Carol A. McAlear

Identification of multiple genetic susceptibility loci in Takayasu arteritis

Takayasu arteritis is a rare inflammatory disease of large arteries. The etiology of Takayasu arteritis remains poorly understood, but genetic contribution to the disease pathogenesis is supported by the genetic association with HLA-B*52. We genotyped ~200,000 genetic variants in two ethnically divergent Takayasu arteritis cohorts from Turkey and North America by using a custom-designed genotyping platform (Immunochip). Additional genetic variants and the classical HLA alleles were imputed and analyzed. We identified and confirmed two independent susceptibility loci within the HLA region (r(2) < 0.2): HLA-B/MICA (rs12524487, OR = 3.29, p = 5.57 × 10(-16)) and HLA-DQB1/HLA-DRB1 (rs113452171, OR = 2.34, p = 3.74 × 10(-9); and rs189754752, OR = 2.47, p = 4.22 × 10(-9)). In addition, we identified and confirmed a genetic association between Takayasu arteritis and the FCGR2A/FCGR3A locus on chromosome 1 (rs10919543, OR = 1.81, p = 5.89 × 10(-12)). The risk allele in this locus results in increased mRNA expression of FCGR2A. We also established the genetic association between IL12B and Takayasu arteritis (rs56167332, OR = 1.54, p = 2.18 × 10(-8)).

A Randomized, Double-Blind Trial of Abatacept (CTLA-4Ig) for the Treatment of Takayasu Arteritis

To compare the efficacy of abatacept to that of placebo for the treatment of giant cell arteritis (GCA).

An open-label trial of abatacept (CTLA4-IG) in non-severe relapsing granulomatosis with polyangiitis (Wegener's)

Objectives To determine the safety and efficacy of abatacept in non-severe relapsing granulomatosis with polyangiitis (Wegeners)(GPA). Methods An open-label trial of intravenous abatacept was conducted in 20 patients with non-severe relapsing GPA. Prednisone up to 30 mg daily was permitted within the first 2 months, and patients on methotrexate, azathioprine, or mycophenolate mofetil continued these agents. Patients remained on study until common closing or early termination. Results Of the 20 patients, 18 (90%) had disease improvement, 16 (80%) achieved remission (BVAS/WG=0) at a median of 1.9 months, and 14 (70%) reached common closing. Six patients (30%) met criteria for early termination due to increased disease activity; 3 of 6 achieved remission and relapsed at a median of 8.6 months. The median duration of remission before common closing was 14.4 months, with the median duration of time on study for all patients being 12.3 months (range 2–35 months). Eleven of the 15 (73%) patients on prednisone reached 0 mg. Nine severe adverse events occurred in 7 patients, including 7 infections that were successfully treated. Conclusions In this study of patients with non-severe relapsing GPA, abatacept was well tolerated and was associated with a high frequency of disease remission and prednisone discontinuation.

A Randomized, Double-Blind Trial of Abatacept (CTLA-4Ig) for the Treatment of Giant Cell Arteritis: ABATACEPT FOR THE TREATMENT OF GCA

To compare the efficacy of abatacept to that of placebo for the treatment of Takayasu arteritis (TAK).

IgA and IgG antineutrophil cytoplasmic antibody engagement of Fc receptor genetic variants influences granulomatosis with polyangiitis

Granulomatosis with polyangiitis (Wegeners) is a rare autoimmune neutrophil-mediated vasculitis that can cause renal disease and mucosal manifestations. Antineutrophil cytoplasmic antibodies (ANCA) are present in many patients, vary in level over time, and induce neutrophil activation through engagement with Fc receptors (FcRs). Given roles for FcRs in ANCA-mediated neutrophil activation and IgA antibodies in mucosal immunity, we hypothesized that FcR genetics and previously unappreciated IgA ANCA affect clinical presentation. We assembled a total of 673 patients and 413 controls from two multicenter cohorts, performed ELISA and immunofluorescence assays to determine IgA and IgG ANCA positivity, and used Illumina, TaqMan, or Pyrosequencing to genotype eight haplotype-tagging SNPs in the IgA FcR (FCAR) and to determine NA1/NA2 genotype of FCGR3B, the most prevalent neutrophil IgG FcR. We evaluated neutrophil activation by measuring degranulation marker CD11b with flow cytometry or neutrophil extracellcular trap formation with confocal microscopy. Functional polymorphisms in FCGR3B and FCAR differed between patient groups stratified by renal involvement. IgA ANCA were found in ∼30% of patients and were less common in patients with severe renal disease. Neutrophil stimulation by IgA or IgG ANCA led to degranulation and neutrophil extracellcular trap formation in a FcR allele-specific manner (IgA:FCAR P = 0.008; IgG:FCGR3B P = 0.003). When stimulated with IgA and IgG ANCA together, IgG ANCA induced neutrophil activation was reduced (P = 0.0001). FcR genotypes, IgA ANCA, and IgG ANCA are potential prognostic and therapeutic targets for understanding the pathogenesis and presentation of granulomatosis with polyangiitis (Wegeners).

Disease Relapses among Patients with Giant Cell Arteritis: A Prospective, Longitudinal Cohort Study

Objective. To evaluate the frequency, timing, and clinical features of relapses in giant cell arteritis (GCA). Methods. Patients with GCA enrolled in a prospective, multicenter, longitudinal study were included in the analysis. Relapse was defined as either new disease activity after a period of remission or worsening disease activity. Results. The study included 128 subjects: 102 women (80%) and 26 men (20%). Mean ± SD age at diagnosis of GCA was 69.9 ± 8.6 years. Mean followup for the cohort was 21.4 ± 13.9 months. Median (interquartile range) duration of disease at study enrollment was 4.6 months (1.2, 16.8). During followup, 59 relapses were observed in 44 patients (34%). Ten patients (8%) experienced 2 or more relapses. The most common symptoms at relapse were headache (42%) and polymyalgia rheumatica (51%), but ischemic (some transient) manifestations (visual symptoms, tongue or jaw claudication, and/or limb claudication) occurred in 29% of relapses (12% cohort). Forty-three relapses (73%) occurred while patients were taking glucocorticoid therapy at a median (range) prednisone dose of 7.5 (0–35) mg. In 21% of relapses, both erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were normal. Among 69 patients enrolled in the cohort with newly diagnosed disease, 24% experienced a first relapse within 12 months after diagnosis. Conclusion. Among patients with GCA, relapses are common, often occurring during treatment. ESR and CRP are frequently normal at times of clinical relapse, highlighting the need for better biomarkers to assess disease activity in GCA. There remains a need for effective therapeutic alternatives to glucocorticoids in GCA.

Assessment of health‐related quality of life as an outcome measure in granulomatosis with polyangiitis (Wegener's)

To assess a generic measure of health‐related quality of life (HRQOL) as an outcome measure in granulomatosis with polyangiitis (Wegeners) (GPA).

Association of Vascular Physical Examination Findings and Arteriographic Lesions in Large Vessel Vasculitis

Objective. To assess the utility of the vascular physical examination to detect arteriographic lesions in patients with established large vessel vasculitis (LVV), including Takayasu’s arteritis (TAK) and giant cell arteritis (GCA). Methods. In total, 100 patients (TAK = 68, GCA = 32) underwent standardized physical examination and angiography of the carotid, subclavian, and axillary arteries. Sensitivity and specificity were calculated for the association between findings on physical examination focusing on the vascular system (absent pulse, bruit, and blood pressure difference) and arteriographic lesions defined as stenosis, occlusion, or aneurysm. Results. We found 67% of patients had at least 1 abnormality on physical examination (74% TAK, 53% GCA). Arteriographic lesions were seen in 76% of patients (82% TAK, 63% GCA). Individual physical examination findings had poor sensitivity (range 14%–50%) and good-excellent specificity (range 71%–98%) to detect arteriographic lesions. Even when considering physical examination findings in combination, at least 30% of arteriographic lesions were missed. Specificity improved (range 88%–100%) if individual physical examination findings were compared to a broader region of vessels rather than specific anatomically correlated vessels and if ≥ 1 physical examination findings were combined. Conclusion. In patients with established LVV, physical examination alone is worthwhile to detect arterial disease but does not always localize or reveal the full extent of arteriographic lesions. Abnormal vascular system findings on physical examination are highly associated with the presence of arterial lesions, but normal findings on physical examination do not exclude the possibility of arterial disease. Serial angiographic assessment is advisable to monitor arterial disease in patients with established LVV.

Vasculitis in patients with inflammatory bowel diseases: A study of 32 patients and systematic review of the literature

BACKGROUND Published small case series suggest that inflammatory bowel disease [IBD; Crohns disease (CD) or ulcerative colitis (UC)] and vasculitis co-occur more frequently than would be expected by chance. OBJECTIVES To describe this association by an analysis of a large cohort of carefully studied patients and through a systematic literature review. METHODS Patients with both IBD and vasculitis enrolled in the Vasculitis Clinical Research Consortium (VCRC) Longitudinal Studies, followed in Canadian Vasculitis research network (CanVasc) centers and/or in the University of Torontos IBD clinic were included in this case series. A systematic literature review of patients with IBD and vasculitis involved a PubMed search through February 2014. The main characteristics of patients with Takayasu arteritis (TAK) and IBD were compared to those in patients with TAK without IBD followed in the VCRC. RESULTS The study identified 32 patients with IBD and vasculitis: 13 with large-vessel vasculitis [LVV; 12 with TAK, 1 with giant cell arteritis (GCA); 8 with CD, 5 with UC]; 8 with ANCA-associated vasculitis [AAV; 6 granulomatosis with polyangiitis (GPA), 2 with eosinophilic granulomatosis with polyangiitis (EGPA)]; 5 with isolated cutaneous vasculitis; and 6 with other vasculitides. Patients with LVV and AAV were mostly female (18/21). The diagnosis of IBD preceded that of vasculitis in 12/13 patients with LVV and 8/8 patients with AAV. The review of the literature identified 306 patients with IBD and vasculitis: 144 with LVV (133 TAK; 87 with IBD preceding LVV), 19 with AAV [14 GPA, 1 EGPA, 4 microscopic polyangiitis (MPA)], 66 with isolated cutaneous vasculitis, and 77 with other vasculitides. Patients with IBD and TAK were younger and had more frequent headaches, constitutional symptoms, or gastrointestinal symptoms compared to those patients in the VCRC who had TAK without IBD. CONCLUSIONS These findings highlight the risk of vasculitis, especially TAK, in patients with IBD (both CD and UC).

Identification of Susceptibility Loci in IL6, RPS9/LILRB3, and an Intergenic Locus on Chromosome 21q22 in Takayasu Arteritis in a Genome-Wide Association Study

Takayasu arteritis is a rare large vessel vasculitis with incompletely understood etiology. This study was undertaken to perform the first unbiased genome‐wide association analysis of Takayasu arteritis.