Immunoregulatory defects in patients with systemic lupus erythematosus in clinical remission

Exploiting Signal Joint T Cell Receptor Excision Circle to Investigate the Impact of COVID-19 and Autoimmune Diseases on Age Prediction and Immunosenescence

Signal joint T cell receptor excision circles (sjTRECs) are a promising marker for age estimation and immunosenescence in different ethnic groups. Several limitations are expected to overshadow their use as accurate markers for age prediction. The current study was conducted to determine the influence of immunologic disorders, such as autoimmune diseases and COVID-19, on the accuracy of sjTRECs as molecular markers for age estimation and immunosenescence among living Egyptians. Peripheral blood sjTRECs level was measured by qPCR in 90 autoimmune patients, 58 COVID-19 patients, and 85 healthy controls. The mean dCt values were significantly (p = 0.0002) different between the three groups, with the highest values in healthy subjects, followed by autoimmune and COVID-19 patients. A significant negative correlation was identified between the sjTRECs levels and ages in all studied cases. There were significant positive correlations between chronological age and predicted age for healthy individuals, autoimmune, and COVID-19 patients with mean absolute deviations (MAD) of 9.40, 11.04, and 9.71, respectively. The two patients' groups exhibited early immunosenescence, which was more noticeable among the young adults with COVID-19 and autoimmune patients of age range (18-49 years). Autoimmunity may represent a critical factor impacting the accuracy of sjTRECs quantitation for age prediction.

The peripheral blood regulatory T-cells analysis as a criterion for assessing the therapy efficacy and a prognostic marker for the duration of remission of psoriasis

Background. The recently discovered regulatory T-cells CD4+CD25+FOXP3+CD127low (Treg-cells) plays an important role in sustaining immune tolerance. These cells demonstrated a significant tremendous potential in suppressing the pathological immune response associated with various autoimmune diseases, including psoriasis vulgaris (VP). Aims. To find the role of Treg-cells in VP pathogenesis and to show the possible use of the Treg-cells analysis for diagnosis, remission duration prediction and measurement of therapeutic effectiveness. Materials and methods. We studied 60 VP patients (35 females and 25 males) aged 1855. The patients were diagnosed with VP at advanced, remedial and retrogressive phases (28, 19 and 13 participants, respectively). The disease severity was assessed with the PASI (Psoriasis Area and Severity Index). The patients were stratified into two groups based on disease duration (less than 20 years, n = 42; over 20 years, n = 28). The study involved 12 VP patients in the advanced stage, whose Treg level was tested prior and after 311 nm UVB course. We followed up the VP patients for two years following the UVB-311 nm phototherapy course to assess the remission duration and the relapse frequency. Results. We found lower levels of Тreg in patients in the study group. Treg peripheral blood levels in VP patients and in HD were 2.84 1.00% and 4.02 0.73%, respectively. The Treg levels were 2.59 0.68%, 2.82 1.55% and 3.68 1.62% at advanced, remedial and retrogressive stages, respectively. The patients with the VP history less than 20 years demonstrated Treg level of 3.42 1.11% and 2.31 0.62% for patients with VP history over 20 years. We found an inverse correlation between the Treg subpopulation CD4+CD25+FOXP3+CD127low and the VP severity level evaluated with PASI (r = 0.39). The UVB-311 nm phototherapy resulted in the significant Treg level increase in 12 patients (2.11 0.61% and 3.43 1.02% prior and after therapy, respectively). Subsequently, we revealed the direct correlation (r = 0.88) between the Treg cell level increase in patients prior and after the phototherapy and the duration of remission in this group of the VP patients. Conclusions. We found decreased in Treg levels in VP patients compared to HD and revealed correlation between Treg-cells level in VP patients and VP phases, duration and the severity of the clinical picture. We demonstrated Treg feasibility as a laboratory indicator of VP therapy treatment with the example of 311 nm UVB and as a predict factor of remission duration.

[Increased suppressor activity of transformed ex vivo regulatory T-cells in comparison with unstimulated cells of the same donor]

Regulatory T-cells CD4⁺CD25⁺FoxP3⁺CD127low (Tregs) play a key role in the maintenance of tolerance to auto antigens, inhibit function of effector T and B lymphocytes, and provide a balance between effector and regulatory arms of immunity. Patients with autoimmune diseases have decreased Treg numbers and impaired suppressive activity. Transformed ex vivo autologous Tregs could restore destroyed balance of the immune system. We developed a method for Treg precursor cell cultivation. Following the method, we were able to grown up 300-400 million of Tregs cells from 50 ml of peripheral blood during a week. Transformed ex vivo Tregs are 90-95% CD4⁺CD25⁺FoxP3⁺CD127low and have increased expression of transcription genes FoxP3 and Helios. Transformed ex vivo Tregs have increased demethylation of FoxP3 promoter and activated genes of proliferation markers Cycline B1, Ki67 and LGALS 1. Transformed ex vivo Tregs have increased suppressive activity and up to 80-90% these cells secrete cytokines TNFα и IFNγ. Our data suggest transformed ex vivo autologous Tregs have genetic, immunophenotypic and functional characteristics for regulatory T-cells and further can be used for adoptive immunotherapy autoimmune diseases and inhibition of transplantation immunity.

Cellular and Molecular Phenotypes of pConsensus Peptide (pCons) Induced CD8+ and CD4+ Regulatory T Cells in Lupus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with widespread inflammation, immune dysregulation, and is associated with the generation of destructive anti-DNA autoantibodies. We have shown previously the immune modulatory properties of pCons peptide in the induction of both CD4⁺ and CD8⁺ regulatory T cells which can in turn suppress development of the autoimmune disease in (NZB/NZW) F1 (BWF1) mice, an established model of lupus. In the present study, we add novel protein information and further demonstrate the molecular and cellular phenotypes of pCons-induced CD4⁺ and CD8⁺ T_reg subsets. Flow cytometry analyses revealed that pCons induced CD8⁺ T_reg cells with the following cell surface molecules: CD25^highCD28^{high and low} subsets (shown earlier), CD62L^high, CD122^low, PD1^low, CTLA4^low, CCR7^low and 41BB^high. Quantitative real-time PCR (qRT-PCR) gene expression analyses revealed that pCons-induced CD8⁺ T_reg cells downregulated the following several genes: Regulator of G protein signaling (RGS2), RGS16, RGS17, BAX, GPT2, PDE3b, GADD45β and programmed cell death 1 (PD1). Further, we confirmed the down regulation of these genes by Western blot analyses at the protein level. To our translational significance, we showed herein that pCons significantly increased the percentage of CD8⁺FoxP3⁺ T cells and further increased the mean fluorescence intensity (MFI) of FoxP3 when healthy peripheral blood mononuclear cells (PBMCs) are treated with pCons (10 μg/ml, for 24-48 hours). In addition, we found that pCons reduced apoptosis in CD4⁺ and CD8⁺ T cells and B220⁺ B cells of BWF1 lupus mice. These data suggest that pCons stimulates cellular, immunological, and molecular changes in regulatory T cells which in turn protect against SLE autoimmunity.

CD8+ T regulatory cells in lupus

T regulatory cells (Tregs) have a key role in the maintenance of immune homeostasis and the regulation of immune tolerance by preventing the inflammation and suppressing the autoimmune responses. Numerical and functional deficits of these cells have been reported in systemic lupus erythematosus (SLE) patients and mouse models of SLE, where their imbalance and dysregulated activities have been reported to significantly influence the disease pathogenesis, progression and outcomes. Most studies in SLE have focused on CD4+ Tregs and it has become clear that a critical role in the control of immune tolerance after the breakdown of self-tolerance is provided by CD8+ Tregs. Here we review the role, cellular and molecular phenotypes, and mechanisms of action of CD8+ Tregs in SLE, including ways to induce these cells for immunotherapeutic modulation in SLE.

[The treatment by expanded ex vivo autologous regulatory T-cells CD4+CD25+FoxP3+CD127low restores the balance of immune system in patients with remitting-relapsing multiple sclerosis]

AIM

To assess clinical efficacy and safety of the autologous (own) regulatory T-cells (Tregs)CD4+CD25+Foxp3+CD127low isolated from the blood of patients with remitting-relapsing multiple sclerosis. Patients with autoimmune diseases have the decreased number of peripheral Tregs (pTreg) and impaired suppressive ability. In order to restore levels of pTreg, it is possible to isolate precursor cells, enter expanded ex vivo autologous Treg cells and introduce an expanded amount of autologous cells as Treg vaccine.

MATERIAL AND METHODS

A method of ex vivo Tregs expansion by 30-40 times within 5-7 days has been developed. Expanded ex vivo Tregs are more than 90% CD4+CD25+Foxp3+CD127low and have high suppressor activity. Fourteen patients with remitting-relapsing multiple sclerosis were included in pilot studies.Ex vivoTregs were introduced subcutaneously in dosefrom 2.8 to 4.5 108 cell per injection. The duration of follow-up was 1 year.

RESULTS AND CONCLUSION

The numbers of pTregs in the blood of these patients elevated by 1.5-2 times. No adverse-effects, a decrease of relapses and stabilization of disability index were observed. It has been suggested that ex vivo expanded Tregs can compensate the impaired function of pTregs and can be used for adoptive immunotherapyof multiple sclerosis.

Ex vivo expanded regulatory T cells CD4+CD25+FoxP3+CD127Low develop strong immunosuppressive activity in patients with remitting-relapsing multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease characterized by defect in regulatory function of CD4⁺CD25⁺ T cells. We demonstrated difference in proportion of regulatory T cells CD4⁺CD25⁺FoxP3⁺CD127^low (Tregs) within the same patients' relapse and remission. Proportion of peripheral Tregs (pTregs) dropped almost two times in the relapse compare to remission. Levels of pTregs in patients' remission were lower than in healthy donors. Suppressive ability of pTregs was decreased in MS patients compared to healthy donors. Injections of expanded ex vivo autologous Tregs (eTregs) could be helpful in bringing up the level of Tregs in patients' blood. We developed a simple method for ex vivo expansion of autologous Tregs within a short period of time. The final pool of cells consisted of 90-95% eTregs. When we started the culture with 10-20 × 10⁶ CD4⁺ T cells, we yield 300-400 × 10⁶ eTregs in a week. Expression of FoxP3 and Helios was calculated by two methods. Expanded ex vivo patients' and donors' Tregs were characterized by increased from three to five times expression of FoxP3, as well as almost doubled Helios expression. Peripheral Tregs in MS patients have decreased demethylation of FoxP3 gene promoter in comparison with donors. On the contrary, eTregs showed stable up-regulated demethylation without difference between MS patients and donors. MS patients' and donors' eTregs have much more suppressive ability than pTregs. Our data showed that eTregs can be applied as immunotherapy for MS patients and other autoimmune diseases if further investigated.

Inactive disease and remission in childhood-onset systemic lupus erythematosus

OBJECTIVE

To define inactive disease (ID) and clinical remission (CR) and to delineate variables that can be used to measure ID/CR in childhood-onset systemic lupus erythematosus (cSLE).

METHODS

Delphi questionnaires were sent to an international group of pediatric rheumatologists. Respondents provided information about variables to be used in future algorithms to measure ID/CR. The usefulness of these variables was assessed in 35 children with ID and 31 children with minimally active lupus (MAL).

RESULTS

While ID reflects cSLE status at a specific point in time, CR requires the presence of ID for >6 months and considers treatment. There was consensus that patients in ID/CR can have <2 mild nonlimiting symptoms (i.e., fatigue, arthralgia, headaches, or myalgia) but not Raynaud's phenomenon, chest pain, or objective physical signs of cSLE; antinuclear antibody positivity and erythrocyte sedimentation rate elevation can be present. Complete blood count, renal function testing, and complement C3 all must be within the normal range. Based on consensus, only damage-related laboratory or clinical findings of cSLE are permissible with ID. The above parameters were suitable to differentiate children with ID/CR from those with MAL (area under the receiver operating characteristic curve >0.85). Disease activity scores with or without the physician global assessment of disease activity and patient symptoms were well suited to differentiate children with ID from those with MAL.

CONCLUSION

Consensus has been reached on common definitions of ID/CR with cSLE and relevant patient characteristics with ID/CR. Further studies must assess the usefulness of the data-driven candidate criteria for ID in cSLE.

Genes, tolerance and systemic autoimmunity

The characterization of functional CD8(+) inhibitory or regulatory T cells and their gene regulation remains a critical challenge in the field of tolerance and autoimmunity. Investigating the genes induced in regulatory cells and the regulatory networks and pathways that underlie mechanisms of immune resistance and prevent apoptosis in the CD8(+) T cell compartment are crucial to understanding tolerance mechanisms in systemic autoimmunity. Little is currently known about the genetic control that governs the ability of CD8(+) Ti or regulatory cells to suppress anti-DNA Ab production in B cells. Silencing genes with siRNA or shRNA and overexpression of genes with lentiviral cDNA transduction are established approaches to identifying and understanding the function of candidate genes in tolerance and immunity. Elucidation of interactions between genes and proteins, and their synergistic effects in establishing cell-cell cross talk, including receptor modulation/antagonism, are essential for delineating the roles of these cells. In this review, we will examine recent reports which describe the modulation of cells from lupus prone mice or lupus patients to confer anti-inflammatory and protective gene expression and novel associated phenotypes. We will highlight recent findings on the role of selected genes induced by peptide tolerance in CD8(+) Ti.

Retinal self-antigen induces a predominantly Th1 effector response in Axl and Mertk double-knockout mice

The TAM family of receptors (Tyro3, Axl, and Mertk) plays an important role in the negative regulation of response of dendritic cells (DCs) and macrophages to pathogenic stimuli, and mice lacking this receptor family develop spontaneous lupus-like systemic autoimmunity against a variety of tissues, including retina. To study the molecular mechanism underlying the TAM regulation of APC functions and subsequent effects on the induction of an autoimmune response against the eye, we examined CD4 T cell differentiation following retinal self-antigen immunization. CD4 T cells prepared from naive or interphotoreceptor retinoid-binding protein (IRBP)1-20-immunized Axl and Mertk double-knockout (dko) mice reacted to activation using anti-CD3 and anti-CD28 Abs or to bolster by self-antigen in vitro with a predominantly Th1 effector response, as characterized by increased IFN-γ production and higher frequency of IFN-γ-positive CD4 T cells. The Th17 effector response to IRBP immunization was similar in dko mice to that in wild-type controls, as shown by ELISA measurement of IL-17A in the culture medium and flow cytometric analysis of IL-17A-secreting CD4 T cells. Interestingly, APCs or DCs isolated from IRBP-immunized dko mice exhibited a greater ability to drive the Th1 response. The production of two driving cytokines for Th1 differentiation, IL-12 and IL-18, was dramatically increased in dko DCs and macrophages, and LPS stimulation bolstered their production. The preferential development into the Th1 subset in dko mice suggests that the cytokine milieu produced by the mutant mice in vivo or by mutant APCs in vitro selectively creates a differentiation environment favoring the Th1 effector response.

HDAC inhibition in lupus models

Systemic lupus erythematosus (SLE) is a prototypic autoimmune inflammatory disease characterized by the production of autoantibodies directed against nuclear antigens such as nucleosomes, DNA and histone proteins found within the body's cells and plasma. Autoantibodies may induce disease by forming immune complexes that lodge in target organs or by crossreacting with targeted antigens and damaging tissue. In addition to autoantibody production, apoptotic defects and impaired removal of apoptotic cells contribute to an overload of autoantigens that initiate an autoimmune response. Besides the well-recognized genetic susceptibility to SLE, environmental and epigenetic factors play a crucial role in disease pathogenesis as evidenced by monozygotic twins typically being discordant for disease. Changes in DNA methylation and histone acetylation alter gene expression and are thought to contribute to the epigenetic deregulation in disease. In SLE, global and gene-specific DNA methylation changes have been demonstrated to occur. Additionally, aberrant histone acetylation is evident in individuals with SLE. Moreover, histone deacetylase inhibitors (HDACi) have been shown to reverse the skewed expression of multiple genes involved in SLE. In this review, we discuss the implications of epigenetic alterations in the development and progression of SLE, and how therapeutics designed to alter histone acetylation status may constitute a promising avenue to target disease.

IL-18 activity in systemic lupus erythematosus

Interleukin-18 (IL-18) is an inflammation-related cytokine that plays a central role both in innate defense reactions and in Th1 activation and specific immune responses. Increased levels of IL-18 can be detected in biological fluids and organs of individuals affected by several autoimmune pathologies, as well as in autoimmune animal models. In this review, the role of IL-18 in systemic lupus erythematosus (SLE) is critically examined, including its possible role in the pathogenesis of disease. In SLE, increased levels of IL-18 have been found in serum/plasma of affected persons, which positively correlated with disease severity. The possibility that circulating IL-18 levels are predictive of renal damage has been proposed, suggesting that IL-18 may be a prognostic marker of renal involvement useful to identify patients at risk of renal failure. The evaluation of urinary levels of free active IL-18 indeed suggests a correlation with the degree of renal involvement. The possible pathogenic role of IL-18 in lupus has been studied in a mouse model of progressive disease, which makes possible the identification, at the level of the different affected organs, of IL-18 changes preceding disease development and those appearing after disease onset. It can be concluded that IL-18 has a multifaceted role in autoimmune lupus, being apparently involved both in the effector phases of the late organ damage and, in some organs, in the initial pathogenic events. Therapeutic strategies targeting IL-18 in autoimmunity are under development.

Evidence for a pathogenetic role of interleukin-18 in cutaneous lupus erythematosus

OBJECTIVE

Cutaneous manifestations are the most common clinical features of lupus erythematosus (LE). The aim of this study was to analyze differences in the inflammatory response of keratinocytes from patients with cutaneous LE (CLE) compared with healthy controls.

METHODS

Keratinocytes from LE patients and controls were cultured from epidermal stem cells of the hair follicle of anagen head hairs. Functional responses of keratinocytes to cytokine stimulation were determined by flow cytometry and enzyme-linked immunosorbent assay. Biopsy samples of lesional skin were analyzed by immunohistochemistry.

RESULTS

Keratinocytes from CLE patients expressed higher levels of IL-18 receptor on their cell surface in response to tumor necrosis factor alpha (TNFalpha) or interferon-gamma stimulation. In response to IL-18 stimulation, these cells produced large amounts of TNFalpha. Of note, in the presence of IL-18, CLE keratinocytes failed to express IL-12. IL-12 has previously been shown to protect keratinocytes from ultraviolet irradiation-induced apoptosis. Keratinocytes from LE patients were more prone to die upon exposure to IL-18, and this increased apoptosis was abrogated by blockade of endogenously produced TNFalpha as well as by the addition of exogenous IL-12. IL-18 was highly expressed in biopsy samples of lesional skin from CLE patients.

CONCLUSION

Our results demonstrate an intrinsic difference in the inflammatory response of keratinocytes and indicate an autocrine feedback loop involving TNFalpha, IL-18, and IL-12 family members. Our results suggest that IL-18 may occupy an important position in the cytokine hierarchy in CLE, indicating the potential benefit of a local agent that blocks IL-18 activity in the treatment of the manifestations of CLE.

N-Ras or K-Ras inhibition increases the number and enhances the function of Foxp3 regulatory T cells

Naturally occurring regulatory T cells (Treg) driven by their transcriptional controller Foxp3 are compromised in immune-mediated disorders and confer protection when adoptively transferred. We examined the Ras-inhibitory effect on functional determinants of Treg in vivo and in vitro. Ras was inhibited in Jurkat T cells by transfection with a dominant-negative form of Ras, or by shRNA for N-Ras, K-Ras, and H-Ras, or by farnesylthiosalycylic acid, a small-molecule inhibitor. Except for H-Ras transduction with shRNA, each inhibitory mode increased expression of Foxp3 and nuclear factor of activated T cell proteins, and surface expression of CD25. Ras inhibition in PBMC and spleen-derived lymphocytes reproduced these findings. The heightened Foxp3 expression reflected both increased basal cellular protein and peripheral conversion of non-Treg to Treg. Ras inhibition enhanced Treg-induced suppression; thus, when adoptively transferred to mice, Ras-inhibited Treg reduced the incidence of diabetes. Inhibition of Foxp3 by respective siRNA reversed the enhancement. Thus, inhibition of the N- or K-Ras isoform triggers an anti-inflammatory effect by up-regulating, via Foxp3 elevation, the numbers and functional suppressive properties of Treg.