Reduction of immune function in life stress and depression

Reduced primary antibody responses in a genetic animal model of depression

OBJECTIVE

Clinical depression is associated with multiple abnormalities of immune function, including reduced virus-specific responses. This study tested the hypothesis that the Flinders Sensitive Line (FSL) rat, a promising genetic animal model of depression, would exhibit reductions in antigen-specific primary antibody responses to immunization.

METHODS

FSL (N = 13) and control Flinders Resistant Line (FRL; N = 14) rats were immunized with the protein antigen keyhole limpet hemocyanin (KLH; 300 microg/kg), and KLH-specific immunoglobulin (Ig)M, IgG, IgG1, and IgG2a responses were measured before and 3, 5, 7, 11, and 14 days after immunization. In separate experiments, production of interferon-gamma (IFN-gamma) by cells from naive and KLH-immunized animals was measured in vitro to determine whether strain differences in antibody production might be associated with differential production of this regulatory cytokine.

RESULTS

KLH-specific production of IgM (p <.01) and IgG2a (p <.05) was significantly reduced in the FSL rats compared with the FRL controls. There were no strain differences in IgG or IgG1 production. Although IFN-gamma production between the two strains was similar in naive animals, cells from KLH-immunized FSL rats produced significantly less IFN-gamma when stimulated with KLH in vitro than cells from KLH-immunized FRL controls (p =.01).

CONCLUSIONS

This study extends previous reports of altered immune function in the FSL rats to include reduced in vivo antigen-specific antibody responses. Moreover, diminished production of IFN-gamma by KLH-primed lymphocytes may contribute to lower antibody production in these animals. Collectively, these data suggest deficiencies in type 1 T-helper cell-mediated immunity in the FSL rats.

Association of plasma free-3-methoxy-4-hydroxyphenyl (ethylene)glycol, natural killer cell activity and delirium in postoperative patients

We measured and compared levels of plasma free 3-methoxy-4-hydroxyphenyl (ethylene)glycol (pMHPG), a major metabolite of noradrenaline, and natural killer (NK) cell activity in 26 patients prior to their undergoing an operation for cardiovascular diseases; 11 of whom expressed delirium and 15 who did not. In conclusion, we found that pMHPG levels before an operation were higher in patients with postoperative delirium than in the patients without, while NK cell activity showed no difference between the two groups. It is possible that hyperactivity of noradrenargic neurons is connected with the development of postoperative delirium. Furthermore, we considered that measurement of pMHPG level before operation might be a useful tool to predict the occurrence of postoperative delirium.

The relationship of depression and stressors to immunological assays: a meta-analytic review

This is a broad meta-analysis of the relations of both depression and stressors to immunological assays. The number of study samples (greater than 180) and measures (greater than 40) is much more extensive than any so far. Analyses are done by both fixed and random effects. By a fixed-effects analysis, both major depression and naturally occurring acute stressors are associated with (1) an overall leukocytosis, (2) mild reductions in absolute NK-cell counts and relative T-cell proportions, (3) marginal increases in CD4/CD8 ratios, and (4) moderate decreases in T- and NK-cell function. However, the degree of heterogeneity of the studies' results raises questions about their robustness. Therefore, we also did the first random effects analysis to estimate what is likely to appear in future studies. For depression, the analysis showed the immunological correlates included (1) an overall leukocytosis, manifesting as a relative neutrophilia and lymphoenia; (2) increased CD4/CD8 ratios; (3) increased circulating haptoglobin, PGE(2), and IL-6 levels; (4) reduced NK-cell cytotoxicity; and (5) reduced lymphocyte proliferative response to mitogen. For stressors, the random effects analysis showed that future studies are likely to find the following effects: (1) an overall leukocytosis, manifesting as an absolute lymphocytosis; (2) alterations in cytotoxic lymphocyte levels, CD4/CD8 ratios, and natural killer cell cytotoxicity with the direction of change depending on the chronicity of the stressor; (3) a relative reduction of T-cell levels; (3) increased EBV antibody titers; (4) reduced lymphocyte proliferative response and proportion of IL-2r bearing cells following mitogenic stimulation; and (5) increased leukocyte adhesiveness. The random-effects analysis revealed that for both major depression and naturally occurring stressors the following effects are shared: leukocytosis, increased CD4/CD8 ratios, reduced proliferative response to mitogen, and reduced NK cell cytotoxicity. The implications for these findings for disease susceptibility and the pathophysiology of these conditions is discussed.

Anxiety and pain suppress the natural killer cell activity in oral surgery outpatients

OBJECTIVE

Psychological stress has an influence on natural killer cell (NK) activity, which plays a central role in protection against microbial infection and cancer. Anxiety concerning cancer is a typical type of psychological stress observed in patients and is associated with various diseases. In this study, we examined whether anxiety about cancer reduces the NK activity or quality of life (QOL), or both, of outpatients.

PATIENTS AND METHODS

NK activity was determined by means of a 4-hour 51 chromium-release assay, and a QOL questionnaire by the World Health Organization called QOL-BRIEF was also used. One hundred forty-four patients were asked a variety of questions about anxiety with respect to cancer and pain on their first visit to the outpatient clinic of our Department of Oral Surgery.

RESULTS

The NK activity in patients with anxiety about cancer was significantly lower (P < .001) than that in those with no such anxiety. In contrast, NK activity was not influenced by any other factor tested, including differences in diseases and QOL scores.

CONCLUSION

Anxiety about cancer may be one of the primary factors for suppression of NK activity in oral surgery outpatients.

Changes in the immune system in depression and dementia: causal or co-incidental effects?

It is now widely accepted that psychological stress and psychiatric illness can compromise immune function. Furthermore the mechanisms whereby such changes occur are probably associated with the activities of the cytokines and other inflammatory mediators of the immune system which are known to initiate changes in behaviour. This review aims to summarise the experimental and clinical evidence that implicates the pro-inflammatory cytokines in the pathological changes seen in major depression and in Alzheimer's disease (AD). In major depression, evidence is provided to show that both activation (e.g., macrophage activity, acute phase proteins) and inhibition (e.g., natural killer cell activity) of the immune system occur. Many of the behavioural changes seen in depression are simulated by three pro-inflammatory cytokines (IL-1, IL-6 and TNF-alpha), which may produce their impact on the brain by activating cyclooxygenase, nitric acid synthase and corticotrophin releasing factor. Effective antidepressant treatments largely attenuate the immune changes thereby raising the possibility that the normalisation of central biogenic amine function that are conventionally implicated in the cause of depression may be secondary to those of the pro-inflammatory cytokines. With respect to AD, while the cause(s) are unknown, there is both experimental and clinical evidence to suggest that inflammatory processes in the brain caused in particular by TNF-alpha together with the subsequent rise in free radicals, are instrumental in causing the pathological changes which underlie the disease. Evidence in favour of the inflammatory hypothesis is supported by the finding that nonsteroidal anti-inflammatory drugs slow down the progression of the disease.Although, more research is needed into the inter-relationships between the various pro-inflammatory cytokines and the behavioural changes invoked in major depression and AD, the immunological hypothesis has been important in stimulating new concepts regarding the causes of the pathological changes in these diseases and how effective drug treatments may attenuate them.

Social stress in anorexia nervosa: a review of immuno-endocrine relationships

Anorexia nervosa (AN) patients have difficulty in establishing social contacts, leading to tension, anxiety and full-blown stress reactions. Stress hormones are chronically increased in AN, while immune function, which is involved in physical and psychological coping capacities, is mostly unimpaired. We examined immune function in a group of anorexics by measuring the T-lymphocyte proliferative response to stimulation with phytohemagglutinin (PHA), before and after in vivo acute administration of corticotropin-releasing hormone (CRH), to mirror a stress reaction. The responses of anorexics, before and after CRH stimulation, did not differ from those of controls. In a second group of anorexics, we measured plasma concentrations of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) before and after psychopharmacological (fluoxetine, amineptine) therapy. Basal values of the cytokines were not different in patients and controls, and did not change during therapy. In the same patients, we measured basal concentrations of soluble IL-1 beta receptor antagonist (s-IL-1 beta-RA), soluble IL-6 receptor (sIL-6-R) and soluble TNF-alpha receptors I and II (sTNF-alpha-R-I and -II). S-IL-1 beta-RA and sTNF-alpha-R-I and -II levels were not different in patients and controls, while those of s-IL-6-R were lower than normal in anorexics. The normality of most of the immune parameters in our anorexics, in basal conditions, after a stressful stimulation and after pharmacological manipulation of neurotransmitters suggests that the well-known interrelation among immune, neuroendocrine and central nervous system functions is not maintained in AN, the immune system being somehow unresponsive to stimuli.

Changes in Lymphocyte Subsets in Depressed HIV-Infected Patients Without Antiretroviral Therapy

The authors studied the effects of major depression on lymphocyte subsets by comparing depressed and matched control subjects in a population of HIV-seropositive outpatients not treated with antiretroviral therapy. Twelve patients with major depression, as determined by the Structured Clinical Interview for DSM-III-R, were assessed in comparison with 15 matched nondepressed control subjects. Flow cytometric analysis of peripheral blood lymphocyte subsets together with immunological parameters were performed. In HIV-infected patients, major depression was significantly (P=0.001) associated with a reduction in natural killer cell absolute count and percentage. This report suggests that depression may alter the natural killer cell population that provides a cytotoxic defense against HIV infection.

Acute stress enhances while chronic stress suppresses skin immunity. The role of stress hormones and leukocyte trafficking

Delayed-type hypersensitivity (DTH) reactions are antigen-specific, cell-mediated immune responses that, depending on the antigen, mediate beneficial (resistance to viruses, bacteria, fungi) or harmful (allergic dermatitis, autoimmunity) aspects of immunity. Contrary to the widely held notion that stress is immunosuppressive, we have shown that under certain conditions, stress can enhance immune function. DTH reactions can be studied in rats or mice by challenging the pinnae of previously sensitized animals with antigen. Studies have shown that acute stress administered immediately before antigen exposure significantly enhances skin DTH. In contrast, chronic stress significantly suppresses skin DTH. Stress-induced changes in leukocyte distribution may contribute to these bidirectional effects of stress, since acute stress induces a significant mobilization of leukocytes from the blood to the skin, whereas chronic stress suppresses leukocyte mobilization. In order to identify the hormonal mediators of the observed effects of stress, we first showed that adrenalectomy (ADX) eliminates the stress-induced enhancement of DTH. Acute administration (to ADX animals) of low doses of corticosterone and/or epinephrine significantly enhances skin DTH. In contrast, acute administration of high doses of corticosterone, low doses of dexamethasone, or chronic administration of moderate doses of corticosterone, suppress skin DTH. Thus, the timing and duration of stress may significantly affect the nature (enhancing versus suppressive) of the effects of stress on skin immune function. These results suggest that during acute stress, stress hormones may help enhance immune function by informing the immune system about impending challenges (e.g., wounding or infection) that may be imposed by a stressor (e.g., an aggressor). Thus, during acute stress, the brain may send a warning signal to the immune system, just as it does to other fight/flight systems in the body.

Alterations of host defence system after sleep deprivation are followed by impaired mood and psychosocial functioning

In healthy humans, sleep deprivation (SD) has consistently been demonstrated to impair different parameters of the host defence system and of psychosocial functioning. However, the individual timing of these alterations and their possible association have remained unknown so far. We therefore investigated functional measures of the individual host defence system as well as of subjective well-being and psychosocial performance in 10 healthy male adults before and after SD, as well as after recovery sleep. In detail, we examined the number of leukocytes, granulocytes, monocytes, lymphocytes, B cells, T cells, T helper and cytotoxic T cells, natural killer (NK) cells as well as the interleukin-1 beta (IL-1 beta) release from platelets after serotonin (5-HT) stimulation. Mood and psychosocial performance (excitement, energy, ability to work and timidity) were measured by visual analogue scales. Taken together, SD induced a deterioration of both mood and ability to work, which was most prominent in the evening after SD, while the maximal alterations of the host defence system could be found twelve hours earlier, i.e., already in the morning following SD. Our findings therefore suggest an SD-induced alteration of these psychoimmune response patterns in healthy humans preceding deterioration of mood and psychosocial functioning.

Cytokines and chronic fatigue syndrome

Chronic fatigue syndrome (CFS) patients show evidence of immune activation, as demonstrated by increased numbers of activated T lymphocytes, including cytotoxic T cells, as well as elevated levels of circulating cytokines. Nevertheless, immune cell function of CFS patients is poor, with low natural killer cell cytotoxicity (NKCC), poor lymphocyte response to mitogens in culture, and frequent immunoglobulin deficiencies, most often IgG1 and IgG3. Immune dysfunction in CFS, with predominance of so-called T-helper type 2 and proinflammatory cytokines, can be episodic and associated with either cause or effect of the physiological and psychological function derangement and/or activation of latent viruses or other pathogens. The interplay of these factors can account for the perpetuation of disease with remission/exacerbation cycles. A T-helper type 2 predominance has been seen among Gulf War syndrome patients and this feature may also be present in other related disorders, such as multiple chemical sensitivity. Therapeutic intervention aimed at induction of a more favorable cytokine expression pattern and immune status appears promising.

Stress-induced increment on total bronchoalveolar cell count in OVA-sensitized rats

The influence of stress on total leukocyte count from bronchoalveolar lavage (BAL) was investigated in rats sensitized and challenged with ovalbumin (OVA). The animals were injected intraperitoneally with a suspension of OVA plus aluminum hydroxide in 0.9% NaCl (Day 0) and boosted at Day 7 with an identical OVA solution, administered subcutaneously. From the first to the 13th day after sensitization, rats were placed individually in a shuttle box where they received 50 escapable footshocks per day, always preceded by a sound signal (S); the responses that occurred during both S and shocks canceled the stressful stimulation. On Day 14, animals were submitted to a single session of 50 inescapable footshocks, preceded by the same S; immediately after, the animals were submitted to a 1% OVA-inhalation challenge. Results showed high levels of stress in the shocked animals as detected through both ultrasonic vocalizations (UVs) and social interaction test in an open field. Total leukocyte count in BAL from stressed animals (24 h post-OVA challenge) revealed a significant increase in the number of inflammatory cells in comparison to that measured in sensitized, nonstressed challenged rats. These data demonstrate that stress plays a relevant and important role on total bronchoalveolar cell count in OVA-sensitized rats.

Mortality and depressive symptoms in inhabitants of residential homes

It has been hypothesised that there is a relationship between depression and mortality rate. Some earlier studies have confirmed this relationship, but others have not. In the present study the association was examined between depressive symptoms and mortality in the inhabitants of ten residential homes for the elderly in The Netherlands. Four hundred and twenty-four subjects who were not cognitively impaired, and who participated in an intervention study, were included. One year after the initial interview, they were contacted again and it was found that 69 (16.3%) had died. In the initial interview, depressive symptoms and psychological distress were assessed with the Geriatric Depression Scale and the mental health subscale of the MOS-SF-20. The following correlates of depression were assessed: functional impairment, earlier depression, pain, social support, loneliness, and the presence of seven common chronic illnesses. In bivariate analyses no significant relationship was found between depression and mortality, while controlling for living in an experimental or control home. In logistic regression analyses with mortality as the dependent variable and depressive symptoms, demographic variables, and correlates of depression as predictors, no significant relationship between depression and mortality was found either. It is concluded that no evidence was found in this population for a significant relationship between depression and mortality. Mortality was related to measures of social support, to activities of daily living, and to the presence of chronic non-specific lung disease.

DNA repair capacity in healthy medical students during and after exam stress

There has been extensive research into the effects of stress on immune function but little on the effects of stress on DNA repair capacity (DRC), a process central to maintaining a normal cell cycle. Defective DRC is one of the factors responsible for carcinogenesis. In the present study we assessed DRC in healthy medical students during times of high and low stress. Sixteen medical students were evaluated during the third day of a 5-day exam period and then again 3 weeks later, after vacation. At both time points, participants underwent a brief physical examination, had venous blood drawn, and completed questionnaires to identify subjective stress levels. The DRC was assessed by the host-cell reaction assay, which measures nucleotide excision repair capacity. Participants reported significantly higher levels of subjective stress during the exam period than after vacation. DRC was also significantly higher during the exam period than after vacation, suggesting a positive association between subject stress levels and DRC. The results are discussed in relation to previous findings and implications for cancer research.

Inflammation, depressive symptomtology, and coronary artery disease

OBJECTIVE

Many patients feel exhausted or depressed before the onset of an acute coronary event, but little is known about the origin of these feelings. We tested the hypothesis that the depressive symptomatology is associated with a reactivation of latent viruses and inflammation of a coronary vessel.

METHODS

A blood sample was drawn and a biopsy sample was obtained from the coronary lesion of 15 exhausted and 15 nonexhausted patients treated with directional coronary angioplasty because of severe angina. Blood samples were analyzed to measure antibody titers against Chlamydia pneumoniae, cytomegalovirus, and the cytokines interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha. The biopsy sample was analyzed for the presence of IL-1beta and TNF-alpha.

RESULTS

Exhausted/depressed patients had higher antibody titers against cytomegalovirus, higher levels of C. pneumoniae immunoglobulin G, and higher levels of IL-1beta and TNF-alpha. No associations between the mental state of a patient and cytokine mRNA in the biopsy sample were found.

CONCLUSIONS

The findings indicate that the mental state of angioplasty patients is positively associated with serological markers of inflammation. It remains to be seen whether the inflammation causes feelings of exhaustion, whether exhaustion and depression set the stage for inflammation, or whether existing feelings of exhaustion are amplified by the inflammation.

Antidepressants augment natural killer cell activity: in vivo and in vitro

Depressed mood has been associated with reduced natural killer cell activity (NKCA). Further, amelioration of depressive symptoms by pharmacotherapy has resulted in augmented NKCA. Serotonin, an indoleamine implicated in the pathophysiology of affective disorders, enhances NKCA in vitro and lymphocytes possess serotonin transporters and receptors. The present study evaluated NKCA in depressed outpatients before and during treatment with the selective serotonin reuptake inhibitor (SSRI) fluoxetine (Prozac(R)). Further, the SSRIs, fluoxetine and paroxetine (Paxil(R)), were also incubated in vitro with lymphoid cells to evaluate possible direct effects of SSRIs on NKCA. Depressed outpatients were administered fluoxetine (20 mg/day) for 4 weeks. NKCA and severity of depression were evaluated at weeks 0, 1, 2, and 4. Serum concentrations of fluoxetine and norfluoxetine were obtained as well. Mononuclear cells obtained from nonpatient volunteers were incubated with pharmacologic concentrations of fluoxetine or paroxetine and NKCA measured with a standard chromium release assay. Fluoxetine treatment resulted in decreased symptoms of depression and increased serum concentrations of fluoxetine and norfluoxetine. Further, fluoxetine treatment was associated with augmented NKCA in a subgroup of depressed outpatients exhibiting low NKCA at baseline. Fluoxetine had no effect on NKCA in depressed individuals exhibiting high NKCA at baseline. Incubation of mononuclear cells with fluoxetine and paroxetine augmented NKCA in vitro. The enhancing effects of antidepressants on NKCA in vivo and in vitro indicate a possible direct drug interaction with lymphoid cells during pharmacotherapy, suggesting that pharmacologic treatment of depression may result in enhanced immune competence as indexed by enhanced NKCA and that NKCA could be pharmacologically augmented with antidepressants in individuals with compromised immune function.

Stress-induced enhancement of skin immune function: A role for gamma interferon

Contrary to the widespread belief that stress is necessarily immunosuppressive, recent studies have shown that, under certain conditions, stress can induce a significant enhancement of a skin cell-mediated immune response [delayed-type hypersensitivity (DTH) or contact hypersensitivity]. Adrenal stress hormones and a stress-induced trafficking of leukocytes from the blood to the skin have been identified as systemic mediators of this immunoenhancement. Because gamma interferon (IFNgamma) is an important cytokine mediator of DTH, the studies described here were designed to examine its role as a local mediator of the stress-induced enhancement of skin DTH. The effect of acute stress on skin DTH was examined in wild-type and IFNgamma receptor-deficient (IFNgammaR-/-) mice that had previously been sensitized with 2,4-dinitro-1-fluorobenzene. Acutely stressed wild-type mice showed a significantly larger DTH response than nonstressed mice. In contrast, IFNgammaR-/- mice failed to show a stress-induced enhancement of skin DTH. Immunoneutralization of IFNgamma in wild-type mice significantly reduced the stress-induced enhancement of skin DTH. In addition, an inflammatory response induced by direct IFNgamma administration to the skin was significantly enhanced by acute stress. Our results suggest that IFNgamma is an important local mediator of a stress-induced enhancement of skin DTH. These studies are clinically relevant because, depending on the nature of the antigen, DTH reactions mediate numerous protective (e.g., resistance to viral, bacterial, parasitic, and fungal infections) or pathological (e.g., autoimmune reactions and contact sensitivity reactions such as that to poison ivy) immune responses.

Negative life experiences, depression, and immune function in abused and nonabused women

Abuse of women by their intimate partner is a staggering national problem. Abused women have a higher number of medically unexplained somatic symptoms, more functional disability, a lower self-rating of general health, and higher health care utilization when compared to nonabused women. The authors' purpose in this study was to examine differences in occurrences of negative life experiences, level of depression, and T-cell function between abused and nonabused women. The sample consisted of abused women (n = 12) and nonabused women (n = 12). Hypotheses tested were (1) abused women will have more negative life experiences than nonabused women, (2) abused women will have higher levels of depression than nonabused women, and (3) abused women will have reduced T-cell function compared to nonabused women. A cross-sectional cohort design was used to compare differences in negative life experiences, levels of depression, and T-cell function. Independent sample t-tests were performed comparing the abused versus nonabused women on the dependent measures. Significant differences were found between the groups for negative life experiences (LES; t = 2.29, p < 0.05), level of depression (BDI; t = 3.48, p < 0.01), and T-cell function (TMR; t = -5.62, p < 0.01). These findings are descriptive and do not establish causal links. However, this is an inquiry into the psychological and biobehavioral responses of women experiencing abuse and their potential health problems. The study shows that abused women reported more negative life experiences, experienced higher levels of depression, and experienced lower T-cell function when compared with nonabused women.

Ultrastructural and three dimensional aspects of the lymphatic vessels of the absorbing peripheral lymphatic apparatus in Peyer's patches of the rabbit

We studied the absorbing lymphatic peripheral vessels of the Peyer's patches of the small and large intestine of the rabbit by means of light microscopy after injection of Neoprene latex and transmission electron microscopy in order to highlight their topographical distributions to blood vessels as well as the morphologic mechanism of transendothelial passage of the lymphocytes to the lymph. The distribution of absorbing lymphatic vessels originates from the lacteal vessels and the subepithelial mucosal lymphatic network, which continue without interruptions and dilations into the vessels of the interfollicular area which are woven into basket-like networks entwining the medio-basal portion of each lymphoid follicle. The interfollicular area vessels then drain into the large vessels of the tunica submucosa, which in turn drain into the valved precollector vessels of the subserosa by way of intramuscular vessels. TEM revealed the absorbing lymphatic vessels to have a continuous endothelial wall without open junctions, fenestrations, and continuous basal lamina. We observed many lymphocytes wedged in the lymphatic endothelial wall. This underlines the different phases of their migration from the lymphoid tissue in the lumen of the lymphatic vessel. Results of ultrathin serial sections and three dimensional reconstruction of lymphatic vessel segments with included lymphocyte showed the transendothelial passage of lymphocyte, through the "intraendothelial channels."

Time-dependent effects of stressor application on metastasis of tumor cells in the lung and its regulation by an immunomodulator in mice

The effects of the timing of stressor application on transplanted tumor cells and its possible regulation by an immunomodulator was investigated. Male C57 BL/6N mice were subjected to rotational stressor for 7 days relative to tumor cell inoculation: stressor after inoculation of Lewis lung cancer cells, stressor during inoculation and stressor before inoculation. Stressor application and tumor cell inoculation induced transient decreases in body weight, particularly in mice stressed after inoculation. The mice exposed to the stressor during inoculation or before inoculation showed significant increases in the number of metastatic foci relative to control mice. Early administration of an immunomodulator, PSK, significantly attenuated the increase of metastatic foci in stressed mice. The weights of thymus gland and spleen at 14 days after inoculation were similar in the three stressor groups and the control group. Application of the stressor reduced NK cell activity of the normal mice as well as tumor bearing mice. The lowest pre-inoculation NK cell activity was observed in mice stressed for 7 days beginning on the day of inoculation. The NK cell activity decreased in the tumor bearing mice which were stressed at the time of tumor inoculation. Decreased NK cell activity was reversed at day 14 after tumor inoculation. The mice exposed to the stressor after inoculation showed lowest level of NK cell activity relative to mice exposed to the stressor before or during inoculation. The treatment of mice with PSK reduced these changes significantly. The present results suggest that the rotational stress reduces splenic NK cell activity, which may influence the magnitude of tumor metastasis, depending on the time of tumor cell injection. Further, administration of an immunomodulator may counteract the reduction of the NK cell activity.

Immunological alterations in adult obsessive-compulsive disorder

BACKGROUND

Some recent findings suggest the involvement of autoimmune mechanisms in childhood onset of obsessive-compulsive disorder (OCD), on the basis of a parallel drawn with Sydenham's chorea, a manifestation of rheumatic fever. A monoclonal antibody called D8/D17 characterizing a B-lymphocyte antigen, present in almost all patients with rheumatic fever, has been found also in children affected by OCD, Tourette syndrome, and chronic tics to a greater degree than in healthy control subjects. The few observations of disturbances of some immunologic parameters in adult OCD patients, prompted the authors to investigate and compare subsets of peripheral immunological cells for differences in adult patients with OCD and healthy control subjects.

METHODS

Twenty patients suffering from OCD, with no comorbidity for other psychiatric disorders, were compared with a similar group of healthy control subjects. The immune subsets were measured by flow cytometry.

RESULTS

The CD8+ lymphocytes were significantly increased and CD4+ lymphocytes significantly decreased in OCD patients, while the other cells did not differ between the two groups. No correlation was found between immunologic and clinical parameters.

CONCLUSIONS

These data indicate that patients with adult OCD showed increased CD8+, i.e., suppressor T lymphocytes, and decreased CD4+, which identify helper T lymphocytes, as compared with a similar group of healthy control subjects. The findings appear peculiar to patients with OCD and are suggestive of an immunologic imbalance, which might be related to the stress deriving from the frustrating situation determined by the disorder itself.

Immune correlates of depression

The relation of depression to immunological assays is complex and variable. However, meta-analyses have demonstrated that depressed subjects are likely to show changes in several immune assays. Depressed subjects are likely to have changes in major immune cell classes with an increase in total white blood cell counts and a relative increase in numbers of neutrophils. However, the relative number of lymphocytes is likely to be reduced in depressed subjects. Depression also appears to be associated with increases in at least one measure of immune activation, although further investigations are clearly needed to replicate these interesting observations. Finally, depression is reliably associated with a suppression of mitogen-induced lymphocyte proliferation and with a reduction of NK activity. Despite the heterogeneity of findings, the effect sizes in the relationship between depression and lymphocyte proliferation and NK activity are large as compared to those observed in other areas of psychological and medical research. Several moderating factors may explain and account for the heterogeneity that has been found in the depression-immune results. Future immunologic studies in depressed subjects are needed to clarify the effects of gender and reproductive hormones on the relation between depression and immunity. Severity of melancholic symptoms and sleep disturbance appear to moderate the immune changes in depression but the biological mechanisms that account for the link between these neurovegetative symptoms and depression are not yet known. Finally, assessment of co-morbidity in depressed subjects deserves an increased focus. Data generated from our laboratory clearly show that assessment of alcohol- and tobacco dependence is critical in the interpretation of immune changes in depressed subjects. The clinical significance of changes in immune responses in depressed subjects remains an unanswered question. Studies that use immune measures with disease specific endpoints, as has been recently conducted in the study of VZV immune responses, would help identify the possible link between depression, immune system alterations, and health outcomes.

Reduction of natural killer cytotoxic activity in major depression: interaction between depression and cigarette smoking

OBJECTIVE

Epidemiological data suggest that the presence of a depressed mood combined with cigarette smoking increases the risk of cancer at sites associated with smoking and at sites not associated with smoking. This study tested the hypothesis that major depression and smoking together contribute to a decline of natural killer cell (NK) activity, an immune parameter thought to be important in immune surveillance.

METHODS

A sample of 245 men were stratified into four groups: control subjects who were not smokers, control subjects who were smokers, subjects with major depression who were not smokers, and subjects with major depression who were smokers. Blood samples were obtained for measurement of total white blood cell (WBC) counts, differential cell counts, and assay of NK activity.

RESULTS

Major depression and cigarette smoking interact and were together associated with changes in WBC counts and NK activity. Depressed subjects who were smokers had higher WBC counts (p < .001) and lower NK activity (p < .01) than depressed nonsmoking subjects. However, WBC counts and NK activity were similar in control smokers and nonsmokers. Backward elimination regression analyses showed that the interaction of depression and smoking significantly (p < .001) predicted WBC counts and NK activity.

CONCLUSIONS

This study extends previous findings of immune alterations in patients with major depression. Major depression and smoking interact and together contribute to an elevation of total WBC count and a decline of NK activity.

Stressful events, pessimism, natural killer cell cytotoxicity, and cytotoxic/suppressor T cells in HIV+ black women at risk for cervical cancer

OBJECTIVE

This study examines whether stressful negative life events and pessimism were associated with lower natural killer cell cytotoxicity (NKCC) and T cytotoxic/suppressor cell (CD8+CD3+) percentage in black women co-infected with human immunodeficiency virus Type 1 (HIV-1) and human papillomavirus (HPV), a viral initiator of cervical cancer.

METHOD

Psychosocial interviews, immunological evaluations, and cervical swabs for HPV detection and subtyping were conducted on 36 HIV+ African-American, Haitian, and Caribbean women.

RESULTS

Greater pessimism was related to lower NKCC and cytotoxic/suppressor cells after controlling for presence/absence of HPV Types 16 or 18, behavioral/lifestyle factors, and subjective impact of negative life events.

CONCLUSIONS

A pessimistic attitude may be associated with immune decrements, and possibly poorer control over HPV infection and increased risk for future promotion of cervical dysplasia to invasive cervical cancer in HIV+ minority women co-infected with HPV.

Emotion and immunity

Earlier studies have suggested that depression is associated with decreased immune function, but a recent literature review has revealed that a majority of studies reached inconsistent or conflicting conclusions. On the other hand, studies on immune function in anxiety disorders are sparse, and their findings are also inconsistent. Despite a few contradictory results, a clinical level of anxiety seems to reduce immune function, whereas a subclinical level of anxiety seems to enhance immunity. The latter may be a transient phenomenon occurring prior to the downregulation of immune function, reflecting the body's defense to a stressor. Thus, research needs to be conducted to elucidate the relationship between those hormones related to hypothalamic-pituitary-adrenal axis and a variety of immune measures at the subclinical level of anxiety. In addition, to confirm the interaction between emotion and immune function, the effectiveness of treatment with medication and psychotherapy on immunity should be investigated.

Alzheimer caregiver stress: basal natural killer cell activity, pituitary-adrenal cortical function, and sympathetic tone

The association between Alzheimer caregiving and natural killer (NK) cell activity and basal plasma levels of adrenocorticotropic hormone (ACTH), cortisol, beta-endorphin, prolactin, epinephrine, norepinephrine, and neuropeptide Y was determined in 100 spousal Alzheimer caregivers and 33 age- and gender-comparable control volunteers upon intake into a study of the psychological and physiologic impact of caregiving. The relationship between these physiologic measures and individual characteristics such as age, gender, medical status, severity of stress, severity of depressive symptoms, and caregiver burden was tested. In addition, the association between NK activity and alterations of the neuroendocrine measures was investigated. As compared to controls, the Alzheimer caregivers had similar levels of NK activity and of basal plasma neuroendocrine hormones and sympathetic measures. While older age and male gender status were associated with increased levels of ACTH, neither medical caseness, severity of life stress, nor severity of depressive symptoms was associated with alterations in any of the multiple physiologic domains. Classification of Alzheimer caregiver burden identified caregivers who were mismatched in terms of the amount of care they were required to provide and the amount of respite time received. The mismatched caregivers had significantly higher basal plasma ACTH but no change in other physiological measures, as compared to non-mismatched caregivers. NK activity was negatively correlated with plasma levels of neuropeptide Y but not with any of the other neuroendocrine measures. Based on this cross-sectional evaluation of NK activity and neuroendocrine and sympathetic measures, we conclude that most Alzheimer caregivers do not show evidence of altered basal physiology.

Attendance at religious services, interleukin-6, and other biological parameters of immune function in older adults

OBJECTIVE

First, to examine and explain the relationship between religious service attendance and plasma Interleukin-6 (IL-6) levels, and second, to examine the relationship between religious attendance and other immune-system regulators and inflammatory substances.

METHODS

During the third in-person interview (1992) of the Establishment of Populations for Epidemiologic Studies of the Elderly (EPESE) project, Duke site, 1718 subjects age sixty-five or over had blood drawn for analysis of immune regulators and inflammatory factors, including IL-6 measurements. IL-6 was examined both as a continuous variable and at a cutoff of 5 pg/ml. Information on attendance at religious services was available from the 1992 interview and two prior interviews (1986 and 1989).

RESULTS

Religious attendance was inversely related to high IL-6 levels (> 5 pg/ml), but not to IL-6 measured as a continuous variable. Bivariate analyses revealed that high religious attendance in 1989 predicted a lower proportion of subjects with high IL-6 in 1992 (beta-.10, p = .01) High religious attendance in 1992 also predicted a lower proportion of subjects with high IL-6 levels in 1992 (beta-.14, p = .0005). When age, sex, race, education, chronic illnesses, and physical functioning were controlled, 1989 religious attendance weakened as a predictor of high IL-6 (beta-.07, p = .10), but 1992 religious attendance retained its effect (beta-.10, p = .02). When religious attenders were compared to non- attenders, they were only about one-half as likely to have IL-6 levels greater than 5 ng/ml (OR 0.58, 95% CI 0.40-0.84, p < .005). Religious attendance was also related to lower levels of the immune-inflammatory markers alpha-2 globulin, fibrin d-dimers, polymorphonuclear leukocytes, and lymphocytes. While controlling for covariates weakened most of these relationships, adjusting analyses for depression and negative life events had little effect.

CONCLUSIONS

There is a weak relationship between religious attendance and high IL-6 levels that could not be explained by other covariates, depression, or negative life events. This finding provides some support for the hypothesis that older adults who frequently attend religious services have healthier immune systems, although mechanism of effect remains unknown.

Circulating lymphocyte phenotypic surface markers in anxiety disorder patients and normal volunteers

BACKGROUND

Although the relationship between stress and immune function is an area of active investigation, there have been few reports studying the relationship between anxiety disorders and the immune system.

METHODS

This study employs flow cytometry to measure circulating lymphocyte phenotypic markers in 20 medication-free patients with panic disorder, 33 medication-free patients with generalized social phobia, and 32 healthy controls.

RESULTS

Both patients with panic disorder and patients with social phobia had increased CD16 (natural killer) cell numbers. Panic disorder patients also had increased numbers of CD19 cells (B lymphocytes), human leukocyte antigen (HLA)-DR-presenting cells, and more cells with the combination of HLA-DR and CD19 surface markers (B lymphocytes with HLA-DR on their surface).

CONCLUSIONS

These preliminary data suggest that subjects with panic disorder may have alterations in circulating lymphocyte profiles.

Depression, stress and immunological activation: the role of cytokines in depressive disorders

Traditionally, both stress and depression have been associated with impaired immune function and increased susceptibility to infectious and neoplastic disease. However over the last number of years a large body of evidence suggests that major depression is associated with signs of immunological activation. Moreover it has been suggested that cytokine hypersecretion may be involved in the aetiology of depressive disorders. The present article reviews the evidence from both clinical and experimental studies which implicates immunological activation and particularly hypersecretion of cytokines in the onset and maintenance of depressive illness. Both clinical and experimental studies indicate that stress and depression are associated with increased circulating concentrations of cytokines such as IL-1beta, IL-6 and gamma-IFN and positive acute phase proteins, and hyperactivity of the HPA-axis. In addition, it has been reported that immunological activation induces "stress-like" behavioural and neurochemical changes in laboratory animals. Although for many years it has been suggested that stress acts a predisposing factor to depressive illness, the precise mechanisms by which stress-induced depressive symptoms occur are not fully understood. Nevertheless, behavioural changes due to stress have often been explained in terms of changes in neurotransmitter function in the brain. In the present article increased cytokine secretion is implicated as a mechanism whereby stress can induce depression.

Stress and sensitization in children: a controlled prospective psychophysiological study of children exposed to international relocation

This controlled prospective study investigated the development of sensitization as a result of international relocation in children, using the analyzing system Phadiatop. The effects of climate and predisposition to allergy were also measured. Children were examined prior to and during their first year of living abroad. A control group living at home was also examined during the same period. Participants answered a questionnaire before and after 1 year abroad, and blood samples were collected to determine sensitization. Before going abroad, there were no significant differences in atopic sensitization between groups nor in other key variables. After 1 year abroad, the proportion of children showing sensitization had increased significantly as compared with the control group at home. The exposed group reported an increase in skin symptoms during the year abroad. This study suggests that unidentified factors associated with foreign relocation increase the risk of sensitization in predisposed children. Stress might be one factor.

Glucocorticoid regulation of natural cytotoxicity: effects of cortisol on the phenotype and function of a cloned human natural killer cell line

The ability of glucocorticoids to suppress cellular immune functions, including the cytotoxic activity of natural killer cells, is well known. However, the molecular mechanism(s) of glucocorticoid-mediated suppression of cellular cytotoxicity mediated by natural killer cells is not understood. We have investigated the effects of cortisol on protein expression and cytotoxic function of natural killer cells using NK3.3, a well-characterized, cloned human natural killer cell line. Cortisol, at concentrations up to 2 microM, does not significantly alter the viability or proliferative capacity of NK3.3 cells. However, micromolar concentrations of cortisol induce the expression of a small set of proteins which are not synthesized by NK3.3 cells in the absence of cortisol, and repress the synthesis of another set of proteins including several phenotypic determinants and cytokines. In the presence of added cortisol, the synthesis of perforin mRNA was partially repressed. However, the most striking effect of cortisol on this NK clone was its repression of granzyme A synthesis. In conjunction with the downregulation of adhesion proteins, NK3.3 cells cultured in the presence of cortisol exhibit a reduced capacity to form conjugates with K562 target cells. Whereas cortisol treatment of NK3.3 cells causes an approximately 50% decrease in their ability to form conjugates with K.562 target cells, the cytotoxic function of these cells is completely abolished under the same conditions. This first report of hormonal regulation of granzyme expression and the strong correlation between granzyme A repression and cytotoxic function suggests that cortisol may regulate NK function by repression of granzyme A synthesis. In addition to demonstrating the significant influence of cortisol on natural killer cell function, these studies provide a model system for elucidation of molecular mechanism(s) whereby glucocorticoids repress cellular immune function, especially with respect to natural killer cells.

Depressive states and health problems in caregivers of the disabled elderly at home

This study investigated the prevalence of depression and health problems in caregivers for the disabled elderly at home, and identified factors associated with the risk of depression. Four hundred thirty-four caregivers for disabled elderly persons in a suburban city were surveyed by in-home interviews. Two hundred ten non-caregivers were also interviewed as an age and gender-matched control group. Overall, 16.8% of caregivers met the DSM-III-R criteria for major depression and 10.6% met the criteria for depressive disorders not otherwise specified, for a total of 27.4% meeting the criteria for affective disorders, while 8.6% of controls met the criteria for depressive disorders not otherwise specified. The prevalence of major depression in caregivers was associated with mental problems and ADL limitations of the elderly. Moreover, non-cooperation by other family members or relatives contributed to an increase in the prevalence of depression. Caregivers who met the criteria for major depression had a higher frequency and longer duration of upper respiratory infections than other caregivers or controls, and showed greater fatigue than the other caregivers or controls. Approximately 90% of caregivers who met the criteria for major depression had also insomnia. Overall, it was shown that caregivers who met the criteria for major depressin had not only emotional distress but also higher morbidity.

Cytokine production in obsessive-compulsive disorder

Cytokine production was previously demonstrated to be reduced in untreated major affective patients. In addition, recovery from depression following clomipramine (CMI) treatment was accompanied by the restoration of interleukin-1 beta (IL-1 beta) and interleukin-3-like activity (IL-3-LA) to normal range. In the present study we assessed the in vitro production of IL-1 beta IL-2, and IL-3-LA by peripheral blood mononuclear cells (PBMC) in 11 nondepressed patients with obsessive compulsive disorder (OCD) before and after 8 weeks of CMI treatment. Results were compared with those of 11 healthy subjects. CMI treatment induced a significant improvement in OCD symptoms. No alteration was observed in cytokine production in OCD patients before treatment as compared to control subjects. Moreover, 8 weeks of drug treatment had no effect on cytokine production. In conclusion, OCD per se, as well as CMI treatment, have no effect on interleukin production as measured in this study.

Variations of lymphocyte subsets associated with stress in depressive populations

Major depression and dysthymia have been associated with increased perception of day-to-day stressors, greater reliance on emotion-focused coping efforts, and reduced perception of uplifting events. Moreover, it has been observed that levels of circulating natural killer (NK) cells were elevated in depressed patients. Given that mild stressors may increase circulating NK cells, it is conceivable that the elevated NK cells in depression may be secondary to the increased stress perception associated with the illness. In the present investigation a laboratory stressor, comprising a mathematical challenge, increased circulating NK cells; however, the extent of the increase was comparable in depressive, dysthymic and control subjects. Moreover, the increased NK cells induced by the stressor procedure appeared to be independent of variations of plasma cortisol, ACTH or norepinephrine. Interestingly, although the NK changes were not differentially influenced by stressors in the subject populations, in the major depressive patients correspondence existed between NK cell levels and emotion-focused coping styles. Likewise, the response to a laboratory stressor was directly related to the severity of depression and to the use of coping styles involving cognitive restructuring or problem solving.

Viral serologies in patients with chronic fatigue and chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is an illness characterized by disabling fatigue associated with complaints of fevers, sore throat, myalgia, lymphadenopathy, sleep disturbances, neurocognitive difficulties, and depression. A striking feature of CFS is its sudden onset following an acute, presumably viral, illness and the subsequent recurrent "flu-like" symptoms. It has been speculated that both CFS and debilitating chronic fatigue (CF) that does not meet strict criteria for CFS may be the direct or indirect result of viral infections. We therefore tested 548 chronically fatigued patients who underwent a comprehensive medical and psychiatric evaluation for antibodies to 13 viruses. Our objectives were to compare the seroprevalence and/or geometric mean titer (GMT) of antibodies to herpes simplex virus 1 and 2, rubella, adenovirus, human herpesvirus 6, Epstein-Barr virus, cytomegalovirus, and Cox-sackie B virus, types 1-6 in patients with CF to healthy control subjects. Other goals were to determine if greater rates of seropositivity or higher GMTs occurred among subsets of patients with CFS, fibromyalgia, psychiatric disorders, a self-reported illness onset with a viral syndrome, and a documented temperature > 37 degrees C on physical examination. Differences in the seroprevalence or GMTs of antibodies to 13 viruses were not consistently found in those with CF compared with control subjects, or in any subsets of patients including those with CFS, an acute onset of illness, or a documented fever. These particular viral serologies were not useful in evaluating patients presenting with CF.

Mortality after the death of a spouse: rates and causes of death in a large Finnish cohort

OBJECTIVES

This study examines excess mortality among Finnish persons after the death of a spouse, by sex, the subject's cause of death, duration of bereavement, and age.

METHODS

The subjects were 1580000 married Finnish persons aged 35 through 84 years who were followed up from 1986 through 1991.

RESULTS

Excess mortality among the bereaved was high from accidental, violent, and alcohol-related causes (50% to 150%), moderate for chronic ischemic heart disease and lung cancer (20% to 35%), and small for other causes (5% to 15%). Excess mortality was greater at short ( < 6 months) rather than long durations of bereavement and among younger rather than older bereaved persons for most causes of death; it was also greater among men that women.

CONCLUSIONS

The results are consistent with the hypothesis that excess mortality after the death of a spouse is partly caused by stress. The loss of social support or the inability to cope with stress may explain why men suffer from bereavement more than do women.

Psychosocial modulation of cytokine-induced natural killer cell activity in older adults

The objective of this study was to address the cellular and psychological mechanisms underlying previously observed changes in natural killer (NK) cell cytotoxicity associated with chronic stress. We compared 28 current and former spousal caregivers of patients with Alzheimer's disease (AD) and 29 control subjects. NK cells were enriched (E-NK) using a 4-step procedure that resulted in a cell preparation consisting of 88.2% NK cells. These cells were then incubated with either recombinant interferon-gamma (rIFN-gamma) or recombinant interleukin-2 (rIL-2) for 65 hours. Although an average of over 3 years had elapsed since the death of the patient with AD for the former caregivers, current and former caregivers did not differ in the E-NK cell responses to rIFN-gamma and rIL-2. However, the E-NK cell response for the combined caregiver group was significantly suppressed compared with controls, which is consistent with a previous report from our laboratory. Higher E-NK cell responses to each cytokine were associated with heightened levels of positive emotional and tangible social support, independent of levels of depression. Preliminary data suggest that defects of NK cell function in response to rIFN-gamma and rIL-2 as a consequence of caregiver stress may be independent of non-NK cells. Finally, our data are consistent with other studies regarding the role of social support in immune modulation.

Health psychology: psychological factors and physical disease from the perspective of human psychoneuroimmunology

This review addresses the importance of studies of human psychoneuroimmunology in understanding the role of psychological factors in physical illness. First, it provides psychologically and biologically plausible explanations for how psychological factors might influence immunity and immune system-mediated disease. Second, it covers substantial evidence that factors such as stress, negative affect, clinical depression, social support, and repression/denial can influence both cellular and humoral indicators of immune status and function. Third, at least in the case of the less serious infectious diseases (colds, influenza, herpes), it considers consistent and convincing evidence of links between stress and negative affect and disease onset and progression. Although still early in its development, research also suggests a role of psychological factors in autoimmune diseases. Evidence for effects of stress, depression, and repression/denial on onset and progression of AIDs and cancer is less consistent and inconclusive, possibly owing to methodological limitations inherent in studying these complex illnesses, or because psychological influences on immunity are not of the magnitude or type necessary to alter the body's response in these cases. What is missing in this literature, however, is strong evidence that the associations between psychological factors and disease that do exist are attributable to immune changes.

Increased serum interleukin-1-receptor-antagonist concentrations in major depression

Recently, it has been shown that major depression may be accompanied by an increased production of interleukin-1 beta (IL-1 beta), an acute phase (AP) response and simultaneous signs of activation and suppression of cell-mediated immunity. The interleukin-1-receptor antagonist (IL-1-rA) is released in vivo during an AP response and serum levels are increased in many immune disorders. The release of IL-1-rA may limit the pro-inflammatory effects of IL-1. This study has been carried out to examine serum IL-1-Ra in 68 depressed subjects (21 minor, 25 simple major and 22 melancholic subjects) vs. 22 normal controls. Depressed subjects showed significantly higher serum IL-1-rA concentrations than healthy controls. 29% of all depressed subjects had serum IL-1-rA levels higher than the mean value +2 standard deviations of normal controls; 44% depressed subjects had IL-1-rA values greater than 0.215 ng/ml with a specificity of 90%. In depressed subjects, there was a significant and positive relationship between serum IL-1-rA and severity of illness. In depression, there were no significant relationships between serum IL-1-rA concentrations and indicants of hypothalamic-pituitary-adrenal (HPA)-axis activity, such as 24-h urinary cortisol and postdexamethasone cortisol values. Women had significantly higher serum IL-1-rA levels than men. The findings support the thesis that depression is accompanied by an immune-inflammatory response.

Lymphocyte subsets associated with major depression and dysthymia: modification by antidepressant treatment

Major depression and dysthymia (chronic, low grade depression) were associated with an increase in the number of CD16/56 (natural killer; NK) cells in blood, whereas other lymphocyte subsets (CD3, CD4, CD8, CD19, and the CD4/CD8 ratio) did not differ from control subjects. After treatment with a specific serotonin reuptake inhibitor, the symptoms of depression were alleviated in both the major depressive and dysthymic patients. Likewise, NK cell numbers declined to control values in these treated groups. Among the major depressive patients, the NK cell number reached control values within 4 weeks, whereas 6 months of treatment was required for such an effect to be achieved in the dysthymic patients. Although plasma levels of epinephrine, norepinephrine, cortisol, and ACTH were not different between groups, among the major depressive patients ACTH was inversely correlated with total lymphocytes, CD3, and CD19, and epinephrine was directly related to the CD4 and CD4/CD8 ratio. Among dysthymics, ACTH was unrelated to any of the lymphocyte subsets, but norepinephrine was directly related to total lymphocytes, CD3, CD4, and NK cells. The data are interpreted in terms of stress perception among major depressive and dysthymic patients and the potential impact of stressor experiences on immune processes.