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Bauer JW, Petri M, Batliwalla FM, Koeuth T, Wilson J, Slattery C, et al

Bauer JW, Petri M, Batliwalla FM, Koeuth T, Wilson J, Slattery C, et al. with that identified by stimulating human whole blood with IFN and with those gene sets reported in the literature to RS-1 be differentially expressed in SLE patients. Serum levels of IFN\induced chemokines, including IFN\inducible protein 10 (IP\10), were found to be elevated at baseline in SLE patients as compared to healthy volunteers. In contrast to previously reported results from studies using type I IFNCblocking brokers, treatment with AMG 811 led to dose\related reductions in the serum levels of CXCL10 (IP\10). Conclusion The scope and nature of the biomarkers impacted by AMG 811 support targeting of IFN as a therapeutic strategy for SLE. Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown etiology that has wide\ranging clinical manifestations and is marked by autoreactivity to nuclear self antigens 1, 2. Interferons (IFNs) are thought to play a pathogenic role in autoimmunity, and in SLE in particular, supported, in part, by the finding of a peripheral blood gene expression profile (IFN signature) in some individuals that is usually distinct from that in individuals without autoimmune disease 3, 4, 5. In addition, serum levels of chemokines related to IFN activity have been found to be elevated in SLE patients, a finding that is usually associated with the extent of disease activity 6, 7, 8, 9, 10. Specifically, CXCL10 has been shown to be a major contributor to the overall association and an independent predictor of future disease flare 6. While considerable attention has been focused on type I IFNs in driving the IFN\associated gene expression profiles observed in SLE, the type I IFN and type II IFN (IFN) pathways overlap considerably in the immune response, making it difficult to distinguish their relative contributions in disease pathogenesis. Type I and type II IFNs signal through distinct receptors (IFN receptor and RS-1 IFN receptor, respectively), but their signaling pathways overlap with variable and, at times, opposing functional effects 11, 12, 13. Recent investigations of synovial tissue from subjects with rheumatic diseases have identified specific gene transcripts and proteins that may be useful RS-1 for distinguishing between the 2 IFN pathways 14, 15. Data supporting a pathogenic role for IFN in SLE include findings from murine models of SLE 16, 17, 18, 19, 20 and from in vitro studies of blood from SLE patients 21, 22. In humans, administration of IFN can induce IL1R SLE or a lupus\like phenomenon such as production of autoantibodies 23. Administration of monoclonal antibodies against the IFN pathway results in decreases in RNA expression from IFN\inducible genes in whole blood from SLE patients 24, 25, 26, but RS-1 change in IFN\associated serum protein levels has not been reported. In the present study, we describe the immunologic impact of the first clinical experience of IFN blockade in SLE patients. Single\dose administration of AMG 811, an investigational monoclonal antibody that blocks the function of IFN, led to normalization of the levels of IFN\inducible genes in the patients peripheral blood and normalization of the serum levels of CXCL10 protein, a key chemokine associated with lupus disease activity. PATIENTS AND METHODS Study design The present study was a multicenter, randomized, double\blind, placebo\controlled, single\dose escalation study that enrolled patients with moderate\to\moderate, stable SLE in 6 cohorts. Informed consent was obtained from all study participants. Patients in cohorts 1C5 received a single subcutaneous (SC) dose of either 2, 6, 20, 60, or 180 mg AMG RS-1 811 or placebo. Patients in cohort 6 received an intravenous (IV) dose of 60 mg AMG 811 or placebo. Criteria for enrollment included men and women ages 18C65 years with a diagnosis of SLE according to the American College of Rheumatology revised criteria for SLE 27 as updated in 1997 28, including a positive obtaining of antinuclear antibodies at screening. Patients with severe disease were excluded; severe disease was defined on the basis of the clinical judgment of the investigator or as one domain A score or two domain name B scores around the British Isles Lupus Assessment Group (BILAG) clinical disease activity index 29 in any of the assessed organ systems at screening. Antimalarial brokers, leflunomide, azathioprine, methotrexate, and up to 20 mg/day of prednisone (or comparative) were permitted as concomitant therapies. Following treatment, patients in each cohort were.