Higher abnormal leukocyte and lymphocyte counts 20 years after exposure to severe stress: research and clinical implications.

OBJECTIVES: Research suggests that individuals with posttraumatic stress disorder (PTSD) are more likely to develop medical conditions and other stress-related psychiatric disorders. Given these findings and others suggesting that PTSD victims may have altered neuroendocrine and immune systems, the hypothesis that Vietnam veterans with PTSD have abnormally high leukocyte and lymphocyte counts was tested.

METHODS: The leukocyte and lymphocyte status of male Vietnam "theater" veterans with current partial posttraumatic stress (N = 286), anxiety (N = 274), and depression disorders (N = 192) were compared with those of Vietnam veterans without these disorders 20 years after military service (N = 2190), controlling for intelligence, race, age, income, education, type of enlistment, Vietnam volunteer status, region of birth, cigarette smoking, illicit drug use, body mass index, and alcohol consumption. Abnormal values were defined using standard laboratory reference ranges. Adjusted mean differences also were compared.

RESULTS: Based on the results of two-tailed tests, PTSD-positive veterans are more likely to have adjusted leukocyte (OR = 1.83, p = .04) and T-cell (OR = 1.82, p = .045) counts above the normal range and higher mean adjusted leukocyte (p = .042), lymphocyte (p = .01), T-cell (p = .008), and CD4 cell (p = .027) counts. Those with anxiety disorders have adjusted lymphocyte (OR = 1.68, p = .048) and T-cell (OR = 2.06, p = .011) counts above range. They also have test results indicating reactive delayed cutaneous hypersensitivity (OR = 1.77, p = .006), which suggests the presence of highly sensitized T-cell lymphocytes. Finally, depressed veterans are less likely to have B-cell counts above the reference range (OR = 0.55, p = .006). Results of one-tailed tests further suggest that PTSD-positive men also have abnormally high CD4 and CD8 T-cell lymphocyte counts as well (p < .05).

CONCLUSIONS: Our findings suggest that chronic, primarily combat-related PTSD is associated with clinically elevated leukocyte and total T-cell counts. Those with current anxiety also have some of these abnormalities in addition to highly sensitized T-cell lymphocytes. Additional research is needed to specify the mechanisms involved here and to investigate the health risks associated with these findings.