Table 2.
Studies exploring serum anti-inflammatory cytokines IL-4 and IL-10 alteration in PTSD.
| Trauma Types | N (m/f) | Altered Direction | Main Findings | Ref. |
|---|---|---|---|---|
| Accident | 19 (2/17) | None | - PTSD symptom severity is not significantly associated with IL-10 levels. | [68] |
| 187 (71/116) | None | - There are no differences in levels of IL-10 between individuals with PTSD and those without PTSD. | [25] | |
| Assault | 60 (10/50) | Decrease | - Individuals with PTSD presented lower IL-10 levels than the trauma-exposed individuals without PTSD. | [56] |
| 30 (10/20) | None | - There are no differences in levels of IL-10 between individuals with PTSD and those without PTSD. | [69] †,‡ | |
| Combat | 167 (87/80) | Increase | - PTSD symptom severity is positively associated with higher IL-10 levels, and is mediated by attenuated vagal activity, smoking, and alcohol dependence. | [48] |
| 83 (82/1) | None | - There were no anti-inflammatory cytokine level alterations between individuals with PTSD and TBI versus those with PTSD without TBI. | [44] | |
| 64 (60/4) | Increase | - PTSD individuals with mTBI had elevated IL-10 levels compared to individuals with PTSD but without mTBI. - IL-10 concentration is positively correlated with PTSD symptom severity. |
[52] | |
| 299 (299/0) | Decrease | - PTSD symptom severity had a trend-line negative correlation with IL-10 levels. | [61] | |
| 52 (51/1) | None | - CRP and hair cortisol are correlated with symptoms of depression and PTSD. | [57] | |
| 143 (138/5) | None | - There are no between-group differences in IL-10 levels among individuals with PTSD and TBI with loss of consciousness versus individuals with PTSD and TBI without loss of consciousness, as well as individuals with PTSD but no TBI. - PTSD symptom severity is not significantly associated with IL-10 levels. |
[45] | |
| 61 (61/0) | None | - There are no significant differences in IL-10 levels between individuals with PTSD and those without PTSD. | [16] | |
| 104 (104/0) | None | - Concentrations of IL-10 are not significantly altered in PTSD subjects. | [15] | |
| 13 (12/1) | Decrease | - Plasma and salivary levels of IL-10 are lower in veterans with PTSD compared to veterans without PTSD. | [46] | |
| Refugee | 60 (27/33) | None | - IL-10 levels are not significantly different between individuals with PTSD and healthy controls. | [71] † |
| Other | 273 (141/132) | None | - Anti-inflammatory cytokine levels are not different in the chronic PTSD group compared with those in the recovery and resilient group. | [70] |
| 104 (64/40) | Decrease | - Individuals with PTSD showed increased global DNA methylation and decreased IL-4 than to healthy controls. | [73] | |
| 100 (47/53) | Increase | - Individuals with PTSD showed increased cytokine levels compared to healthy controls in 6 cytokines including IL-2, IL-4, IL-6, IL-8, IL-10, and TNF-α. | [72] | |
| 30 (27/3) § | None | - There are no significant difference in IL-4 levels between individuals with PTSD and healthy controls. | [49] | |
| 82 (16/66) | Increase | - Individuals with PTSD had a significant increase in the serum levels of IL-6 and IL-10 than the control group. | [54] † |
† Indicate studies that included a trauma-unexposed healthy control group. ‡ Trauma types of the individuals in the PTSD group of this study were described as other for two individuals, car accident for five individuals, and miscellaneous forms of assault for the remaining individuals. § Depicts the sample size of the PTSD group only, as gender distribution for the control group was not provided. Abbreviations: CRP, c-reactive protein; f, female; IFN, interferon; IL, interleukin; m, male; mTBI, mild traumatic brain injury; N, sample size; PTSD, post-traumatic stress disorder; Ref., reference; TBI, traumatic brain injury; TNF, tumor necrosis factor.