Pro-fibrotic effect of the susceptible gene PCSK5 in vascular fibrosis of Takayasu arteritis via TGF-ß and SMAD3 signaling pathway activation.

BACKGROUND: Vascular fibrosis directly causes vascular thickening in Takayasu arteritis (TAK), in which sustained transforming growth factor beta (TGF-ß) activation is critical. Understanding TGF-ß activation regulation and blocking it might yield a therapeutic effect in TAK. Proprotein convertase subtilisin/kexin type 5 (PCSK5) rs6560480 (T/C) is associated with TAK development. In this study, we assessed the association between the PCSK5 rs6560480 genotype and PCSK5 expression in TAK and explored its molecular role in TGF-ß activation and vascular fibrosis development. METHODS: In TAK patients, PCSK5 and TGF-ß expression in plasma and aortic tissue was examined by ELISA and immunohistochemical staining, and PCSK5 rs6560480 was genotyped. The correlation between PCSK5 and extracellular matrix (ECM) expression was examined by Western blotting (WB) and immunohistochemistry staining. Detection by co-immunoprecipitation was performed to detect the interaction between PCSK5 and TGF-ß in adventitial fibroblasts (AAFs). Downstream signaling pathways were detected by WB and validated with appropriate inhibitors. Potential immunosuppressive agents to inhibit the effects of PCSK5 were explored in cell culture and TAK patients. RESULTS: Patients with PCSK5 rs6560480 TT patients had significantly higher PCSK5 levels and more thickened vascular lesions than patients with PCSK5 rs6560480 CT. PCSK5 expression was significantly increased in alpha smooth muscle actin (α-SMA)-positive myofibroblasts in TAK vascular lesions. Overexpressing PCSK5 facilitated TGF-ß and downstream SMAD2/3 activation and ECM expression in AAFs and aorta in in-vitro culture. The mechanistic study supported that PCSK5 activated precursor TGF-ß (pro-TGF-ß) to the mature form by binding the pro-TGF-ß cleavage site. Leflunomide inhibited PCSK5 and pro-TGF-ß binding, decreasing TGF-ß activation and ECM expression, which was also partially validated in leflunomide-treated patients. CONCLUSION: The findings revealed a novel pro-fibrotic mechanism of PCSK5 in TAK vascular fibrosis via TGF-ß and downstream SMAD2/3 pathway activation. Leflunomide might be anti-fibrotic by disrupting PCSK5 and pro-TGF-ß binding, presenting a new TAK treatment approach.

A pilot study of childhood-onset Takayasu arteritis using whole exome sequencing suggests oligogenic inheritance involving classical complement, collagen, and autoinflammatory pathways.

Takayasu arteritis (TA) is a chronic granulomatous inflammatory disease affecting the aorta and its branches. Paediatric TA (pTA) may present from 6 months after birth till the adolescent age group. Genetics and pathogenesis of pTA are not fully understood. Earlier studies reported monogenic mutation in NOD2, XIAP, and STAT1 genes in patients with pTA. TA, a relatively rare disease, is more common in geographical pockets, including India. We hypothesized that South Asian patients with pTA, namely, those of Indian subcontinent origin, may have clinically relevant and unique pathogenic variants involving one or more genes, especially those linked to genetically driven vasculitic illnesses, including autoinflammatory pathologies. Children with pTA fulfilling EULAR/PRINTO/PReS classification criteria and presenting with clinical symptoms to the Paediatric Rheumatology clinic of Christian Medical College, Vellore, were included. Blood samples were collected after getting informed consent from parents or guardians and assent forms from children. DNA was extracted from whole blood using the Qiagen DNA extraction kit. Initially, the common variant in Indian population, namely, ADA2 c.139G > A; p.Gly47Arg, was screened, followed by whole exome sequencing. Fourteen children were recruited for the study. Median age of patients was 11 years (4 months-14 years) with a male-to-female ratio of 4:10. Distribution of angiographic subsets by Numano's classification of included children were as follows: type 5 (n = 7), type 4 (n = 5), and type 3 (n = 2). We identified novel variants in ten different genes. This include variants in genes of classical complement pathway, namely, C2, C3, C6, C7, and C9, and other genes, namely, CYBA, SH3BP2, GUCY2C, CTC1, COL5A1, and NLPR3. Two of 14 patients have heterozygous pathogenic variants; this implies that combination of heterozygous variants in C3 and COL5A1 might lead to disease development, suggesting digenic inheritance. One patient has a homozygous variant in CYBA. None of the patients were identified to have ADA2 variants. Whole exome sequencing reveals combination of rare variants in genes C3, COL5A1, and CYBA associated with disease development in children with Takayasu Arteritis. Key Points • We identified novel variants in genes of classical complement pathway, namely, C2, C3, C6, C7, and C9, and other genes, namely, CYBA, SH3BP2, GUCY2C, CTC1, COL5A1, and NLPR3. • Two of 14 patients have heterozygous pathogenic variants in C3 and COL5A1; this may have implications in disease development, suggesting digenic inheritance. • One patient has homozygous variant in CYBA. • None of the patients were identified to have ADA2 variants.

Serum osteoprotegerin and its gene polymorphisms in patients with Takayasu's arteritis: a bicentric cross-sectional study.

INTRODUCTION: Takayasu's arteritis (TAK) patients are at an elevated risk of metabolic syndrome and cardiovascular diseases (CVD). Currently, there are no well-validated biomarkers to assess this risk in this population. Previous research in different cohorts has linked serum levels of osteoprotegerin (OPG) and its polymorphisms to accelerated atherosclerosis and a marker of poor prognosis in CVD. Thus, we assessed this protein as a potential biomarker of CVD in TAK patients. OBJECTIVES: To evaluate the serum levels of OPG and its SNPs (single nucleotide polymorphisms) in TAK patients and healthy controls, and to associate these parameters with clinical data. METHODS: This bicentric cross-sectional study included TAK patients who were compared with healthy individuals (control group). The serum levels of OPG and the frequency of OPG SNPs [1181G > C (rs2073618), 245 A > C (rs3134069), 163T > C (rs3102735), and 209 C > T (rs3134070)] were compared between the both groups and associated with clinical data. RESULTS: In total, 101 TAK patients and 93 controls were included in the study. The serum levels of OPG (3.8 ± 1.9 vs. 4.3 ± 1.8pmol/L, respectively; P = 0.059), and its four polymorphisms were comparable between both groups. In an additional analysis of only TAK patients, serum OPG levels and its four genes were not associated with any CVD parameters, except for higher OPG levels among patients without dyslipidemia. CONCLUSION: No significant differences were observed in serum OPG levels or in the genotype frequencies of OPG SNPs between the patient and control groups. Similarly, no correlation was found between laboratory parameters and clinical data on CVD risk in TAK patients.

Anti-integrin αvß6 antibody in Takayasu arteritis patients with or without ulcerative colitis.

Background: It has been well documented that Takayasu arteritis (TAK) and ulcerative colitis (UC) coexist in the same patients. HLA-B*52 characterizes the co-occurrence, which is one of the common genetic features between these two diseases, indicating shared underlying pathologic mechanisms. Anti-integrin αvß6 antibody (Ab) is present in sera of UC patients in a highly specific manner. We investigated if there were any associations between anti-integrin αvß6 Ab and TAK, considering the risk HLA alleles. Methods: A total of 227 Japanese TAK patients were recruited in the current study and their serum samples were subjected to measurement of anti-integrin αvß6 Ab by ELISA. The clinical information, including the co-occurrence of UC, was collected. The HLA allele carrier status was determined by Luminex or genotype imputation. Results: The information about the presence of UC was available for 165 patients, among which eight (4.84%) patients had UC. Anti-integrin αvß6 antibody was identified in 7 out of 8 TAK subjects with UC (87.5%) while only 5 out of 157 (3.18%) TAK subjects without UC had the antibody (OR 121, p=7.46×10-8). A total of 99 out of 218 (45.4%) patients were HLA-B*52 carriers. There was no significant association between the presence of anti-integrin αvß6 Ab and HLA-B*52 carrier status in those without UC (OR 2.01, 95% CI 0.33-12.4, p = 0.189). Conclusions: The prevalence of anti-integrin αvß6 Ab was high in TAK patients with UC, but not in the absence of concomitant UC. The effect of HLA-B*52 on anti-integrin αvß6 Ab production would be minimal.

Exploring the causal relationship between Takayasu arteritis and inflammatory bowel disease using Mendelian randomization.

Takayasu arteritis (TA) and inflammatory bowel disease (IBD) are two distinct diseases; however, previous studies have reported many cases of IBD-TA coexistence. Additionally, the incidence of IBD in patients with TA is estimated to be significantly higher than the incidence in the general population. Therefore, the two diseases are anticipated to be linked. Mendelian randomization (MR) analysis assesses whether an exposure might causally affect an outcome by using genetic variants inherited randomly at conception, thereby reducing the impact of confounding and reverse causality. The present study aimed to investigate the potential causal relationship between TA and IBD using MR analysis. Two-sample MR analysis, in which TA and IBD were regarded as the exposure and outcome, respectively, was conducted to investigate whether the two diseases are causally related using the R TwoSampleMR package. Summary GWAS data of TA consisted of 516 Turkish cohorts and 462 controls, and 119 patients and 993 controls of European ancestry. Summary data of IBD was from a sub-study of the International Inflammatory Bowel Disease Genetics Consortium (IIBDGC) that comprised 31,665 cases and 33,977 controls of European ancestry. Additionally, separate MR analyses stratified by the two major subtypes of IBD, Crohn's disease (CD) and ulcerative colitis (UC), were performed. Various statistical tests, including the intercept of MR-Egger regression, funnel plots, Cochran's Q tests, and leave-one-out sensitivity analyses, were employed to assess the presence of heterogeneity and horizontal pleiotropy among single nucleotide polymorphisms (SNPs). In the primary analysis using the inverse-variance weighted (IVW) method, the risk of developing IBD for a patient with TA compared to a non-TA control increased 1.053 times (Odds Ratio (OR) = 1.053, P = 0.065). The MR-Egger method (OR = 1.025, P = 0.470) yielded results consistent with this null finding. However, both the weighted median method (OR = 1.038, P = 0.002) and the weighted mode method (OR = 1.051, P = 0.009) identified a significant harmful causal effect. The MR outcomes from separate subgroup analyses slightly diverged from those of IBD and TA. Specifically, for CD, three methods indicated that TA is a risk factor: IVW estimated the OR as 1.045 (P = 0.032), MR-Egger as 0.997 (P = 0.957), weighed median as 1.028 (P = 0.021), and weighted mode as 1.031 (P = 0.022), respectively. This study represents one of the initial investigations into the potential causal association between TA and IBD. With three MR methods, including the primary IVW approach, indicating a notable effect on TA on CD, our analysis findings offer some indication that TA could be a contributing risk factor for CD.

Dysregulation of long non-coding RNAs in Takayasu arteritis: A proof-of-concept study.

Takayasu arteritis (TAK) is a rare systemic vasculitis primarily affecting the aorta and its major branches. Early diagnosis is critical to prevent severe vascular complications, yet current biomarkers are insufficient. This proof-of-concept study explores the potential of long non-coding RNAs (lncRNAs) in TAK, an area largely unexplored. In this cross-sectional study, 53 TAK patients, 53 healthy controls, and 10 rheumatoid arthritis (RA) patients were enrolled. Clinical evaluations, disease activity assessments, and lncRNA expression levels were analyzed. TAK patients exhibited significant dysregulation in several lncRNAs, including THRIL (19.4, 11.1-48.8 vs. 62.5, 48.6-91.4 arbitrary units [a.u.]; p < 0.0001), HIF1A-AS1 (4.5, 1.8-16.6 vs. 26.5, 19.8-33.7 a.u.; p < 0.0001), MALAT-1 (26.9, 13.8-52.5 vs. 92.1, 58.5-92.1 a.u.; p < 0.0001), and HOTAIR (8.0, 2.5-24.5 vs. 36.0, 30.0-43.8 a.u.; p < 0.0001), compared to healthy controls. Notably, HOTAIR (area under the ROC curve [AUC] = 0.825), HIF1A-AS1 (AUC = 0.820), and THRIL (AUC = 0.781) demonstrated high diagnostic potential with superior specificity (approximately 95%). While lncRNAs showed diagnostic promise, no significant correlations with TAK activity were observed. Comparative analysis with RA patients revealed distinct lncRNA expression patterns. This study unveils significant dysregulation of lncRNAs THRIL, HIF1A-AS1, and HOTAIR in TAK patients, underscoring their potential as biomarkers and opening avenues for further research into the mechanistic roles of these lncRNAs in TAK pathogenesis.

Angiogenesis related genes in Takayasu Arteritis (TAK): robust association with Tag SNPs of IL-18 and FGF-2 in a South Asian Cohort.

We performed genetic association study for genes encoding angiogenic and angiostatic proteins in patients with Takayasu arteritis (TAK). A total of 96 SNPs involving 60 genes were studied. Genotyping was performed in Fluidigm 96.96 Dynamic Array chip. All statistical analysis for SNP evaluation was performed using PLINK software. Initial analyses revealed five SNPs from three genes [IL-18 (encodes Interleukin-18), FGF2 (encodes Fibroblast Growth Factor-2), and ANGPT1 (encodes Angiopoietin-1)] as significantly different between controls and cases (uncorrected p < 0.05). After permutation-based analysis, two tag SNPs on the promoter region of IL-18 (rs187238 and rs1946518) and one 3'UTR tag SNP (rs1476217) of FGF2 were significantly associated with susceptibility to TAK, with p and OR (95% CI) of 0.0006 and 1.64 (1.25-2.17), 0.03 and 1.28 (1.02-1.64) & 0.016 and 1.33 (1.05-1.67), respectively; while, the two tag SNPs of ANGPT1 gene (rs6469101 and rs16875900) showed a trend (p = 0.055 & p = 0.051, respectively after permutation based correction). There is robust linkage disequilibrium between the two tag SNPs of IL-18 gene as validated by 1000 genome data of South Asian population; the eQTL effects of these tag SNPs of IL-18 and FGF2 genes on adjacent genes further suggest that these tag SNPs act as genetic risks for development of TAK in South Asians, with possible functional implications towards future biomarker development. Genotype phenotype study by genetic model-based analysis also revealed associations between genotype subsets and clinical features like fever, visual loss, left subclavian and coronary artery involvement in our TAK patients.

High-throughput sequencing reveals the change of TCR α chain CDR3 with Takayasu arteritis.

OBJECTIVE: Takayasu arteritis (TAK) is an inflammatory disease of blood vessels, and its pathogenesis is not clear at present. In this study, we explored the immunological characteristics of T cell receptor (TCR) α-chain complementarity-determining region 3 (CDR3) in patients with TAK. METHODS: Five untreated patients with TAK were collected from June 2019 to December 2019. Four healthy blood samples were matched as the control group. The blood mononuclear cells were separated, and RNA was extracted for reverse transcription to obtain complementary DNA. Then high-throughput sequencing was performed. The quality of samples was evaluated by principal component analysis. We compared the diversity and expression of TCR α-chain between TAK group and control group. R software was used for statistical analysis and drawing, and Mann-Whitney U test was used to analyze the differences between the two groups. RESULTS: The results showed that there was a significant difference in the diversity of TCR α-chain CDR3 between the two groups. Three V region genes expression significantly higher in the TAK patients than in the control group. A total of 196 VJ rearrangement genes are significantly different between the two groups, of which 149 rearrangement genes in the TAK group are lower than those in the control group, and 47 rearrangement genes in the TAK group are higher than those in the control group. CONCLUSION: Patients with TAK have a unique TCR α-chain CDR3 library. These characteristic genes may be a marker for early diagnosis and provide a new theoretical basis for treating TAK.

Systemic review and meta-analysis of the association between interleukin-10 and Takayasu arteritis.

OBJECTIVE: The aim of this meta-analysis is to investigate the relationship between interleukin (IL)-10 levels and its polymorphism and Takayasu arteritis (TAK). METHODS: Five databases including PubMed, Web of Science, Ovid, Sinomed and China National Knowledge Infrastructure (CNKI) were gone through from inception to March 31, 2022. Studies were screened according to the inclusion and exclusion criteria. Newcastle-Ottawa Scale (NOS) was applied to assess study quality. Strengths of association were evaluated by odds ratio (OR) and 95% CI. The T v. t (allele contrast), TT v. tt (homozygous contrast), Tt vs tt (heterozygous contrast), TT + Tt vs tt (dominant contrast) and TT vs Tt + tt (recessive contrast) models were adopted. RESULTS: Seven studies were included. No significant relationship between IL-10 and TAK was detected in the included patients (P > 0.05). The levels of IL-10 were lower in the active group than those in the stable group, which was -0.47 (95% CI: -0.93, 0.00) (P = 0.05). No significant relationships between IL-10 and TAK were found under all contrasts for polymorphisms rs1800871, rs1800872 and rs1800896 (P > 0.05). CONCLUSIONS: There was no significant difference in IL-10 levels between TAK patients and control subjects. The levels of IL-10 were lower in TAK patients in the active stage. There was no significant association between IL-10 gene polymorphisms and TAK. Further well-designed studies with larger sample sizes in patients with different stages are needed.

Association of Killer Cell Immunoglobulin-like Receptor (KIR) Genes and their HLA Ligands with Susceptibility to Takayasu Arteritis in the Iranian Population.

Takayasu arteritis (TA) is a chronic inflammatory disorder characterized by vascular damage and fibrosis in the intima that commonly occurs in the aorta. In many damaged sites in TA patients, natural killer (NK) cells have been shown to be hyperactivated and produce inflammatory cytokines and toxic components. Killer cell immunoglobulin-like receptors (KIRs) are found on NK cells and interact with human leukocyte antigen (HLA) class I ligands to activate or suppress NK cells. The present study assessed the possible role of KIR and their HLA ligand genes in susceptibility to TA in Iranian patients. This case-control study included 50 TA patients and 50 healthy subjects. DNA was extracted from whole peripheral blood samples, and polymerase chain reaction with sequence-specific primers (PCR-SSP) was performed to recognize the presence or absence of polymorphism in 17 KIR genes and 5 HLA class I ligands in each participant. Among the KIR and HLA genes, a significant decrease was detected in the frequency of 2DS4 (full allele) in TA patients (38%) compared with healthy controls (82%) (OR=0.13, 95% CI=0.05-0.34). However, none of the KIR and HLA genotypes or the interactions between these genes were associated with susceptibility to TA. The KIR2DS4 gene might be involved in the regulation of activation as well as the production of cytotoxic mediators of NK cells in patients with TA.

Coexistence of 3q29 microdeletion syndrome and Takayasu arteritis: A case report.

Takayasu arteritis (TAK) is a rare type of large and medial vessel systemic vasculitis. A variety of factors are thought to play a role in the occurrence and development of TAK such as human leukocyte antigen-B52, autoimmunity, inflammation and environmental factors. 3q29 microdeletion syndrome is also a very rare inherited disease, which includes intellectual disability, growth retardation and neuropsychiatric disorders. Here, we present a case with concomitant TAK and 3q29 microdeletion syndrome. A 22-year-old woman presented to the emergency department with sudden bilateral vision loss and severe headache. During physical examination, the patient was noted to have a difference in blood pressure between extremities. Computed tomography angiography revealed vascular wall inflammation in the abdominal aorta. Based on clinical and radiographical findings, a diagnosis of TAK was made. Concurrently, the patient was found to have short stature and intellectual disability. A possible genetic etiology was sought out. Chromosome analysis showed a 1.5 Mb heterozygous deletion on chromosome 3 and a diagnosis of 3q29 microdeletion was made. Additional imaging also revealed a split cord in medulla spinalis along with hemivertebrae and fusion anomalies, neither of which were reported in TAK or 3q29 microdeletion cases in the literature.

High expression of pro-inflammatory cytokine genes IL-1ß and IL-1R2 upon TLR4 activation in Takayasu arteritis.

Toll-like receptors (TLR) 4 and its endogenous ligands are highly expressed in aorta. In the present study, we have explored the effect of TLR-4 activation by pro-inflammatory and angiogenic factors in PBMCs of patients with Takayasu Arteritis (TA). In the screening cohort, PBMCs of TA (n = 6) and healthy controls (n = 6) were stimulated with LPS and cultured. mRNA expression of 84 genes were quantitated by RT2 Profiler™ PCR Array kit in PBMCs. Validation set of additional PBMCs from TA (n = 7) and healthy controls [HC) (n = 7) were then stimulated with LPS to study expression of selected genes with delta Ct > 0.1 in the screening cohort. Significant gene expressions were correlated with Indian Takayasu arteritis activity scores (ITAS 2010). Increased expression of CCL2 was observed only in unstimulated PBMCs of patients with TA [median relative difference (RD) of 2.37] as compared to HC (RD 1.37, p < 0.03) in validation cohort, while stimulation with TLR4 ligand led to increased mRNA expression of IL-1ß (RD 7.9, p < 0.028) and IL-1R2 (RD 0.08 p < 0.013) genes as compared to that of HC [RD of 5.32 for IL-1ß and 0.01 for IL-1R2, respectively] in validation cohort. TLR4 activation also led to significantly higher expression of HPSE, TIMP1 and low expression of VEGFB, S1PR1, SERPINF1, ANGPLT4, ANGPT2, TIE1 and NOS3 genes in the screening cohort. But expression of VEGFB was not significant in validation cohort. The significant gene expressions, however, did not correlate with ITAS [ITAS2010 and ITAS-A (CRP)]. TLR4 activation leads to increased expression of IL-1ß and IL-1R2 genes in PBMCs of patients with TA.

Comprehensive Analysis of the HLA Class I and the HLA Class II Alleles in Patients with Takayasu Arteritis: Relationship with Clinical Patterns and Prognosis

BACKGROUND: Takayasu arteritis (TA) is a systemic vasculitis, affecting mainly the aorta and its branches. OBJECTIVE: To analyze the HLA class I and class II alleles in patients with TA and explore their relationship with clinical and demographic characteristics, and potential significance in prognosis. METHODS: Twenty-five, unrelated TA patients were genotyped for HLA-A, HLA-B, HLA-C, HLA-DRB1, and the HLA-DQB1 loci. The frequencies of the HLA-A, HLA-B, and the HLA-DRB1 were compared with a control group of 1992, while the HLA-C and the HLA-DQB1 were compared with a group of 159 healthy, unrelated individuals. RESULTS: Among TA patients, 5/25 (20%) were identified as the HLA-B*52 carriers. There was a significant difference in the HLA-B*52 allele frequency in the TA patients (10%) compared with the healthy controls (1.2%). Moreover, presence of the HLA-B*52 was associated with significantly earlier disease onset, more severe clinical presentations, and a poorer response to treatment. The HLA-C*03 was detected in 32% of patients and was present exclusively in those with a clinically mild form of the TA, indicating a putative protective effect. CONCLUSION: These findings indicate that the HLA-B*52 allele contributes to a higher susceptibility to the TA whereas the HLA-C*03, can be a protective factor in the TA.

Using the co-expression network of T cell-activation-related genes to assess the disease activity in Takayasu's arteritis patients.

BACKGROUND: There have been lacking reliable serum biomarkers in assessing the disease activity of Takayasu's arteritis (TAK). This study aimed to assess the disease activity of TAK by assayed gene expression levels in peripheral mononuclear cells (PBMCs). METHODS: The expression level of genes that essential in T cell activation in PBMCs in active TAK patients, inactive TAK patients, and healthy controls were detected by real-time fluorescence quantitative polymerase chain reaction, including TCR, CD28, CD40, CD40L, PD-1, PD-L1, PD-L2, CTLA4, TIGIT, TIM3, LAG3, CCL5, T-bet, RORC, and FOXP3. Gene co-expression network was established, and the signature of the topology structure in active TAK patients compared to the inactive TAK patients were extracted and described by formulas. Respectively, the disease activity was assessed by the routine serum biomarkers, including ESR, CRP, IL-6, and TNF-α, the gene expression level of TCR, CD28, T-bet, and RORC, as well as the signature of the topology structure, and the diagnostic efficacies were compared. RESULTS: Compared with the inactive TAK patient group, the active TAK patient group had a greater clustering coefficient in the network consisting of genes that essential in T cell activation. When assessing the disease activity used this signature of topology structure, the sensitivity was 90.9%, the specificity was 100%, and the AUC was 0.98, which was greater than the AUCs of these biomarkers. CONCLUSIONS: The signature of the topology structure could distinguish the active TAK patients from inactive TAK patients. This maybe is a novel evaluation algorithm of disease activity.

A susceptibility locus in the IL12B but not LILRA3 region is associated with vascular damage in Takayasu arteritis.

HLA-B*52 is an established genetic factor in Takayasu arteritis (TAK). Recently, single nucleotide polymorphisms (SNPs) in IL12B (rs6871626) and LILRA3 (rs103294) were newly identified as non-HLA susceptibility loci in TAK. Here, we examined how these SNPs contribute to clinical characteristics and vascular damage in TAK. We retrospectively reviewed the medical records of 99 TAK patients enrolled in our previous genome-wide association study, and whose genotypes for IL12B rs6871626, LILRA3 rs103294, and HLA-B*52 were available. Incidence of aortic regurgitation (AR) was significantly associated with the A allele (risk allele) of IL12B rs6871626 (CC 42%, AC 61%, AA 81%; p = 0.0052; odds ratio [OR] 2.45), as well as with the incidence of hypertension (p = 0.049; OR 1.82) and the proportion of patients who underwent aortic valve replacement (p = 0.023; OR 3.64). Regarding vascular damage, there was positive correlation between the Takayasu Arteritis Damage Score and the A allele of IL12B rs6871626 (CC 3.42 ± 2.71, AC 4.06 ± 3.25, AA 6.00 ± 2.81; p = 0.0035; ß = 1.35) and between the Vasculitis Damage Index and the A allele (CC 3.47 ± 1.98, AC 4.33 ± 2.40, AA 5.37 ± 2.22; p = 0.0054; ß = 0.96). Contrarily, no correlation was found between LILRA3 rs103294 and vascular damage. In the present study, IL12B rs6871626 was associated with vascular damage in TAK, whereas LILRA3 rs103294 was not. Genotyping of IL12B rs6871626 may help to identify patients at risk of disease progression.

Polymorphisms in TNFAIP3, but not in STAT4, BANK1, BLK, and TNFSF4, are associated with susceptibility to Takayasu arteritis.

BACKGROUND: Takayasu arteritis (TAK) is considered a rare disease characterized by nonspecific inflammation of the large arteries, especially the aorta and its major branches. Because TAK is an autoimmune disease (AD), it could share susceptibility loci with other pathologies such as systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA), among others. Widely explored polymorphisms in non-HLA genes, including TNFAIP3, STAT4, TNFSF4, BANK1, and BLK have been consistently associated with both SLE and RA, but they have not been evaluated in TAK. OBJECTIVE: The aim of our study was to investigate whether TNFAIP3, STAT4, BANK1, BLK, and TNFSF4 polymorphisms are associated with susceptibility to TAK. METHODS: The TNFAIP3 rs2230926T/G and rs5029924C/T, STAT4 rs7574865G/T, BANK1 10516487G/A, BLK rs2736340T/C, rs13277113A/G, and TNFS4 rs2205960G/T polymorphisms were genotyped in 101 cases and 276 controls by using a TaqMan SNP genotyping assay. An association analysis was performed. RESULTS: The TNFAIP3 rs2230926T/G and rs5029924C/T polymorphisms were in complete linkage disequilibrium and turned out to be risk factors for TAK (OR = 4.88, p = 0.0001). The STAT4, BANK1, BLK, and TNFSF4 polymorphisms were not associated with the disease. CONCLUSIONS: This is the first study documenting an association of TNFAIP3 rs2230926T/G and rs5029924C/T with TAK. Our results provide new information on the genetic bases of TAK.

Specific Follicular Helper T Cell Signature in Takayasu Arteritis.

OBJECTIVE: Our aim was to compare transcriptome and phenotype profiles of CD4+ T cells and CD19+ B cells in patients with Takayasu arteritis (TAK), patients with giant cell arteritis (GCA), and healthy donors. METHODS: Gene expression analyses, flow cytometry immunophenotyping, T cell receptor (TCR) gene sequencing, and functional assessments of cells from peripheral blood and arterial lesions from TAK patients, GCA patients, and healthy donors were performed. RESULTS: Among the most significantly dysregulated genes in CD4+ T cells of TAK patients compared to GCA patients (n = 720 genes) and in CD4+ T cells of TAK patients compared to healthy donors (n = 1,447 genes), we identified a follicular helper T (Tfh) cell signature, which included CXCR5, CCR6, and CCL20 genes, that was transcriptionally up-regulated in TAK patients. Phenotypically, there was an increase in CD4+CXCR5+CCR6+CXCR3- Tfh17 cells in TAK patients that was associated with a significant enrichment of CD19+ B cell activation. Functionally, Tfh cells helped B cells to proliferate, differentiate into memory cells, and secrete IgG antibodies. Maturation of B cells was inhibited by JAK inhibitors. Locally, in areas of arterial inflammation, we found a higher proportion of tertiary lymphoid structures comprised CD4+, CXCR5+, programmed death 1+, and CD20+ cells in TAK patients compared to GCA patients. CD4+CXCR5+ T cells in the aortas of TAK patients had an oligoclonal α/ß TCR repertoire. CONCLUSION: We established the presence of a specific Tfh cell signature in both circulating and aorta-infiltrating CD4+ T cells from TAK patients. The cooperation of Tfh cells and B cells might be critical in the occurrence of vascular inflammation in patients with TAK.

Identification of susceptibility loci for Takayasu arteritis through a large multi-ancestral genome-wide association study.

Takayasu arteritis is a rare inflammatory disease of large arteries. We performed a genetic study in Takayasu arteritis comprising 6,670 individuals (1,226 affected individuals) from five different populations. We discovered HLA risk factors and four non-HLA susceptibility loci in VPS8, SVEP1, CFL2, and chr13q21 and reinforced IL12B, PTK2B, and chr21q22 as robust susceptibility loci shared across ancestries. Functional analysis proposed plausible underlying disease mechanisms and pinpointed ETS2 as a potential causal gene for chr21q22 association. We also identified >60 candidate loci with suggestive association (p < 5 × 10-5) and devised a genetic risk score for Takayasu arteritis. Takayasu arteritis was compared to hundreds of other traits, revealing the closest genetic relatedness to inflammatory bowel disease. Epigenetic patterns within risk loci suggest roles for monocytes and B cells in Takayasu arteritis. This work enhances understanding of the genetic basis and pathophysiology of Takayasu arteritis and provides clues for potential new therapeutic targets.

Association of interleukin-18 gene polymorphisms with Takayasu arteritis in a Chinese Han population.

BACKGROUND: Interleukin-18 (IL18) gene polymorphisms are related to many inflammatory and autoimmune diseases. However, a correlation analysis between IL18 -607C/A and -137G/C gene polymorphisms and Takayasu arteritis (TA) is lacking. METHODS: This study enrolled 200 patients with TA as the case group and 334 region-, age-, and sex-matched healthy subjects as the control group. We genotyped alleles and genotypes at positions -607 and -137 of the IL18 gene and analyzed the distribution frequencies. Mann-Whitney U test, t test, Chi-squared test and Hardy-Weinberg equilibrium were performed. RESULTS: After adjusting for risk factors, the adjusted odds ratios and 95% confidence intervals at position -607C/A were 0.533, 0.391 to 0.880 (P = 0.010); 0.266, 0.586 to 1.002 (P = 0.051); and 0.122, 0.552 to 1.420 (P = 0.613) under the dominant, additive, and recessive models, respectively. For the -137G/C polymorphism, the adjusted odds ratios and 95% confidence intervals were 1.571, 1.068 to 2.311 (P = 0.022); 1.467, 1.086 to 1.980 (P = 0.012); and 1.815, 0.901 to 3.656 (P = 0.095) under the dominant, additive, and recessive models, respectively. Moreover, regardless of the model used, we found no statistical difference in distribution frequency between the active and quiescent states of TA for the -607C/A (P = 0.355, 0.631, and 0.705, respectively) and -137G/C polymorphisms (P = 0.205, 0.385, and 0.208, respectively). CONCLUSIONS: The IL18 -607C/A gene polymorphism may decrease the risk of TA, and thus is a protective factor, whereas -137G/C may increase the risk of TA, and thus is a risk factor. However, neither polymorphism was related to activity (active vs. quiescent) of TA.

X-linked inhibitor of apoptosis protein deficiency complicated with Crohn's disease-like enterocolitis and Takayasu arteritis: A case report.

X-linked inhibitor of apoptosis protein (XIAP) deficiency results in monogenic inflammatory bowel disease. To date, no vasculitis associated with XIAP deficiency has been reported. A 10-year-old boy was diagnosed with Crohn's disease and he responded poorly to conventional treatment for Crohn's disease. He was dependent on corticosteroids and parenteral nutrition. To manage severe colitis, he underwent ileostomy followed by ileocolectomy for an ileo-sigmoid fistula. At the age of 15 years, he developed IgA vasculitis and at the age of 17 years, he developed refractory Takayasu arteritis (TAK), which was resistant to corticosteroid and immunosuppressive therapy. Whole-exome sequencing revealed a novel mutation of the splice acceptor site in XIAP (c.1057-1G > A) at the age of 19 years. Allogeneic hematopoietic stem cell transplantation was successful with subsequent withdrawal of intensive immunosuppressive therapy and clinical remission of both enterocolitis and TAK. This case suggests that patients with XIAP deficiency could develop intractable inflammatory disease involving the intestinal tract and blood vessels.