary gland swelling, higher Tarpley score and focus score, and extraglandular involvement but, at multivariate analysis, only extraglandular involvement was independently associated to GC. pSS patients displayed higher level of all cytokines compared to those with sicca symptoms. GC+ pSS patients displayed higher level of all cytokines compared to those GC-. Conclusions: Our study demonstrates that different histopathological patterns, including GC presence, reflect different cytokine expression and different clinical subsets. We believe that the combined immunofluorescence/molecular approach in MSGs would help to tailor diagnostic and therapeutic approach for different subsets of pSS patients

Interferon gamma-inducible protein 16 (IFI16) and anti-IFI16 antibodies in primary Sj\uf6gren\u2019s syndrome: Findings in serum and minor salivary glands

The interferon (IFN) signature, namely the overexpression of IFN-inducible genes is a crucial aspect in the pathogenesis of primary Sjögren’s syndrome (pSS). The IFN-inducible IFI16 protein, normally expressed in cell nuclei, may be overexpressed, mislocalized in the cytoplasm and secreted in the extracellular milieu in several autoimmune disorders including pSS. This leads to tolerance breaking to this self-protein and development of anti-IFI16 antibodies. The aim of this study was to identify pathogenic and clinical significance of IFI16 and anti-IFI16 autoantibodies in pSS. IFI16 and anti-IFI16 were assessed in the serum of 30 pSS patients and one-hundred healthy donors (HD) by ELISA. IFI16 was also evaluated in 5 minor salivary glands (MSGs) of pSS patients and 5 MSGs of non-pSS patients with sicca symptoms by immunohistochemistry. Normal MSGs do not constitutively express IFI16. Conversely, in pSS-MSGs a marked expression and cytoplasmic mislocalization of IFI16 by epithelial cells was observed with infiltrations in lymphocytes and peri/ intra-lesional endothelium. pSS patients display higher serum levels of both IFI16 and anti-IFI16 autoantibodies compared to HD. Our data suggest that IFI16 protein may be involved in the initiation and perpetuation of glandular inflammation occurring in pSS

Phytoderivates in rabbit diet and immune responses

In order to investigate the effects of some dietary phytoderivates (Origanum vulgare L. and Rosmarinus officinalis L.) on rabbit peripheral lymphocyte proliferation and subsets populations, a total of 100 New Zealand mixed-sex rabbits were weaned at 30 days of age and immediately split into homogeneous groups submitted to the following dietary treatments: 1) Standard diet (Ctrl); 2) Standard diet +150 ppm Vit E (Vit E); 3) Standard diet +0.2% oregano (O); 4) Standard diet +0.2% rosemary (R) and 5) Standard diet +0,1% oregano + 0.1% rosemary (OR). Blood samples were collected from rabbits at 30 days (Time 0, n.10 rabbits) and 90 days of age (Time 1; n.5 animals/diet group). A diet effect on lymphocyte proliferation test was observed in the “O” group, where its response to pokeweed mitogen (PWM) and interleukin-2 (IL-2) at Time 1 resulted significantly higher than that of the other experimental diet groups (PWM, P<0,001 and IL-2, P< 0,000), with the exception of “OR” group whose IL-2 mitogen response was as significant higher as that of “O” group. Furthermore, the basal mitogenesis values revealed higher responses at Time 1 in the “Vit E” and “O”, but the addition of mitogens induced significant increased responses only in the “O” group. No diet effects were registered on the lymphocyte subsets. The lymphocyte proliferation test in the control group showed a general reduction of leukocytes response with age, in particular it was observed a significant reduced response to PWM and PHA mitogens (P<0,021). Age effects were also recorded on lymphocyte subsets with a significant increase of CD8+ % with age (P<0,000). These results seem to encourage the integration of rabbit diet with oregano for its positive effect on adaptive immune response (a better in vitro reactivity of B cells)

Interferon gamma-inducible protein 16 (IFI16) and anti-IFI16 antibodies in primary Sjögren’s syndrome: findings in serum and minor salivary glands

The interferon (IFN) signature, namely the overexpression of IFN-inducible genes is a crucial aspect in the pathogenesis of primary Sjögren’s syndrome (pSS). The IFN-inducible IFI16 protein, normally expressed in cell nuclei, may be overexpressed, mislocalized in the cytoplasm and secreted in the extracellular milieu in several autoimmune disorders including pSS. This leads to tolerance breaking to this self-protein and development of anti-IFI16 antibodies. The aim of this study was to identify pathogenic and clinical significance of IFI16 and anti-IFI16 autoantibodies in pSS. IFI16 and anti-IFI16 were assessed in the serum of 30 pSS patients and one-hundred healthy donors (HD) by ELISA. IFI16 was also evaluated in 5 minor salivary glands (MSGs) of pSS patients and 5 MSGs of non-pSS patients with sicca symptoms by immunohistochemistry. Normal MSGs do not constitutively express IFI16. Conversely, in pSS-MSGs a marked expression and cytoplasmic mislocalization of IFI16 by epithelial cells was observed with infiltrations in lymphocytes and peri/ intra-lesional endothelium. pSS patients display higher serum levels of both IFI16 and anti-IFI16 autoantibodies compared to HD. Our data suggest that IFI16 protein may be involved in the initiation and perpetuation of glandular inflammation occurring in pSS