Cytokine levels in patients with SLE and 31 healthy controls (reference levels) at the research visit, compared across smoking status
| Participants, n | Healthy controls | SLE | t-test | SLE smokers | SLE non-smokers | t-test | ANOVA* |
| 31 | 99 | P value | 35 | 64 | P value | P value | |
| Geometric mean (95% CI) | Geometric mean (95% CI) | Geometric mean (95% CI) | Geometric mean (95% CI) | ||||
| BAFF, ng/mL | 0.94 (0.84 to 1.04) | 1.74 (1.58 to 1.92) | <0.001 * | 2.01 (1.72 to 2.34) | 1.61 (1.42 to 1.83) | 0.034 # | <0.001 % |
| IFN-γ, pg/mL | 53.88 (35.81 to 81.06) | 63.75 (50.51 to 80.47) | 0.480 | 39.37 (27.80 to 55.74) | 82.98 (61.96 to 111.13) | 0.002 # | 0.006 % |
| IL-1β, pg/mL | 67.86 (40.08 to 114.90) | 26.85 (22.08 to 32.63) | <0.001 * | 21.85 (16.80 to 28.43) | 30.04 (23.02 to 39.22) | 0.123 | <0.001 % |
| IL-4, pg/mL | 10.98 (7.47 to 16.14) | 11.65 (9.23 to 14.70) | 0.801 | 8.99 (6.58 to 12.28) | 13.43 (9.78 to 18.44) | 0.102 | 0.237 |
| IL-6, pg/mL | 19.12 (14.72 to 24.84) | 20.84 (17.66 to 24.59) | 0.605 | 18.23 (13.93 to 23.87) | 22.42 (18.12 to 27.73) | 0.239 | 0.416 |
| IL-10, pg/mL | 11.14 (7.82 to 15.86) | 13.31 (10.28 to 17.24) | 0.481 | 10.87 (7.56 to 15.65) | 14.87 (10.47 to 21.11) | 0.253 | 0.374 |
| IL-12, pg/mL | 38.92 (27.44 to 55.20) | 31.51 (25.58 to 38.81) | 0.318 | 24.18 (17.39 to 33.62) | 36.41 (27.88 to 47.55) | 0.062 | 0.099 |
| IL-17, pg/mL | 51.01 (37.26 to 69.82) | 49.65 (41.20 to 59.82) | 0.887 | 40.18 (30.82 to 52.38) | 55.74 (43.42 to 71.55) | 0.096 | 0.233 |
| MCP-1, pg/mL | 98.22 (76.47 to 126.15) | 137.42 (118.36 to 159.54) | 0.028 * | 118.90 (93.40 to 151.37) | 148.74 (122.84 to 180.10) | 0.156 | 0.031 % |
| TNF-α, pg/mL | 47.91 (33.68 to 68.15) | 48.91 (39.58 to 60.45) | 0.923 | 35.41 (26.10 to 48.03) | 58.37 (44.20 to 77.07) | 0.024 # | 0.070 |
| TGF-β1, pg/mL | 733.39 (663.16 to 811.06) | 581.74 (524.97 to 644.65) | 0.018 * | 509.26 (419.01 to 618.96) | 625.65 (556.02 to 703.99) | 0.057 | 0.007 % |
| MIP-1α, pg/mL | Not available | 42.10 (31.65 to 55.99) | – | 34.72 (21.44 to 56.22) | 47.22 (32.54 to 68.50) | 0.319 | – |
| MIP-1β, pg/mL | Not available | 228.65 (206.54 to 253.13) | – | 195.24 (165.18 to 230.78) | 249.30 (219.74 to 282.83) | 0.022 # | – |
Bolded findings are significantly different across either * SLE patients and healthy controls; # SLE patients who were currently smoking vs notcurrently smoking; and, % healthy controls, SLE non-smokers and SLE current smokers.
*One-way ANOVA compared cytokine levels between healthy controls, SLE smokers and SLE non-smokers.
ANOVA, analysis of variance; BAFF, B cell-activating factor; IFN-γ, interferon-gamma; IL, interleukin; MCP-1, monocyte chemoattractant protein 1; MIP-1α, macrophage inflammatory protein 1 alpha; MIP-1β, macrophage inflammatory protein 1 beta; TGF-β1, transforming growth factor beta 1; TNF-α, tumour necrosis factor-alpha.