Inflammasome-Related Genetic Polymorphisms as Severity Biomarkers of COVID-19.

The most critical forms of coronavirus disease 2019 (COVID-19) are associated with excessive activation of the inflammasome. Despite the COVID-19 impact on public health, we still do not fully understand the mechanisms by which the inflammatory response influences disease prognosis. Accordingly, we aimed to elucidate the role of polymorphisms in the key genes of the formation and signaling of the inflammasome as biomarkers of COVID-19 severity. For this purpose, a large and well-defined cohort of 377 COVID-19 patients with mild (n = 72), moderate (n = 84), severe (n = 100), and critical (n = 121) infections were included. A total of 24 polymorphisms located in inflammasome-related genes (NLRP3, NLRC4, NLRP1, CARD8, CASP1, IL1B, IL18, NFKB1, ATG16L1, and MIF) were genotyped in all of the patients and in the 192 healthy controls (HCs) (who were without COVID-19 at the time of and before the study) by RT-qPCR. Our results showed that patients with mild, moderate, severe, and critical COVID-19 presented similar allelic and genotypic distribution in all the variants studied. No statistically significant differences in the haplotypic distribution of NLRP3, NLRC4, NLRP1, CARD8, CASP1, IL1B, and ATG16L1 were observed between COVID-19 patients, who were stratified by disease severity. Each stratified group of patients presented a similar genetic distribution to the HCs. In conclusion, our results suggest that the inflammasome polymorphisms studied are not associated with the worsening of COVID-19.

Vascular involvement in Behçet's disease: ultrasound assessment of femoral vein intima-media thickness, nailfold capillaroscopy and endothelial progenitor cells in a national referral centre.

OBJECTIVES: To assess vascular involvement at different levels in patients with Behçet's disease (BD). METHODS: We conducted an observational study of unselected consecutive patients with BD assessed in a national referral centre. Demographic and clinical variables were collected. Common femoral vein (CFV) intima-media thickness (IMT) was measured with a high-resolution Doppler ultrasound (US). Microvascular involvement was evaluated performing a nailfold capillaroscopy (NFC). Endothelial progenitor cells (EPC) were measured in peripheral blood of patients and healthy controls (HC) by flow cytometry. RESULTS: A total of 42 patients with BD were evaluated. Clinical vascular manifestations were present in 17 of them. Arterial hypertension was associated with a higher frequency of vascular manifestations (p=0.003). The median [IQR] value of the CFV IMT was significantly higher in patients with vascular manifestations (0.65 [0.45-0.82] vs 0.49 [0.39-0.55]; p= 0.028). The NFC examination was abnormal in 54.8% of the patients, being the most common findings: capillary loop dilation (45.2%), mega capillaries (21.4%) and micro haemorrhages (16.7%). A significant increase in EPC frequency was observed in patients with BD when compared with HC (p=0.011). CONCLUSIONS: The assessment of CFV IMT with Doppler US constitutes a useful technique to evaluate clinical vascular involvement in BD patients. Microvascular involvement is not uncommon in BD and can be easily assessed by NFC. Furthermore, EPC may be a useful blood biomarker of the disease.

Cranial and extracranial large-vessel giant cell arteritis share a genetic pattern of interferon-gamma pathway.

OBJECTIVES: Two main different clinical phenotypes of giant cell arteritis (GCA) have been described, the classic cranial pattern and the extracranial large-vessel (LV) pattern. Since interferon gamma (IFNG) has shown to be a pivotal cytokine in the pathophysiology of GCA, our aim was to evaluate for the first time the influence of IFNG and IFNG receptor 1 (IFNGR1) polymorphisms in the different clinical phenotypes of GCA. METHODS: Two IFNG polymorphisms (rs2069718 G/A and rs1861493 A/G) and one polymorphism in IFNGR1 (rs1327474 G/A) were genotyped in 191 patients with biopsy-proven cranial GCA, 109 with extracranial LV-GCA and 490 healthy controls. A comparative study was conducted between patients with cranial and extracranial LV-GCA. RESULTS: No significant differences in genotype, allele, and haplotype frequencies of IFNG polymorphisms were found between GCA patients with the classic cranial pattern and the extracranial LV-GCA pattern. Similar results were found for genotype and allele frequencies of IFNGR1 polymorphism. It was also the case when patients with extracranial LV-GCA were compared with healthy controls. CONCLUSIONS: Our results show that IFNG and IFNGR1 polymorphisms do not influence the clinical phenotype of expression of GCA. Classic cranial GCA and extracranial LV-GCA seem to share a genetic pattern of IFNG pathway.

Cranial and extracranial giant cell arteritis do not exhibit differences in the IL6 -174 G/C gene polymorphism.

OBJECTIVES: Since interleukin-6 (IL-6) is a pivotal proinflammatory cytokine implicated in the pathogenesis of giant cell arteritis (GCA), we aimed to determine the potential association of the functional IL6 -174 G/C polymorphism with GCA as well as if the single base change variation at the promoter region in the human IL-6 gene may account for differences in the clinical spectrum of GCA between cranial and extracranial large vessel vasculitis (LVV)-GCA. METHODS: The IL6 -174 G/C polymorphism (rs1800795) was genotyped in 191 patients with biopsy-proven GCA who had typical cranial manifestations of the disease, 109 patients with extracranial LVV-GCA, without cranial ischaemic manifestations of GCA, and 877 ethnically matched unaffected controls. A comparative study was carried out between patients with cranial and extracranial LVV-GCA and controls. RESULTS: No significant differences in genotype and allele frequencies of IL6 -174 G/C polymorphism were found between the whole cohort of GCA patients and healthy controls. It was also the case when cranial and extracranial LVV-GCA were compared or when each of these subgroups was compared to controls. Moreover, no significant results in genotype and allele frequencies of IL6 -174 G/C polymorphism were disclosed when the whole cohort of GCA patients were stratified according to the presence of polymyalgia rheumatica, severe ischaemic manifestations, including permanent visual loss and peripheral arteriopathy, and HLA-DRB1*04:01 status. CONCLUSIONS: Our results show that the IL6 -174 G/C polymorphism does not influence the phenotypic expression of GCA.

Endothelin-1 as a Biomarker of Idiopathic Pulmonary Fibrosis and Interstitial Lung Disease Associated with Autoimmune Diseases.

The aim of this study was to determine the role of endothelin-1 (ET-1), a molecule involved in multiple vascular and fibrosing abnormalities, as a biomarker of interstitial lung disease (ILD), as well as its use for the differential diagnosis between idiopathic pulmonary fibrosis (IPF) and ILD associated with autoimmune diseases (AD-ILD), using a large and well-defined cohort of patients with ILD. A total of 112 patients with IPF, 91 patients with AD-ILD (28 rheumatoid arthritis (RA), 26 systemic sclerosis, 20 idiopathic inflammatory myositis and 17 interstitial pneumonia with autoimmune features) and 44 healthy controls were included. ET-1 serum levels were determined by enzyme-linked immunosorbent assay. A significant increase in ET-1 levels was found in patients with IPF compared to controls. Likewise, AD-ILD patients also showed higher ET-1 levels than controls when the whole cohort was stratified by the type of AD. Similar ET-1 levels were found in IPF and AD-ILD patients, regardless of the underlying AD. Interestingly, increased ET-1 levels were correlated with worse lung function in IPF and RA-ILD patients. Our study supports that serum ET-1 may be useful as a biomarker of ILD, although it could not help in the differential diagnosis between IPF and AD-ILD. Moreover, ET-1 levels may be associated with ILD severity.

E-Selectin, ICAM-1, and ET-1 Biomarkers Address the Concern of the Challenging Diagnosis of Interstitial Lung Disease in Patients with Autoimmune Diseases.

Interstitial lung disease (ILD) constitutes the most critical comorbidity in autoimmune diseases (ADs) and its early diagnosis remains a challenge for clinicians. Accordingly, we evaluated whether E-selectin, ICAM-1, and ET-1, key molecules in endothelial damage, could be useful biomarkers for the detection of AD-ILD+. We recruited patients with rheumatoid arthritis (RA)-ILD+ (n = 21) and systemic sclerosis (SSc)-ILD+ (n = 21). We included comparison groups of patients: RA-ILD- (n = 25), SSc-ILD- (n = 20), and idiopathic pulmonary fibrosis (IPF) (n = 21). Serum levels of these proteins were determined by ELISA. E-selectin, ICAM-1, and ET-1 serum levels were increased in RA-ILD+ and IPF patients in comparison to RA-ILD- patients. Additionally, SSc-ILD+ and IPF patients exhibited higher ICAM-1 levels than those with SSc-ILD-. The ability of E-selectin, ICAM-1, and ET-1 to discriminate RA-ILD+ from RA-ILD- patients, and ICAM-1 to distinguish SSc-ILD+ from SSc-ILD- patients was confirmed using ROC curve analysis. Furthermore, elevated levels of ET-1 and E-selectin correlated with lung function decline in RA-ILD+ and SSc-ILD+ patients, respectively. In conclusion, our findings support the relevant role of E-selectin, ICAM-1, and ET-1 in RA-ILD+ patients as well as of ICAM-1 in SSc-ILD+ patients, constituting potential screening blood biomarkers of ILD in AD. Moreover, this study suggests ET-1 and E-selectin as possible indicators of worsening lung function in RA-ILD+ and SSc-ILD+ patients, respectively.

Mucosal Immune Defence Gene Polymorphisms as Relevant Players in the Pathogenesis of IgA Vasculitis?

ITGAM-ITGAX (rs11150612, rs11574637), VAV3 rs17019602, CARD9 rs4077515, DEFA (rs2738048, rs10086568), and HORMAD2 rs2412971 are mucosal immune defence polymorphisms, that have an impact on IgA production, described as risk loci for IgA nephropathy (IgAN). Since IgAN and Immunoglobulin-A vasculitis (IgAV) share molecular mechanisms, with the aberrant deposit of IgA1 being the main pathophysiologic feature of both entities, we assessed the potential influence of the seven abovementioned polymorphisms on IgAV pathogenesis. These seven variants were genotyped in 381 Caucasian IgAV patients and 997 matched healthy controls. No statistically significant differences were observed in the genotype and allele frequencies of these seven polymorphisms when the whole cohort of IgAV patients and those with nephritis were compared to controls. Similar genotype and allele frequencies of all polymorphisms were disclosed when IgAV patients were stratified according to the age at disease onset or the presence/absence of gastrointestinal or renal manifestations. Likewise, no ITGAM-ITGAX and DEFA haplotype differences were observed when the whole cohort of IgAV patients, along with those with nephritis and controls, as well as IgAV patients, stratified according to the abovementioned clinical characteristics, were compared. Our results suggest that mucosal immune defence polymorphisms do not represent novel genetic risk factors for IgAV pathogenesis.

Role of adiponectin in non-diabetic patients with rheumatoid arthritis undergoing anti-IL-6 therapy.

OBJECTIVES: Adiponectin is an adipokine that plays a relevant role in the development of metabolic syndrome (MetS), a complication that increases the risk of cardiovascular (CV) disease in patients with rheumatoid arthritis (RA). Accordingly, we assessed for the first time the short-term effect of anti-IL-6 receptor tocilizumab (TCZ) administration on adiponectin serum levels in RA patients and explored the potential association of adiponectin levels with MetS features, other CV risk factors and demographic and clinical characteristics of these patients. METHODS: Adiponectin serum levels were evaluated in 50 non-diabetic RA patients, undergoing TCZ treatment, immediately prior to (pre-infusion) and 60 minutes after the end of a TCZ intravenous infusion (post-infusion). RESULTS: No significant differences in adiponectin levels pre- and post-TCZ infusion were found in RA patients (p=0.69). Patients with obesity exhibited decreased basal levels of adiponectin with respect to those non-obese (p=0.03). Additionally, a negative association of adiponectin basal levels with body mass index, insulin, insulin/glucose index, C-peptide and leptin levels (p<0.01; p=0.02; p=0.03; p=0.03 and p=0.01, respectively), as well as a positive correlation with HDL-cholesterol levels (p<0.001) was seen. CONCLUSIONS: Our results support the claim that low adiponectin may contribute to the development of MetS and, consequently, CV disease in RA. Anti-IL-6 therapy does not seem to exert a short-term effect on adiponectin levels.

Anti-IL-6 therapy reduces leptin serum levels in patients with rheumatoid arthritis.

OBJECTIVES: Leptin is an adipokine that participates in the regulation of the immune and inflammatory response. Chronic systemic inflammation contributes to the development of cardiovascular (CV) disease in rheumatoid arthritis (RA). In this study, we aimed to assess the short-term effect of the anti-IL-6 receptor tocilizumab (TCZ) administration on circulating leptin concentrations in patients with RA, as well as the potential association of leptin with CV risk factors and demographic and clinical characteristics of these patients. METHODS: We recruited 50 consecutive non-diabetic patients with RA undergoing periodic treatment with TCZ. Leptin serum levels were determined by a commercial immunoassay kit in samples obtained immediately prior to (pre-infusion) and 60 minutes after the end of a TCZ intravenous infusion (post-infusion). RESULTS: A significant reduction of leptin levels was observed following the TCZ infusion (9.24±7.98 ng/mL vs. 7.92±7.32 ng/mL, pre- and post-infusion, respectively, p=0.002). Additionally, there was a strong positive correlation between body mass index of RA patients and basal levels of leptin (r=0.56; p=0.0001). Moreover, high basal levels of leptin in RA patients were associated with female sex (p=0.006), obesity (p<0.001) and rheumatoid factor negative status (p=0.006). CONCLUSIONS: Our study disclosed a short-term effect of anti-IL-6 therapy on leptin serum levels in RA patients. Decreased leptin levels may explain the beneficial effect of anti-IL-6 blockade on CV disease associated to RA.

Influence of IL17A gene on the pathogenesis of immunoglobulin-A vasculitis.

OBJECTIVES: Cytokines signaling pathway genes represent a key component of the genetic network implicated in the pathogenesis of immunoglobulin-A vasculitis (IgAV), an inflammatory vascular pathology. Interleukin (IL)17A is described as a genetic risk locus for some autoimmune diseases, such as giant cell arteritis and spondyloarthritis. Accordingly, we aimed to determine the potential influence of IL17A on the pathogenesis of IgAV. METHODS: Five IL17A tag polymorphisms (rs4711998, rs8193036, rs3819024, rs2275913 and rs7747909), which cover the major variability of this gene, were genotyped in 360 Caucasian patients with IgAV and 1,003 sex and ethnically matched healthy controls using TaqMan probes. RESULTS: No statistically significant differences between patients with IgAV and healthy controls were observed when each IL17A genetic variant was analysed independently. Similarly, no statistically significant differences between patients with IgAV and healthy controls were found when the five IL17A polymorphisms were evaluated combined conforming haplotypes. In addition, there were no statistically significant differences in genotype, allele and haplotype frequencies of IL17A when patients with IgAV were stratified according to the age at disease onset or to the presence/absence of gastrointestinal or renal manifestations. CONCLUSIONS: Our results do not support an influence of IL17A on the pathogenesis of IgAV.

Role of IRF5 in the pathogenesis of immunoglobulin-A vasculitis.

OBJECTIVES: Interferon regulatory factor 5 (IRF5) is a major regulator of type I interferon induction and is also critical to produce pro-inflammatory cytokines. An influence of IRF5 genetic variants on the increased risk of immune-mediated diseases has been described. Accordingly, we aimed to evaluate the implication of IRF5 in the pathogenesis of Immunoglobulin-A vasculitis (IgAV), an inflammatory vascular pathology. METHODS: Three tag genetic variants (rs2004640, rs2070197 and rs10954213), representative of 3 different haplotype blocks within IRF5, were genotyped in 372 Caucasian patients with IgAV and 876 sex and ethnically matched healthy controls by TaqMan assays. RESULTS: No significant differences in the genotype and allele frequencies between patients with IgAV and healthy controls were observed when each IRF5 polymorphism was evaluated independently. Likewise, no significant differences between patients with IgAV and healthy controls were found when we assessed the three IRF5 polymorphisms combined, conforming haplotypes. In addition, there were no significant differences in genotype, allele and haplotype frequencies of IRF5 when patients with IgAV were stratified according to the age at disease onset or to the presence/absence of gastrointestinal or renal manifestations. CONCLUSIONS: Our results do not support an influence of IRF5 on the pathogenesis of IgAV.

Osteopontin as a Biomarker in Interstitial Lung Diseases.

Osteopontin (OPN) is a glycoprotein involved in Th1 and Th17 differentiation, and inflammation and tissue remodeling. OPN is a biomarker of disease activity in patients with autoimmune inflammatory conditions. This study aimed to assess the diagnostic and prognostic value of OPN in interstitial lung diseases (ILDs). Between May 2016 and October 2019, 344 patients with ILD were recruited at the Hospital Universitario Marqués de Valdecilla (Spain) and were prospectively followed-up. This study involved the determination of OPN serum levels by ELISA and OPN RNA expression quantified using qPCR. Six genetic polymorphisms in OPN (rs28357094, rs2853749, rs2853750, rs11728697, rs7695531, and rs1126616) were genotyped using TaqMan assays. OPN serum levels were also assessed in 140 healthy controls. OPN serum levels (median [interquartile range]) were significantly higher in ILD patients than in controls (1.05 [0.75-1.51] ng/mL versus 0.81 [0.65-0.98] ng/mL in healthy controls; p < 0.01). OPN serum levels were inversely correlated with the forced vital capacity. OPN serum levels were also higher in ILD patients who died or underwent lung transplantation when compared with the remaining ILD patients (1.15 [0.80-1.72] ng/mL versus 0.99 [0.66-1.32] ng/mL; p = 0.05). Survival worsened in ILD patients with OPN > 1.03 ng/mL at 1, 3, and 5 years. No statistically significant differences in the genetic frequencies of OPN polymorphisms or the RNA expression were found among the different ILD groups. Elevated levels of OPN in the serum may be a useful indicator in identifying patients with ILD who are more likely to experience poor outcomes.

Serum and genetic markers related to rapid clinical progression of coronary artery disease.

INTRODUCTION AND OBJECTIVES: Patients with clinically evident coronary artery disease differ in their rate of progression, which impacts prognosis. We aimed to characterize serum and genetic markers in patients with rapid clinical progression (RCP) of coronary artery disease vs those with long standing stable (LSS) disease. METHODS: Retrospective study of cases (RCP) and controls (LSS) (1:2). Patients requiring ≥ 2 revascularizations due to atherosclerotic progression in the 10 years after a first angioplasty were considered to be RCP and those without events during the same period after the first angioplasty were considered to have LSS disease. After patient selection, we analyzed serum values, mRNA expression and genetic polymorphisms of inflammatory markers, including interleukin-6, C-reactive protein, and tumor necrosis factor (TNF)-a, and atherogenic markers consisted of proprotein convertase subtilisin/kexin type 9 (PCSK9), low-density lipoprotein receptor, sterol regulatory element binding transcription factor 2, and apolipoprotein-B. RESULTS: The study included 180 patients (58 RCP and 122 LSS). Demographic characteristics, classic risk factors and the extent of coronary disease were similar in the 2 groups. Patients with RCP showed higher serum levels of interleukin-6 and PCSK9 and higher TNF mRNA expression. Interleukin-6 rs180075C, TNF rs3093664 non-G and PCSK9 rs2483205 T alleles conferred a risk of RCP (P<.05 in all cases). Among patients with RCP, 51.7% had all 3 risk alleles vs 18% of those with LSS (P<.001). CONCLUSIONS: We suggest the existence of specific phenotypic and genotypic markers associated with RCP of coronary artery disease that could help to individualize the type and intensity of treatment.

Angiogenic T Cells: Potential Biomarkers for the Early Diagnosis of Interstitial Lung Disease in Autoimmune Diseases?

(1) Background: We explored, for the first time, the contribution of angiogenic T cells (TAng) in interstitial lung disease associated to autoimmune disease (AD-ILD+) as potential biomarkers of the disease, evaluating their role in the underlying vasculopathy and lung fibrosis. Additionally, the relationship of TAng with clinical manifestations and cellular and molecular endothelial dysfunction-related biomarkers was assessed. (2) Methods: We included 57 AD-ILD+ patients (21 with rheumatoid arthritis (RA)-ILD+, 21 with systemic sclerosis (SSc)-ILD+ and 15 with other AD-ILD+) and three comparative groups: 45 AD-ILD- patients (25 RA-ILD- and 20 SSc-ILD-); 21 idiopathic pulmonary fibrosis (IPF) patients; 21 healthy controls (HC). TAng were considered as CD3+CD184+CD31+ by flow cytometry. (3) Results: A similar TAng frequency was found between AD-ILD+ and IPF, being in both cases lower than that observed in AD-ILD- and HC. A lower TAng frequency was associated with negative Scl-70 status and lower FEV1/FVC ratio in SSc-ILD+, as well as with men in RA-ILD+ and non-specific interstitial pneumonia radiological pattern in other AD-ILD+. No relationship between TAng and endothelial progenitor cells, endothelial cells and vascular endothelial growth factor gene expression and protein levels was disclosed. (4) Conclusions: Our findings suggest TAng as potential biomarkers for the early diagnosis of ILD in AD.

Elevated VCAM-1, MCP-1 and ADMA serum levels related to pulmonary fibrosis of interstitial lung disease associated with rheumatoid arthritis.

Introduction: Early diagnosis of interstitial lung disease (ILD) associated with rheumatoid arthritis (RA) constitutes a challenge for the clinicians. Pulmonary vasculopathy is relevant in the development of interstitial lung disease. Accordingly, we aimed to explore the role of vascular cell adhesion molecule-1 (VCAM-1), monocyte chemoattractant protein-1 (MCP-1) and asymmetric dimethylarginine (ADMA), key molecules in the vasculopathy, as potential biomarkers of pulmonary fibrosis in RA-ILD+. Methods: We included 21 RA-ILD+ patients and two comparative groups: 25 RA-ILD- patients and 21 idiopathic pulmonary fibrosis (IPF) patients. Serum levels of the molecules were determined by ELISA, and mRNA expression was quantified by qPCR. Results: VCAM-1, MCP-1 and ADMA serum levels were increased in RA-ILD+ patients in relation to RA-ILD- and IPF patients. Additionally, RA-ILD+ patients exhibited increased CCL2 (gene encoding MCP-1) and decreased PRMT1 (gene related to ADMA synthesis) mRNA expression in relation to RA-ILD- patients. A lower expression of VCAM1, CCL2, and PRMT1 was observed in RA-ILD+ patients when compared with those with IPF. Furthermore, MCP-1 serum levels and PRMT1 mRNA expression were positively correlated with RA duration, and ADMA serum levels were positively associated with C-reactive protein in RA-ILD+ patients. Conclusion: Our study suggests that VCAM-1, MCP-1 and ADMA could be considered as useful biomarkers to identify ILD in RA patients, as well as to discriminate RA-ILD+ from IPF, contributing to the early diagnosis of RA-ILD+.

IgA Vasculitis: Influence of CD40, BLK and BANK1 Gene Polymorphisms.

CD40, BLK and BANK1 genes involved in the development and signaling of B-cells are identified as susceptibility loci for numerous inflammatory diseases. Accordingly, we assessed the potential influence of CD40, BLK and BANK1 on the pathogenesis of immunoglobulin-A vasculitis (IgAV), predominantly a B-lymphocyte inflammatory condition. Three genetic variants within CD40 (rs1883832, rs1535045, rs4813003) and BLK (rs2254546, rs2736340, rs2618476) as well as two BANK1 polymorphisms (rs10516487, rs3733197), previously associated with inflammatory diseases, were genotyped in 382 Caucasian patients with IgAV and 955 sex- and ethnically matched healthy controls. No statistically significant differences were observed in the genotype and allele frequencies of CD40, BLK and BANK1 when IgAV patients and healthy controls were compared. Similar results were found when CD40, BLK and BANK1 genotypes or alleles frequencies were compared between patients with IgAV stratified according to the age at disease onset or to the presence/absence of gastrointestinal or renal manifestations. Moreover, no CD40, BLK and BANK1 haplotype differences were disclosed between patients with IgAV and healthy controls and between patients with IgAV stratified according to the clinical characteristics mentioned above. Our findings indicate that CD40, BLK and BANK1 do not contribute to the genetic background of IgAV.

Irisin as a Novel Biomarker of Subclinical Atherosclerosis, Cardiovascular Risk and Severe Disease in Axial Spondyloarthritis.

Introduction: Patients with axial spondyloarthritis (axSpA) have a high disease burden mainly due to the rheumatic disease itself, and also exhibit accelerated atherosclerosis, that leads to a higher incidence of cardiovascular (CV) disease. Accordingly, the identification of biomarkers of CV risk and inflammation in axSpA patients is clinically relevant. In this sense, given the beneficial functions exerted by the adipomyokine irisin in processes related to CV disease and inflammation, our aim was to assess, for the first time, the role of irisin as a genetic and serological biomarker of subclinical atherosclerosis, CV risk and disease severity in axSpA patients. Methods: A large cohort of 725 Spanish patients with axSpA was included. Subclinical atherosclerosis (presence of plaques and abnormal carotid intima-media thickness values) was evaluated by carotid ultrasound. Four irisin polymorphisms (rs16835198 G/T, rs3480 A/G, rs726344 G/A, and rs1570569 G/T) were genotyped by TaqMan probes. Additionally, serum irisin levels were determined by ELISA. Results: Low irisin levels were linked to the presence of plaques (p=0.002) and atherogenic index values ≥4 (p=0.01). Serum irisin were positively correlated with C-peptide levels (p<0.001) and negatively correlated with visual analogue scale and Bath Ankylosing Spondylitis Metrology Index (p<0.05 in all the cases). Moreover, lower irisin levels were observed in patients with sacroiliitis and in those with a negative HLA-B27 status (p<0.001 and p=0.006, respectively), as well as in those treated with non-steroidal anti-inflammatory drugs and conventional disease-modifying antirheumatic drugs (p<0.001 and p=0.002, respectively). Interestingly, the TT genotype and the T allele of rs16835198 were less frequent in axSpA patients with ASDAS >2.1 (Odds Ratio (OR): 0.48 [0.28-0.83] and OR: 0.73 [0.57-0.92], respectively, p=0.01 in both cases). Additionally, the frequency of rs1570569 T allele was higher in these patients (OR: 1.46 [1.08-1.97], p=0.01). Furthermore, the GGGT haplotype was more frequent in patients with ASDAS values >2.1 (OR: 1.73 [1.13-2.66], p=0.01). Conclusions: Our results indicate that low serum irisin levels could be indicators of the presence of subclinical atherosclerosis, high CV risk and more severe disease in axSpA patients. In addition, irisin may also constitute a genetic biomarker of disease activity in axSpA.

Endothelial Progenitor Cells: Relevant Players in the Vasculopathy and Lung Fibrosis Associated with the Presence of Interstitial Lung Disease in Systemic Sclerosis Patients.

Endothelial progenitor cells (EPC), which are key effectors in the physiologic vascular network, have been described as relevant players in autoimmune diseases. We previously showed that EPC frequency may help to identify the presence of interstitial lung disease (ILD) in rheumatoid arthritis patients. Given that ILD constitutes the main cause of mortality in systemic sclerosis (SSc) patients, we aimed to determine the EPC contribution to the pathogenic processes of vasculopathy and lung fibrosis in SSc-ILD+. EPC quantification was performed by flow cytometry on blood from 83 individuals: 21 SSc-ILD+ patients and subjects from comparative groups (20 SSc-ILD- and 21 idiopathic pulmonary fibrosis (IPF) patients and 21 healthy controls (HC)). EPC were considered as CD34+, CD45low, CD309+, and CD133+. A significant increase in EPC frequency was found in SSc-ILD+ patients when compared to HC (p < 0.001). SSc-ILD+ patients exhibited a higher EPC frequency than SSc-ILD- patients (p = 0.012), whereas it was markedly reduced compared to IPF patients (p < 0.001). EPC frequency was higher in males (p = 0.04) and negatively correlated to SSc duration (p = 0.04) in SSc-ILD+ patients. Our results indicate a role of EPC in the processes of vasculopathy and lung fibrosis in SSc-ILD+. EPC frequency may be considered as a biomarker of ILD in SSc patients.

Role of VEGF Polymorphisms in the Susceptibility and Severity of Interstitial Lung Disease.

The search for biomarkers that can help to establish an early diagnosis and prognosis of interstitial lung disease (ILD) is of potential interest. VEGF polymorphisms have been implicated in the development of several lung disorders. Consequently, we assessed, for the first time, the role of VEGF polymorphisms in the susceptibility and severity of ILD. A total of 436 Caucasian ILD patients (244 with idiopathic interstitial pneumonias (IIPs) and 192 with non-IIP) and 536 ethnically-matched healthy controls were genotyped for VEGF rs833061, rs1570360, rs2010963, rs3025020, and rs3025039 polymorphisms by TaqMan assays. Pulmonary function tests were collected from all the patients. VEGF serum levels were determined by ELISA in a subgroup of patients. No VEGF genotype, allele, carrier, or haplotype differences were found between ILD patients and controls as well as between IIP and non-IIP patients. However, an association of rs1570360 with IIP in women and also with lung function in IIP patients was found. None of the VEGF polymorphisms were associated with VEGF levels. In conclusion, our results suggest that VEGF does not seem to play a relevant role in ILD, although rs1570360 may influence the severity of ILD in women and a worse outcome in IIP patients.