Single nucleotide polymorphisms of IL12B are associated with Takayasu arteritis in Chinese Han population

Baricitinib for refractory Takayasu arteritis: a prospective cohort study in a tertiary referral centre

OBJECTIVE

To investigate the treatment efficacy and safety of baricitinib in patients with refractory Takayasu arteritis (TAK).

METHODS

We performed a prospective cohort study in which baricitinib 4 mg daily was prescribed to patients with refractory TAK, combined with oral glucocorticoids (GCs).

RESULTS

10 patients with refractory TAK were enrolled with a median age of 28 (IQR=22-37) years, median disease duration of 50 (IQR=24-65) months. The median dose of GCs was 10 (IQR=8.1-22.5) mg prednisone or equivalence dosage at baseline. At 6 months of baricitinib treatment, 6/10 (60%) patients had an overall treatment response. During an average follow-up of 15.3 (range 4-31) months, 4/10 (40%) patients maintained overall treatment response. 8/10 (80%) patients tapered or maintained the same dose of GCs with no change of the combined classical synthetic disease-modifying antirheumatic drugs. Two patients discontinued GCs at 18 and 24 months and were in continuous remission till the end of the study. One patient withdrew baricitinib due to liver dysfunction.

CONCLUSION

Baricitinib 4 mg daily is effective for refractory TAK and is well tolerated.

New Therapeutic Approaches to Large-Vessel Vasculitis

Giant cell arteritis (GCA) and Takayasu arteritis (TAK) are large-vessel vasculitides affecting the aorta and its branches. Arterial damage from these diseases may result in ischemic complications, aneurysms, and dissections. Despite their similarities, the management of GCA and TAK differs. Glucocorticoids are used frequently but relapses are common, and glucocorticoid toxicity contributes to significant morbidity. Conventional immunosuppressive therapies can be beneficial in TAK, though their role in the management of GCA remains unclear. Tumor necrosis factor inhibitors improve remission rates and appear to limit vascular damage in TAK; these agents are not beneficial in GCA. Tocilizumab is the first biologic glucocorticoid-sparing agent approved for use in GCA and also appears to be effective in TAK. A better understanding of the pathogenesis of both conditions and the availability of targeted therapies hold much promise for future management.

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.

Animal models for large vessel vasculitis - The unmet need

Our understanding of the pathogenesis of large vessel vasculitis (LVV) are mainly achieved by studying the arteries taken from temporal artery biopsy in giant cell arteries (GCA) or surgical or autopsy specimens in Takayasu arteritis (TAK). These artery specimens provide invaluable information about pathological changes in these conditions that GCA and TAK are similar but are distinctly different in immune cell infiltrate and distribution of inflammatory cells in anatomical locations. However, these specimens of established arteritis do not provide information of the arteritis initiation and early events which are impossible to obtain in human artery specimens. Animal models for LVV are needed but not available. Here, several approaches are proposed for experimentation to generate animal models to aid in delineating the interaction of immune reaction with arterial wall components.

New insights into the IL-12 and IL-23: From a molecular basis to clinical application in immune-mediated inflammation and cancers

The cytokines interleukin-12 (IL-12) and IL-23 share a common IL-12/IL-23p40 subunit in structure and play a central role in T cell-mediated responses in inflammation. Over-activated IL-12 and IL-23 signaling drives aberrant T helper (Th) 1 and Th17 immune responses and contributes to immune-mediated diseases. Evidence from genome-wide association studies has shown that genetic alterations in the IL-12/IL-23 signaling pathways have significant links with chronic inflammation. In addition, accumulating evidence from animal models and clinical trials has provided insights into the effectiveness of blocking the IL-12/IL-23 pathways in immune regulation, broadening the clinical indications of IL-12/IL-23 pathway effectors in immune-mediated diseases. More recently, it has been addressed that the balance between IL and 12 and IL-23 is also critical in carcinogenesis. IL-12- and IL-23-driven T cell cytokines are especially important in controlling tumor initiation, growth, and metastasis, and thus, the IL-12/IL-23 pathway may be a promising target for immunotherapy. This review focuses on IL-12/IL-23 signal transduction and biological functionality in autoimmunity and oncoimmunology. We discuss the therapeutic rationale for targeting these cytokines to treat immune-mediated diseases and issues regarding their inadvertent consequences in the balance of host defense and tumor surveillance and summarize their recent clinical applications in immune-mediated diseases.

Immune Relevant and Immune Deficient Mice: Options and Opportunities in Translational Research

In 1989 ILAR published a list and description of immunodeficient rodents used in research. Since then, advances in understanding of molecular mechanisms; recognition of genetic, epigenetic microbial, and other influences on immunity; and capabilities in manipulating genomes and microbiomes have increased options and opportunities for selecting mice and designing studies to answer important mechanistic and therapeutic questions. Despite numerous scientific breakthroughs that have benefitted from research in mice, there is debate about the relevance and predictive or translational value of research in mice. Reproducibility of results obtained from mice and other research models also is a well-publicized concern. This review summarizes resources to inform the selection and use of immune relevant mouse strains and stocks, aiming to improve the utility, validity, and reproducibility of research in mice. Immune sufficient genetic variations, immune relevant spontaneous mutations, immunodeficient and autoimmune phenotypes, and selected induced conditions are emphasized.

New Insights on the Pathogenesis of Takayasu Arteritis: Revisiting the Microbial Theory

Takayasu arteritis (TAK) is a chronic vasculitis that mainly affects the aorta, its major branches, and the pulmonary arteries. Since the description of the first case by Mikito Takayasu in 1908, several aspects of this rare disease, including the epidemiology, diagnosis, and the appropriate clinical assessment, have been substantially defined. Nevertheless, while it is well-known that TAK is associated with a profound inflammatory process, possibly rooted to an autoimmune disorder, its precise etiology has remained largely unknown. Efforts to identify the antigen(s) that trigger autoimmunity in this disease have been unsuccessful, however, it is likely that viruses or bacteria, by a molecular mimicry mechanism, initiate or propagate the auto-immune process in this disease. In this article, we summarize recent advances in the understanding of TAK, with emphasis on new insights related to the pathogenesis of this entity that may contribute to the design of novel therapeutic approaches.

Association of interleukin-6 and interleukin-10 expression, gene polymorphisms, and Takayasu arteritis in a Chinese Han population

Takayasu arteritis (TA) is a chronic inflammatory disease. Interleukin (IL)-6 and IL-10 are important cytokines involved in the immune response of TA in some ethnicities. We investigated whether the single-nucleotide polymorphism (SNP) of IL-6 and IL-10 genes and their expressions were associated with TA in a Chinese Han population. One hundred eighty-four TA patients and 235 healthy controls (HC) were recruited. DNA and RNA were extracted from peripheral blood cells. Genotyping of IL-6 and -10 was performed using polymerase chain reaction-ligase detection reaction (PCR-LDR). The mRNA levels of IL-6 and IL-10 were semi-quantified using reverse transcription polymerase chain reaction (RT-PCR) and real-time polymerase chain reaction (real-time PCR). Plasma levels of them were examined by enzyme-linked immunosorbent assay (ELISA). The mRNA levels of IL-6 in active phase of TA were higher than those in stable phase (p = 0.015); the IL-10 in active phase was lower compared with stable phase (p = 0.046). Plasma levels of IL-6 in TA were higher than those in HC (p = 0.024). Plasma levels of IL-10 showed no difference between the two groups (p = 0.264). Plasma levels of IL-6 in active phase were increased than those in stable phase (p = 0.043) while those of IL-10 were decreased in active phase (p = 0.041). We found no significant differences between TA and HC in the frequency of any of the variations in the SNPs of IL-6 and IL-10 genes. The expression levels of both cytokines were associated with the disease status, indicating that they may serve as potential biomarkers for monitoring disease activity.