Table 1.
Baseline levels of cytokines in the blood of individuals with autism compared with controls.
| Cytokine affected | Sample type | No. of studies | Age range (in years) (mean ± SD) | Total sample size | % Males | Reported findings in autism compared with controls (in at least N = 3 references) | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| Autism | Controls | Autism | Controls | Autism; Controls | ↑ | ↓ | ≈ | |||
| IL-6 | Plasma and serum | 12 | 2 to 21 (6.85 ± 2.21) |
2 to 21 (7.04 ± 2.08) |
540 | 470 | 86;75 | (22–28) | (29–33) | |
| Plasma | 4 | 3 to 8 (6.78 ± 2.73) |
3 to 8 (6.36 ± 2.43) |
134 | 122 | 85;73 | (29–32) | |||
| Serum | 5 | 2 to 21 (5.91 ± 1.82) |
2 to 21 (6.60 ± 1.97) |
244 | 202 | 86;74 | (22–26) | |||
| IL-17 | Plasma | 5 | 2.1 to 11.8 (7.11 ± 2.35) |
2.6 to 12 (6.83 ± 2.41) |
200 | 168 | 82;71 | (29–31, 34, 35) | ||
| Serum | 3 | 3 to 14.5 (6.70 ± 1.86) |
3 to 11 (7.06 ± 1.56) |
127 | 98 | 89;83 | (22, 33, 36) | |||
| TNF-α | Plasma and serum | 13 | 2 to 21 (6.18 ± 2.29) |
2 to 21 (7.03 ± 2.17) |
615 | 446 | 84;70 | (24, 29, 33, 37–40 | (25, 27, 30–32, 41) | |
| Plasma | 3 | 3 to 8 (6.67 ± 2.34) |
3 to 8 (6.23 ± 1.92) |
94 | 87 | 89;77 | (30–32) | |||
| Serum | 5 | 2 to 21 (5.23 ± 2.11) |
2 to 21 (7.33 ± 2.51) |
156 | 142 | 84;64 | (24, 33, 37, 38, 40) | |||
| IL-1β | Plasma and serum | 15 | 2 to 21 (6.43 ± 2.63) |
2 to 21 (7.08 ± 2.31) |
659 | 496 | 85;73 | (23–25, 27, 33, 37, 42, 43) | (22, 29, 30, 32, 40, 41, 44) | |
| Plasma | 4 | NR (8.08 ± 3.80) |
NR (7.43 ± 2.93) |
119 | 102 | 83;80 | (29, 30, 32, 44) | |||
| Serum | 6 | 2 to 21 (5.25 ± 1.95) |
2 to 21 (5.76 ± 1.81) |
243 | 202 | 84;70 | (24, 25, 33, 37, 42, 43) | |||
| IFN-γ | Plasma and serum | 11 | 1.58 to 14.5 (6.02 ± 2.21) |
2.3 to 12 (7.00 ± 2.08) |
564 | 374 | 88;73 | (22, 25, 27, 29–31, 33, 39–41, 45) | ||
| Plasma | 10 | 2.2 to 16 (6.98 ± 2.51) |
2.3 to 16 (6.61 ± 2.30) |
474 | 344 | 85;77 | (32, 46, 47) | (27, 29–31, 39, 41, 45) | ||
| Serum | 4 | 2 to 14.5 (5.17 ± 1.87) |
3 to 16 (7.55 ± 1.63) |
154 | 92 | 93;71 | (22, 25, 33, 40) | |||
| TGF-β | Plasma and serum | 8 | 2 to 28 (11.46 ± 1.73) |
2 to 26 (14.16 ± 2.15) |
349 | 243 | 89;77 | (39, 40, 46, 48) | (35, 49–51) | |
| Plasma | 6 | 1.6 to 13 (8.70 ± 1.20) |
2 to 14 (9.10 ± 1.70) |
300 | 208 | 83;73 | (39, 46, 48) | (35, 50, 51) | ||
| RANTES | Plasma | 3 | 3 to 8 (4.40 ± 0.83) |
2.8 to 8 (4.21 ± 0.98) |
167 | 131 | 88;59 | (31, 52, 53) | ||
| IL-13 | Plasma and serum | 4 | 2 to 21 (6.31 ± 2.17) |
2 to 21 (5.75 ± 1.99) |
196 | 179 | 93;79 | (24, 27, 30, 31) | ||
| IL-12p70 | Plasma | 4 | 2.2 to 10 (6.79 ± 2.00) |
2.3 to 10 (6.36 ± 1.91) |
186 | 119 | 87;77 | (30, 31, 41, 45) | ||
| IL-12p40 | Plasma | 3 | 3 to 10 (6.79 ± 2.00) |
3 to 10 (6.36 ± 1.91) |
169 | 103 | 89;75 | (30, 31, 41) | ||
| IL-10 | Plasma and serum | 7 | 2.2 to 10 (6.44 ± 2.32) |
2.3 to 12 (6.48 ± 2.11) |
225 | 186 | 86;74 | (25, 29–33, 45) | ||
| Plasma | 5 | 2.2 to 8 (6.78 ± 2.73) |
2.3 to 8 (6.36 ± 2.43) |
151 | 138 | 85;75 | (29–32, 45) | |||
| IL-8 | Plasma and serum | 10 | 1.58 to 10 (5.68 ± 2.03) |
2 to 16 (6.97 ± 2.01) |
710 | 397 | 88;73 | (27, 31, 37, 54) | (7, 25, 30, 39–41) | |
| IL-5 | Plasma | 4 | 2.2 to 8 (7.10 ± 1.84) |
2.3 to 8 (6.86 ± 1.89) |
160 | 133 | 84;73 | (27, 30, 31, 45) | ||
| IL-4 | Plasma and serum | 8 | 2.2 to 14.5 (6.47 ± 2.46) |
2.3 to 11 (6.38 ± 2.11) |
330 | 283 | 87;78 | (22, 27, 29–33, 45) | ||
| Plasma | 6 | 2.2 to 8 (6.78 ± 2.73) |
2.3 to 8 (6.36 ± 2.43) |
248 | 225 | 85;76 | (27, 29–32, 45) | |||
| IL-2 | Plasma and serum | 5 | 2.9 to 10 (7.19 ± 2.32) |
2.8 to 10 (7.08 ± 1.93) |
277 | 204 | 85;81 | (27, 30, 32, 33, 41) | ||
| Plasma | 4 | 2.9 to 10 (7.76 ± 2.67) |
2.8 to 10 (7.41 ± 2.23) |
245 | 176 | 84;82 | (27, 30, 32, 41) | |||
| MCP-1 | Plasma | 4 | 1.6 to 6 (5.63 ± 1.77) |
3 to 6.6 (5.29 ± 1.69) |
1141 | 1295 | 88;76 | (30, 31, 39, 53) | ||
| Bloodspot | 3 | Neonates | Neonates | 942 | 1181 | 84;81 | (7, 8, 11) | |||
| MIP-1α | Plasma | 3 | 1.58 to 6.17 (8.11 ± 3.65) |
2.8 to 6.58 (7.44 ± 3.12) |
192 | 124 | 89;79 | (30, 39, 52) | ||
| Bloodspot | 3 | Neonates | Neonates | 656 | 962 | 85;68 | (7, 10, 11) | |||
| GM-CSF | Plasma | 4 | 2.9 to 10 (6.79 ± 2.00) |
2.8 to 10 (6.36 ± 1.91) |
266 | 190 | 88;77 | (27, 30, 31, 41) | ||
| Eotaxin | Plasma | 4 | 3 to 10 (6.17 ± 1.74) |
3 to 10 (5.86 ± 1.71) |
211 | 138 | 89;67 | (30, 31, 41, 53) | ||
Symbols: ↑, increased; ↓, decreased; ≈, unchanged; in autism compared with controls
GM-CSF, granulocyte monocyte colony-stimulating factor; IFN-γ, interferon-γ; IL, interleukin; MCP-1, monocyte chemoattractant protein-1; MIP-1α, macrophage inflammatory protein; NR, not reported; RANTES, regulated upon activation, normal T cell expressed and presumably secreted; TGF-β, transforming growth factor-β; TNF-α, tumor necrosis factor-α.