Epidemiological profile and north-south gradient driving baseline systemic involvement of primary Sjögren's syndrome.

OBJECTIVE: To characterize the systemic phenotype of primary Sjögren's syndrome at diagnosis by analysing the EULAR-SS disease activity index (ESSDAI) scores. METHODS: The Sjögren Big Data Consortium is an international, multicentre registry based on worldwide data-sharing cooperative merging of pre-existing databases from leading centres in clinical research in Sjögren's syndrome from the five continents. RESULTS: The cohort included 10 007 patients (9352 female, mean 53 years) with recorded ESSDAI scores available. At diagnosis, the mean total ESSDAI score was 6.1; 81.8% of patients had systemic activity (ESSDAI score ≥1). Males had a higher mean ESSDAI (8.1 vs 6.0, P < 0.001) compared with females, as did patients diagnosed at <35 years (6.7 vs 5.6 in patients diagnosed at >65 years, P < 0.001). The highest global ESSDAI score was reported in Black/African Americans, followed by White, Asian and Hispanic patients (6.7, 6.5, 5.4 and 4.8, respectively; P < 0.001). The frequency of involvement of each systemic organ also differed between ethnic groups, with Black/African American patients showing the highest frequencies in the lymphadenopathy, articular, peripheral nervous system, CNS and biological domains, White patients in the glandular, cutaneous and muscular domains, Asian patients in the pulmonary, renal and haematological domains and Hispanic patients in the constitutional domain. Systemic activity measured by the ESSDAI, clinical ESSDAI (clinESSDAI) and disease activity states was higher in patients from southern countries (P < 0.001). CONCLUSION: The systemic phenotype of primary Sjögren's syndrome is strongly influenced by personal determinants such as age, gender, ethnicity and place of residence, which are key geoepidemiological players in driving the expression of systemic disease at diagnosis.

[The importance of microRNAs in the development of systemic autoimmune disorders]. / A mikro-RNS-ek jelentosége szisztémás autoimmun betegségek kialakulásában.

MicroRNAs (miRNAs) are 18-25 nucleotide long, single stranded, endogenous, non-coding small RNAs playing an important role in regulating gene expression at posttranscriptional level. miRNAs control approximately 90% of protein-coding genes, and play a central role in various biological processes including immune cell lineage commitment, differentiation, proliferation, apoptosis and maintenance of immune homeostasis. Changes in the expression of certain miRNAs may lead to the development of many diseases, including systemic autoimmune diseases. In this study, we summarize the biogenesis of miRNAs, their role in regulation of the immune system, and review the latest research findings in systemic lupus erythematosus, primary Sjögren's syndrome, rheumatoid arthritis and systemic sclerosis. In the future, miRNAs may help not only in establishing diagnosis and prognosis but potentially serve as targets for modern therapeutic approaches in autoimmune diseases. Orv Hetil. 2019; 160(15): 563-572.

Season Dependent Changes in the Expression of Protein Kinase C Isoenzymes in a Female Patient with Systemic Lupus Erythematosus.

We aimed to answer the question whether the decreased expression of protein kinase C (PKC) isoenzymes in the peripheral blood mononuclear cells (PBMC) of patients with systemic lupus erythematosus (SLE) is inherited or not. For this reason we examined the expression of PKC isoenzymes in a European white girl with acute SLE and in her healthy mother and father simultaneously in summer and winter during one year using western blotting and densitometry. We found that in the father the expression of PKC isoenzymes did not differ from that of eight healthy controls included women and men. However, in the "SLE-free" mother and in the patient arrived in July with acute symptoms of lupus, the expression of PKC isoenzymes showed a season dependent undulation in parallel. Namely, in summer the expression values were significantly lower, in winter they were significantly higher than those in the controls. Thus, the decreased expression of PKC isoenzymes in the PBMC of SLE patient is not a disease specific marker; it appears also in her lupus free mother. This phenomenon may be due to a season dependent female genetic background. However, the low PKC levels in summer can still decrease further the low production of IL-2 in T cells of lupus patients augmenting the existing AP-1 defects. This is the first report on the season and female dependent inherited changing of PKC expression in a European white patient with SLE and her mother. Further studies are needed to confirm these findings in other populations.

How immunological profile drives clinical phenotype of primary Sjögren's syndrome at diagnosis: analysis of 10,500 patients (Sjögren Big Data Project).

OBJECTIVES: To evaluate the influence of the main immunological markers on the disease phenotype at diagnosis in a large international cohort of patients with primary Sjögren's syndrome (SjS). METHODS: The Big Data Sjögren Project Consortium is an international, multicentre registry created in 2014. As a first step, baseline clinical information from leading centres on clinical research in SjS of the 5 continents was collected. The centres shared a harmonised data architecture and conducted cooperative online efforts in order to refine collected data under the coordination of a big data statistical team. Inclusion criteria were the fulfillment of the 2002 classification criteria. Immunological tests were carried out using standard commercial assays. RESULTS: By January 2018, the participant centres had included 10,500 valid patients from 22 countries. The cohort included 9,806 (93%) women and 694 (7%) men, with a mean age at diagnosis of primary SjS of 53 years, mainly White (78%) and included from European countries (71%). The frequency of positive immunological markers at diagnosis was 79.3% for ANA, 73.2% for anti-Ro, 48.6% for RF, 45.1% for anti- La, 13.4% for low C3 levels, 14.5% for low C4 levels and 7.3% for cryoglobulins. Positive autoantibodies (ANA, Ro, La) correlated with a positive result in salivary gland biopsy, while hypocomplementaemia and especially cryoglo-bulinaemia correlated with systemic activity (mean ESSDAI score of 17.7 for cryoglobulins, 11.3 for low C3 and 9.2 for low C4, in comparison with 3.8 for negative markers). The immunological markers with a great number of statistically-significant associations (p<0.001) in the organ-by-organ ESS- DAI evaluation were cryoglobulins (9 domains), low C3 (8 domains), anti-La (7 domains) and low C4 (6 domains). CONCLUSIONS: We confirm the strong influence of immunological markers on the phenotype of primary SjS at diagnosis in the largest multi-ethnic international cohort ever analysed, with a greater influence for cryoglobulinaemic-related markers in comparison with Ro/La autoantibodies and ANA. Immunological patterns play a central role in the phenotypic expression of the disease already at the time of diagnosis, and may guide physicians to design a specific personalised management during the follow-up of patients with primary SjS.

Hematopoietic stem cell transplantation in autoimmune disorders: From immune-regulatory processes to clinical implications.

Autoimmune diseases are characterized by the development of autoreactive T- and B-cells targeting self-antigens, which eventually can result in chronic and persistent organ damage. The autologous hematopoietic stem cell transplantation (AHSCT) opened new avenues in the treatment of patients with severe, treatment-resistant autoimmune diseases. This paper reviews the immune-regulatory mechanisms behind AHSCT, and also summarizes the experiences of clinical practice related to the therapy in organ-specific and systemic autoimmune diseases. It seems that the intricate interplay of various immune competent cells with regulatory capacity control in a synergistic manner the repopulated immune system after AHSCT, which potentially leads to a significant clinical improvement in certain autoimmune diseases. However, the widespread use of AHSCT was intrinsically limited, due to the serious side-effects of conditioning treatment and relatively high treatment-related mortality; moreover, the development of new effective and safe therapeutic approaches and the dawn of biological agents further limited its indications in the last decade. Nevertheless, with an appropriate patient selection and increased experience of transplant centres, the risks can be minimized, and AHSCT remained still a reasonable choice in multiple sclerosis and systemic sclerosis when the conventional therapy failed and further progression of disease is inevitable.

Down-regulation of increased TRAF6 expression in the peripheral mononuclear cells of patients with primary Sjögren's syndrome by an EBV-EBER1-specific synthetic single-stranded complementary DNA molecule.

AIM: We described earlier a simultaneously increased that the increased expression of miRNA-146a/b was accompanied by an increase in the expression of and TRAF6 and a decrease in the expression of IRAK1 genes in the peripheral mononuclear cells (PBMCs) of patients with primary Sjogren's syndrome (pSS) patients. Recently, the expression of EBV encoded. RNA (EBER) was published in the B cells of salivary glands of in pSS. In the present study, we applied an EBV-EBER1 specific synthetic single stranded complementary DNA molecule (EBV-EBER1-cDNA) to test whether any EBER1 related effect exists also in PBMCs of pSS patients. METHODS: In the PBMCs of pSS patients and healthy controls, we investigated in vitro the effects of a synthetic single stranded EBV-EBER1-cDNA molecule, synthetic double-stranded (ds)RNA polyinosinic-polycytidylic acid [poly (I:C)] and polyadenylic acid potassium salt poly-adenylic acid [poly-(A)] on the expression of TRAF6 gene tested by qRTPCR. The release of interferon -α was detected by ELISA. RESULTS: EBV-EBER1-cDNA resulted in a significant reduction in the expression of TRAF6 in the cells of patients, but in the healthy controls not, whereas the treatments with poly (I:C) and poly-(A) could not reduce the TRAF6 over-expression. No release of EBER1 could be observed in the culture supernatants of patients with pSS. Only the treatment with poly (I:C) resulted in a significant increase of interferon -α release, and only in the heathy controls. No release of EBER1 molecules took place during the culturing of cells. EBV-EBER- cDNA acted functionally on the cells of patients only. CONCLUSION: These findings give a further evidence of the linkage between EBV and pSS, furthermore, they show the possible role of EBV-EBER1 in the induction of increased TRAF6 expression in the peripheral B cells of Sjögren's patients.

Biomarkers for rheumatoid arthritis: From molecular processes to diagnostic applications-current concepts and future perspectives.

Early diagnosis and immediately started appropriate treatment are mandatory for the prevention of radiographic progression, functional disability and unfavourable disease outcome in rheumatoid arthritis (RA). The current classification criteria for RA include two different types of biomarkers representing inflammatory processes, such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) or immune processes including autoantibodies, such as rheumatoid factor (RF) and antibodies against citrullinated proteins (ACPA). After the discovery of RF, the recent recognition of various autoantibodies against post-translationally modified proteins opened new avenues to diagnosing RA and predicting the course of the disease. Citrullination and carbamylation of amino acids generate new epitopes that can potentially promote the production of novel autoantibodies. In spite of growing knowledge, the pathogenic role of these autoantibodies is still not fully elucidated in RA. In this paper, we review the currently available and novel promising immune biomarkers, which may help in early diagnosis and estimating prognosis in RA.

Expansion of circulating follicular T helper cells associates with disease severity in childhood atopic dermatitis.

Follicular helper T (TFH) cells play crucial role in B-cell differentiation and antibody production. Although, atopic dermatitis (AD) is often associated with increased serum IgE levels, B-cell mediated responses have not been studied thoroughly. The aim of our study was to investigate the proportion of TFH-like cells in the disease. Twelve children and 17 adults with AD as well as 14 healthy controls were enrolled in the study. The frequency of CD4+CXCR5+ICOS+PD-1+ TFH-like cells and their IL-21 cytokine production were determined by flow cytometry. Immunohistochemical analysis was performed on skin biopsy specimens from AD patients for the detection of TFH markers. The percentages and absolute numbers of circulating TFH-like cells were significantly increased in children with AD compared to adult patients and healthy controls. IL-21 cytokine production of TFH-like cells was also elevated and showed a strong positive correlation with paediatric patients' SCORAD index. The expression of TFH-specific markers showed only a non-specific scattered pattern in skin biopsy specimens. This is the first study to demonstrate that TFH-like cells expanded in the peripheral blood of children with AD compared to adults. These results reinforce the importance of further investigations on TFH-like cells in different phenotypes and endotypes of AD.

Regulatory immune cells and functions in autoimmunity and transplantation immunology.

In physiological circumstances, various tolerogenic mechanisms support the protection of self-structures during immune responses. However, quantitative and/or qualitative changes in regulatory immune cells and mediators can evoke auto-reactive immune responses, and upon susceptible genetic background, along with the presence of other concomitant etiological factors, autoimmune disease may develop. In transplant immunology, tolerogenic mechanisms are also critical, since the balance between of alloantigen-reactive effector cells and the regulatory immune cells will ultimately determine whether a graft is accepted or rejected. Better understanding of the immunological tolerance and the potential modulations of immune regulatory processes are crucial for developing effective therapies in autoimmune diseases as well as in organ transplantation. In this review, we focus on the novel insights regarding the impaired immune regulation and other relevant factors contributing to the development of auto-reactive and graft-reactive immune responses in autoimmune diseases and transplant rejection, respectively. We also address some promising approaches for modification of immune-regulatory processes and tolerogenic mechanisms in autoimmunity and solid organ transplantation, which may be beneficial in future therapeutic strategies.

MicroRNA expression profiles identify disease-specific alterations in systemic lupus erythematosus and primary Sjögren's syndrome.

The discovery of microRNAs (miRNAs) and their critical role in genetic control opened new avenues in understanding of various biological processes including immune cell lineage commitment, differentiation, proliferation and apoptosis. However, a given miRNA may have hundreds of different mRNA targets and a target might be regulated by multiple miRNAs, thus the characterisation of dysregulated miRNA expression profiles could give a better insight into the development of immunological disturbances in autoimmune diseases. The aim of our study was to examine the changes in miRNA expression profiles in patients with systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS). Eight SLE patients, 8 pSS patients and 7 healthy subjects were enrolled in the investigation. MiRNAs were isolated from peripheral blood mononuclear cells, and expression patterns were determined with Illumina next-generation sequencing technology. Since the immunopathogenesis of pSS and SLE encompasses pronounced B cell hyperactivity along with specific autoantibody production, we paid a special attention on the association between miRNA expression levels and altered peripheral B cell distribution. In SLE patients 135, while in pSS patients 26 miRNAs showed altered expression. Interestingly, the 25 miRNAs including miR-146a, miR-16 and miR-21, which were over-expressed in pSS patients, were found to be elevated in SLE group, as well. On the contrary, we observed the down-regulation of miR-150-5p, which is a novel and unique finding in pSS. Levels of several miRNAs over-expressed in SLE, were not changed in pSS, such as miR-148a-3p, miR-152, miR-155, miR-223, miR-224, miR-326 and miR-342. Expression levels of miR-223-5p, miR-150-5p, miR-155-5p and miR-342-3p, which miRNAs are potentially linked to B cell functions, showed associations with the B cell proportions within peripheral blood mononuclear cells. The observed differences in miRNA expression profiles and the better understanding of immune regulatory mechanisms of miRNAs may help to elucidate the pathogenesis of SLE and pSS.

Elemental Analysis of Whole and Protein Separated Blood Serum of Patients with Systemic Lupus Erythematosus and Sjögren's Syndrome.

Systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS) are systemic autoimmune diseases with complex symptoms and pathogenesis that are still not completely understood. Several studies showed that the trace element homeostasis and also the levels of antioxidant plasma proteins are changed in autoimmune disorders; however, these results are controversial. In this study, the potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), and iron (Fe) concentrations of the serum and proteins-immunoglobulin G (IgG), transferrin (Trf), albumin (Alb), and ceruloplasmin (Cp)-separated from serum samples by affinity chromatography were determined in patients with SLE and SS. Ca and K levels were found to be decreased in the case of both disorders compared to the control group, and the competitive antagonism of Cu and Zn was also observed: elevated Cu concentration together with a lower Zn concentration was measured in the sera of patients with autoimmune diseases. After fractionation, the trace element concentration of protein containing fractions altered to that of the control group. In case of the autoimmune disorders, the highest Cu concentration was determined in the Alb-containing protein fractions while the Zn level decreased in the Alb and increased in the Cp as well as in the IgG- and Trf-containing fractions compared to the healthy samples. Changes have also been found in the level and distribution of K and Ca.

Simultaneously increased expression of microRNA-155 and suppressor of cytokine signaling 1 (SOCS1) gene in the peripheral blood mononuclear cells of patients with primary Sjögren's syndrome.

AIM: The microRNA-155 (miR-155) is regarded as a central modulator of T-cell responses and could be a potential therapeutic target for certain inflammatory diseases. In our present study we analyzed the expression rate of miR-155 and its functionally linked gene, the suppressor gene of cytokine signaling 1 (SOCS1) in primary Sjögren's syndrome (pSS). METHOD: We enrolled 23 pSS patients and 10 healthy individuals in the study. The expression of miR-155 and SOCS1 gene were measured by real-time polymerase chain reaction. RESULTS: We observed the over-expression of miR-155 in the peripheral mononuclear cells of patients with pSS. Surprisingly, SOCS1 gene was also over-expressed in pSS patients. CONCLUSION: This unanticipated phenomenon might be a laboratory characteristic of Sjögren's syndrome, and presumably a consequence of the noteworthy difference in the pSS immune system reacting with Epstein-Barr virus.

Influence of geolocation and ethnicity on the phenotypic expression of primary Sjögren's syndrome at diagnosis in 8310 patients: a cross-sectional study from the Big Data Sjögren Project Consortium.

OBJECTIVES: To analyse the influence of geolocation and ethnicity on the clinical presentation of primary Sjögren's syndrome (SjS) at diagnosis. METHODS: The Big Data Sjögren Project Consortium is an international, multicentre registry designed in 2014. By January 2016, 20 centres from five continents were participating. Multivariable logistic regression analyses were performed. RESULTS: We included 7748 women (93%) and 562 men (7%), with a mean age at diagnosis of primary SjS of 53 years. Ethnicity data were available for 7884 patients (95%): 6174 patients (78%) were white, 1066 patients (14%) were Asian, 393 patients (5%) were Hispanic, 104 patients (1%) were black/African-American and 147 patients (2%) were of other ethnicities. SjS was diagnosed a mean of 7 years earlier in black/African-American compared with white patients; the female-to-male ratio was highest in Asian patients (27:1) and lowest in black/African-American patients (7:1); the prevalence of sicca symptoms was lowest in Asian patients; a higher frequency of positive salivary biopsy was found in Hispanic and white patients. A north-south gradient was found with respect to a lower frequency of ocular involvement in northern countries for dry eyes and abnormal ocular tests in Europe (OR 0.46 and 0.44, respectively) and Asia (OR 0.18 and 0.49, respectively) compared with southern countries. Higher frequencies of antinuclear antibodies (ANAs) were reported in northern countries in America (OR=1.48) and Asia (OR=3.80) while, in Europe, northern countries had lowest frequencies of ANAs (OR=0.67) and Ro/La (OR=0.69). CONCLUSIONS: This study provides the first evidence of a strong influence of geolocation and ethnicity on the phenotype of primary SjS at diagnosis.

Chronic high-dose glucocorticoid therapy triggers the development of chronic organ damage and worsens disease outcome in systemic lupus erythematosus.

Long-term survival of patients with systemic lupus erythematosus (SLE) improved worldwide; thus, prevention of cumulative organ damage became a major goal in disease management. The aim of our study was to investigate the chronic organ damages and their influence on disease outcome in SLE. We evaluated clinical conditions, laboratory findings and medications of 357 consecutive SLE patients and assessed their impact on Systemic Lupus Collaborating Clinics (SLICC)/American College of Rheumatology (ACR) Damage Index (SDI) and disease outcome. We detected one or more SDI scores in 77.87% of patients. Patients with disease duration of more than 10 years and subjects diagnosed at age above 40 had significantly higher SDI values. The most frequent damages were valvulopathies, cognitive dysfunction, angina pectoris and venous thrombosis. Higher cumulative glucocorticoid dose increased SDI, while chloroquin treatment was favourable for patients. Male gender, elevated SDI scores and higher cumulative doses of glucocorticoids increased mortality risk. Our data confirmed that disease duration, age at diagnosis and chronic high-dose glucocorticoid therapy have significant effects on the development of chronic organ damage. Higher SDI score is characterized with worse survival ratios. The most common chronic organ damages affected the cardiovascular or neuropsychiatric system. As long-term survival in SLE improves, it becomes increasingly important to identify the determinants of chronic organ damage. Most of the chronic organ damage occurs in the cardiovascular and the neuropsychiatric systems; thus, regular follow-up, screening and adequate therapy are essential for the best clinical outcome.

The role of microRNAs in the pathogenesis of autoimmune diseases.

MicroRNAs (miRNAs) are single-stranded, endogenous non-coding small RNAs, ranging from 18 to 25 nucleotides in length. Growing evidence suggests that miRNAs are essential in regulating gene expression, cell development, differentiation and function. Autoimmune diseases are a family of chronic systemic inflammatory diseases. Recent findings on miRNA expression profiles have been suggesting their role as biomarkers in autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis and Sjögren's syndrome. In this review, we summarize the characteristics of miRNAs and their functional role in the immune system and autoimmune diseases including systemic lupus erythematosus, primary Sjögren's syndrome, rheumatoid arthritis, systemic sclerosis, multiple sclerosis and psoriasis; moreover, we depict the advantages of miRNAs in modern diagnostics.

Myeloid derived suppressor cells and autoimmunity.

Myeloid-derived suppressor cells are a heterogeneous group of immature myeloid cells with immunoregulatory function. When activated and expanded, these cells can suppress T cell functions via cell-to cell interactions as well as soluble mediators. Recent studies investigated the involvement of MDSC in autoimmune diseases. Some papers have described beneficial effect of MDSC during the course of autoimmune diseases, and suggest a potential role as a treatment option, while others failed to detect these effects. Their contributions to autoimmune diseases are not fully understood, and many questions and some controversies remain as to the expansion, activation, and inhibitory functions of MDSC. This review aims to summarize current knowledge of MDSC in autoimmune disorders.

Increased IL-21 Expression Induces Granzyme B in Peripheral CD5(+) B Cells as a Potential Counter-Regulatory Effect in Primary Sjögren's Syndrome.

Recently, we reported elevated proportions of circulating follicular T helper cells and higher levels of interleukin- (IL-) 21 in primary Sjögren's syndrome (pSS). Interaction of invariant natural killer T (iNKT) cells with B cells and granzyme B (GrB) production may be also important in pSS. Thirty-two pSS patients and 24 healthy controls were enrolled in our study. We investigated the expression of intracellular GrB and IL-21 receptor (IL-21R) of CD19(+)CD5(+) and CD19(+)CD5(-) B cells; furthermore, we determined the IL-21 expression of iNKT cells as well. We also assessed the proportion of transitional (CD19(+)CD24(high)CD38(high)), mature (CD19(+)CD24(int)CD38(int)) and primarily memory (CD19(+)CD24(high)CD38(-)) B cells. CD5(+) but not CD5(-) B cells showed elevated GrB and IL-21R expression in pSS; additionally IL-21 expression of iNKT cells was also elevated. The ratios of transitional and mature B cells were elevated in pSS, while primarily memory B cell percentages were decreased, which correlated with GrB and IL-21R expression of CD19(+) B cells. Our results suggest that enhanced IL-21R expression of CD19(+)CD5(+) B cells and production of IL-21 by iNKT cells may play an important role in the pathogenesis of pSS by regulating CD19(+)CD5(+) B cell functions and increasing GrB production, presumably leading to a counter-regulatory effect in the disease.

Characterization and Comparison of Patient Subgroups Suspicious for IgG4-Related Disease and Malignant Lymphoma in Patients Followed-up for Sjögren's Syndrome.

Differential diagnosis of patients with Sjögren's syndrome (SS), IgG4-related disease (IgG4-RD) and SS patients having high risk for lymphoma (LHR) can be challenging. Some patients with IgG4-RD might be misdiagnosed as having SS. There are special symptoms of SS that raise the possibility of IgG4-RD whereas other symptoms identify patients as having LHR. The purpose of this study was to characterize and compare patients with SS, possible IgG4-RD and SS patients with LHR. Sixty-five SS patients were divided into 4 subgroups according to having possible IgG4-RD (n = 15), LHR (n = 16), eligible for both aforementioned groups (n = 20) and not eligible for either group (n = 14), respectively. Four patients fulfilled the diagnostic criteria for IgG4-RD. The serum levels of IgG4 were significantly higher in patients suspicious for IgG4-RD compared to that of LHR patients (0.46 g/l vs. 0.12 g/l, p = 0.032). Shared features of the patient groups (salivary gland swelling (SGS) and lymphadenopathy), were separately analysed: SGS patients had higher IgG4/IgG ratio (p = 0.036), lymphadenopathic patients had higher IgG4 levels (p = 0.042). Some patients may be "hidden" under the diagnosis of SS. Although patients with LHR and patients with possible IgG4-RD share some symptoms, they differ significantly regarding IgG4 levels and IgG4/IgG ratio.

Toll-Like Receptor Pathways in Autoimmune Diseases.

Autoimmune diseases are a family of chronic systemic inflammatory disorders, characterized by the dysregulation of the immune system which finally results in the break of tolerance to self-antigen. Several studies suggest that Toll-like receptors (TLRs) play an essential role in the pathogenesis of autoimmune diseases. TLRs belong to the family of pattern recognition receptors (PRRs) that recognize a wide range of pathogen-associated molecular patterns (PAMPs). TLRs are type I transmembrane proteins and located on various cellular membranes. Two main groups have been classified based on their location; the extracelluar group referred to the ones located on the plasma membrane while the intracellular group all located in endosomal compartments responsible for the recognition of nucleic acids. They are released by the host cells and trigger various intracellular pathways which results in the production of proinflammatory cytokines, chemokines, as well as the expression of co-stimulatory molecules to protect against invading microorganisms. In particular, TLR pathway-associated proteins, such as IRAK, TRAF, and SOCS, are often dysregulated in this group of diseases. TLR-associated gene expression profile analysis together with single nucleotide polymorphism (SNP) assessment could be important to explain the pathomechanism driving autoimmune diseases. In this review, we summarize recent findings on TLR pathway regulation in various autoimmune diseases, including Sjögren's syndrome (SS), systemic lupus erythematosus (SLE), multiple sclerosis (MS), rheumatoid arthritis (RA), systemic sclerosis (SSc), and psoriasis.

The assessment of immune-regulatory effects of extracorporeal photopheresis in systemic sclerosis: a long-term follow-up study.

The therapeutic options in systemic sclerosis (SSc) are limited mainly to the management of complications, and decelerating fibrosis and preventing disease progression are still great challenges. Extracorporeal photopheresis (ECP) is one of the promising therapeutic strategies in SSc; nevertheless, there is no consensus on the ideal timing and frequency of treatment cycles. In the present study, we evaluated the long-term effects of consecutive ECP treatments, and the stability of clinical and laboratory improvements. We enrolled nine patients with diffuse cutaneous SSc and performed 12 ECP cycles (24 ECP treatments) per patient in total. ECP cycles were carried out once in every 6 weeks, and each cycle consisted of two procedures. Sixteen healthy individuals served as controls for laboratory assessment. Following the sixth ECP cycle, we observed further improvement in skin score, which was confirmed by high-resolution ultrasonography as well. After the second ECP cycle, values of Tr1 and CD4+CD25(bright) Treg cells increased; however, Tr1 cells remained under control values until the 10th cycle. Suppressor activity of CD4+CD25+ Treg cells improved, while percentages of Th17 cells decreased. At the end of 12-month follow-up, we did not observe significant deterioration in skin involvement; however, improvement in laboratory parameters diminished after 12 months. If the first six ECP cycles are effective, uninterrupted continuation of treatment should be considered, which may lead to the normalization of Tr1 cell values along with further clinical improvement. Our laboratory observations indicate that immunomodulatory effect of ECP treatments lasts for 1 year only.