Mixed Connective Tissue Disease as Different Entity: Global Methylation Aspect.

Mixed connective tissue disease (MCTD) is a very rare disorder that belongs in the rare and clinically multifactorial groups of diseases. The pathogenesis of MCTD is still unclear. The best understood epigenetic alteration is DNA methylation whose role is to regulate gene expression. In the literature, there are ever-increasing assumptions that DNA methylation can be one of the possible reasons for the development of Autoimmune Connective Tissue Diseases (ACTDs) such as systemic sclerosis (SSc) and systemic lupus erythematosus (SLE). The aim of this study was to define the global DNA methylation changes between MCTD and other ACTDs patients in whole blood samples. The study included 54 MCTD patients, 43 SSc patients, 45 SLE patients, and 43 healthy donors (HC). The global DNA methylation level was measured by ELISA. Although the global DNA methylation was not significantly different between MCTD and control, we observed that hypomethylation distinguishes the MCTD patients from the SSc and SLE patients. The present analysis revealed a statistically significant difference of global methylation between SLE and MCTD (p < 0.001), SLE and HC (p = 0.008), SSc and MCTD (p ≤ 0.001), and SSc and HC (p < 0.001), but neither between MCTD and HC (p = 0.09) nor SSc and SLE (p = 0.08). The highest % of global methylation (median, IQR) has been observed in the group of patients with SLE [0.73 (0.43, 1.22] and SSc [0,91 (0.59, 1.50)], whereas in the MCTD [0.29 (0.20, 0.54)], patients and healthy subjects [0.51 (0.24, 0.70)] were comparable. In addition, our study provided evidence of different levels of global DNA methylation between the SSc subtypes (p = 0.01). Our study showed that patients with limited SSc had a significantly higher global methylation level when compared to diffuse SSc. Our data has shown that the level of global DNA methylation may not be a good diagnostic marker to distinguish MCTD from other ACTDs. Our research provides the groundwork for a more detailed examination of the significance of global DNA methylation as a distinguishing factor in patients with MCTD compared to other ACTDs patients.

Serum microRNAs in Systemic Sclerosis, Associations with Digital Vasculopathy and Lung Involvement.

Background and aims: Systemic sclerosis (SSc) is an autoimmune, rare multisystem chronic disease that is still not well-understood aetiologically and is challenging diagnostically. In the literature, there are ever-increasing assumptions regarding the epigenetic mechanisms involved in SSc development; one of them is circulating microRNAs. Many of them regulate TLR pathways and are significant in autoimmune balance. The aim of this study was to determine profile expression of selected microRNAs in SSc patients, including miR-126, -132, -143, -145, -155, -181a, -29a and -3148, in comparison to healthy controls. Methods: Serum microRNAs were isolated from 45 patients with SSc and 57 healthy donors (HC). Additionally, SSc patients were considered in the aspect of disease subtype, including diffuse systemic sclerosis (dcSSc) and limited systemic sclerosis (lcSSc). Results: miR-3148 was detected neither in the serum of HC nor in SSc patients. All of the rest of the analyzed microRNAs, excluding miR-126, miR-29a and miR-181a, were significantly upregulated in SSc patients in comparison to HC. However, miR-181a has been revealed only in the serum of patients with lcSSc but not dcSSc. Moderate positive correlations between the transfer factor of the lung for carbon monoxide (TLCO) and miR-126 and miR-145 were observed. A significant correlation has been found between serum miR-143 level and forced vital capacity (FVC). SSc patients with FVC ≤ 70% were characterized by significantly lower levels of miR-143 compared to patients with normal FVC. Additionally, the expression of miR-132 was significantly higher in dcSSc subgroup with detected active lung lesions compared to dcSSc patients with fibrotic lesions. Patients with an early scleroderma pattern of microangiopathy seen on nailfold video-capillaroscopy (NVC) revealed higher expression of miR-155 in serum than those with a late pattern. Conclusions: The expression profile of circulating cell-free miRNAs is significantly changed in the serum of SSc patients compared to healthy individuals. Downregulation of miRNA-181a and overexpression of miR-132, miR-143, miR-145 and miR-155 in serum may be significant in SSc in the context of biomarkers.

The Serum Cell-Free microRNA Expression Profile in MCTD, SLE, SSc, and RA Patients.

Mixed connective tissue disease (MCTD) is a rare disorder characterized by symptoms that overlap two or more Autoimmune Connective Tissue Diseases (ACTDs). The aim of this study was to determine whether miRNAs participating in the TLRs signaling pathway could serve as biomarkers differentiating MCTD or other ACTD entities from a healthy control group and between groups of patients. Although the selected miRNA expression level was not significantly different between MCTD and control, we observed that miR-126 distinguishes MCTD patients from all other ACTD groups. The expression level of miRNAs was significantly higher in the serum of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) patients compared to controls. The miR-145 and -181a levels distinguished RA from other ACDT patients. miR-155 was specific for SLE patients. MiR-132, miR-143, and miR-29a distinguished RA and SLE patients from the systemic sclerosis (SSc) group. Additionally, some clinical parameters were significantly related to the miRNA expression profile in the SLE group. SLE and RA are characterized by a specific serum expression profile of the microRNAs associated with the Toll-like receptors (TLRs) signaling pathway. The analysis showed that their level distinguishes these groups from the control and from other ACTD patients. The present study did not reveal a good biomarker for MCTD patients.

Interferons (IFN-A/-B/-G) Genetic Variants in Patients with Mixed Connective Tissue Disease (MCTD).

Mixed connective tissue disease (MCTD) is a rare complex autoimmune disease in which autoantigens are recognized by endosomal TLRs. Their activation induces a higher secretion of the type I interferons, IFN-γ and the up-regulation of the INF-inducible genes. The present study aimed to investigate whether SNPs that are located in the IFN-A, IFN-B, and IFN-G genes are associated with MCTD. 145 MCTD patients and 281 healthy subjects were examined for IFN-A, IFN-B, and IFN-G genetic variants by TaqMan SNP genotyping assay. ELISA determined IFN-α/-ß/-γ serum levels. Among the seven tested SNPs, four polymorphisms: IFN-A rs10757212, IFN-A rs3758236, IFN-G rs2069705, IFN-G rs2069718, as well as INF-G rs1861493A/rs2069705A/rs2069718G haplotype were significantly associated with a predisposition for MCTD. Raynaud's phenomenon, erosive arthritis, swollen hands and fingers, and sclerodactyly were significantly more frequently observed in MCTD patients with IFN-G rs2069718 G allele than in patients with IFN-G rs2069718 A allele. We also found that anti-U1-A autoantibodies most frequently occurred in MCTD patients with rs2069718 GA genotype, while the IFN-G rs2069705 AG and rs2069718 GA genotypes might be a marker of anti-Ro60 presence in MCTD patients. Our results indicate that IFN-G genetic variants may be potential genetic biomarkers for MCTD susceptibility and severity.

Is the T-G-CT-G SNRNP70 haplotype another proof that mixed connective tissue disease is distinct from systemic lupus erythematosus and systemic sclerosis? A novel gene variant in SNRNP70 gene.

OBJECTIVES: U1-70K, encoded by the SNRNP70 gene, is a key early immunogen in connective tissue disease. The aim of the study was the genetic analysis of the SNRNP70 gene in mixed connective tissue disease (MCTD), systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) patients. METHODS: SNRNP70 genetic variants were detected using 3730 DNA Analyzer. SNRNP70 rs560811128 G/A (c.476-252 G/A), rs78616533delCT (c.475+130_475+131delCT) and rs117167710 T/C (c.393+326 T/C) variants were genotyped using the technique of sequence-specific hybridisation probe binding assays. SNRNP70 393_47 G/A mutation was detected using TaqMan SNP genotyping assay. RESULTS: We found one novel c.393+47G>A and three, c.476-252 G/A, c.475+130_475+131delCT and c.393+326 T/C, previously recorded variants. The present study revealed that T-G-CT-G haplotype demonstrated significantly higher frequencies in MCTD patients than in SLE and SSc patients. In MCTD patients c.475+130_475+131delCT distribution of genotype was gender-dependent and showed association with thrombo-/leukocytopenia. Mutation at position c.476-252G>A was predicted to possibly have an impact on splicing of the SNRNP70 transcript and it was present only in one MCTD patient. CONCLUSIONS: Our results demonstrated that the T-G-CT-G SNRNP70 haplotype is another proof that MCTD may be distinct from SLE and SSc. The novel c.476-252G>A mutation in SNRNP70 gene created a new acceptor splice site and may potentially alert of splicing of the SNRNP70 transcript.

IL-35, TNF-α, BAFF, and VEGF serum levels in patients with different rheumatic diseases.

OBJECTIVES: Inflammatory processes in rheumatic diseases spread via various types of immune system cells and tissues with the aid of inflammatory cytokines and growth factors and the participation of vascular endothelium. Research is still conducted to determine the role of individual factors in the pathophysiology of rheumatic diseases. The task is complicated because the multiplane network of cytokines is characterized by complex correlations manifesting as positive and negative feedback, which impedes the definitive interpretation of the role of specific cytokines. Therefore, it seems justified to perform a comparative analysis of the expression of at least several molecules in one study, which may help reveal their role in the pathogenesis of rheumatic diseases and have prognostic value. MATERIAL AND METHODS: The aim of the study involves the assessment and comparative analysis of the concentrations of interleukin 35 (IL-35), tumour necrosis factor α (TNF-α), B-cell-activating factor (BAFF), and vascular endothelial growth factor (VEGF) in peripheral blood serum in patients with rheumatoid arthritis (RA) (n = 43), systemic lupus erythematosus (SLE) (n = 28), antiphospholipid syndrome (APS) (n = 24), and mixed connective tissue disease (MCTD) (n = 9). The main intention is to search for biomarkers for specific rheumatic diseases. Cytokine and growth factor levels were determined using specific ELISA kits. RESULTS: Statistically significant differences in VEGF and IL-35 concentrations occurred between patients with APS vs. RA and SLE vs. RA. There was a significant high positive correlation between the concentration of BAFF and TNF-α (r = 0.77, p < 0.0000) in patients with APS, as well as in patients with SLE (r = 0.55, p = 0.00). CONCLUSIONS: BAFF and TNF-α may be promising biomarkers in patients with APS and VEGF in patients with RA. Additionally, IL-35 may be a useful marker for the diagnosis of APS. Positive correlation of BAFF and TNF-α concentrations in APS and SLE potentially indicates much more similar etiopathogenesis of these diseases than it could be previously predicted.

IL-6 and TGF-ß gene polymorphisms, their serum levels, as well as HLA profile, in patients with systemic lupus erythematosus.

OBJECTIVES: The aim of the study was to explore whether TGF-ß and IL-6 gene polymorphisms may be associated with SLE and assess the frequency of HLA-DRB1 alleles in Polish systemic lupus erythematosus (SLE) patients. METHODS: 216 SLE patients and 552 healthy individuals were examined for TGF-ß rs1800469 and rs1800470 by TaqMan SNP genotyping assay and for and IL-6(rs2069827 and rs1800795 using the PCR- RFLP method. RESULTS: An increased frequency of TT genotype and T allele of the TGF ß -509 C/T was found in SLE patients (p=0.02). The TGF-ß 869 C allele was more frequent in SLE patients. The genotype-phenotype analysis showed association between the TGF ß -509 C/T and mean value of CRP, ESR, haemoglobin, APTT, Pt and INR (p=0.05, p=0.03, p<0.001, p=0.03, p=0.03 and p=0.05, respectively) as well as anti-SSA and anti-Sm presence (p=0.04 and p=0.03, respectively); the TGF- ß 869 T/C and mean value of APTT and INR (p=0.01 and p=0.05, respectively); the IL-6 -174 G/C and SLICC (p=0.05), anti-SSA (p=0.05) and anti-SSB (p=0.05). A higher TGF-ß and IL-6 serum level were found in SLE patients compared to controls (both p<0.0001). In SLE patients with the TGF-ß -509 TT genotype have shown positive association with the TGF-ß serum levels. Polish SLE patients have strong positive association with HLA-DRB1*52.1, and negative with the HLA-DRB1*07:01 allele. HLA-DRB1*52.1 was also associated with higher TGF-ß serum levels in the Polish population. CONCLUSIONS: Our results suggested that the TGF ß -509 C/T variant may be considered as a genetic marker for SLE in the Polish population.

Impact of the IL-17F, IL-23 and IL-23R on susceptibility and phenotype of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a disease characterized by excessive proinflammatory cytokine production and damage to multiple organ systems. To investigate the potential association between cytokine gene polymorphisms and SLE, we performed a case-control study based on Polish population. SLE patients and controls, were examined for IL-23A rs11171806 G/A and IL-23R (rs1884444 G/T, rs10489629 G/A) by TaqMan SNP genotyping assay, for IL-17F rs763780 A/G and rs2397084A/G using the PCR- RFLP method. An increased frequency of AG genotype as well as G allele of the IL-17F rs763780 was found in patients with SLE, as compared with healthy subjects (OR = 3.947; p = 0.001 and OR = 3.538; p = 0.002, respectively). Frequencies of the rs1884444 TT genotype (OR = 138.1) and the rs1884444 T allele (OR = 2.176) were also higher in SLE patients (both p < 0.0001). Overall, weak LD was observed between the IL-17F rs763780 A/G and rs2397084 A/G polymorphisms (D'-0.003, r2 - 0.000). From four possible haplotypes, frequencies of AG showed differences between both examined groups (p < 0.0001). We also observed a weak LD between the IL-23R rs10489629G/A and rs1884444 G/T (D'-0.199, r2 -0.026). The genotype-phenotype analysis showed significant association between the IL-17F rs2397084 and mean value of the hemoglobin (p = 0.01), the IL-17F rs763780 and age (p = 0.008) and lupus anticoagulant (p = 0.09), the IL-23 rs11171806 and urea (p = 0.08) and C3 complement (p = 0.03), and the IL-23R rs1884444 G/T and activated partial thromboplastin time (p = 0.06). Present findings indicated that IL-17F rs763780 A/G and IL-23R rs1884444 G/T polymorphisms may be involved in susceptibility to SLE in the Polish population.

Recognizing systemic sclerosis: comparative analysis of various sets of classification criteria.

Systemic sclerosis is a complex disease characterized by autoimmunity, vasculopathy and tissue fibrosis. Although most patients present with some degree of skin sclerosis, which is a distinguishing hallmark, the clinical presentation vary greatly complicating the diagnosis. In this regard, new classification criteria were jointly published in 2013 by American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR). A recent major development in the classification criteria is improved sensitivity, particularly for detecting early disease. The new criteria allow more cases to be classified as having systemic sclerosis (SSc), which leads to earlier treatment. Moreover it is clinically beneficial in preventing the disease progression with its irreversible fibrosis and organ damage. The aim of this review is to give insight into new classification criteria and current trends in the diagnosis of systemic sclerosis.