Impaired lymphocyte function in depressive illness

Antiphospholipid, antinuclear, Epstein-Barr and cytomegalovirus antibodies, and soluble interleukin-2 receptors in depressive patients

To determine whether depression might be associated with serologic indices of autoimmune processes or active virus infections, we measured the following parameters in healthy controls, minor, simple major and melancholic patients: antiphospholipid (anticardiolipin, antiphosphatidylserine), antinuclear, and Epstein-Barr (EBV) and cytomegalovirus (CMV) antibodies. In addition, the soluble interleukin-2 receptor (sIL-2R) circulating levels in serum were measured and used as a marker of T cell activation. The anticardiolipin antibody titers were higher in melancholics than in healthy controls and minor depressives. Antinuclear antibodies were present significantly more frequently in depressed patients than in normal volunteers. The anticardiolipin and antinuclear antibody titers were significantly and positively intercorrelated. Depression is characterized by increased serum circulating levels of sIL-2Rs compared to the healthy state. Antinuclear-positive subjects exhibited significantly higher sIL-2Rs than those without detectable antinuclear titers. There was a positive correlation between anticardiolipin activity and sIL-2Rs. We found no evidence that depression is linked to EBV or CMV infection.

Social psychology of the immune system: a conceptual framework and review of the literature

The literature on psychosocial factors affecting the immune system is reviewed. The literature is summarized in terms of a provisional model accounting for immunosuppression in terms of four mutually influential explanatory constructs (dysphoric responses; immunosuppressive behaviors; adverse life experiences; and vulnerability) and the relationships among the diverse manifestations of the constructs. The literature and the summary provisional model point to directions for future research that should establish the intervening role of immunosuppression in the relationships between psychosocial factors and the disease process.

In vivo and in vitro effects of glucocorticoids on lymphocyte proliferation in depression

Twelve severely depressed patients and 13 healthy controls were studied under baseline, metyrapone and metyrapone plus dexamethasone pretreated conditions. Lymphocyte proliferation data were obtained by concanavalin A, phytohaemagglutinin and pokeweed mitogen (PWM) stimulation. There was a decrease in PWM-induced B-cell proliferation and an increase in inhibition of spontaneous leucocyte proliferation by dexamethasone added in vitro following metyrapone administration in vivo, in healthy controls, which was not present in the depressed patients. These data support the concept of a decreased functional plasticity of the glucocorticoid receptor in depression also at the cellular level.

Immunosuppression in mice induced by cold water stress

A number of studies indicate that stress can result in suppression of the immune system in animals and man. Most of the studies have focused on alterations of lymphocyte function while only a few have investigated alterations of macrophage function or macrophage cytokine production. Macrophages play an essential role in homeostasis of the immune response. Indeed, the earliest events of the immune response occur in cells of the monocytic lineage, and their secretion of various cytokines may have both immunological and nonimmunological effects. The present studies were undertaken to determine whether alterations in macrophage physiology occur in mice subjected to a stress stimulus. Our studies in mice exposed to cold water stress for 4 days indicated reduced numbers of thymocytes and splenocytes, decreased T-cell blastogenesis, and reduced NK activity. Examination of elicited peritoneal macrophages from stressed mice revealed increased prostaglandin E2 (PGE2) secretion and decreased immune region associated antigen (Ia) expression in response to interferon-gamma. Despite elevated PGE2 levels, indomethacin was generally unable to restore depressed immune function. Of special interest was the finding that cell-associated and secreted interleukin 1 were significantly higher from unstimulated elicited macrophages from stressed mice. These results suggest that early in the response to stress, functions of a variety of cells within the immune system, especially macrophages, are altered and that dysregulated macrophage function may well contribute to the generalized suppression of the immune response in cold water stressed mice.

Facial pain, distress, and immune function

Chronic facial pain syndromes are associated with high levels of distress and depression. Immune system measures were investigated in otherwise healthy patients suffering from chronic temporomandibular pain and dysfunction syndrome (TMPDS) and in matched controls. No mean differences were found between TMPDS patients and the controls on any of the immune measures; however, both ConA and PWM responses in TMPDS patients were decreased in relation to the level of demoralization (P less than 0.05). Cognitive symptoms such as low self-esteem and perceptions of helplessness/hopelessness were implicated in these effects. In addition, among patients pain severity was independently associated with decreased ConA response (P less than 0.05). The data suggest possible correlates of stress-induced changes in the immune system.

Abnormal zymosan-induced neutrophil chemiluminescence as a marker of depression

Preliminary studies have shown that polymorphonuclear neutrophil (PMN) activity is decreased in a state-dependent manner in patients with endogenous depression. The present study investigates this finding in a larger group of psychiatric patients and attempts to determine the identification of the factor responsible for the abnormal neutrophil function. Chemiluminescence responses of PMNs from patients with diagnoses of endogenous depression, panic disorder, anxiety, schizophrenia and alcoholism were assessed concurrently with age- and sex-matched control subjects. The reduction in PMN activity was observed in panic disorder patients as well as during depression but remained normal in schizophrenia, alcoholism and generalised anxiety. The defect in PMN function appears to be related to an abnormal factor in the serum of the patient which is corrected on clinical recovery. Aspirin-inhibited prostaglandin synthesis resulted in an enhancement of PMN activity in healthy subjects, suggesting a possible role for prostaglandins in the abnormal PMN response.

Decreased density of benzodiazepine receptors in lymphocytes of anxious patients: reversal after chronic diazepam treatment

Peripheral-type benzodiazepine receptors were measured in human circulating lymphocytes using 3H-PK 11195 as specific ligand. In a group of outpatients with anxiety disorders a significant decrease of receptor density (-37%) was found compared with age-matched controls. In these patients long-term diazepam treatment restored binding density to normal levels: the effect persisted after drug withdrawal. Acute i.v. diazepam administration did not change receptor density. The observed receptor changes could reflect a down-regulation phenomenon and indicate that lymphocyte function reflect central nervous events.

Effects of stress on the immune system

Stress, distress and a variety of psychiatric illnesses, notably the affective disorders, are increasingly reported to be associated with immunosuppression. The concept that psychic distress may predispose to medical illness is centuries old but has only recently attracted the attention of the scientific community at large. Interdisciplinary collaboration has established psychoneuroimmunology, or neuroimmunomodulation, as a new field of investigation with the goal of rigorous scientific research into the elusive mind-body connection. This has resulted in the rapid accumulation of information which falls across the boundary lines of psychiatry, immunology, neurosciences and endocrinology. Here David Khansari, Anthony Murgo and Robert Faith review the effects of stress on the endocrine and central nervous systems and the interactions between these systems and the immune response after exposure to stress signals.

Motivational syndromes associated with natural killer cell activity

This article reports three studies that taken together support two hypotheses: (a) that the stressed power motivation syndrome is associated with relatively low natural killer cell activity (NKCA) and (b) that the unstressed affiliation motivation syndrome is associated with higher NKCA. In Study 1, college students who were relatively high in stressed power motivation had significantly lower NKCA than did their peers. In addition, students high in unstressed affiliation motivation had significantly greater NKCA than did those showing less evidence of this syndrome. Study 2 replicated these findings on a sample of middle-class men. In Study 3, which tested the hypotheses among adult patients from a Health Maintenance Organization, results were in the same direction but less significant. Meta-analyses clearly indicate that the combined evidence from the three studies reliably supports both hypotheses.

Measurement of cortisol and lymphocyte subpopulations in depressed and conduct-disordered adolescents

Lymphocyte subpopulations were analyzed in 11 adolescents with major depressive disorder, 11 with conduct disorder, and eight normal age-matched subjects. No significant differences were noted on any T or B cell measure between the groups. Further, no significant correlations were found between any cortisol measure (baseline cortisol, post-dexamethasone cortisol, urinary free cortisol) and any lymphocyte measure in either depressed or conduct-disordered adolescents. The negative findings in this small sample contrast with those reported in adult patients and suggest that an aging effect may be associated with the immunological changes reported in older depressed patients.

Psychoneuroimmunology: An area of interest for the psychopharmacologist?

Anecdotal evidence suggesting a causal relationship between psychiatric illness, environmental stress and a malfunctioning immune system goes back to antiquity. Recently, clinical and experimental studies have established the interrelationship between neuro- endocrine regulation, the immune system and abnormalities in central neurotransmission which may be deranged as a consequence of stressful events. This short review is an attempt to assess the evidence implicating altered immune responsiveness in depression and to consider the impact of different types of environmental stress in triggering the immune malfunction. While these findings are of considerable biological importance, it is presently unclear whether the immunological changes are primary or secondary to the disease states.

Human psychoneuroimmunology today

Studies in human psychoneuroimmunology began around 1919, but a systematic approach wasn't used until the work of Solomon in the 1960s. Recently, the new specialty has achieved relative independence due to considerable data acquisition. Stress research has revealed relationships between neuroendocrine and immune changes. In parallel, increasing evidence of immunological alterations in psychiatric diseases has expanded the field; presently, immunological correlates of psychosomatic diseases and personality are sought. On the other hand, while immunological disease has been psychologically assessed for many years, a clear-cut link between psyche and immunological changes has yet to be shown. This fact, along with the therapeutic implications of advancing knowledge, will influence strongly the future trends of psychoneuroimmunology. Concepts emerging from the study of this field will be of heuristic value to both psychiatry and immunology and will help define new and expanded limits for both disciplines.

The presence of antithyroid antibodies in patients with affective and nonaffective psychiatric disorders

We determined the frequency of antithyroglobulin and antimicrosomal antibodies in 173 consecutively admitted psychiatric inpatients. (We found antithyroid antibodies in 8% (5/65) of patients with DSM-III major depression, 13% (4/31) with biploar disorder, and in 0% (0/4) of those with schizoaffective disorder.) The rate of antibody occurrence was unrelated to lithium exposure either within individual diagnostic categories or for the sample as a whole. The overall frequency of positive antithyroid antibody titers in patients with DSM-III affective disorder, 9% (9/99), did not differ from that in patients with nonaffective disorders, 10% (7/68). However, patients with bipolar affective disorder-mixed or bipolar affective disorder-depressed had a higher rate of positive antithyroid antibody titers than other patients. Our findings confirm earlier reports that thyroid disorders may be particularly common in patients with bipolar affective disorder, even in the absence of lithium exposure. However, as antithyroid antibodies also occurred at a relatively high rate in nonaffective disorders, the possible psychiatric effects of autoimmune thyroiditis do not appear to be limited to affective dysregulation.

Reduction of immune function in life stress and depression

Reduced cell-mediated immune function has been found in depressed patients and in distressed persons undergoing threatening life events. The present study examines the interaction between severe life stress and major depression to produce immune alterations in 36 matched pairs of hospitalized depressed patients and nondepressed controls. Both major depressive disorder and the presence of threatening life events in control subjects are independently associated with a 50% reduction of natural killer (NK) cytotoxicity. A decrease in natural cytotoxicity is significantly associated with depressive symptoms but not with age, alcohol consumption, or tobacco smoking. These findings of altered immunity provide further evidence that the physiological responses in chronic stress parallel those found in the syndrome of depression.

Impaired lymphocyte stimulation by mitogens in severely depressed patients. A complex interface with HPA-axis hyperfunction, noradrenergic activity and the ageing process

To investigate the relationships between the immune apparatus, major depression, and HPA-axis and noradrenergic activity, the authors measured the lymphocyte stimulation responses to the mitogens phytohaemagglutinin (PHA), pokeweed mitogen (PWM) and concanavalin A (CON A), post-dexamethasone cortisol (DST) values and 3-methoxy-4-hydroxyphenylglycol (MHPG) excretion in 24-hour urine samples from 48 patients. We found that lymphocyte responses to PHA and PWM in melancholic and psychotic depressives were significantly lower than in minor depressives. The lymphocyte responses to PHA, PWM and CON A showed significantly negative correlations with age, DST results and HRSD score. Responses to PHA were significantly negatively correlated with MHPG excretion. Up to +/- 33% of the variance in the three mitogenic lymphocyte responses could be explained by canonical correlation with age, DST results and MHPG values.

The effect of antidepressants on immune function in mice

Depression or its treatment with antidepressant agents may have an impact on the normal function of the immune system. To address this issue in an animal model, we studied the effect of maprotiline and desipramine treatment of mice on several immunological activities associated with host resistance to cancer and infections. Our results indicate that chronic maprotiline treatment depressed natural killer (NK) cell function, measured in vivo as clearance of tumor cells from the lung or in vitro as cytolytic activity. Cell-mediated immunity, measured as delayed hypersensitivity in vivo and T and B lymphocyte proliferative responses in vitro, was largely unaffected. Although antidepressant toxicity at high concentrations inhibited T, B, and NK cell activity, it is unlikely that this is the basis for the in vivo effects.

Lymphocyte subpopulations in depressed elderly women

Dexamethasone Suppression Tests (DST) and measurement of lymphocyte subpopulations were conducted in 21 medically healthy elderly women with major depressive disorder and 77 healthy elderly women volunteers. Depressed women revealed significantly reduced absolute lymphocytes (p less than 0.01), T cells (p less than 0.01), and T helper cells (p less than 0.02) compared to normal elderly women. Of the depressed women, 50% had positive DSTs (postdexamethasone cortisols greater than 5 micrograms/dl) compared to 5.4% of the normal women (p less than 0.0001). Within the depressed group, patients with positive DSTs had significantly reduced absolute lymphocytes (p less than 0.05) and T helper cells (p less than 0.025) compared with depressed women who had normal DSTs. Further, a significant negative correlation was found between postdexamethasone cortisols (at both 4:00 and 11:00 PM) and absolute lymphocyte count and T helper cells. These data suggest that the hypercortisolemia seen in some patients with major depressive disorder is sufficient to alter leukocyte distribution in the peripheral circulation, particularly that of the T helper cell subset. The association between cortisol and lymphopenia appears to be more pronounced in an elderly population than in younger depressed patients.

Immune cell parameters in severely depressed patients: negative findings

Cross-sectional population studies reported decreased mitogen-induced lymphocyte responsiveness in severely depressed patients. This immunologic impairment, indicative of T- and/or B-cell dysfunction, was related to disturbances in the dexamethasone suppression test (DST) and to age effects. Glucocorticoid overdrive, a hallmark for severe depression, exerts immunosuppressive effects through the impact on neutrophils, lymphocytes, and monocytes and natural killer cells (NKC). This paper has analyzed the relation of peripheral blood immune parameters to severe depression, DST results and age. The population consisted of 37 inpatients categorized according to DSM-III as minor depression (300.40, 309.00), simple major depression (296.X2) or major depression with melancholia and/or with psychotic features (296.X3, 296.X4). The number of leukocytes, neutrophils, lymphocytes and monocytes was counted. T-cell (total T-cell, T-helper, T-suppressor, HLA-DR), B-cell (LN1 and immunoglobulin (Ig) receptors), monocytes (M1 and M3 membrane antigens) and NKC activity were identified by phenotype using monoclonal antibodies. No differences were detected between the depressive subgroups for any of the parameters examined. There were no relationships between these immune variables and the severity of illness, DST results or age.

Effect of music-assisted imagery on neutrophils and lymphocytes

The purpose of this study was to determine the effects of cell-specific mental imagery on neutrophil and lymphocyte cell counts. Subjects (N = 30) were randomly assigned to one of two experimental groups that underwent a 6-week training program focusing on images of morphology, location, and movement of either neutrophils or lymphocytes. Music was used to enhance the imagery of the subjects. Peripheral white blood cell and differential counts were determined before and after the final 20-minute imagery session. Results indicated that neutrophils decreased significantly (p less than .04) in the neutrophil-change group while lymphocytes did not. The reverse occurred in the lymphocyte-change group, with only the lymphocytes decreasing significantly (p less than .03). The authors concluded that under the conditions of the present study, cell-specific imagery was associated with decreases in peripheral blood cell counts of lymphocytes and neutrophils.

Lymphocyte function in major depression

Immunologic function as measured by lymphocyte response to phytohemagglutinin (PHA) mitogen was evaluated in 8 psychiatric inpatients. All were less than 45 years of age and had a DSM-III diagnosis of major depression. When patient's immunologic responses were compared with healthy age- and sex-matched controls, a significant increase in PHA mitogen stimulation was observed in the depressed group. Further, a significantly greater variance in PHA response was observed in the patients compared with controls. The literature on depression and immunity is reviewed and the clinical implications of our findings are discussed.

Lymphocyte mitogenesis, immunoglobulin and complement levels in depressed patients and normal controls

The central nervous system and the immune system are closely related. Psychiatric illness is often associated with a dysregulation of the immune response. In an attempt to expand on previously reported immune abnormalities in patients with depressive illness, we compared several immune measures in a group of hospitalized depressed patients and healthy normal controls. Depressed patients had significantly higher percentages of circulating neutrophils, significantly lower percentages of circulating lymphocytes and significantly lower in vitro lymphocyte responses to mitogenic stimulation than normal controls. Basal plasma cortisol and circulating levels of the complement components C3 and C4 were also higher in the depressed group. We also found a significant association between cortisol values and the traffic of leukocytes on the one hand, and complement levels and the lymphocyte mitogenic activities on the other. These findings expand previously reported evidence of immune abnormalities in depressive illness and provide a partial explanation for some of these findings.

Epstein-Barr virus as a cause of autoimmune disease and other medical morbidity in patients with affective disorders

We hypothesize that psychiatric patients suffering from the major affective disorders (depression and manic-depressive illness) may commonly also suffer from a chronic active infection with the Epstein-Barr virus. This infection would be a consequence of the immune dysfunction known to be associated with these disorders of mood. According to this hypothesis, the increased medical morbidity and mortality reported in these psychiatric patients would be attributable in part to diseases in which Epstein-Barr virus is implicated or suspected as a cause.

Mitogen-stimulated lymphocyte proliferation and pituitary hormones in major depression

To assess cellular immune status and the hypothalamic-pituitary (HP) axis in patients with major depression, we examined peripheral blood mononuclear cells (PBMC) and measured the plasma levels of cortisol, adrenocorticotropin hormone (ACTH), growth hormone (GH), and prolactin (PRL). Twenty patients with major depression were compared with 20 control subjects matched for age, sex, and race. The dose-response curves for concanavalin-A (Con-A) and phytohemagglutinin (PHA) stimulation were not significantly different between the two groups. The patients had decreased Con-A-stimulated T-lymphocyte proliferation when compared to the control subjects, but only at the lowest suboptimal concentration of Con-A. None of the four concentrations of PHA-stimulated proliferation were different between the two groups, neither was PHA-induced interleukin-2 production. Within the patient group only, plasma prolactin (PRL) correlated significantly with stimulated lymphocyte proliferation using two optimal concentrations of PHA and one optimal concentration of Con-A, when the proliferation was expressed using the stimulation index.

Impaired mitogen-induced lymphocyte responses and the hypothalamic-pituitary-adrenal axis in depressive disorders

The lymphocyte stimulation responses to the mitogens phytohemagglutinin (PHA), concanavalin A (Con A) and pokeweed (PWM) were investigated in 30 hospitalized depressed women undergoing a dexamethasone suppression test (DST). Patients were classified according to DSM-III as having major depression with melancholia, without melancholia, and minor depression. The Hamilton Depression Rating Scale (HDRS) and the State-Trait Anxiety Inventory (STAI) were measured. Patients with major depression showed significantly decreased lymphocyte stimulation induced by PHA, Con A, and PWM as compared to those with minor depression. These differences could not be attributed to age, body weight, weight loss, total number of leukocytes, menopausal status, sleep disturbances, concomitant use of low-dosage benzodiazepines or length of drug-free period before testing. The group mean differences in lymphocyte stimulation counts were not affected by the severity of illness or the severity of state and trait anxiety. There were no significant differences in the lymphocyte responses to PHA, Con A, and PWM between DST non-suppressors and DST suppressors. No significant correlations were established between baseline and post dexamethasone cortisol values and the lymphocyte stimulation counts.

Reduced natural killer cell activity in major depression: neuroendocrine implications

Natural killer cell activity (NKCA) was significantly reduced in a group of depressed patients, melancholic subtype, compared to sex- and age-matched controls. Corticotropin and cortisol values were significantly higher in the depressed subjects than in the controls, but no correlation between high hormone levels and low immunological activity was found in the patients.

Viruses, immunity and mental disorder

Are viruses the cause of mental illness, or does stress or mental disorder produce impaired immunity, with increased susceptibility to infection? These two separate but not unrelated questions have been debated periodically and there has been much renewed interest recently, with increased sophistication in immunology and widespread topical concern about immunodeficiency. The neuropsychiatry of the acquired immunodeficiency syndrome (AIDS) (Snider et al, 1983; Carne & Adler, 1986; Wortis, 1986; Burton, 1987; Fenton, 1987) and the validity of a ‘post-viral fatigue syndrome’ as a clinical entity (Behan, 1983; Southern & Oldstone, 1986; Dawson, 1987; David et al, 1988) are not discussed here, but have been dealt with in the editorials and reviews cited.

Current perspectives on immunology and psychiatry

We selectively review recent research findings in the field of psychoimmunology which test the hypotheses that immunological dysfunction may be aetiologically related to mental illnesses such as schizophrenia, and that certain morbid affective states such as depression and other forms of psychosocial distress may be the cause of immunosuppression and through this mechanism affect the outcome of illnesses such as cancer. Our examination of research implicating immunological or infective mechanisms in the aetiology of schizophrenia indicates that most studies have been unable to control for major methodological difficulties but the compatibility of these theories with the dopamine hypothesis suggests that further research attention is warranted. More clearly, there is growing evidence demonstrating a link between depression, other states of psychological distress and immunosuppression, but the clinical significance of these findings remains uncertain. The complex relationship between stress and the outcome of illnesses such as cancer is discussed and the possible implications of these findings for clinical psychiatry are suggested.

Confirmation of the relationship of HLA (chromosome 6) genes to depression and manic depression. II. The Ontario follow-up and analysis of 117 kindreds

HLA typing was conducted on 577 family members of 86 families having at least two first-degree family members with a lifetime history of major depression or bipolar disorder. The results were combined with a follow-up study of 10 Newfoundland kindreds and with the data obtained from our previous studies, giving a total cohort of 117 families of diverse ethnic and geographic origin. There was increased sharing of HLA haplotypes, as compared with random expectation, over all possible pairwise comparisons both in the follow-up studies (P less than 0.025) and in the total data (P less than 0.01). The increase in HLA haplotype sharing over random expectation was greater if comparisons within heavily loaded sibships (by prior convention, sibships with three or more affected siblings) were omitted from the analysis (P less than 0.002). There was also non-random transmission of HLA haplotypes in 50 families selected for a low-load, unaffected parent (P less than 0.005). Thus, we conclude that genes in the HLA region of chromosome 6 constitute one of the elements in the multifactorial etiology of affective disorder. This conclusion does not depend on any assumption concerning genetic heterogeneity or epistasis or on specific modes of transmission, penetrance values or linkage distances. In addition, the data suggest that chromosome 6 region genes may have a different effect in unipolar and bipolar illness.

Cellular immunity and the hypothalamic-pituitary axis in major affective disorder: a preliminary study

To assess cellular immune status and the hypothalamic-pituitary axis in patients with major depression, we examined peripheral blood mononuclear cells and measured the plasma levels of four neurohormones. Eleven patients with major depression had increased % of T4 lymphocytes and decreased concanavalin (Con A) stimulated T lymphocyte proliferation when compared with 11 age-, sex-, and race-matched control subjects. Percent of total lymphocytes labeled as all T lymphocytes, all B lymphocytes, and natural killer cells did not differ in the two groups, nor did mitogen-induced interleukin-2 production. These findings support theories of interaction between depression and immune cell function.

Increased level of salivary prostaglandins in patients with major depression

We quantified the amounts of salivary prostaglandin (PG) D2, PGE2, and PGF2 alpha by radioimmunoassay in 32 patients with major depressive disorder, 16 patients with minor depressive disorder, 24 patients with neurotic disorders (panic, generalized anxiety, phobic, somatization, and obsessive compulsive), and 28 healthy controls. In the saliva of patients with major depressive disorder, the concentrations of immunoreactive PGs (PGD2, 385 +/- 71 pg/ml; PGE2, 498 +/- 105 pg/ml; PGF2 alpha, 444 +/- 100 pg/ml) were significantly higher than those of the healthy controls (PGD2, 129 +/- 18 pg/ml; PGE2, 207 +/- 25 pg/ml; PGF2 alpha, 164 +/- 17 pg/ml). On the other hand, the salivary concentrations of immunoreactive PGs from patients with minor depressive disorder or neurotic disorders were comparable to those of the controls. These results suggest that the level of salivary PGs may be an indicator of major depressive disorder.

Major depression and immunity: preliminary evidence of decreased natural killer cell populations

1. Alterations in cellular immunity have been suggested to occur in major depressed patients. 2. To investigate the populations of B-cells, T-cells and T-cell subsets in major depression, the authors utilized monoclonal antibody techniques to enumerate the number of total lymphocytes, B-cells and T-cell subpopulations in recently admitted patients with major depression or non-affective disorders. 3. The authors also studied the relationship between the immune state and hypercortisolism as measured by post-dexamethasone serum cortisol. 4. The preliminary findings from this pilot study suggest that major depressed patients may have altered cellular immunity as demonstrated by lower numbers of natural killer cells. 5. Further study will be necessary to confirm the trend for lower numbers of T-cell lymphocytes and T-cell subpopulations including helper cells, suppressor cells and natural killer cells in patients with non-suppression of serum cortisol following dexamethasone.

Age, cellular immunity and the HP axis in major depression

1. To assess the effect of age on cellular immune status and the HP axis in patients with major depression, we examined peripheral blood mononuclear cells (PBMC) and measured the plasma level of four neurohormones. 2. In 36 subjects, decreasing T lymphocyte response to con A covaried with age. Percent of lymphocytes labeled as T8 lymphocytes tended to decrease and T4/T8 ratio tended to increase with increasing age. 3. Hamilton and Beck scores were significantly different between the two sex and race matched groups of 18 depressed patients and 18 control subjects, and plasma prolactin was significantly higher in depressed subjects. 4. Increasing age correlated with decreasing T lymphocyte response to con A in the combined group of all subjects, and in the control group, but not in the patient group. 5. Hamilton and Beck scores correlated inversely with T lymphocytes response in the combined group of all subjects. 6. Differences in mitogen responsiveness between patient and control groups were not found, having been obscured by the effect of age. 7. These findings indicate the need to age match subjects when studying the interaction between depression and immune cell function.

Low natural killer cytotoxicity in major depression

Natural killer cell cytotoxicity was significantly lower in a group of hospitalized depressed men than in matched controls. The absolute number of neutrophils was increased in the depressed group, but the numbers of other cell types did not differ between groups. These findings further demonstrate that altered immunity is a biologic concomitant of affective disorders.

Lymphocyte numbers in endogenous depression

The blood counts of 80 patients with depression were examined (50 unipolar, 30 bipolar). Many had reduced numbers of circulating lymphocytes. This abnormality was more common in the unipolar group (52%) than in the bipolar group (27%). When those patients with an abnormal dexamethasone suppression test response in both groups were compared, the relative and absolute lymphocyte counts were significantly lower in unipolars. Although cortisol hypersecretion may reduce lymphocyte numbers it is not yet clear whether the findings can be satisfactorily explained in this way.