Robert D. Inman

The Impact of Tumor Necrosis Factor α Inhibitors on Radiographic Progression in Ankylosing Spondylitis

OBJECTIVEnTo study the effect of tumor necrosis factor α (TNFα) inhibitors on progressive spinal damage in patients with ankylosing spondylitis (AS).nnnMETHODSnAll AS patients meeting the modified New York criteria who had been monitored prospectively and had at least 2 sets of spinal radiographs a minimum of 1.5 years apart were included in the study (n=334). The patients received standard therapy, which included nonsteroidal antiinflammatory drugs and TNFα inhibitors. Radiographic severity was assessed by the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS). Patients with a rate of AS progression that was ≥1 mSASSS unit/year were considered progressors. Univariable and multivariable regression analyses were done. Propensity score matching and sensitivity analysis were performed. A zero-inflated negative binomial (ZINB) model was used to analyze the effect of TNFα inhibitors on the change in the mSASSS with varying followup periods. Potential confounders, such as disease activity (as assessed by the Bath Ankylosing Spondylitis Disease Activity Index), the erythrocyte sedimentation rate, C-reactive protein level, HLA-B27 positivity, sex, age at onset, smoking burden (number of pack-years), and baseline damage, were included in the model.nnnRESULTSnTNFα inhibitor treatment was associated with a 50% reduction in the odds of progression, with an odds ratio (OR) of 0.52 (95% confidence interval [95% CI] 0.30-0.88, P=0.02). Patients with a delay of >10 years in starting therapy were more likely to experience progression as compared to those who started earlier (OR 2.4 [95% CI 1.09-5.3], P=0.03). In the ZINB model, the use of TNFα inhibitors significantly reduced disease progression when the gap between radiographs was >3.9 years. The protective effect of TNFα inhibitors was stronger after propensity score matching.nnnCONCLUSIONnTreatment with TNFα inhibitors appears to reduce radiographic progression in AS patients, especially with early initiation and with longer duration of followup.

Sustained durability and tolerability of etanercept in ankylosing spondylitis for 96 weeks.

Objective: To evaluate the continued safety and durability of clinical response in patients with ankylosing spondylitis receiving etanercept. Methods: 277 patients who had participated in a previous randomised, double blind, placebo controlled 24 week trial were eligible to continue in this open label extension study. All patients who enrolled in the open label extension (nu200a=u200a257) received subcutaneous etanercept 25 mg twice weekly for up to 72 weeks, for a combined 96 weeks of cumulative trial and open label experience. For the patients who had received etanercept for 24 weeks in the double blind trial, this represented almost 2 years of continuous etanercept treatment. Results: Patients continuing etanercept treatment had a sustained response for almost 2 years, with 74% achieving an ASsessments in Ankylosing Spondylitis 20% (ASAS 20) response after 96 weeks of etanercept treatment. Patients who had received placebo in the preceding double blind trial had similar responses, with 70% of patients attaining an ASAS 20 response after 24 weeks of etanercept treatment and 78% achieving an ASAS 20 response after 72 weeks. Improved spinal mobility was seen in both groups. Etanercept was well tolerated in patients treated for up to 96 weeks. Conclusion: The subcutaneous administration of twice weekly doses of etanercept provided sustained durability of response in the improvement of signs and symptoms of ankylosing spondylitis for nearly 2 years.

Preventing autoimmune arthritis using antigen-specific immature dendritic cells: a novel tolerogenic vaccine

Conventional treatments for autoimmune diseases have relied heavily on nonspecific immune suppressants, which possess a variety of adverse effects without inhibiting the autoimmune process in a specific manner. In the present study we demonstrate the effectiveness of antigen-specific, maturation-resistant, tolerogenic dendritic cells (DC) in suppressing collagen-induced arthritis, a murine model of rheumatoid arthritis. Treatment of DC progenitors with the NF-κB inhibiting agent LF 15-0195 (LF) resulted in a population of tolerogenic DC that are characterized by low expression of MHC class II, CD40, and CD86 molecules, as well as by poor allostimulatory capacity in a mixed leukocyte reaction. Administering LF-treated DC pulsed with keyhole limpet hemocyanin antigen to naïve mice resulted hyporesponsiveness specific for this antigen. Furthermore, administration of LF-treated DC to mice with collagen-induced arthritis resulted in an improved clinical score, in an inhibited antigen-specific T-cell response, and in reduced antibody response to the collagen. The efficacy of LF-treated DC in preventing arthritis was substantiated by histological examination, which revealed a significant decrease in inflammatory cell infiltration in the joints. In conclusion, we demonstrate that in vitro-generated antigen-specific immature DC may have important potential as a tolerogenic vaccine for the treatment of autoimmune arthritis.

Treating axial spondyloarthritis and peripheral spondyloarthritis, especially psoriatic arthritis, to target: 2017 update of recommendations by an international task force

Therapeutic targets have been defined for axial and peripheral spondyloarthritis (SpA) in 2012, but the evidence for these recommendations was only of indirect nature. These recommendations were re-evaluated in light of new insights. Based on the results of a systematic literature review and expert opinion, a task force of rheumatologists, dermatologists, patients and a health professional developed an update of the 2012 recommendations. These underwent intensive discussions, on site voting and subsequent anonymous electronic voting on levels of agreement with each item. A set of 5 overarching principles and 11 recommendations were developed and voted on. Some items were present in the previous recommendations, while others were significantly changed or newly formulated. The 2017 task force arrived at a single set of recommendations for axial and peripheral SpA, including psoriatic arthritis (PsA). The most exhaustive discussions related to whether PsA should be assessed using unidimensional composite scores for its different domains or multidimensional scores that comprise multiple domains. This question was not resolved and constitutes an important research agenda. There was broad agreement, now better supported by data than in 2012, that remission/inactive disease and, alternatively, low/minimal disease activity are the principal targets for the treatment of PsA. As instruments to assess the patients on the path to the target, the Ankylosing Spondylitis Disease Activity Score (ASDAS) for axial SpA and the Disease Activity index for PSoriatic Arthritis (DAPSA) and Minimal Disease Activity (MDA) for PsA were recommended, although not supported by all. Shared decision-making between the clinician and the patient was seen as pivotal to the process. The task force defined the treatment target for SpA as remission or low disease activity and developed a large research agenda to further advance the field.

Treatment of Autoimmune Arthritis Using RNA Interference-Modulated Dendritic Cells

Dendritic cells (DCs) have a dual ability to either stimulate or suppress immunity, which is primarily associated with the expression of costimulatory molecules. Ag-loaded DCs have shown encouraging clinical results for treating cancer and infectious diseases; however, the use of these cells as a means of suppressing immune responses is only recently being explored. Here, we describe the induction of RNA interference through administering short interfering RNA (siRNA) as a means of specifically generating tolerogenic DCs. Knockdown of CD40, CD80, and CD86, prior to loading DCs with the arthritogenic Ag collagen II, led to a population of cells that could effectively suppress onset of collagen-induced arthritis. Maximum benefits were observed when all three genes were concurrently silenced. Disease suppression was associated with inhibition of collagen II-specific Ab production and suppression of T cell recall responses. Downregulation of IL-2, IFN-γ, TNF-α, and IL-17 and increased FoxP3+ cells with regulatory activity were observed in collagen-induced arthritis mice treated with siRNA-transfected DCs. Collectively, these data support the use of ex vivo gene manipulation in DCs using siRNA to generate tailor-made tolerogenic vaccines for treating autoimmunity.

Toll-like Receptor 2 Variants Are Associated With Acute Reactive Arthritis

OBJECTIVEnWe previously reported a recent outbreak of salmonellosis in which some individuals developed complications of the enteric infection. The objective of this study was to identify genetic variants that might predispose infected individuals to develop articular and/or extraarticular sequelae after Salmonella enteritidis infection.nnnMETHODSnThe entire exposed cohort was invited to participate in the study by sending a saliva sample for DNA analysis. Seventy-five Salmonella-infected subjects for whom there was clinical information agreed to participate and were stratified into 4 groups. Group 1 patients had arthritis and extraarticular features, group 2 patients had arthritis alone, group 3 patients had extraarticular features alone, and group 4 patients had neither. DNA samples from an uninfected cohort of 91 normal subjects were also genotyped. Genotyping was performed using 2 Toll-like receptor 2 (TLR-2) (rs5743708 and rs5743704) and 2 TLR-4 (rs4986790 and rs4986791) single-nucleotide polymorphisms (SNPs). Statistical analyses were carried out using chi-square tests.nnnRESULTSnThere was no association of TLR-4 exonic variants with any clinical events that were reported as accompanying the Salmonella infection. In contrast, compared with normal controls, one of the rare TLR-2 SNPs (rs5743708, R753Q) was associated with the development of arthritis and extraarticular features (P = 0.015 by chi-square test). The TLR-2 variant 753Q was not detected in any of the infected individuals with an uncomplicated course. Another TLR-2 variant, 631H, was associated with articular symptoms in infected males (P = 0.03 by chi-square test).nnnCONCLUSIONnIn this outbreak, genetic variants of TLR-2, but not TLR-4, were associated with acute reactive arthritis following infection with S enteritidis.

RNAi-mediated CD40-CD154 interruption promotes tolerance in autoimmune arthritis

IntroductionWe have previously demonstrated that ex vivo inhibition of costimulatory molecules on antigen-pulsed dendritic cells (DCs) can be useful for induction of antigen-specific immune deviation and suppression of autoimmune arthritis in the collagen induced arthritis (CIA) model. The current study evaluated a practical method of immune modulation through temporary systemic inhibition of the costimulatory molecule CD40.MethodsMice with collagen II (CII)-induced arthritis (CIA) were administered siRNA targeting the CD40 molecule. Therapeutic effects were evaluated by clinical symptoms, histopathology, Ag-specific T cell and B cell immune responses.ResultsSystemic administration of CD40-targeting siRNA can inhibit antigen-specific T cell response to collagen II, as well as prevent pathogenesis of disease in both a pre- and post-immunization manner in the CIA model. Disease amelioration was associated with suppression of Th1 cytokines, attenuation of antibody production, and upregulation of T regulatory cells.ConclusionsThese studies support the feasibility of transient gene silencing at a systemic level as a mechanism of resetting autoreactive immunity.

Breakdown of CTL Tolerance to Self HLA-B*2705 Induced by Exposure to Chlamydia trachomatis

There is a strong association between seronegative arthritis and HLA B27, but it is still unresolved whether the contribution of B27 to disease pathogenesis is solely as a restriction element for an arthritogenic peptide, or whether B27 itself serves as an autoantigen. This study uses transgenic rats to address the question as to whether exposure to an arthritogenic pathogen can alter tolerance to B27. Unlike their nontransgenic counterparts, B27-transgenic rats are tolerant of B27 immunization using either B27+ splenocytes or plasmid DNA and do not develop anti-B27 CTL. However, if splenocytes from such immunized animals are exposed to Chlamydia in vitro, CTL are generated that lyse B27+ targets. No killing was seen with targets transfected with control B7, B14, B40, or B44. This phenomenon was not observed with immunization by nontransgenic splenocytes, or HLA-A2 DNA alone. Using targets expressing mutated B27, we show that the epitope for autoreactive CTL recognition of B27 involves the Lys70 amino acid residue in the α1 domain of the MHC class I molecule. The generation of CTL with specificity for B27 under these conditions demonstrates that tolerance to B27 can be subverted by Chlamydia. This indicates a dynamic interrelationship between the pathogen and B27, which may have important implications for B27-related spondyloarthropathies triggered by intracellular bacteria.

Gene silencing of IL-12 in dendritic cells inhibits autoimmune arthritis

BackgroundWe have previously demonstrated that immune modulation can be accomplished by administration of gene silenced dendritic cells (DC) using siRNA. In this study, we demonstrate the therapeutic utilization of shRNA-modified DC as an antigen-specific tolerogenic vaccine strategy for autoimmune arthritis.MethodsA shRNA that specifically targets IL-12 p35 was designed and cloned into a plasmid vectors (IL-12 shRNA). Bone marrow-derived DC from DBA/1 mice were transfected with the IL-12 shRNA construct in vitro. Mice with collagen II (CII)-induced arthritis (CIA) were treated with the modified DCs expressing the shRNA. Recall response and disease progression were assessed.ResultsAfter gene silencing of IL-12 in DC, DC were shown to selectively inhibit T cell proliferation on recall responses and in an MLR. In murine CIA, we demonstrated that administration of IL-12 shRNA-expressing DC that were pulsed with CII inhibited progression of arthritis. The therapeutic effects were evidenced by decreased clinical scores, inhibition of inflammatory cell infiltration in the joint, and suppression of T cell and B cell responses to CII.ConclusionWe demonstrate a novel tolerance-inducing protocol for the treatment of autoimmune inflammatory joint disease in which the target antigen is known, utilizing DNA-directed RNA interference.

The Effect of an Anti-HLA-B27 Immune Response on CTL Recognition of Chlamydia

The interplay between triggering bacteria and HLA-B27 in the pathogenesis of the spondyloarthropathies remains one of the most active areas of investigation in the rheumatic diseases. This has proved difficult to study systematically in the clinical setting, and in this study we utilized a rat model to address the influence that B27-related immunity may have on the process of generating anti-Chlamydia immunity. When splenocytes from HLA-B27 DNA-immunized Lewis (LEW) animals received restimulation in vitro with Chlamydia-treated cells from B27-transgenic LEW rats, we observed that in addition to the expected CTL recognition of HLA-B27, there was also anti-Chlamydia CTL killing of Chlamydia-sensitized syngeneic fibroblast targets. This was not seen when responding cells in vitro were naive LEW splenocytes. To confirm the existence of CTLs recognizing both HLA-B27 and Chlamydia, LEW rats were immunized with B27-transgenic LEW cells, instead of the B27 DNA construct. Splenocytes from the immune rats were restimulated in vitro with Chlamydia-treated B27-transgenic LEW cells. In this instance, the CTLs retained the allele-specific recognition of HLA-B27, as well as recognition of Chlamydia-sensitized syngeneic fibroblasts. Thus, if there is prior expansion of an immune response against HLA-B27, then the resulting splenocytes demonstrate a reduced threshold for generating a primary anti-Chlamydia CTL response. These studies implicate a dynamic interrelationship between recognition of HLA-B27 and Chlamydia trachomatis. The results may have implications for deciphering the cellular basis of Chlamydia-induced reactive arthritis.