Association between perceived social support and Th1 dominance.

Social support is supposed to have a positive health effect via alteration of immunity. In this study, associations between perceived social support and immune systems were examined. Immunological assessments, e.g. T cell count, Natural Killer cell count, Interferon-gamma, Interleukin-4, and psychological assessments, e.g. Generic Job Stress Questionnaire were conducted on male employees. Two-way (social support x job stressor) analyses of covariance controlling for age, smoking, alcohol consumption, and exercise revealed that there were main effects of perceived social support on NK cell counts, IL-4, and Th1/Th2 balance. On the other hand, interaction effects were observed on T cell counts and INF-gamma production in vitro. Social support affects immune function in a way that is consistent with both the direct and buffering hypotheses depending on the sources of support and the immune parameter.

Long-term influence of working abroad on returnees' mental health.

Although international business travel is increasing, there is a lack of research on its repercussions for mental health. This study analysed the long-term influence of international business travel on the mental health status by comparing depression, anxiety and job stress between workers with and without international assignment experience. The subjects were divided into an 'experienced group' composed of 70 male workers who had experienced an overseas assignment of at least six months, and a 'non-experienced group' consisting of 2,163 male workers who had not. To assess the mental health status, Zung's Self-Rating Depression Scale (SDS) and Sheehan's Patient Rated Anxiety Scale (Sheehan) were employed. The Job Content Questionnaire (JCQ) was used to examine job stress. In addition, information about the characteristics of the overseas assignments was collected. The experienced group had significantly higher scores for job control, supervisor support and co-worker support in the JCQ, while no differences were observed for the SDS and Sheehan. Whether or not the subjects travelled abroad with their families, whether or not they went against their will, and whether or not they enjoyed their stay had no effects on their mental health. Job demand had a significantly positive correlation with the duration of the assignment.

Psychological stress increases human T cell apoptosis in vitro.

OBJECTIVES: Recent studies have shown that apoptosis is involved in stress responses. The present study examined if stressors increase in vitro apoptosis of peripheral blood T lymphocytes in a dose-dependent manner. METHODS: Daily subjective stress was quantitatively analyzed in 40 nonsmoking men with a daily hassles questionnaire. Apoptosis of T lymphocytes was measured by flowcytometry using Annexin V/PI double staining method after 0, 12, and 24 h of culture in the presence or absence of dexamethasone (DEX). Using a cross-sectional design, the current study examined the relationship between stress and in vitro apoptosis of T cells. RESULTS: Results showed that apoptosis of T lymphocytes in vitro has a significant correlation with stress and age. Stress was positively correlated with percentage of apoptosis in T cells after 12 h of culture, irrespective of DEX treatment. Age was positively correlated with the percentage of T cell apoptosis after 0 and 12 h of coculture with DEX. CONCLUSIONS: These results indicate that age-related apoptosis and stress-related apoptosis of T cells are modulated through different mechanisms. This is the first study to show that in vitro lymphocyte apoptosis is influenced by daily stress in a dose-dependent manner.

Positive coping up- and down-regulates in vitro cytokine productions from T cells dependent on stress levels.

BACKGROUND: Specific coping styles have been shown to modulate stress-induced immune alterations and influence actual health outcomes. This study examined the effects of stressors and coping styles on human T-cell subpopulations and in vitro cytokine production using a cross-sectional design. METHODS: Seventy-one men (18-60 years old) were asked to complete a self-administered questionnaire that evaluates quantitative workload, mental demand and coping styles. The numbers of T-cell subpopulations and concentrations of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) after stimulation with phytohemaglutinin were measured. RESULTS: Positive and negative coping were negatively related to IL-4 and the number of CD4+ cells, respectively. Interactions between positive coping and mental demand significantly affected the number of CD8+ cells, IFN-gamma, IL-4 and the IFN-gamma/IL-4 ratio. Among men reporting high mental demand, positive coping was related to increased IFN-gamma and IFN-gamma/IL-4. Among men reporting low mental demand, positive coping was related to a decreased number of CD8+ cells and lower concentrations of IFN-gamma and IL-4. Analyses adjusting for the numbers of CD3+ and CD8+ cells revealed that the interactive effects of positive coping and mental demand on cytokine levels were attributable to the changes in T-cell function rather than the number of T cells. No modulating effect of anxiety on the associations of stressors and coping with immune function was observed. Depressive symptoms slightly, though not significantly, modulated the association of negative coping and the number of CD4+ cells. CONCLUSIONS: From the perspective of immunology, optimal stress characteristics were determined by an individual's coping styles, with positive coping being associated with stress-induced changes in the number of CD8+ cells and in vitro cytokine production from T cells. Our findings suggest that it is important to consider the interactive effects of the complexity of work and the individual coping style in stress management.

Coemergence of insomnia and a shift in the Th1/Th2 balance toward Th2 dominance.

OBJECTIVES: Insomnia is associated with physical and mental disorders. We examined the effect of insomnia on immune functions, focusing on the T helper 1 (Th1)/ T helper 2 (Th2) balance, by a cross-sectional design. METHODS: We provided a self-administered questionnaire to evaluate sleep habits, smoking and medical disorders to 578 men without any toxic exposure (20-64 years old), and measured natural killer (NK) cell activity in 324 men and production of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) after stimulation with phytohemagglutinin in 254 men. According to the criteria of DSM-IV, in which insomnia is classified into primary and secondary insomnia, we assessed the effect of insomnia on immune functions, controlling for age and smoking in groups with and without medical disorders. RESULTS: The prevalence of insomnia in the present study was 9.2%. In the absence of medical disorders, insomniac men had a significantly lower IFN-gamma and ratio of IFN-gamma to IL-4 than noninsomniac men. Men with insufficient sleep or difficulty initiating sleep (DIS) had a significantly lower IFN-gamma to IL-4 ratio than those not suffering from insufficient sleep or DIS. In the presence of medical disorders, insomniac men had significantly higher IL-4 than noninsomniac men. Men with difficulty maintaining sleep (DMS) had a significantly lower IFN-gamma to IL-4 ratio than men without DMS. NK cell activity was independent of insomnia. CONCLUSIONS: The present results showed a link between insomnia unrelated to medical disorders and a shift in the Th1/Th2 balance toward Th2 dominance, indicating that the relationship between sleep quality and the etiology of immune-related diseases should be reconsidered.