C5a and C5aR are elevated in joints of rheumatoid and psoriatic arthritis patients, and C5aR blockade attenuates leukocyte migration to synovial fluid

Lars Hornum, Anker Jon Hansen, Ditte Tornehave, Marianne Scheel Fjording, Paula Colmenero, Inger Falbe Wätjen, Niels Henrik Søe Nielsen, Henning Bliddal, Else Marie Bartels

35 Citations (Scopus)

Abstract

Complement activation correlates to rheumatoid arthritis disease activity, and increased amounts of the complement split product C5a is observed in synovial fluids from rheumatoid arthritis patients. Blockade of C5a or its receptor (C5aR) is efficacious in several arthritis models. The aim of this study was to investigate the role of C5a and C5aR in human rheumatoid arthritis and psoriatic arthritis-both with respect to expression and function. Synovial fluid, blood and synovial samples were obtained from rheumatoid arthritis, psoriatic arthritis and osteoarthritis patients as a less inflammatory arthritis type, and blood from healthy subjects. Cells infiltrating synovial tissue were analysed by immunohistochemistry and flow cytometry. SF and blood were analysed for biomarkers by flow cytometry or ELISA. The effect of a blocking anti-human C5aR mAb on leukocyte migration was determined using a Boyden chamber. Appropriate statistical tests were applied for comparisons. C5aR+ cells were detected in most rheumatoid arthritis, in all psoriatic arthritis, but not in non-inflammatory control synovia. C5aR+ cells were primarily neutrophils and macrophages. C5aR+ macrophages were mainly found in lymphoid aggregates in close contact with T cells. C5a levels were increased in both rheumatoid arthritis and psoriatic arthritis synovial fluid compared to osteoarthritis, and in blood from rheumatoid arthritis compared to healthy subjects. Neutrophil and monocyte migration to rheumatoid arthritis synovial fluid was significantly inhibited by anti-C5aR. The data support that the C5a-C5aR axis may be driving the infiltration of inflammatory cells into the synovial fluid and synovium in both rheumatoid and psoriatic arthritis, and suggest that C5a or C5aR may be a promising treatment target in both diseases.

Original languageEnglish
JournalP L o S One
Volume12
Issue number12
Pages (from-to)e0189017
ISSN1932-6203
DOIs
Publication statusPublished - 2017

Keywords

  • Arthritis, Psoriatic
  • Arthritis, Rheumatoid
  • Chemotaxis, Leukocyte
  • Complement C5a
  • Enzyme-Linked Immunosorbent Assay
  • Flow Cytometry
  • Humans
  • Immunohistochemistry
  • Leukocytes
  • Receptor, Anaphylatoxin C5a
  • Synovial Fluid
  • Journal Article

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