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Human Anti (human + anti)

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Medical Sciences	85%

Selected Abstracts

Neuromyelitis optica: Pathogenicity of patient immunoglobulin in vivo,

ANNALS OF NEUROLOGY, Issue 5 2009
Monika Bradl PhD
Objective Severe inflammation and astrocyte loss with profound demyelination in spinal cord and optic nerves are typical pathological features of neuromyelitis optica (NMO). A diagnostic hallmark of this disease is the presence of serum autoantibodies against the water channel aquaporin-4 (AQP-4) on astrocytes. Methods We induced acute T-cell,mediated experimental autoimmune encephalomyelitis in Lewis rats and confronted the animals with an additional application of immunoglobulins from AQP-4 antibody,positive and ,negative NMO patients, multiple sclerosis patients, and control subjects. Results The immunoglobulins from AQP-4 antibody,positive NMO patients are pathogenic. When they reach serum titers in experimental animals comparable with those seen in NMO patients, they augment clinical disease and induce lesions in the central nervous system that are similar in structure and distribution to those seen in NMO patients, consisting of AQP-4 and astrocyte loss, granulocytic infiltrates, T cells and activated macrophages/microglia cells, and an extensive immunoglobulin and complement deposition on astrocyte processes of the perivascular and superficial glia limitans. AQP-4 antibody containing NMO immunoglobulin injected into naïve rats, young rats with leaky blood,brain barrier, or after transfer of a nonencephalitogenic T-cell line did not induce disease or neuropathological alterations in the central nervous system. Absorption of NMO immunoglobulins with AQP-4,transfected cells, but not with mock-transfected control cells, reduced the AQP-4 antibody titers and was associated with a reduction of astrocyte pathology after transfer. Interpretation Human anti,AQP-4 antibodies are not only important in the diagnosis of NMO but also augment disease and induce NMO-like lesions in animals with T-cell,mediated brain inflammation. Ann Neurol 2009;66:630,643 [source]

Anti-,2 -glycoprotein I antibodies recognizing platelet factor 4,heparin complex in antiphospholipid syndrome in patient substantiated with mouse Model

JOURNAL OF MOLECULAR RECOGNITION, Issue 3 2003
Mustapha Bourhim
Abstract The antiphospholipid syndrome is defined by the presence of antiphospholipid antibodies associated with arterial and/or venous thrombosis, and recurrent abortion accompanied often by thrombocytopenia. These antibodies are heterogeneous and react against phospholipid-binding proteins such as ,2 -glycoprotein I (,2GPI) and prothrombin. The recognition of anti-,2 -glycoprotein I (anti-,2GPI) by platelet factor 4,heparin complex (PF4,Hc) has been previously evoked and partially confirmed by the present inhibition studies. Further, the anti-,2 -glycoprotein I antibodies were purified from a patient with primary antiphospholipid syndrome using Affi-gel®-10-,2GPI immunoaffinity chromatography. The purified anti-,2GPI IgM as well as patient serum equally recognized PF4,Hc in ELISA mode. In order to substantiate this data and to better understand we studied an animal model using mouse active immunization with the purified human anti-,2GPI. The mice showed a significant decrease in their platelet count. In addition the ELISA responses of the immunized mice sera were positive against both ,2GPI and PF4,Hc, substantiating the double recognition. Despite many previous reported animal model studies, this is the first time we have shown the specific recognition of anti-,2GPI antibodies by PF4,Hc, the results in the induced mice correlating the data observed with some patients. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Canakinumab for the treatment of acute flares in difficult-to-treat gouty arthritis: Results of a multicenter, phase II, dose-ranging study,

ARTHRITIS & RHEUMATISM, Issue 10 2010
Alexander So
Objective To assess the efficacy and tolerability of canakinumab, a fully human anti,interleukin-1, monoclonal antibody, for the treatment of acute gouty arthritis. Methods In this 8-week, single-blind, double-dummy, dose-ranging study, patients with acute gouty arthritis whose disease was refractory to or who had contraindications to nonsteroidal antiinflammatory drugs and/or colchicine were randomized to receive a single subcutaneous dose of canakinumab (10, 25, 50, 90, or 150 mg; n = 143) or an intramuscular dose of triamcinolone acetonide (40 mg; n = 57). Patients assessed pain using a 100-mm visual analog scale. Results Seventy-two hours after treatment, a statistically significant dose response was observed for canakinumab. All canakinumab doses were associated with numerically less pain than triamcinolone acetonide; thus, a dose with equivalent efficacy to triamcinolone acetonide 72 hours after treatment could not be determined. The reduction from baseline in pain intensity with canakinumab 150 mg was greater than with triamcinolone acetonide 24, 48, and 72 hours after treatment (differences of ,11.5 mm [P = 0.04], ,18.2 mm [P = 0.002], and ,19.2 mm [P < 0.001], respectively), and 4, 5, and 7 days after treatment (all P < 0.05). Canakinumab significantly reduced the risk of recurrent flares versus triamcinolone acetonide (P , 0.01 for all doses) (relative risk reduction 94% for canakinumab 150 mg versus triamcinolone acetonide). The overall incidence of adverse events was similar for canakinumab (41%) and triamcinolone acetonide (42%); most were mild or moderate in severity. Conclusion Our findings indicate that canakinumab 150 mg provides rapid and sustained pain relief in patients with acute gouty arthritis, and significantly reduces the risk of recurrent flares compared with triamcinolone acetonide. [source]

Autocitrullination of human peptidyl arginine deiminase type 4 regulates protein citrullination during cell activation

ARTHRITIS & RHEUMATISM, Issue 6 2010
Felipe Andrade
Objective To address mechanisms that control the activity of human peptidyl arginine deiminase type 4 (PAD-4). Methods PAD-4 autocitrullination was determined by anti,modified citrulline immunoblotting, using purified recombinant and endogenous PAD-4 from activated human primary neutrophils and cell lines expressing PAD-4. The citrullination sites in PAD-4 were determined by mass spectrometry. Mechanisms of autocitrullination-induced inactivation and the functional consequences of autocitrullination in PAD-4 polymorphic variants were addressed using purified components and cell lines expressing PAD-4 wild-type, PAD-4 mutant, and PAD-4 polymorphic variants relevant to rheumatoid arthritis (RA). Results PAD-4 is autocitrullinated in vitro and during activation of primary cells and cell lines expressing PAD-4. Interestingly, this modification inactivated the function of the enzyme. The efficiency of inactivation differed among genetically defined PAD-4 variants relevant to RA. PAD-4 was citrullinated at 10 sites, which are clustered into 3 distinct regions, including a cluster of arginines around the active site cleft where Arg-372 and -374 were identified as the potential autocitrullination targets that inactivate the enzyme. Autocitrullination also modified the structure of PAD-4, abrogating its recognition by multiple rabbit antibodies, but augmenting its recognition by human anti,PAD-4 autoantibodies. Conclusion Our findings suggest that autocitrullination regulates the production of citrullinated proteins during cell activation, and that this is affected by structural polymorphisms in PAD-4. Autocitrullination also influences PAD-4 structure and immune response. [source]

Golimumab, a new human anti,tumor necrosis factor , antibody, administered intravenously in patients with active rheumatoid arthritis: Forty-eight,week efficacy and safety results of a phase III randomized, double-blind, placebo-controlled study ,

ARTHRITIS & RHEUMATISM, Issue 4 2010
Joel Kremer
Objective To assess the efficacy and safety of intravenous administration of golimumab in patients with rheumatoid arthritis (RA). Methods Adult patients with RA in whom disease activity was persistent despite treatment with methotrexate (MTX) at a dosage of 15,25 mg/week for ,4 weeks were randomized to receive intravenous infusions of placebo plus MTX or intravenous infusions of golimumab at a dose of 2 mg/kg or 4 mg/kg, with or without MTX, every 12 weeks through week 48. Patients with <20% improvement in the swollen and tender joint counts could enter early escape and receive additional active treatment (week 16) or could have their dose regimen adjusted (week 24). The primary end point was the proportion of patients achieving a 50% response according to the American College of Rheumatology improvement criteria (ACR50) at week 14. Results The primary study end point was not met (at week 14, an ACR50 response was observed in 21% of the patients treated with golimumab plus MTX compared with 13% of the patients treated with placebo plus MTX [P = 0.051]). By week 24, significantly more patients treated with golimumab plus MTX had achieved an ACR50 response. Differences in the proportion of patients achieving an ACR50 response between the group receiving golimumab monotherapy and the group receiving placebo plus MTX were not significant at either week 14 (16% versus 13%) or week 24 (10% versus 9%). At week 48, the proportions of patients achieving ACR20 and ACR50 responses were highest among those who had received golimumab 4 mg/kg plus MTX (70% and 48%, respectively). Concomitant treatment with MTX was associated with a lower incidence of antibodies to golimumab. The most commonly reported adverse events through week 48 were infections (48% of patients treated with golimumab with or without MTX and 41% of patients receiving placebo plus MTX). Conclusion The primary end point was not met. However, intravenously administered golimumab plus MTX appears to have benefit in the longer-term reduction of RA signs/symptoms in MTX-resistant patients, with no unexpected safety concerns. [source]

Golimumab, a human anti,tumor necrosis factor , monoclonal antibody, injected subcutaneously every four weeks in methotrexate-naive patients with active rheumatoid arthritis: Twenty-four,week results of a phase III, multicenter, randomized, double-blind, placebo-controlled study of golimumab before methotrexate as first-line therapy for early-onset rheumatoid arthritis,

ARTHRITIS & RHEUMATISM, Issue 8 2009
Paul Emery
Objective To assess the safety and efficacy of golimumab in methotrexate (MTX),naive patients with active rheumatoid arthritis (RA). Methods MTX-naive patients with RA (n = 637) were randomized to receive placebo plus MTX (group 1), golimumab 100 mg plus placebo (group 2), golimumab 50 mg plus MTX (group 3), or golimumab 100 mg plus MTX (group 4). Subcutaneous injections of golimumab or placebo were administered every 4 weeks. The dosage of MTX/placebo capsules started at 10 mg/week and escalated to 20 mg/week. The primary end point, the proportion of patients meeting the American College of Rheumatology 50% improvement criteria (achieving an ACR50 response) at week 24, required significant differences between groups 3 and 4 combined (combined group) versus group 1 and significant differences in a pairwise comparison (group 3 or group 4 versus group 1). Results An intent-to-treat (ITT) analysis of the ACR50 response at week 24 did not show a significant difference between the combined group and group 1 (38.4% and 29.4%, respectively; P = 0.053), while a post hoc modified ITT analysis (excluding 3 untreated patients) of the ACR50 response showed statistically significant differences between the combined group and group 1 (38.5% versus 29.4%; P = 0.049) and between group 3 (40.5%; P = 0.038) but not group 4 (36.5%; P = 0.177) and group 1. Group 2 was noninferior to group 1 for the ACR50 response at week 24 (33.1%; 95% confidence interval lower bound ,5.2%; predefined delta value for noninferiority ,10%). The combination of golimumab plus MTX demonstrated a significantly better response compared with placebo plus MTX in most other efficacy parameters, including response/remission according to the Disease Activity Score in 28 joints. Serious adverse events occurred in 7%, 3%, 6%, and 6% of patients in groups 1, 2, 3, and 4, respectively. Conclusion Although the primary end point was not met, the modified ITT analysis of the primary end point and other prespecified efficacy measures demonstrated that the efficacy of golimumab plus MTX is better than, and the efficacy of golimumab alone is similar to, the efficacy of MTX alone in reducing RA signs and symptoms in MTX-naive patients, with no unexpected safety concerns. [source]

Anti,cyclic citrullinated peptide antibodies from rheumatoid arthritis patients activate complement via both the classical and alternative pathways

ARTHRITIS & RHEUMATISM, Issue 7 2009
L. A. Trouw
Objective It has been suggested that anti,citrullinated protein antibodies (ACPAs) play an important role in the pathogenesis of rheumatoid arthritis (RA). To exert their pathologic effects, ACPAs must recruit immune effector mechanisms such as activation of the complement system. Mouse models of RA have shown that, surprisingly, arthritogenic antibodies activate the alternative pathway of complement rather than the expected classical pathway. This study was undertaken to investigate whether human anti,cyclic citrullinated peptide (anti-CCP) antibodies activate the complement system in vitro and, if so, which pathways of complement activation are used. Methods We set up novel assays to analyze complement activation by anti-CCP antibodies, using cyclic citrullinated peptide,coated plates, specific buffers, and normal and complement-deficient sera as a source of complement. Results Anti-CCP antibodies activated complement in a dose-dependent manner via the classical pathway of complement, and, surprisingly, via the alternative pathway of complement. The lectin pathway was not activated by anti-CCP antibodies. Complement activation proceeded in vitro up to the formation of the membrane attack complex, indicating that all activation steps, including the release of C5a, took place. Conclusion Our findings indicate that anti-CCP antibodies activate the complement system in vitro via the classical and alternative pathways but not via the lectin pathway. These findings are relevant for the design of interventions aimed at inhibition of complement-mediated damage in RA. [source]