Personality, endocrine and immune changes after eight months in healthy individuals under normal daily stress

The impact of stress and its neuroendocrine correlates on immune function are well established and individual variations could be attributed to modulation by personality characteristics. To assess the influence of everyday life stress and personality on neuroendocrine and immune function, we administered, to 18 healthy adults, the Minnesota Multiphasic Personality Inventory (MMPI) to assess their personality, the State-Trait Anxiety Inventory to measure anxiety, the Reaction Scheme Test to assess their coping reaction style, the Life Events Survey to assess the impact of stressful life events, and the Subjective Stress Questionnaire to assess perceived stress. The endocrine evaluation comprised prolactin, cortisol, and growth hormone plasma levels, while the immunological evaluation assessed T4, T8, and T11 lymphocyte percentages, as well as natural killer cell count and activity. All evaluations were made at baseline and after 8 months. We found a reduction of the T11 lymphocyte percentage to be accompanied by a reduction in the scores of the MMPI scale of Subtle Defensiveness and by an increase in the scores of the Social Introversion Scale. A positive correlation was found between prolactin and T4 lymphocyte percentage. These preliminary data show that some personality and endocrine measures correlate with immune function.