Table 1.
Human tissues used in the present study.
Fig 1.
C5aR expression in the synovium from rheumatoid arthritis, osteoarthritis psoriatic arthritis, and non-inflammatory control.
Immunohistochemical staining for C5aR (A, B, C, E and F), and for the IgG2a isotype control antibody (D). Synovium from patients with RA undergoing joint replacement is shown in (A), and synovectomy, (C, D). Synovium from patients with OA is shown in (E), and PsA in (F). Synovium from a non-inflammatory control is seen in (B). Numerous infiltrating C5aR+ cells (in brown) are seen in A, C and F. Intravascular C5aR+ neutrophils are seen in C and E (arrowheads). Note the lack of immunoreactivity in the non-inflammatory control (B). Nuclei (in blue) were counterstained with haematoxylin. Bars: (A, B, E and F) 50 μm, (C and D) 100 μm.
Fig 2.
C5aR expression by macrophages and neutrophils, but not by T cells in the synovium of rheumatoid arthritis.
Double immunofluorescence staining for C5aR (red signal A—F) and either CD68+ macrophages (green signal A, B and C), CD3+ T cells (green signal in D), or MPO+ neutrophils (green signal in E and F) of the synovium from rheumatoid arthritis patients undergoing joint replacement (A, B, D and E) or synovectomy (C and F), analysed by confocal microscopy (A, B, D and E) and epifluorescence microscopy (C and F). Framed area in E is seen in B. Note the co-localization of C5aR and CD68+ macrophages in A, B and C, and MPO+ neutrophils F, and lack of co-localization with a CD3+ T cell in D. The nuclei (in blue) were counterstained with Hoechst. Bars: (A) 100 μm, (B and D) 5 μm, (E) 500 μm, (C and F) 50 μm.
Table 2.
Summary of C5aR expression and characterization of C5aR-positive cells in the synovium from patients with RA, OA, PsA and from non-inflammatory controls.
Table 3.
Demographic data on the subjects providing blood and synovial fluid.
Fig 3.
C5a levels in synovial fluids and plasma.
A. Synovial fluid levels. B. Plasma levels. Statistical analysis was with the Student’s t-test. P-values are uncorrected for multiple testing.
Fig 4.
C5a levels in synovial fluids correlate to disease activity.
A and B: From RA patients; synovial fluid C5a levels correlate to both DAS28 and plasma CRP (r values of respectively 0.5122 (p = 0.0075) and 0.6881 (p < 0.0001). C and D: From PsA patients; synovial fluid C5a levels correlate to DAS28 and plasma CRP (r value = 0.7727 (p = 0.0053), but not to CRP. Statistical analysis was with Spearman’s Rank correlation test.
Table 4.
Biomarkers in RA SF correlating to C5a levels.
Fig 5.
Anti-C5aR mAb inhibition of migration towards RA synovial fluids.
A. PML and monocyte migration. All values were normalized by setting the migration with isotype control mAb added to 100. Average inhibition by anti-C5aR mAb was 60% (p = 0.014) for PMLs (n 0 16) and 33% (p = 0.0012) for monocytes (n = 22). B. Relative neutrophil number vs. C5a levels in RA SF. Percentage neutrophils in the synovial fluid correlate to synovial fluid C5a levels (r value = 0.8182; p < 0.0001). Statistical analyses were Student’s paired t-test in A and Spearman’s Rank correlation test in B.