Objective. The aim of this study was to compare baseline variables, treatment and outcomes in patients with large-vessel GCA (LV-GCA), primarily of the upper extremities, with those with cranial disease (C-GCA). Methods. All patients >50 years of age with radiographic evidence of subclavian LV-GCA diagnosed between 1 January 1999 and 31 December 2008 were identified and compared with those with biopsy-positive C-GCA diagnosed in the same period. Results. The study included 120 LV-GCA patients and 212 C-GCA patients. Compared with C-GCA, patients with LV-GCA were younger [68.2 years ( s.d. 7.5) vs 75.7 (7.4), P < 0.001] and had longer duration of symptoms at GCA diagnosis (median 3.5 vs 2.2 months, P < 0.001). A history of PMR was more common in LV-GCA patients (26% vs 15%, P = 0.012), but a smaller proportion had cranial symptoms (41% vs 83%, P < 0.001) and vision loss (4% vs 11%, P = 0.035). ACR classification criteria for GCA were satisfied in 39% of LV-GCA patients and 95% of C-GCA patients ( P < 0.001). Compared with C-GCA, patients with LV-GCA had more relapses (4.9 vs 3.0/10 person-years, P < 0.001), higher cumulative corticosteroid (CS) doses at 1 year [11.4 g ( s.d. 5.9) vs 9.1 ( s.d. 3.7), P < 0.001] and required longer treatment (median 4.5 vs 2.2 years, P < 0.001). Conclusion. Although patients with LV-GCA had a lower rate of vision loss, they had a higher relapse rate and greater CS requirements. The ACR criteria for GCA are inadequate for the classification of patients with LV-GCA.

We conducted a large-scale genetic analysis on giant cell arteritis (GCA), a polygenic immune-mediated vasculitis. A case-control cohort, comprising 1,651 case subjects with GCA and 15,306 unrelated control subjects from six different countries of European ancestry, was genotyped by the Immunochip array. We also imputed HLA data with a previously validated imputation method to perform a more comprehensive analysis of this genomic region. The strongest association signals were observed in the HLA region, with rs477515 representing the highest peak (p = 4.05 × 10(-40), OR = 1.73). A multivariate model including class II amino acids of HLA-DRβ1 and HLA-DQα1 and one class I amino acid of HLA-B explained most of the HLA association with GCA, consistent with previously reported associations of classical HLA alleles like HLA-DRB1(∗)04. An omnibus test on polymorphic amino acid positions highlighted DRβ1 13 (p = 4.08 × 10(-43)) and HLA-DQα1 47 (p = 4.02 × 10(-46)), 56, and 76 (both p = 1.84 × 10(-45)) as relevant positions for disease susceptibility. Outside the HLA region, the most significant loci included PTPN22 (rs2476601, p = 1.73 × 10(-6), OR = 1.38), LRRC32 (rs10160518, p = 4.39 × 10(-6), OR = 1.20), and REL (rs115674477, p = 1.10 × 10(-5), OR = 1.63). Our study provides evidence of a strong contribution of HLA class I and II molecules to susceptibility to GCA. In the non-HLA region, we confirmed a key role for the functional PTPN22 rs2476601 variant and proposed other putative risk loci for GCA involved in Th1, Th17, and Treg cell function.

This study evaluated the frequency, timing, and characteristics of flares in a large cohort of Italian patients with biopsy-proven giant cell arteritis (GCA) and to identify factors at diagnosis able to predict the occurrence of flares. We evaluated 157 patients with biopsy-proven transmural GCA diagnosed and followed at the Rheumatology Unit of Reggio Emilia Hospital (Italy) for whom sufficient information was available from the time of diagnosis until at least 4 years of follow-up. Fifty-seven patients (36.5%) experienced ≥1 flares. Fifty-one (46.4%) of the 110 total flares (88 relapses and 22 recurrences) were experienced during the first 2 years after diagnosis. The majority of relapses occurred with doses of prednisone ≤ 10 mg/day (82.9%), whereas only 3.4% of relapses occurred for doses ≥ 25 mg/day. Polymyalgia rheumatica (46.5%) and cranial symptoms (41.9%) were the most frequent manifestations at the time of the first relapse. Cumulative prednisone dose during the first year and total cumulative prednisone dose were significantly higher in flaring patients compared with those without flares (7.8 ± 2.4 vs 6.7 ± 2.4 g, P = 0.02; 15.5 ± 8.9 vs 10.0 ± 9.2 g, P = 0.0001, respectively). The total duration of prednisone treatment was longer in flaring patients (58 ± 44 vs 30 ± 30 months, P = 0.0001). Patients with disease flares had at diagnosis more frequently systemic manifestations (P = 0.02) and fever ≥ 38°C (P = 0.02), significantly lower hemoglobin levels (P = 0.05), more frequent presence at temporal artery biopsy (TAB) specimens of giant cells (P = 0.04) and intraluminal acute thrombosis (P = 0.007), and more moderate/severe arterial inflammation (P = 0.009) compared with those without flares. In the multivariate model fever ≥ 38 °C (hazard ratio 2.14; 95% confidence interval, 1.06–4.32, P = 0.03) and the severity of inflammatory infiltrate (moderate/severe versus mild) (hazard ratio 5.41; 95% confidence interval, 1.64–17.87, P = 0.006) were significantly associated with an increased risk of flares. In conclusion, a flaring course is common in GCA and it is associated with prolonged GC requirements. Fever at diagnosis and severity of inflammation at TAB appear to predict the development of disease flares.

Objective: To evaluate the frequency and clinical characteristics of periadventitial small‐vessel vasculitis (SVV) and isolated vasa vasorum vasculitis (VVV).Methods: We identified 455 temporal artery biopsies performed in residents of Reggio Emilia, Italy between 1986 and 2003. Slides of temporal artery biopsy specimens were reviewed by a pathologist who was blinded with regard to clinical data. SVV was defined as inflammation of the small vessels external to the temporal artery adventitia, and VVV was defined as isolated inflammation of temporal artery vasa vasorum. Medical records of patients with SVV and/or VVV were reviewed, and demographic, clinical, laboratory, and followup data were collected. For comparison purposes, we collected the same data from an equal number of randomly selected patients with evidence of classic giant cell arteritis (GCA).Results: Sixteen patients had SVV, 18 had isolated VVV, and 5 had both SVV and VVV. Compared with patients with classic GCA, the frequencies of headache, scalp tenderness, abnormalities of temporal arteries, jaw claudication, anorexia, and weight loss, the levels of acute‐phase reactant at diagnosis, and the initial and cumulative doses prednisone were significantly lower and the frequency of peripheral synovitis was higher in the patients with SVV, and the frequency of cranial ischemic events was similar in the 2 groups. In contrast, the clinical characteristics and erythrocyte sedimentation rate at diagnosis of patients with isolated VVV were similar to those of patients with classic GCA.Conclusion: Our findings indicate that isolated VVV and SVV should be considered part of the histopathologic spectrum of GCA.