Table 2.
Representation of selected articles examining the relationship between PTSD and systemic low-grade inflammation
| Reference | N | Study population | Design | Focus | Inflammatory markers | Significant clinical findings |
|---|---|---|---|---|---|---|
| Lindqvist et al (2017)6 | 61 | Male war veterans (31 with PTSD and 30 without) | Cross-sectional replication study | To compare the PIC levels of the two groups | CRP, IL-6, TNF-α, IFN-γ, IL-10, and PIC score | Results: mean±SD (pg/mL except for CRP, which is in mg/L) CRP: PTSD (4.10±5.81) and Control (1.59±2.58) (p<0.01) IL-6: PTSD (0.60±0.51) and Control (0.35±0.19) (p<0.01) TNF-α: PTSD (3.40±3.59) and Control (3.30±5.80) (p<0.1) IFN-γ: PTSD (6.16±7.06) and Control (3.60±1.45) (p>0.05) IL-10: PTSD (0.26±0.12) and Control (0.28±0.26) (p>0.05) Total PIC score: PTSD (1.03±2.99) and Control (–0.97±2.31) (p<0.01) |
| Lindqvist et al (2014)23 | 102 | Male war veterans (51 with PTSD and 51 without) | Cross-sectional | To investigate whether combat-exposed males have elevated levels of PICs | CRP, IL-6, TNF-α, IFN-γ, IL-10, IL-1, and total PIC score | Results: mean±SD (pg/mL, except for CRP which is in mg/L) CRP: PTSD (3.27±5.66) and Control (1.66±2.30) (p=0.301) IL-6: PTSD (1.04±0.17) and Control (0.81±0.78) (p=0.096) TNF-α: PTSD (4.27±4.00) and Control (3.07±0.70) (p=0.005) IFN-γ: PTSD (1.41±1.79) Control (0.65±0.38) (p=0.005) IL-10: PTSD (2.15±1.49) and Control (1.94±1.47) (p=0.163) Total PIC score: PTSD (0.89±3.48) and Control (–0.81±2.45) (p=0.002) |
| Heath et al (2013)30 | 139 | Females with IPV exposure; 17 participants had PTSD | Cross-sectional | To determine the relationship between IPV, psychological stress, and inflammation as a means of explaining the psychobiological mechanism by which IPV may cause altered inflammatory processes | CRP | Results: mean±SD (mg/L) CRP: PTSD (1.81±1.39) and Non-PTSD (1.32±0.89) (p=0.057) |
| Gola et al (2013)5 | 60 | 35 participants with PTSD from war and torture trauma and 25 healthy controls | Cross-sectional | To investigate and compare the plasma cytokine levels of PTSD-affected and non-affected individuals | IL-6, TNF-α, IL-10, IL-8, MCP-1; leukocytes were also measured but they were removed from this table as they were not measured in any of the other articles in this review | Results: median (pg/mL) IL-6: PTSD (0.5) and Control (0.35) (p=0.72) TNF-α: PTSD (0.21) and Control (0.24) (p=0.37) L-10: PTSD (0.20) and Control (0.20) (p=0.08) IL-8: PTSD (5.2) and Control (8.6) (p value was lost after multiple comparisons with Holm’s stepwise procedure) MCP-1: PTSD (2.00) and Control (5.95) (p=0.82) |
| Spitzer et al (2010)24 | 3049 | Community sample (55 participants with PTSD of mixed cause: combat, rape, abuse, etc.) | Cross-sectional | To compare the relationship between PTSD and serum CRP in a large general-population sample | CRP | Results: mean±SD (mg/L) CRP: PTSD (2.81±2.49) and Control (2.14±2.17) (p=0.027) |
| Hoge et al (2009)21 | 96 | 48 subjects with panic disorder and PTSD (28 with PTSD) and 48 healthy subjects | Cross-sectional | To test whether individuals with anxiety disorders have a chronically elevated pro-inflammatory state based on the presence of PICs found in peripheral blood | IL-6, TNF-α, IFN-y, IL-10, MCP-1; other inflammatory markers were also measured but they were removed from this table as they were not measured in the other articles included in this review | Results: mean±SD (pg/mL) IL-6: PTSD (16.17±15.84) and Control (2.61±8.10) (p=0.000) TNF-α: PTSD (24.98±91.37) and Control (5.36±14.83) (p=0.000) IFN-y: PTSD (46.07±169.16) and Control (4.89±12.10) (p=0.007) IL-10: PTSD (6.37±4.24) and Control (1.71±4.72) (p=0.000) MCP-1: PTSD (158.37±113.22) and Control (124.04±216.05) (p=0.002) |
| von Känel et al (2007)18 | 28 | 85 individuals with PTSD (63 US military veterans) and 82 individuals without PTSD | Cross-sectional | To determine whether or not pro-inflammatory activity is increased in clinically diagnosed PTSD patients compared to the control group | CRP, IL-6, TNF-α, IL-10, IL-4, IL-1β | Results: median (pg/mL, except for CRP which is in mg/L) CRP: PTSD (1.09) and Control (1.57) (p=0.558) IL-6: PTSD (0.21) and Control (0.14) (p=0.669) TNF-α: PTSD (0.85) and Control (0.82) (p=0.184) IL-10: PTSD (0.97) and Control (1.08) (p=0.335) IL-4: PTSD (0.14) and Control (0.16) (p=0.029) IL-1β: PTSD (0.53) and Control (0.34) (p=0.558) |
| Hovhannisyan et al (2010) 22 | 62 | 31 combat veterans with PTSD and 31 non-PTSD volunteers | Cross-sectional | To measure the functional activity of the complement cascade in PTSD sufferers compared to individuals without PTSD | CH50, C2H50, C3H50, C4H50, AH50, fBH50, fDH50 | Results: mean±SD (units/mL) CH50: PTSD (375±29.52) and Control (176±24.56) (p=0.0002) C2H50: PTSD (67.6±1.63) and Control (58.8±3.1) (p=0.05) C3H50: PTSD (37.57±4.2) and Control (55.92±1.82) (p=0.002) C4H50: PTSD (60.1±7.3) and Control (36.64±7.68) (p=0.03) AH50: PTSD (52.3±3.37) and Control (87.6±2.13) (p=0.0001) fBH50: PTSD (40.8±3.6) and Control (65.2±12.9) (p=0.02) fDH50: PTSD (71.7±3.99) and Control (163.7±24.95) (p=0.001) |
| Bersani et al (2016)19 | 84 | 42 male war veterans with PTSD and 42 male war veterans without PTSD | Cross-sectional | To assess the frequencies of dysfunctional and functional NK-cell subsets | CD56−CD16+, CD56brightCD16−, CD56dimCD16+, CD4+, CD8+, CD4+CD28−, CD4+CD28+, CD8+CD28−, CD8+CD28+ | Results: mean±SD (%) “Discovery Sample” (PTSD N=42 and Control N=42) CD56−CD16+: PTSD (10.76±8.24) and Control (8.00±6.15) (p=0.027) CD56brightCD16−: PTSD (6.32±3.18) and Control (8.78±6.76) (p=0.082) CD56dimCD16+: PTSD (82.75±8.69) and Control (82.96±8.36) (p=0.699) CD4+: PTSD (43.68±9.12) and Control (41.26±9.19) (p=0.137) CD8+: PTSD (21.64±24.44) and Control (24.44±7.15) (p=0.065) CD4+CD28−: PTSD (1.61±2.64) and Control (1.22±2.45) (p=0.457) CD4+CD28+: PTSD (98.36±2.64) and Control (98.77±2.48) (p=0.551) CD8+CD28−: PTSD (22.73±14.15) and Control (26.15±15.49) (p=0.157) CD8+CD28+: PTSD (76.01±14.09) and Control (73.51±15.60) (p=0.313) “Validation Sample” (PTSD N=25 and Control N=30) CD56−CD16+: PTSD (14.44±8.56) and Control (9.00±9.47) (p=0.004) CD56brightCD16−: PTSD (7.00±3.29) and Control (8.67±4.10) (p=0.118) CD56dimCD16+: PTSD (78.37±8.19) and Control (82.12±10.23) (p=0.240) CD4+: PTSD (43.34±9.03) and Control (43.95±6.33) (p=0.629) CD8+: PTSD (23.99±8.96) and Control (24.63±6.72) (p=0.626) CD4+CD28−: PTSD (1.89±4.47) and Control (1.23±2.27) (p=0.346) CD4+CD28+: PTSD (97.70±4.83) and Control (98.76±2.27) (p=0.354) CD8+CD28−: PTSD (29.27±19.19) and Control (20.99±12.69) (p=0.243) CD8+CD28+: PTSD (70.65±19.26) and Control (78.78±12.85) (p=0.068) |
Abbreviations: PTSD, post-traumatic stress disorder; CRP, C-reactive protein; IL: interleukin; TNF-α, tumor necrosis factor-α; INF-γ, interferon-γ; PIC, pro-inflammatory cytokine; IPV, interpersonal violence; MCP-1, monocyte chemoattractant protein-1; CH50, complement classical pathway; C2H50, C2 complement component; C3H50, C3 complement component; C4H50, C4 complement component; AH50, alternative pathway; fBH50, factor B complement component; fDH50, factor D complement component; NK cell, natural killer cell; CD56, neural cell adhesion molecule; CD56brightCD16−, immature NK cell; CD56dimCD16+, mature NK cell; CD4, T lymphocyte; CD8, T lymphocyte; CD4+CD28− and CD4+CD28+, CD4 T-lymphocyte subtypes; CD8+CD28− and CD8+CD28+, CD8 T-lymphocyte subtypes.