Table 3.
Cytokines in synovial fluid
| Mediator | UC OA | BC OA | P-values |
|---|---|---|---|
| n = 14 | n = 20 | ||
| CXCL1 | 216·1 ± 438 (54·8–1 733) | 243·7 ± 206·4 (70·2–733·2) | 0·011* |
| Eotaxin | 5·93 ± 14·6 (0–40·7) | 14·17 ± 21·1 (0–82·3) | 0·045* |
| IFN-γ | 112·4 ± 37·3 (55·1–189) | 164 ± 85·1 (45·5–406·9) | 0·042* |
| IL-2 | 0·05 ± 0·2 (0–0·6) | 0·5 ± 1·1 (0–4·2) | 0·171 |
| IL-4 | 0·4 ± 0·2 (0·2–0·7) | 0·5 ± 0·2 (0·2-1·2) | 0·558 |
| IL-5 | 0·1 ± 0·2 (0–0·9) | 0·5 ± 1 (0–3·1) | 0·268 |
| IL-6 | 207·7 ± 273·1 (7·2–803·7) | 326·2 ± 423 (22·9–1 666) | 0·365 |
| IL-7 | 29·7 ± 9·1 (14·5–50·1) | 39·2 ± 14·2 (22·8–69·7) | 0·035* |
| IL-8 | 360 ± 923·3 (13·2–3 420) | 436·6 ± 502·9 (19·6–1 576) | 0·039* |
| IL-9 | 3·1 ± 1·5 (0–5·5) | 5·7 ± 4·6 (0·8–18) | 0·048* |
| IL-10 | 27·3 ± 8·1 (13·7–45·6) | 41·1 ± 18·6 (16·9–88·3) | 0·014* |
| IL-12 | 213·7 ± 61·1 (145·9–369·1) | 333·3 ± 174·9 (123·8–786·8) | 0·020* |
| IL-13 | 30·7 ± 11·4 (16·5–59·4) | 43·4 ± 17·9 (24–97·1) | 0·026* |
| IL-15 | 8·6 ± 4·9 (2·8–22·7) | 9·4 ± 3·9 (2·8–17·7) | 0·565 |
| IL-16 | 1127 ± 594·8 (421·1–2 672) | 1119 ± 868·6 (378·2–4256) | 0·975 |
| IL-18 | 90·3 ± 29·7 (48·6–152·1) | 108·1 ± 65·2 (43–321·6) | 0·349 |
| TNF-α | 4 ± 2·8 (0·5–10·5) | 5·6 ± 3·1 (1·7–12·2) | 0·135 |
| LIF | 44·4 ± 23·9 (16·4–85·8) | 49·1 ± 26·5 (10·1–108·6) | 0·602 |
| MCP-1 | 52·7 ± 39·7 (12·4–140·6) | 158 ± 378·7 (8·9–1 656) | 0·847 |
| M-CSF | 76 ± 63·9 (28·4–283·8) | 92·6 ± 41·9 (31·4–177·3) | 0·367 |
| MIF | 5177·5 ± 4499·4 (1461–14 415) | 8929·7 ± 25 029·5 (1000–114 827) | 0·753 |
| MIP-1α | 1·1 ± 1·2 (0–3) | 2·4 ± 2·8 (0–9·8) | 0·069 |
| MIP-1β | 33·3 ± 42·3 (12·8–59·2) | 44·6 ± 28·9 (16·24–133·1) | 0·190 |
| RANTES | 121·2 ± 211·6 (0·1–672·5) | 112·1 ± 397·5 (1·29–1 791) | 0·700 |
| VEGF | 1318·8 ± 655·5 (569·4–2 967) | 2783·3 ± 2519·2 (756·8–10 160) | 0·012* |
| IL-1α, IL-1β, IL-17 | Below detection level | Below detection level | n.a. |
Significant differences are indicated with asterisks: *P < 0·05; **P < 0·01; ***P < 0·001. The Pro-Human Cytokine Multiplex Assay (Bio-Rad) was used to analyse the cytokines in synovial fluid (SF) samples. Cytokine and chemokine concentrations were calculated by reference to the standard curve. The sensitivity of the multiplex kit was <5 pg/ml. The unpaired t-test was also performed to assess the differences between unicompartmental (UC) and bicompartmental (BC) osteoarthritis (OA) SF samples due to the predominantly Gaussian distribution. For cytokines which did not show Gaussian distribution, a Mann–Whitney U-test was performed. All reported P-values are two-tailed. A P-value <0·05 was considered to show a statistically significant difference. IFN = interferon; IL = interleukin; TNF = tumour necrosis factor; LIF = leukaemia inhibitory factor; MCP = monocyte chemotactic protein; M-CSF = macrophage colony-stimulating factor; MIP = macrophage inflammatory protein; RANTES = regulated upon activation normal T cell expressed and secreted; VEGF = vascular endothelial growth factor; n.a. = not applicable.