Gilles Avenel

Atypical forms of syphilis: Two cases

Syphilis is a sexually transmitted disease caused by the spirochete Treponema pallidum. A chancre usually develops initially. Organ involvement and neurological complications may occur, sometimes several years after the initial exposure. We managed two patients with syphilis responsible for joint or neurological manifestations, diagnosed in 2008. One patient presented with oligoarthritis involving the knees and right elbow, coinciding with a maculopapular and pustular eruption. In the other patient, meningoradiculitis involving the T8, T9, and T10 metameres prompted a test for Lyme disease, which was weakly positive, leading to evaluation for false-positivity due to a cross-reaction. Neither patient was infected with the HIV.

Soluble alpha-enolase activates monocytes by CD14-dependent TLR4 signalling pathway and exhibits a dual function

Rheumatoid arthritis (RA) is the most common form of chronic inflammatory rheumatism. Identifying auto-antigens targeted by RA auto-antibodies is of major interest. Alpha-enolase (ENO1) is considered to be a pivotal auto-antigen in early RA but its pathophysiologic role remains unknown. The main objective of this study was to investigate the in vitro effects of soluble ENO1 on peripheral blood mononuclear cells (PBMC) from healthy donors and RA patients in order to determine the potential pathogenic role of ENO1. ELISA, transcriptomic analysis, experiments of receptor inhibition and flow cytometry analysis were performed to determine the effect, the target cell population and the receptor of ENO1. We showed that ENO1 has the ability to induce early production of pro-inflammatory cytokines and chemokines with delayed production of IL-10 and to activate the innate immune system. We demonstrated that ENO1 binds mainly to monocytes and activates the CD14-dependent TLR4 pathway both in healthy subjects and in RA patients. Our results establish for the first time that ENO1 is able to activate in vitro the CD14-dependent TLR4 pathway on monocytes involving a dual mechanism firstly pro-inflammatory and secondly anti-inflammatory. These results contribute to elucidating the role of this auto-antigen in the pathophysiologic mechanisms of RA.

Prophylactic Injection of Recombinant Alpha-Enolase Reduces Arthritis Severity in the Collagen-Induced Arthritis Mice Model

Objective To evaluate the ability of the glycolytic enzyme alpha-enolase (ENO1) or its immunodominant peptide (pEP1) to reduce the severity of CIA in DBA/1 mice when injected in a prophylactic way. Methods Mice were treated with mouse ENO1 or pEP1 one day prior to collagen II immunization. Clinical assessment was evaluated using 4 parameters (global and articular scores, ankle thickness and weight). Titers of serum anti-ENO1, anti-cyclic citrullinated peptides (anti-CCP) and anti-CII (total IgG and IgG1/IgG2a isotypes) antibodies were measured by ELISA at different time-points. Disease activity was assessed by histological analysis of both anterior and hind paws at the end of experimentation. Results Prophylactic injection of 100 μg of ENO1 reduced severity of CIA. Serum levels of anti-CII antibodies were reduced in ENO1-treated mice. Concordantly, ENO1-treated mice joints presented less severe histological signs of arthritis. ENO1 did not induce a shift toward a Th2 response since IgG1/IgG2a ratio of anti-CII antibodies remained unchanged and IL-4 serum levels were similar to those measured in the control group. Conclusions Pre-immunization with ENO1 or its immunodominant peptide pEP1 reduces CIA severity at the clinical, immunological and histological levels. Effects of pEP1 were less pronounced. This immunomodulatory effect is associated with a reduction in anti-CII antibodies production but is not due to a Th1/Th2 shift.

Arthritis due to metastasis.

Joint Bone Spine - In Press.Proof corrected by the author Available online since lundi 22 septembre 2014

A1.32 Alpha-enolase activates monocytes by CD14-dependent TLR4 signalling pathway

Background and objectives Rheumatoid arthritis (RA) is the most common chronic inflammatory rheumatism. Identification of autoantigens targeted by RA autoantibodies has been of major interest. Alpha-enolase (ENO1) is considered as a pivotal autoantigen in early RA. Whatever the nature of this molecule, its role in RA pathophysiology remains unknown. The main objective of this study was to investigate the in vitro effects of soluble ENO1 on peripheral blood mononuclear cells (PBMCs) from healthy donors and RA patients in order to determine the potential pathogenic role of ENO1. Materials and methods PBMCs of healthy donors or RA patients were cultured with ENO1 or control. ELISA and transcriptomic analysis were performed to assess the pro- or anti-inflammatory effect of ENO1. Moreover, flow cytometry analysis, experiments of receptor inhibition and ELISA were performed to determine the target cell population and receptor of ENO1. Results Firstly, we showed that ENO1 has the ability to induce the production of a large amount of pro-inflammatory cytokines and chemokines, and to activate the innate immune system on PBMCs from healthy donors. ENO1 also exhibits this pro-inflammatory effect on cells from RA patients. Then, we demonstrated that ENO1, which exclusively bound monocytes, exhibited a LPS-like action mediated by TLR4. More precisely, the effects of ENO1 specifically involved the CD14-dependent TLR4 pathway. Conclusions Together, these findings illustrate for the first time that ENO1 triggers in vitro an inflammatory response mediated by monocytes through the CD14-dependent TLR4 pathway and contribute to elucidate the role of this autoantigenin the RA pathophysiological mechanisms.

Prophylactic injection of non-citrullinated α-enolase has immunomodulatory effects in collagen-induced arthritis mice

Background Identification of autoantibodies associated with rheumatoid arthritis (RA) has been of major interest. In this context, the authors have previously identified for the first time α-enolase as a new auto-antigen in early RA. Moreover, subsequent studies have shown that citrullination of α-enolase is crucial for its autoantigenicity. α-enolase is an evolutionary conserved protein implicated both in glycolysis pathway and as a plasminogen receptor. Here, the authors have evaluated, in the well-known collagen induced arthritis model, the clinical, immunological and histological effects of both recombinant non-citrullinated α-enolase and immunodominant peptides from human and bacterial species. Methods Different doses of α-enolase (10 and 100 µg) or immunodominant enolase peptide 1 from human (hEP1) or porphyromonas Gingivalis (pEP1) (10 or 100µg) were intraperitoneally injected to 6 week-old DBA/1 mice one day prior to collagen II arthritis induction (CIA). Both clinical (weight, arthritis score, tarsal thickness) and biological (anticollagen II and anti-α-enolase antibodies) were assessed during the 90 days follow-up period. Four histological score were also assessed: inflammation, syniovial thickening, cartilage resorption and bone resorption. Results Prophylactic injection of recombinant α-enolase was able to significantly prevent weight loss and to decrease the severity of arthritis evaluated by the arthritis score as well as the tarsal thickness. There was a dose-effect since 100 µg led to better results. Levels of anticollagen II antibodies were significantly lower whereas titers of anti-α-enolase antibodies were significantly higher in mice treated with 100 µg of α-enolase compared to control mice. Moreover, histological score were in agreement with clinical score. As regards to hEP1 and pEP1, the authors etablished a dose-dependant protective effect in CIA which is significant for pEP1. This protective effect is not due to once again a decrease of anti-collagen II antibodies titer. Conclusion Prophylactic treatment with recombinant α-enolase suggest a protective role of this molecule. The clinical effect is not due to an imunological response mediated by anti-α-enolase antibodies. Prophylactic injection could induce either an immune deviation or an emergence of regulatory lymphocyte population, responsible of a decrease of anti-CII antibodies production. These results suggest α-enolase has an immunomodulatory effect in CIA mice. Those results suggest that non-citrullinated α-enolase could constitute a potential new therapeutic approach in RA.