Quantitative and functional analysis of CD69+ T regulatory lymphocytes in patients with periodontal disease

Quantitative analysis of Tr1 lymphocytes in patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is usually accompanied by a low-grade inflammatory phenomenon, which participates in the pathogenesis of different complications of this condition. The inflammatory response is under the regulation of different mechanisms, including T regulatory (Treg) lymphocytes. However, the possible role of type 1 T regulatory (Tr1) cells in T2DM has not been explored so far.

AIM

To carry out a quantitative analysis of Tr1 lymphocytes and other immune cell subsets in patients with T2DM and correlate these results with clinical findings and treatments.

MATERIALS AND METHODS

Sixty patients with T2DM and twenty-three healthy controls were included in the study. Biochemical and anthropometric variables were evaluated, and Tr1 lymphocytes (CD4+CD49+LAG-3+IL-10+) and other cell subsets (Th17, Th22 and Foxp3 + Treg cells) were analyzed in peripheral blood samples by multiparametric flow cytometry.

RESULTS

Significant increased levels of Tr1 cells were detected in patients with severe and mild disease, compared to healthy controls. In addition, CD4+IL-10+ lymphocytes were also increased in patients with T2DM. In contrast, similar levels of Foxp3+ Treg cells, Th17 and Th22 lymphocytes were observed in patients and controls. Likewise, no significant associations were detected between Tr1 cell levels and different clinical and laboratory parameters. However, those patients receiving glucagon-like peptide-1 receptor agonists (GLP-1-RA) showed similar levels of Tr1 cells than healthy controls, and significant lower numbers than untreated patients.

CONCLUSION

We observed an increase in Tr1 and CD4+IL10+ lymphocyte levels in T2DM. Moreover, GLP1-RA treatment was significantly associated with normalization of the Tr1 levels. This highlights another potential immune dysfunction in patients with T2DM, which could participate in the pathogenesis of this condition.

Effect of different cytokines in combination with IL-15 on the expression of activating receptors in NK cells of patients with Behçet's disease

Behçet's disease (BD) is a systemic, autoinflammatory, chronic disorder which affects various parts of the body in genetically susceptible individuals. BD has a multi-factorial etiopathogenesis which encompasses both innate and adaptive arms of immunity. NK cells, which kill virus-infected or malign cells and provide interaction between adaptive and innate immune system, are also known to involve in the pathogenesis of autoimmune/autoinflammatory diseases including BD. NK cells function in immune responses via the signals obtained from surface-expressed activating and inhibitory receptors. In this study, we aimed to explore NK cell activation status by measuring the levels of activation marker CD69 and activating receptors NKG2D, NKp30, and NKp46 as well as proliferative and cytotoxic capacities in response to stimulation with interleukin (IL)-15-combined cytokines in BD patients. CD4⁺ and CD8⁺ T cell responses were also evaluated to compare with those of NK cells. As a result, the expression of activating receptors on NK cells was demonstrated to be varied among patients with active and inactive BD and healthy controls. The proliferation levels of NK cells were elevated in BD patients, especially in inactive phase of disease compared to healthy controls. Additionally, CD107a levels of inactive BD patients were detected to be lower in comparison with healthy controls and active BD patients. These findings suggest that BD patients in active and inactive phases display different activation status of NK cells which indicate NK cells might be associated with immune attacks and remissions during the course of BD.

Evidence revealing the role of T cell regulators (Tregs) in periodontal diseases: A review

Periodontitis is an inflammatory disease of the periodontium, which is a reflection of the overgrowth of oral commensals. This alteration in the oral microbiota initiates inflammation of the gingiva, which when left untreated, terminates with the resorption of the alveolar bone that may lead to a poor and hopeless prognosis. With upcoming trends in modulating the host's immunity, the role of regulatory T-cells has gained importance. These T-cells defend against inflammation and autoimmunity as they suppress both. However, in both the conditions, the regulatory cells are invariably reduced in number. Novel methods to enhance the function of Tregs have made their way in dentistry, as a promising approach to cure periodontitis. This article discusses various significant tests and trials of Tregs in the recent years.

Novel human immunomodulatory T cell receptors and their double-edged potential in autoimmunity, cardiovascular disease and cancer

In the last decade, approaches based on T cells and their immunomodulatory receptors have emerged as a solid improvement in treatments for various types of cancer. However, the roles of these molecules in the therapeutic context of autoimmune and cardiovascular diseases are still relatively unexplored. Here, we review the best known and most commonly used immunomodulatory T cell receptors in clinical practice (PD-1 and CTLA-4), along with the rest of the receptors with known functions in animal models, which have great potential as modulators in human pathologies in the medium term. Among these other receptors is the receptor CD69, which has recently been described to be expressed in mouse and human T cells in autoimmune and cardiovascular diseases and cancer. However, inhibition of these receptors individually or in combination by drugs or monoclonal antibodies generates a loss of immunological tolerance and can trigger multiple autoimmune disorders in different organs and immune-related adverse effects. In the coming decades, knowledge on the functions of different immunomodulatory receptors will be pivotal for the development of new and better therapies with less harmful side effects. In this review, we discuss the roles of these receptors in the control of immunity from a perspective focused on therapeutic potential in not only cancer but also autoimmune diseases, such as systemic lupus erythematosus, autoimmune diabetes and rheumatoid arthritis, and cardiovascular diseases, such as atherosclerosis, acute myocardial infarction, and myocarditis.

The pivotal role of CD69 in autoimmunity

Autoimmune disorders are outcomes of impaired activity of the immune system regarding the maintenance of tolerance, which results in tissue damage secondary to an excess in the inflammatory response. Under normal conditions, the cells in the adaptive immune system are highly controlled to remain unresponsive against self-antigens (self-Ags) through various mechanisms and during different stages of maturation. CD69 (cluster of differentiation 69), a C-type lectin disulfide-linked homodimer, is expressed on different leukocytes, including newly-activated lymphocytes, certain subtypes of memory T-cells, infiltrating lymphocytes isolated from patients with chronic inflammatory disorders, and regulatory T-cells (Tregs). Cumulative evidence from in vitro and in vivo studies has revealed an immunoregulatory role for CD69. This marker has been reported to play a controversial role in chronic human inflammatory disorders. Many investigations have linked the absence of CD69 with a predisposition to inflammatory and/or autoimmune conditions, which indicates an immunoregulatory function for CD69 by mechanisms such as controlling the balance between differentiation of Th/Treg cells and enhancing the suppressive activity of Tregs. However, some reports from human studies have indicated that CD69 may exert a stimulatory effect on the inflammatory response. In this review, we first present a brief summary of the concept of 'immune tolerance' and, subsequently, review previous studies to uncover the details that underlie the immunoregulatory effects of CD69.

Patients with Systemic Lupus Erythematosus Show Increased Levels and Defective Function of CD69+ T Regulatory Cells

T regulatory (Treg) cells have a key role in the pathogenesis of chronic inflammatory and autoimmune diseases. A CD4⁺CD69⁺ T cell subset has been described that behaves as Treg lymphocytes, exerting an important immune suppressive effect. In this study, we analyzed the levels and function of CD4⁺CD69⁺ Treg cells in patients with systemic lupus erythematosus (SLE). Blood samples were obtained from 22 patients with SLE and 25 healthy subjects. Levels of CD4⁺CD69⁺ Treg cells were analyzed by multiparametric flow cytometry, and their function was measured by an assay of suppression of lymphocyte activation and through the inhibition of cytokine synthesis. We found an increased percent of CD4⁺CD25^varCD69⁺TGF-β⁺IL-10⁺Foxp3⁻ lymphocytes in patients with SLE compared to controls. In addition, a significant diminution in the suppressive effect of these cells on the activation of autologous T lymphocytes was observed in most patients with SLE. Accordingly, CD69⁺ Treg cells from SLE patients showed a defective capability to inhibit the release of IL-2, IL-6, IL-10, and IL-17A by autologous lymphocytes. Our findings suggest that while CD4⁺CD69⁺ Treg lymphocyte levels are increased in SLE patients, these cells are apparently unable to contribute to the downmodulation of the autoimmune response and the tissue damage seen in this condition.