Increased circulating blood cell counts in combat-related ptsda associations with Inflammation and symptom severity

Background: Cytokine levels are increased in post-traumatic stress disorder (PTSD), but their relationship to circulating blood cell counts is unknown. Methods: 163 male combat-exposed veterans (83 with PTSD and 81 non-PTSD controls) had blood assessed for platelet count, white blood cell (WBC) count, and red blood cell (RBC) count. These data were correlated with symptom severity and with pro-inflammatory markers. Results: Platelet count (p=0.028), WBC (p=0.004) and RBC (p=0.003) were significantly elevated in PTSD. Pro-inflammatory blood markers were significantly correlated with WBC count in both groups (PTSD, r=0.26, p=0.022; controls, r=0.46; p<0.001), platelet count in PTSD subjects only (r=0.32, p=0.004), and RBC count in PTSD subjects and controls combined (r=0.21; p=0.009). PTSD symptom severity ratings were directly correlated with platelet count in the PTSD group (r=0.30, p=0.007). When smoking was entered as a covariate, the between-group differences in cell counts became non-significant, although all correlations between cell counts and PTSD severity and inflammatory markers remained significant, with the exception of the correlation between RBC and inflammatory markers. Conclusions: Patients with PTSD have elevated counts of platelets, WBC and RBC. This is at least partly mediated by smoking status. The association of platelet count with inflammation in PTSD, but not in controls, may relate to the increased pro-thrombotic risk, associated with inflammation, in PTSD. The potential importance of increased platelet counts in PTSD is bolstered by its significant positive correlation with PTSD symptoms severity.