AB0080 Modualtion of immunoglobulin G2B binding in combination of methotrexate and aconite in a collagen-induced arthritis setting
Authors: D-S Oh, G Park, SH Lee
Journal: Annals of the Rheumatic Diseases (2017)

<h3>Background</h3> Our previous study showed synergistic responses in TNF-alpha (TNF-α) and interleukin-6 with the combination of methotrexate (MTX) and aconite. Modulation of those cytokines has not been applied to rheumatoid arthritis (RA)-mimicked in vivo models. <h3>Objectives</h3> To translate in vitro effects of MTX, aconite, and MTX/aconite combination towards anti-arthritic responses in vivo, we investigated arthritis index (AI), histopathologic changes, and levels of TNF-α, immunoglobulin G (IgG) 2a and 2b in a collagen-induced arthritis (CIA) setting. <h3>Methods</h3> CIA was induced in five male DBA/OlaHsd mouse per group by intradermal injection of bovine collagen type II and Complete Freund9s Adjuvant. In Day21, a bovine collagen type II and Incomplete Freund9s Adjuvant were given for booster infection. The mice of arthritis onset were treated daily throughout Day49 with per oral administration of pre-investigated ratios of three to one; MTX (3 mg/kg), aconite (Aconibal®, 1 mg/kg), and MTX/aconite (3 and 1 mg/kg) combination. The AIs were evaluated every week. Histological changes, levels of TNF-α as well as IgG2a and IgG2b in blood using ELISA kit were evaluated at finals. Repeat measure and one-way ANOVA were analysed using SPSS (ver. 18.0 KO for Windows; SPSS Inc., Chicago, IL, USA) to evaluate inter-period and inter-group differences with Tukey9s post-hoc tests. <h3>Results</h3> The CIA phenotypes adequately presented through three groups9 AI reductions (CIA vs. MTX, aconite, or MTX/aconite; <i>p</i>&lt;0.001, for three). There were differences of AI scores in aconite group from MTX one in week 4, 5, and 6 (MTX vs. aconite; <i>p</i>=0.038, <i>p</i>=0.001, <i>p</i>=0.042, respectively). Synergistic responses of AI were not shown any of three groups. The recoveries of synovial tissues were observed in MTX and MTX/aconite groups. The levels of TNF-α were not changed (aconite vs. MTX/aconite; <i>p</i>=0.200 and MTX vs. MTX/aconite; <i>p</i>=0.700). MTX group showed IgG2a reduction (CIA vs. MTX; <i>p</i>&lt;0.001). Interestingly, MTX/aconite combination and aconite group slightly downregulated IgG2b levels as 80.8±5.6% and 90.5±7.4%, respectively (CIA vs. MTX/aconite; <i>p</i>=0.001 and CIA vs. aconite; <i>p</i>=0.010). <h3>Conclusions</h3> Synergistic in vitro effects of MTX and aconite combination brought the partial in vivo phenotypic responses: Aconite showed more AI changes than MTX did in 4, 5, and 6 weeks. However, we found the presence of partial FcγRIIB affinity of binding modulation that MTX/aconite could enhance preventing monocyte/macrophage activation via immune complex in RA pathogenesis, as was other benefits of the combination except direct synergies. <h3>References</h3> Oh DS, Park G, Choi S. Characterising multiple molecule-modulating response of TNF-alpha and interleukin-6 by combination of methotrexate and aconite in interferon gamma-induced toxicity setting. Ann Rheum Dis 2016;75:Suppl2 909–910. Wijngaarden S, van Roon JA, van de Winkel JG, Bijlsma JW, Lafeber FP. Down-regulation of activating Fcgamma receptors on monocytes of patients with rheumatoid arthritis upon methotrexate treatment. Rheumatology (Oxford) 2005;44:729–734. Stewart R, Hammond SA, Oberst M, Wilkinson RW. Down-regulation of activating Fcgamma receptors on monocytes of patients with rheumatoid arthritis upon methotrexate treatment. J Immunother Cancer 2014;2:29. <h3>Acknowledgements</h3> This study was supported by KIOM (Grant # K17252). The commercial product was donated by the virtue of HanPoong Pharmaceutical Company. <h3>Disclosure of Interest</h3> None declared