Vascular imaging of patients with refractory Takayasu arteritis treated with tocilizumab: post hoc analysis of a randomized controlled trial

A Glimpse into Humoral Response and Related Therapeutic Approaches of Takayasu's Arteritis

Takayasu's arteritis (TAK) manifests as an insidiously progressive and debilitating form of granulomatous inflammation including the aorta and its major branches. The precise etiology of TAK remains elusive, with current understanding suggesting an autoimmune origin primarily driven by T cells. Notably, a growing body of evidence bears testimony to the widespread effects of B cells on disease pathogenesis and progression. Distinct alterations in peripheral B cell subsets have been described in individuals with TAK. Advancements in technology have facilitated the identification of novel autoantibodies in TAK. Moreover, emerging data suggest that dysregulated signaling cascades downstream of B cell receptor families, including interactions with innate pattern recognition receptors such as toll-like receptors, as well as co-stimulatory molecules like CD40, CD80 and CD86, may result in the selection and proliferation of autoreactive B cell clones in TAK. Additionally, ectopic lymphoid neogenesis within the aortic wall of TAK patients exhibits functional characteristics. In recent decades, therapeutic interventions targeting B cells, notably utilizing the anti-CD20 monoclonal antibody rituximab, have demonstrated efficacy in TAK. Despite the importance of the humoral immune response, a systematic understanding of how autoreactive B cells contribute to the pathogenic process is still lacking. This review provides a comprehensive overview of the biological significance of B cell-mediated autoimmunity in TAK pathogenesis, as well as insights into therapeutic strategies targeting the humoral response. Furthermore, it examines the roles of T-helper and T follicular helper cells in humoral immunity and their potential contributions to disease mechanisms. We believe that further identification of the pathogenic role of autoimmune B cells and the underlying regulation system will lead to deeper personalized management of TAK patients. We believe that further elucidation of the pathogenic role of autoimmune B cells and the underlying regulatory mechanisms holds promise for the development of personalized approaches to managing TAK patients.

Treatment efficacy and safety of adalimumab versus tocilizumab in patients with active and severe Takayasu arteritis: an open-label study

OBJECTIVE

This study aimed to compare the efficacy and safety of adalimumab (ADA) vs tocilizumab (TCZ) in patients with Takayasu arteritis (TAK).

METHODS

This was a randomized, controlled, open-label study. Forty patients with active and severe TAK were enrolled. They were treated with ADA (n = 21) combined with glucocorticoids (GCs) and MTX or TCZ (n = 19) combined with GCs and MTX. The planned follow-up duration was 12 months. The primary end point was the efficacy rate (ER) at 6 months. The secondary end points included ER at 9 and 12 months, relapse rate, GC tapering, adverse effects, and life quality changes during treatment.

RESULTS

In the intention-to-treat (ITT) population, the ER at 6 months was higher in the ADA group (85.71% vs 52.63%, P = 0.02). A similar direction of effect was noted in the per-protocol set (89.47% vs 62.50%, P = 0.06). The percentages of patients who achieved a GC dose of ≤10 mg/day at 6 months were similar between the ADA and TCZ groups (47.37% vs 43.75%, P = 0.83). The ERs at 9 and 12 months were similar between the two groups (P > 0.05). During the first 12 months of treatment, the relapse rate and adverse event incidence were comparable between the two groups (ADA vs TCZ: 9.52% vs 10.53%, P = 0.96; 38.10% vs 47.37%, P = 0.55, respectively).

CONCLUSION

ADA combined with GCs and MTX may be more efficacious than TCZ combined with GCs and MTX among patients with active and severe TAK.

TRIAL REGISTRATION

Clinicaltrials.gov; NCT04300686.

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.

Exploration of molecular signatures associated with different clinical features of Takayasu arteritis based on a prospective cohort study

Takayasu arteritis (TAK) is complicated disorder without reliable biomarkers. Here, we aimed to explore TAK-associated factor panels and their changes after biologic treatment. Five factor panels were identified: 1. systemic inflammation: C3, ESR, CRP, PLT, IL-6, C4, and IgG; 2. vascular inflammation: YKL40, IL-16, PTX3, and CCL2; 3. immune regulation panel: IL-10, IFN-γ, CCL5, and MMP1; 4. angiogenesis and fibrosis: FGF, PDGFAB, and VEGF; and 5. vascular remodeling: CD19+ B cell ratio, MMP3, and leptin. Panel 1 parameters were closely related to disease activity, while Panel 5 parameters, particularly CD19+ B cell ratio and leptin, were significantly higher in ischemic patients. After treatment, tocilizumab had a stronger inhibitory effect on Panel 1 parameters, PTX3, and YKL-40, while adalimumab led to an increase in IL-16, CCL2, and leptin levels. Altogether, these data expanded our knowledge regarding molecular background in TAK development and shed light on precise treatment in future studies.

A multicentre, large-scale, observational study of tocilizumab in patients with Takayasu arteritis in Japan: The ACTEMRA® (ACT)-Bridge study

OBJECTIVES

We evaluated the real-world tolerability and effectiveness of tocilizumab in Japanese patients with Takayasu arteritis (TAK).

METHODS

Patients with TAK who had not received tocilizumab in the previous 6 months were enrolled in ACTEMRA® (ACT)-Bridge, a phase 4, observational study, from 66 Japanese institutions (enrolment period, September 2017 to September 2020) and received weekly subcutaneous tocilizumab 162 mg (observation period, 52 weeks).

RESULTS

Among 120 patients included (mean age, 38.4 years; mean disease duration, 7.7 years; treated for relapse, 50.8%; previous immunosuppressant use, 57.5%; glucocorticoid use at baseline, 97.5%), 49 (40.8%) reported adverse events. The most common adverse event of special interest was serious infection (7.5%). Relapse was observed in 24 (20.0%) patients (0.8%, 2.5%, and 16.7% reporting ≥3, 2, and 1 relapses, respectively). The reasons for diagnosing relapse included chest and back pain (45.8%), neck pain (25.0%), fatigue (16.7%), fever and headache (12.5% each), abnormal imaging findings (50.0%), and elevated inflammatory markers (16.7%). At the last observation, 83.0% of relapse-free patients recorded a concomitant glucocorticoid dose (prednisolone equivalent) <10 mg/day.

CONCLUSIONS

This study demonstrated the effectiveness of tocilizumab in patients with TAK, with no new safety concerns. Tocilizumab plus glucocorticoids may be considered a treatment option for TAK.

Tocilizumab Treatment for Takayasu Arteritis in Pregnancy: A Case Report With Positive Maternal and Neonatal Outcomes

Takayasu arteritis (TAK) is a rare vasculitis that often affects young women of childbearing age, and its management during pregnancy poses unique challenges. Limited data exist regarding the safety and efficacy of tocilizumab (TCZ), an interleukin-6 receptor antagonist, in the treatment of TAK during pregnancy. This case report presents a unique and valuable insight into the use of TCZ in pregnant patients with TAK. We report an 18-year-old female patient with TAK who was treated with TCZ during two pregnancies, resulting in positive maternal and neonatal outcomes. However, a newly identified descending aortic aneurysm was noted after the second delivery, highlighting the importance of careful monitoring of vascular lesions in patients with TAK receiving TCZ. Our findings suggest that TCZ has a high safety profile for both the mother and fetus; however, further research and close monitoring are essential for its use in pregnant patients with TAK.

Gut dysbiosis is associated with aortic aneurysm formation and progression in Takayasu arteritis

BACKGROUND

Takayasu arteritis (TAK) is an autoimmune large vessel vasculitis that affects the aorta and its major branches, eventually leading to the development of aortic aneurysm and vascular stenosis or occlusion. This retrospective and prospective study aimed to investigate whether the gut dysbiosis exists in patients with TAK and to identify specific gut microorganisms related to aortic aneurysm formation/progression in TAK.

METHODS

We analysed the faecal microbiome of 76 patients with TAK and 56 healthy controls (HCs) using 16S ribosomal RNA sequencing. We examined the relationship between the composition of the gut microbiota and clinical parameters.

RESULTS

The patients with TAK showed an altered gut microbiota with a higher abundance of oral-derived bacteria, such as Streptococcus and Campylobacter, regardless of the disease activity, than HCs. This increase was significantly associated with the administration of a proton pump inhibitor used for preventing gastric ulcers in patients treated with aspirin and glucocorticoids. Among patients taking a proton pump inhibitor, Campylobacter was more frequently detected in those who underwent vascular surgeries and endovascular therapy for aortic dilatation than in those who did not. Among the genus of Campylobacter, Campylobacter gracilis in the gut microbiome was significantly associated with clinical events related to aortic aneurysm formation/worsening in patients with TAK. In a prospective analysis, patients with a gut microbiome positive for Campylobacter were significantly more likely to require interventions for aortic dilatation than those who were negative for Campylobacter. Furthermore, patients with TAK who were positive for C. gracilis by polymerase chain reaction showed a tendency to have severe aortic aneurysms.

CONCLUSIONS

A specific increase in oral-derived Campylobacter in the gut may be a novel predictor of aortic aneurysm formation/progression in patients with TAK.

Management of Takayasu arteritis

This review overviews the challenges in the assessment of disease activity, damage, and therapy of Takayasu arteritis (TAK). Recently developed disease activity scores for TAK are more useful for follow-up visits and require validation of cut-offs for active disease. A validated damage score for TAK is lacking. Computed tomography angiography (CTA), magnetic resonance angiography (MRA), and ultrasound enable the evaluation of vascular anatomy and arterial wall characteristics of TAK. 18-fluorodeoxyglucose (18-FDG) positron emission tomography (PET) visualizes arterial wall metabolic activity and complements the information provided by circulating C-reactive protein (CRP) levels. ESR and CRP alone moderately reflect TAK disease activity. TAK is corticosteroid-responsive but relapses upon tapering corticosteroids. Conventional synthetic disease-modifying anti-rheumatic drugs (DMARDs) are the first-line maintenance agents, and tumor necrosis factor-alpha inhibitors, tocilizumab, or tofacitinib are second-line agents for TAK. Revascularization procedures for TAK should be used judiciously during periods of inactive disease.

The effectiveness of tocilizumab and its comparison with tumor necrosis factor alpha inhibitors for Takayasu Arteritis: A systematic review and meta-analysis

Takayasu arteritis (TAK) refractory to conventional disease-modifying anti-rheumatic drugs (DMARDs) is commonly treated with biologic DMARDs such as tocilizumab or tumor necrosis factor-alpha inhibitors (TNFi). The 2021 American College of Rheumatology (ACR) recommendations preferred TNFi to tocilizumab. Therefore, we conducted a systematic review with meta-analysis to assess the evidence base for tocilizumab in TAK by updating a previous systematic review on DMARDs in TAK through searches on MEDLINE, Pubmed Central, Scopus, major international Rheumatology conference abstracts, and clinical trial databases from January 2021 to November 2022. Thirty-five studies involving 1082 TAK [one randomized controlled trial (RCT), eleven controlled and twenty-one uncontrolled studies, most of moderate to high quality] had evaluated tocilizumab in TAK. The RCT of tocilizumab versus placebo failed to meet its primary end-point of superiority of tocilizumab on an intention-to-treat analysis (hazard ratio 0.41, 95%CI 0.15-1.10) but successfully met the secondary end-point of superiority on per-protocol analysis (hazard ratio 0.34, 95%CI 0.11-1.00). A meta-analysis of six studies identified similar rates of clinical remission [risk ratio (RR) tocilizumab vs TNFi 1.03, 95%CI 0.91-1.17)], angiographic stabilization (RR 1.00, 95%CI 0.72-1.40) or adverse events (RR 0.84, 95%CI 0.54-1.31) with tocilizumab or TNFi. A meta-analysis of three studies identified superior clinical response (RR 1.55, 95%CI 1.15-2.10) and adverse effect profile (RR 0.45, 95%CI 0.25-0.80) with tocilizumab than cyclophosphamide. Pooled data from uncontrolled studies identified clinical response in 85%(95%CI 79-91%) and angiographic stabilization in 82% (95%CI 68-94%). Our study suggests similar evidence for treating TAK with tocilizumab or TNFi, contrary to the ACR 2021 recommendations.

Intravenous tocilizumab for Takayasu arteritis with aortic aneurysms, bilateral renal artery stenosis, and atypical aortic coarctation in a 2-year-old girl

Takayasu arteritis (TAK) is classified as large vessel vasculitis, and continuous inflammation of the vessel results in aneurysm or stenosis, which leads to various serious complications. Recently, a TAKT [TAK treated with tocilizumab (TCZ)] study showed that subcutaneous TCZ, a humanised anti-interleukin-6 receptor monoclonal antibody, is an effective treatment in patients with TAK above 12 years of age; however, the effectiveness of TCZ for juvenile TAK under 12 years old remains unclear. Here, we described the case of a 2-year-old girl with TAK, which was successfully treated with intravenous TCZ. She was diagnosed with TAK type V (Numano's angiographic classification system) with aortic aneurysms, bilateral renal arteries stenosis, and atypical descending aortic coarctation based on contrast-enhanced computed tomography findings. Treatment was started with 2 mg/kg/day prednisolone (PSL) and methotrexate instead of methylprednisolone pulse due to renovascular hypertension. She was immediately afebrile and her C-reactive protein level decreased, although it was elevated 4 weeks after starting PSL. Intravenous TCZ of 8 mg/kg/2 weeks was added because the progression of aneurysms or stenosis might lead to a poor prognosis. PSL was steadily reduced under intravenous TCZ. Magnetic resonance imaging showed that aortic aneurysms, renal arteries stenosis, and aortic coarctation ameliorated 4 months after starting TCZ, with the amelioration maintained at 1 year after starting TCZ. Aneurysms and stenosis improved; therefore, TCZ may be effective for the treatment of inflammation of vessels, aneurysms, and stenosis. It is desirable to examine the effect of TCZ on TAK patients under 12 years of age.

Outcome Measures and Biomarkers for Disease Assessment in Takayasu Arteritis

Takayasu arteritis (TAK) is a less common large vessel vasculitis where histopathology of involved arteries is difficult to access except during open surgical procedures. Assessment of disease activity in TAK, therefore, relies on surrogate measures. Clinical disease activity measures such as the National Institutes of Health (NIH) score, the Disease Extent Index in TAK (DEI.TAK) and the Indian TAK Clinical Activity Score (ITAS2010) inconsistently associate with acute phase reactants (APRs). Computerized tomographic angiography (CTA), magnetic resonance angiography (MRA), or color Doppler Ultrasound (CDUS) enables anatomical characterization of stenosis, dilatation, and vessel wall characteristics. Vascular wall uptake of 18-fluorodeoxyglucose or other ligands using positron emission tomography computerized tomography (PET-CT) helps assess metabolic activity, which reflects disease activity well in a subset of TAK with normal APRs. Angiographic scoring systems to quantitate the extent of vascular involvement in TAK have been developed recently. Erythrocyte sedimentation rate and C-reactive protein have a moderate performance in distinguishing active TAK. Numerous novel biomarkers are under evaluation in TAK. Limited literature suggests a better assessment of active disease by combining APRs, PET-CT, and circulating biomarkers. Validated damage indices and patient-reported outcome measures specific to TAK are lacking. Few biomarkers have been evaluated to reflect vascular damage in TAK and constitute important research agenda.

Augmented PFKFB3-mediated glycolysis by interferon-γ promotes inflammatory M1 polarization through the JAK2/STAT1 pathway in local vascular inflammation in Takayasu arteritis

BACKGROUND

Takayasu arteritis (TAK) is characterized by pro-inflammatory M1 macrophage infiltration and increased interferon (IFN)-γ expression in vascular lesions. IFN-γ is a key cytokine involved in M1 polarization. Macrophage polarization is accompanied by metabolic changes. However, the metabolic regulation mechanism of IFN-γ in M1 macrophage polarization in TAK remains unclear.

METHODS

Immunohistochemistry and immunofluorescence were employed to observe the expression of IFN-γ, PFKFB3 (6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3, the rate-limiting enzyme in glycolysis), and macrophage surface markers in the vascular tissue. Monocyte-derived macrophages from patients with TAK were cultured to examine the role of PFKFB3 in IFN-γ-induced M1 macrophage polarization. Seahorse analysis was used to detect the alterations in glucose metabolism during this process. Quantitative reverse transcription PCR, flow cytometry, and western blot were used to confirm the phenotypes of macrophages and related signaling pathways.

RESULTS

In the vascular adventitia of patients with TAK, an increase in PFKFB3 accompanied by IFN-γ expression was observed in M1 macrophages. In vitro, IFN-γ successfully induced macrophage differentiation into the M1 phenotype, which was manifested as an increase in CD80 and HLA-DR markers and the pro-inflammatory cytokines IL-6 and TNF-α. During this process, PFKFB3 expression and glycolysis levels were significantly increased. However, glycolysis and M1 polarization induced by IFN-γ were suppressed by a PFKFB3 inhibitor. In addition, JAK2/STAT1 phosphorylation was also enhanced in macrophages stimulated by IFN-γ. The effects of IFN-γ on macrophages, including the expression of PFKFB3, glycolysis, and M1 polarization, were also inhibited by the JAK inhibitor tofacitinib or STAT1 inhibitor fludarabine.

CONCLUSION

PFKFB3-mediated glycolysis promotes IFN-γ-induced M1 polarization through the JAK2/STAT1 signaling pathway, indicating that PFKFB3 plays an important role in M1 polarization mediated by IFN-γ; thus, PFKFB3 is a potential intervention target in TAK.