Fig. 1

Patients with osteoarthritis (OA) manifest qualitative and quantitative differences in the immune cell infiltrates in the synovial compartment as compared to patients with rheumatoid arthritis (RA). Frequencies (a) and cumulative statistical analysis (b) of immune cell populations (monocytes, CD14⁺, B cells CD19⁺, natural killer cells, CD56⁺, CD3⁺ CD4⁺ T cells and CD3⁺ CD8⁺ T cells) in peripheral blood (a, b) from healthy donors (HD, n = 25) patients with OA (n = 11) and patients with RA (n = 24). Frequencies (c) and cumulative statistical analysis (d) of immune cell populations in synovial fluid (SF) from patients with OA (n = 6) and patients with RA (n = 8): *p ≤ 0.05, **p ≤ 0.005, ***p ≤ 0.0005, Mann-Whitney unpaired two-tailed t test. Mean value ± SEM are reported. ns not significant, PBMC peripheral blood mononuclear cells, MC mononuclear cells