CARD9 in the pathogenesis of axial spondyloarthritis.

Axial spondyloarthritis (axSpA) has been long classified as an autoimmune disease caused by a breakdown in the ability of the immune system to delineate self from foreign, resulting in self-reactive T cells. The strong genetic association of HLA-B27 supports this role for T cells. More recently, genetic and clinical studies indicate a prominent role of the environment in triggering axSpA, including an important role for microbes and the innate immune response. As an example, mutations in genes associated with innate immunity, including the anti-fungal signaling molecule Caspase recruitment domain-containing protein 9 (CARD9), have been linked to axSpA susceptibility. Thus, current thought classifies axSpA as a "mixed pattern condition" caused by both autoimmune and autoinflammatory mechanisms. The goal of this review is to convey.

Reduced expression of miRNAs as potential biomarkers in axial spondyloarthritis.

OBJECTIVE: This study aimed to investigate the value of miR-29a-3p, miR-27a, miR126-3p, miR-146a-5p, miR-625-3p, miR-130a, miR-32, miR-218, miR-131, and miR5196 in the diagnosis of axial spondyloarthritis and to determine whether there is a difference in miRNA expression levels between radiographic axial spondyloarthritis and non-radiographic axial spondyloarthritis, as well as the relationship between miRNA expression levels, disease activity, and uveitis history. METHODS: This study included 50 patients with axial spondyloarthritis (25 with radiographic axial spondyloarthritis and 25 with non-radiographic axial spondyloarthritis) and 25 healthy individuals. The fold change of miRNA expression for each miRNA was calculated using the 2-ΔΔCt method. RESULTS: The expression of all miRNAs except miR-130a was downregulated in axial spondyloarthritis patients (miR-27a: fold regulation: -11.21, p<0.001; miR-29a-3p: fold regulation: -2.63, p<0.001; miR-32: fold regulation: -2.94, p=0.002; miR-126-3p: fold regulation -10.94, p<0.001; miR-132: fold regulation: -2.18, p<0.001; miR-146-5p: fold regulation: -9.78, p<0.001; miR-218: fold regulation: -2.65, p<0.001; miR-625-3p: fold regulation: -2.01, p=0.001; miR-5196-3p: fold regulation: -7.04, p<0.001). The expression levels of these miRNAs did not differ significantly between non-radiographic axial spondyloarthritis and radiographic axial spondyloarthritis patients (p>0.05 for all). CONCLUSION: Particularly, miR-27a, miR-126-3p, miR-146-5p, and miR-5196-3p were found to be substantially downregulated in both non-radiographic axial spondyloarthritis and radiographic axial spondyloarthritis patients, suggesting their potential as diagnostic biomarkers for axial spondyloarthritis.

Association of MICA and NKG2D genetic variants with disease susceptibility and outcome of anti-TNF therapy in patients with axial spondyloarthritis.

OBJECTIVES: The disruption of the NKG2D-MICA axis can induce an enhanced immune response and promote autoimmune processes during axial spondyloarthritis (axSpA) pathogenesis. We aimed to investigate potential relationships between selected single nucleotide polymorphisms within the MICA and NKG2D genes and disease susceptibility and clinical parameters in axSpA patients treated with TNF inhibitors. METHODS: Genotyping of MICA rs1051792 and NKG2D rs1154831, rs1049174, and rs2255336 was performed in 163 axSpA patients and 234 healthy controls using a real-time PCR method. RESULTS: MICA rs1051792 A allele was more common in patients than in controls (p<0.0001). Patients with the AA genotype showed greater disease activity score (BASDAI) after three (p=4×10-4) and six (p=0.032) months of treatment compared to G carriers. After three months of therapy with anti-TNFs, the MICA AA homozygosity occurred more often in non-responsive or moderately responsive patients than good responders with the same genotype (p=1×10-4). Additionally, patients bearing the NKG2D rs1154831 CC genotype demonstrated lower BASDAI scores (p=0.035) and were significantly more common among subjects with a good outcome (p=0.004) after six months of treatment. CONCLUSIONS: These results suggest that MICA and NKG2D gene polymorphisms may be biomarkers associated with disease susceptibility and clinical outcomes after anti-TNF therapy in axSpA patients and imply a rather less favourable effect of the MICA A and NKG2D G genetic variants.

Genetic Associations Between IL-6 and the Development of Autoimmune Arthritis Are Gender-Specific.

Objectives: To find out the genetic association between IL6 and autoimmune arthritis. Methods: We performed a two-sample Mendelian randomization (MR) study using multiple genome-wide association studies (GWAS) datasets. Furthermore, a sex-stratified MR study was performed to identify sexual dimorphism in the association between IL6 and autoimmune arthritis. Then, LocusZoom plots were displayed based on the IL6R gene region to present evidence of genetic colocalization between diseases. Results: The MR result denoted a genetic association between the increased level of IL-6 signaling and risk of RA (ß=0.325, 95%CI 0.088, 0.561, p=7.08E-03) and AS (ß=1.240, 95%CI 0.495, 1.980, p=1.1E-03). Accordingly, sIL6R was found to have negatively correlation with the onset of RA (ß=-0.020, 95%CI -0.0320, -0.008, p=1.18E-03) and AS (ß=-0.125, 95%CI -0.177, -0.073, p=2.29E-06). However, no genetic association between IL6/sIL6R and PsA was detected. The gender-stratified MR analysis showed that IL6 was associated with AS in the male population, with RA in the female population, and with PsA in the male population. Additionally, ADAR, a gene identified by a sensitive test, could be the reason for the nonsignificant association between IL6 and PsA in a pooled population. Conclusion: Our findings showed that the overactive IL6 signal pathway led to autoimmune arthritis, especially in RA and AS. Sexual difference was also observed in IL6-intermediate susceptibility to autoimmune arthritis.