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.

Objective. To investigate predictors of response, remission, low disease activity, damage, and drug discontinuation in patients with systemic lupus erythematosus (SLE) who were treated with belimumab.Methods. In this retrospective study of a multicenter cohort of SLE patients who received intravenous belimumab, the proportion of patients who achieved remission, low disease activity, and treatment response according to the SLE Responder Index 4 (SRI-4) was determined, and the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) was used to score disease damage yearly over the follow-up. Predictors of outcomes were analyzed by multivariate logistic regression with the results expressed as odds ratios (ORs) and 95% confidence intervals (95% CIs).Results. The study included 466 patients with active SLE from 24 Italian centers, with a median follow-up period of 18 months (range 1-60 months). An SRI-4 response was achieved by 49.2%, 61.3%, 69.7%, 69.6%, and 66.7% of patients at 6, 12, 24, 36, and 48 months, respectively. Baseline predictors of response at 6 months included a score of ≥10 on the SLE Disease Activity Index 2000 (SLEDAI-2K) (OR 3.14 [95% CI 2.033-4.860]) and a disease duration of ≤2 years . Baseline predictors of response at 12 months included a score of ≥10 on the SLEDAI-2K (OR 3.48 [95% CI 2.004-6.025]) and an SDI score of 0 (OR 1.74 [95% CI 1.036-2.923]). Baseline predictors of response at 24 months included a score of ≥10 on the SLEDAI-2K (OR 4.25 [95% CI 2.018-8.940]) and a disease duration of ≤2 years (OR 3.79 [95% CI 1.039-13.52]). Baseline predictors of response at 36 months included a score of ≥10 on the SLEDAI-2K ) and baseline status of current smoker (OR 0.19 [95% CI 0.039-0.69]). Patients who were in remission for ≥25% of the follow-up period (44.3%) or who had low disease activity for ≥50% of the follow-up period (66.1%) accrued significantly less damage (P = 0.046 and P = 0.007). A baseline SDI score of 0 was an independent predictor of achieving low disease activity in ≥50% of the follow-up period and remission in ≥25% of the follow-up period. Our findings suggest that the lower the baseline damage, the greater the probability of achieving remission over the course of ≥25% of the follow-up. Further, there was a negative association between the number of flares reported prior to belimumab initiation and the frequency of belimumab discontinuation due to inefficacy (P = 0.009).Conclusion. In patients with active SLE and low damage at baseline, treatment with belimumab early in the disease may lead to favorable outcomes in a real-life setting.

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Objective.Neutrophil extracellular traps (NET) expose modified antigens for autoantibodies in vasculitis. Little is known about levels and removal pathways of NET in systemic lupus erythematosus (SLE), especially in lupus nephritis (LN). We determined circulating levels and defined NET removal in large subsets of patients with incident SLE (iSLE), some of whom had new-onset nephritis.Methods.Serum levels of NET (ELISA), DNase1/DNase1L3 (ELISA), and DNase activity (functional assay) were determined in 216 patients with iSLE [103 had incident LN (iLN)], in 50 patients with other primary glomerulonephritis, and in healthy controls. Ex vivo NET production by neutrophils purified from a random selection of patients was quantified as elastase/DNA release and by immunofluorescence techniques.Results.Serum NET levels were very high in iSLE/iLN compared to all groups of controls and correlated with anti-dsDNA, C3–C4, and proteinuria; iLN had the highest levels. DNase activity was decreased in iLN compared to SLE (20% had one-half DNase activity) despite similar serum levels of DNase1/DNase1L3. In these cases, pretreatment of serum with protein A restored DNase efficiency; 1 patient was homozygous for a c.289_290delAC variant of DNASE1L3. Ex vivo NET production by neutrophils purified from LN, SLE, and normal controls was similar in all cases.Conclusion.Patients with iLN have increased circulating NET and reduced DNase activity, the latter being explained by the presence of inhibitory substances in circulation and/or by rare DNase1L3 mutations. Accumulation of NET derives from a multifactorial mechanism, and is associated and may contribute to disease severity in SLE, in particular to renal lesions. (Clinical trial registration: The Zeus study was registered at ClinicalTrials.gov, study number NCT02403115).

We reviewed 888 temporal artery biopsies (TAB) performed in 871 patients in a single institution from January 1986 to December 2013. Forty-four biopsies (4.9%) were inadequate, 490 (55.2%) were devoid of inflammation and were considered negative, and 354 (39.9%) showed inflammation and were considered positive. On the basis of the localization of the inflammation, positive TABs were further classified into 4 categories: small vessel vasculitis (SVV), in which inflammation was limited to small periadventitial vessels devoid of muscular coat, with sparing of the temporal artery (32 cases, 9% of the positive biopsies); vasa vasorum vasculitis (VVV), in which inflammation was limited to the adventitial vasa vasorum (23 cases, 6.5% of the positive biopsies); inflammation limited to adventitia (ILA), in which inflammation extended from a strictly perivascular localization to the surrounding adventitia, without medial involvement (25 cases, 7% of the positive biopsies); and transmural inflammation (TMI), in which inflammation crossed the external elastic lamina and extended to the media (274 cases, 77.5% of the positive biopsies). In TMI, inflammation was generally more prominent between media and adventitia and mostly consisted of T lymphocytes and macrophages, with occasionally a significant number of plasma cells. Numerous eosinophils or neutrophils (with or without leucocytoclasia and suppurative necrosis), fibrinoid necrosis (limited to small branches of the temporal artery), and acute thrombosis were unusual, being present in 8%, 1.8%, 0.7%, and 9.5% of our biopsies with TMI, respectively. Giant cells, laminar necrosis, and calcifications prevailed along the internal elastic lamina and were present in 74.8%, 25.2%, and 20% of the biopsies with TMI, respectively. Among the 322 patients with positive TAB on whom we obtained clinical information, 317 had giant cell arteritis and 5 had a different disease: 3 (with SVV at histology) had ANCA-associated vasculitis, 1 (with SVV with amyloid deposits) had primary systemic amyloidosis, and 1 (with TMI limited to a small branch) had polyarteritis nodosa. In none of these cases the biopsy showed fibrinoid necrosis or significant numbers of eosinophils or neutrophils. Considering the 317 patients with giant cell arteritis, those with SVV and VVV compared with those with TMI had a significantly lower frequency of cranial manifestation (including headache, jaw claudication, and abnormalities of temporal arteries), lower serum levels of acute-phase reactants, and a reduced frequency of prednisone therapy at the time of TAB, of the "halo sign" at color duplex sonography of temporal arteries, and of systemic symptoms (for VVV). Polymyalgia rheumatica and blindness were equally represented in all patients groups, whereas there was a higher frequency of male sex and peripheral arthritis in patients with SVV. Patients with ILA were more similar to those with TMI, having a lower frequency of headache, of abnormalities of temporal arteries, and of a positive "halo sign" at color duplex...