Background IL-17A and IL-17F share structural homology and have similar biological function1. Although the contribution of IL-17A to immune-mediated inflammatory diseases has been widely reported1–3, the role of IL-17F is less well characterised in human tissue inflammation. Bimekizumab, a humanised monoclonal IgG1 antibody, was developed to neutralise both IL-17A and IL-17F potently and selectively, and is under clinical development as a treatment for psoriatic arthritis (PsA) and other immune-mediated conditions such as psoriasis.
Objectives To assess the involvement of IL-17F in chronic inflammation in tissue from patients with PsA and disease-relevant cells, and to determine the effect of dual neutralisation of IL-17A and IL-17F in suppressing inflammation, compared with blockade of IL-17A.
Methods Synovial and lesional skin tissue from patients with PsA was probed by immunostaining for expression of IL-17F protein. Normal dermal fibroblasts and synoviocytes, in the presence of TNFα, were stimulated with recombinant IL-17A and IL-17F to assess the inflammatory response. Using cytokine-specific blocking antibodies, the individual and combined effects of IL-17A and IL-17F were explored with: pro-inflammatory cytokine expression in a complex in vitro model (synoviocytes from patients with PsA and normal dermal fibroblasts were treated with pro-inflammatory mediators from supernatant [SN] of sorted Th17 cells), microarray and cell migration studies.
Results IL-17F expression was observed in tissue biopsies from patients with PsA. In normal dermal fibroblasts, normal synoviocytes and synoviocytes from patients with PsA, stimulation with recombinant IL-17F promoted production of pro-inflammatory mediators, such as IL-6 and IL-8, though to a lesser extent than with recombinant IL-17A. Treatment of Th17 SN-stimulated synoviocytes from patients with PsA with bimekizumab (neutralising IL-17A and IL-17F) led to greater reductions of IL-6 (42% lower p<0.05) and IL-8 (35% lower p<0.05) production than IL-17A inhibition. Bimekizumab treatment of Th17 SN-stimulated normal dermal fibroblasts also reduced production of IL-6 (35% lower p<0.0001) and IL-8 (57% lower p<0.0001) more than IL-17A alone. Combining IL-17A + IL-17F monoclonal antibodies produced similar results to bimekizumab. Levels of expression of 27 inflammation-linked genes, including CXCL1, CXCL2, CXCL3 and IL-15RA, were lower with dual neutralisation of IL-17A and IL-17F by bimekizumab versus inhibition of IL-17A. Suppression of migration of neutrophils (Fig.) and monocytes, both involved in tissue destruction in immune-mediated diseases, was substantially greater with bimekizumab treatment than with single blockade of IL-17A.
Conclusions Dual neutralisation of IL-17A and IL-17F provides evidence for the contribution of IL-17F to inflammation in joints and skin beyond IL-17A alone. As a result, dual inhibition of IL-17A and IL-17F by bimekizumab may provide an effective treatment for immune-mediated inflammatory diseases such as PsA.
C Johansen et al. Br J Dermatol 2009:160:319–24.
AL Lima et al. Br J Dermatol 2016:174:514–21.
C Doe et al. Chest 2010:138:1140–7.
Disclosure of Interest A. Maroof Employee of: UCB Pharma, R. Okoye Employee of: UCB Pharma, T. Smallie Employee of: UCB Pharma, D. Baeten Grant/research support from: UCB Pharma, Consultant for: AbbVie, Pfizer, MSD, Roche, BMS, Novartis, Eli Lilly, Boehringer Ingelhaim and Glenmark, S. Archer Employee of: UCB Pharma, C. Simpson Employee of: UCB Pharma, M. Griffiths Consultant for: UCB Pharma, Employee of: UCB Pharma, S. Shaw Employee of: UCB Pharma
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.