Depression, immunocompetence, and prostaglandins of the E series

Increased neopterin and interferon-gamma secretion and lower availability of L-tryptophan in major depression: further evidence for an immune response

There is now some evidence that major depression may be accompanied by an immune response. The latter condition is suggested by elevated secretion of neopterin and interferon-gamma (IFN gamma) and by lower L-tryptophan (L-TRP) plasma levels. This study investigated the plasma levels of neopterin, L-TRP, and the L-TRP/competing amino acids (CAA) ratio in 30 normal control subjects and 47 depressed subjects (16 minor depressed, 13 simple major depressed, and 18 melancholic subjects), and IFN gamma secretion by mitogen-stimulated peripheral blood mononuclear cells in 7 normal control subjects and 13 major depressed subjects. Plasma neopterin levels were significantly higher in depressed subjects than in normal controls; 61% of melancholic patients had increased neopterin levels (> or = 7 nmol/l) with a specificity of 90%. Patients with major depression had significantly lower L-TRP and L-TRP/CAA values compared with normal control subjects. The amino acid values were significantly and negatively correlated with plasma neopterin levels. Major depressed subjects exhibited significantly higher IFN gamma secretion than did normal control subjects. The results further support the hypothesis that major depression is accompanied by an immune response and that the lower L-TRP availability in that illness may be an epiphenomenon of immune activation.

Natural killer cell activity in major depression: relation to circulating natural killer cells, cellular indices of the immune response, and depressive phenomenology

1. Recently, blunted natural killer cell activity (NKCA) has been found in major depression. The present study investigates the relationships between ex vivo blunted NKCA in major depression, number or percentage of NKC, in vivo indices of systemic immune activation and depressive phenomenology. 2. Toward this end, NKCA, absolute number of leukocytes and number or percentage of lymphocytes, monocytes, neutrophils, activated T lymphocytes (HLA-DR+, CD25+) and NKC (CD3-CD56+) were determined in 13 normal controls and 36 depressed inpatients. 3. NKCA was significantly and positively related to number and percentage of NKC in the peripheral blood. The major depression-related reduction in NKCA was not related to alterations in peripheral NKC. There were significant negative correlations between NKCA and number or percentage of leukocytes, monocytes, neutrophils and HLA-DR+ T cells. Up to 50% of the variance in NKCA could be explained by the regression on the number of monocytes, percentage of HLA-DR+ T and NKC cells, and diagnostic classification. Up to 43% of the variance in NKCA was explained by depressed mood, somatic anxiety and less diurnal variation. 4. The results show that blunted NKCA in major depression is not related to alterations in peripheral NKC, but reflects in part the systemic immune activation in that illness.

Dysphoria and immune status in postpartum women

This study investigated the relationship between psychological factors and circulating immune cell populations in postpartum women. The study group was 75 women who had vaginal deliveries and were free of psychotropic medication. Four days postpartum each subject completed three mood questionnaires, and a small blood sample was taken. All questionnaire scores were shown to be highly inter-correlated and principal component factor analysis revealed a single factor which we term dysphoria. This factor was significantly associated with lower total circulating lymphocyte counts. The effect was strongest for T cells (largely attributable to a reduction in CD4+ ve T helper cells) and weaker for NK cell counts. No evidence was found of a mediating role for serum cortisol although serum cortisol levels were weakly related to immune status. This study has thus demonstrated that changes in the distribution of the lymphocyte pool are associated with relatively minor differences in postpartum affect.

Relationships between increased haptoglobin plasma levels and activation of cell-mediated immunity in depression

Recently, it was found that major depression is accompanied by an acute phase (AP) response with increased haptoglobin (Hp) plasma levels and various indices of systemic immune stimulation. The present study has been carried out in order to determine the relationships between hyperhaptoglobinemia and indices of systemic immune activation in severe depression. Toward this end, the authors investigated the relationships between Hp levels and number of leukocytes, monocytes, neutrophils, lymphocytes, and activated T lymphocytes (CD25+, HLA-DR+), in depression. Hp plasma levels were significantly higher in major depressed subjects as compared to healthy controls and minor depressives. There was a significant positive correlation between Hp levels and severity of illness. Hp plasma levels showed significant and positive relationships with the absolute number of leukocytes, neutrophils, monocytes, CD25+ and HLA-DR+ T cells. Up to 35% of the variance in Hp levels could be explained by the regression on the number of neutrophils and HLA-DR+ T cells. The results show that hyperhaptoglobinemia in major depression is significantly related to activation of cell-mediated immunity.

Neutrophil and monocyte phagocytosis in depressed patients

1. Monocyte and neutrophil phagocytosis was investigated in a group of depressed patients during the active phase of their illness and following recovery. The results were compared with those obtained from a group of schizophrenia and manic patients and with age and sex matched controls. Neutrophil phagocytosis was reduced in all three patient groups during the active phase of the illness but returned to control values on recovery. Monocyte phagocytosis was however increased but while it returned to control values following recovery of the depressed patients, it remained raised in the manic and schizophrenic patients. 2. T-cell replication in response to a mitogen challenge was also investigated in the depressed patients. This was found to be significantly reduced in the depressed patients during the active phase of the illness and remained reduced following their recovery. 3. The results suggest that the changes in phagocytosis and T-cell replication are state and trait markers respectively of depression. 4. A differential white blood cell count revealed that the neutrophil number was increased and the monocytes decreased, in the depressed patients during the active phase of the illness, but returned to normal values on recovery. 5. The factor(s) responsible for the changes in these various aspects of the immune function is unknown. However, evidence is presented that the changes are not due to hypercortisolaemia or to the direct effects of the psychotropic medication on phagocytosis or T-cell replication.

A review on the acute phase response in major depression

There is some evidence that major depression is characterized by systemic immune activation with involvement of phagocytic cells, T cell activation, B cell proliferation and increased autoantibody production. This paper reviews that major depression may be accompanied by higher concentrations of positive and lower concentrations of negative acute phase proteins (APPs). The most prominent abnormalities of APPs in major depression are increased haptoglobin (Hp) plasma levels. The latter are significantly and positively correlated with interleukin (IL)-6 production, various indices of systemic immune activation (e.g. monocytosis, neutrophilia, T cell activation) and with the vegetative symptoms of depression (e.g. anorexia, weight loss, psychomotor retardation, sleep disorders, anergy). Major depression is characterized by an altered distribution of Hp phenotypes and genes suggesting that genetic variation on chromosome 16 may be associated with this illness. It is concluded that increased production of IL-6 and IL-1 in major depression may underlie both immune activation and the "acute" phase response in that illness, and that disorders in Hp may be related to the pathophysiology and pathogenesis of major depression.

Depression, adrenal steroids, and the immune system

During the past decade, over 30 studies have examined the immune system in depression. While a number of investigators have reported depression-related alterations in peripheral blood immune cell number and function, many researchers have been unable to replicate these findings. The relationship between depression and the immune system has turned out to be much more complex than was initially anticipated. Factors which have complicated the interpretation of the research include the heterogeneity of depressed patients, the variability of immune assays, and the clinical relevance of these assays. In this review we conclude that alterations in the immune system do not appear to be a specific or reproducible biological correlate of depression but may occur in association with other variables which characterize depressed patients including age, sex and severity of depression. Conceptual frameworks for future research on the immune system and depression are discussed and include: (i) depression as a cofactor in the development, course and outcome of diseases involving the immune system; (ii) depression as a neuroimmunological disease; and (iii) depression as a model for studying neuroendocrine-immune interactions in humans. In terms of this third line of research, patients with depression consistently have been shown to display abnormalities in the secretion of adrenal steroids, and new data is presented which indicates that adrenal steroids may play a much more complex role in the modulation of the immune response than has been previously appreciated.

Relationships between interleukin-6 activity, acute phase proteins, and function of the hypothalamic-pituitary-adrenal axis in severe depression

Recent studies from this laboratory have provided some evidence that major depression, in particular melancholia, may be accompanied by an immune response. The present study was designed to investigate whether severe depression is characterized by increased interleukin-6 (Il-6) activity and whether Il-6 production is related to altered levels of acute phase reactants and to abnormal function of the hypothalamic-pituitary-adrenal (HPA) axis. Measurements were made in 8 healthy control subjects and 24 depressed inpatients of Il-6 production in culture supernatants of mitogen-stimulated peripheral leukocytes and plasma levels of haptoglobin (Hp), transferrin (Tf), and postdexamethasone cortisol. Il-6 activity was significantly higher in melancholic subjects than in healthy control subjects and in patients with minor depression or nonmelancholic major depression. Il-6 production was significantly correlated with Hp (positively) and Tf (negatively) plasma levels. There were significant and positive correlations between Il-6 activity and postdexamethasone cortisol values. The findings may suggest that increased Il-6 activity in severe depression is related to hypotransferrinemia, hyperhaptoglobinemia, and hyperactivity of the HPA axis.

Psychomotor retardation, anorexia, weight loss, sleep disturbances, and loss of energy: psychopathological correlates of hyperhaptoglobinemia during major depression

Recently, we have established that major depression is characterized by hyperhaptoglobinemia, which may be regarded as an index of an "acute" phase response in that illness. The present study investigates the psychopathological correlates of increased plasma concentrations of haptoglobin (Hp) in major depression. To this end, the authors studied the Hp levels in relation to depressive items of the Structured Clinical Interview for DSM-III (SCID) and the Hamilton Rating Scale for Depression (HRSD) in 90 depressed subjects. There was a significant positive relationship between the SCID symptoms anorexia/weight loss, sleep, and psychomotor disorders and Hp plasma concentrations. Hp plasma levels were significantly and positively correlated with overall severity of illness (HRSD). The HRSD symptom correlates of higher Hp levels were loss of interest, middle insomnia, and psychomotor retardation. Up to 31.4% of the variance in Hp plasma values could be explained by psychomotor disorders, anorexia, weight loss, middle insomnia, and less diurnal variation of mood. It is suggested that hyperhaptoglobinemia, as an index of an "acute" phase response in major depression, is related to the somatic dimension of depressive illness.

Immune disorders in depression: higher T helper/T suppressor-cytotoxic cell ratio

This study investigated the leukocyte T helper and T suppressor-cytotoxic cell (sub)set profile of minor, simple major and melancholic depressives versus normal controls. Using both monoclonal antibody staining and flow cytometry, we determined the absolute numbers and percentages of the following T cell immune subsets: T helper (CD4+), T virgin (CD4+CD45+), T memory (CD4+CD45-), T suppressor/cytotoxic (CD8+), CD8+ T suppressor (CD8+CD57-) and CD8+ T cytotoxic (CD8+CD57+) cells. After computing the CD4+/CD8+ ratio, we detected a significantly increased ratio in depressed patients as compared with healthy controls. Depression per se is characterized by a higher percentage of CD4+ and a lower percentage of CD8+CD57- cells. Melancholic depressed subjects exhibit a significantly increased number of CD4+ and CD4+CD45- cells. The combined use of various percentages of CD4+ and CD8+ (sub)sets yields a high degree of marker positivity for melancholia: through cumulative evaluation of those percentages, the marker positivity increases to 68% (sensitivity) and the specificity is 95%. These results together with our previous reports may refer to a depression-related state of T cell activation.

Immunological variability associated with experimentally-induced positive and negative affective states

Functional and phenotypic immunological parameters were examined immediately before, after, and 30 minutes after experimentally-induced short-term positive (happiness) and negative (anxiety, depression) affective states and a neutral state, in five healthy subjects. Results indicated that all affective states induced more immune fluctuations (regardless of the direction) than the neutral state. Furthermore, among the affective states, anxiety induced the most immunological variability and depression the least.

Prostaglandins and premenstrual syndrome

We examined plasma PGF2 alpha, PGE, PGE2, TXB2 and 6-keto-PGF1 alpha at intervals throughout 3 menstrual cycles in 20 patients with PMS. Similar measurements throughout 1 menstrual cycle were made in 12 age-matched control women. The plasma concentration of PGF2 alpha in the late luteal phase was significantly lower in patients with PMS compared with that in the control subjects. The plasma concentrations of PGE in the middle follicular phase and middle luteal phase, PGE2 alpha in the middle follicular phase and TXB2 in the middle and late luteal phase were significantly higher in 20 patients compared with the values in the controls. A disturbance of PG metabolism may contribute to the etiology of PMS.

A study on the blunted natural killer cell activity in severely depressed patients

Recently, some investigators have established a blunted natural killer cell activity (NKCA) in severely depressed patients. In order to replicate these findings NKC cytotoxicity assays--on fresh cell suspensions in human plasma and fetal calf serum--were performed in healthy controls and depressed inpatients. Instead of the commonly used 51Cr-release assay we have used a fluorescent NKC cytotoxicity assay, which allows a greater sensitivity. We observed a significantly blunted NKCA in melancholic patients as compared with healthy controls and minor depressives, whilst simple major depressives exhibited an intermediate position. NKC cytotoxicity assays in fetal calf serum were significantly and negatively correlated with the severity of illness. We were unable to establish any relationship between NKCA and measures of hypothalamic-pituitary-adrenal-axis function, such as baseline, postdexamethasone plasma cortisol and 24 hr urinary cortisol secretion. In addition, we did not find any effects of dexamethasone administration (1 mg orally) on NKCA.

Normal lymphocyte responsiveness to lectins but impaired sensitivity to in vitro glucocorticoids in major depression

The mitogen-induced lymphocyte proliferative response and its sensitivity to in vitro (10(-10)-10(-6) M) dexamethasone (DEX) administration were investigated in 12 severely depressed patients and 13 healthy controls. Patients with major depressive disorder exhibited no impairment of lectin-induced blastogenesis, but a significantly weaker suppressive effect of in vitro DEX on 1.0 microgram/ml phytohemagglutinin A-induced proliferation. The inhibitory potency of in vitro DEX was inversely correlated with in vivo adrenal cortical hormone levels at 4.00 p.m. These effects were not observed with pokeweed mitogen- and concanavalin A-stimulated cells. There were no correlations with age, weight, sex or severity of depression. These results do not support the hypothesis of a primarily impaired cell-mediated immunity, but might be indicative of reduced glucocorticoid receptor sensitivity in major depressive disorder.

Anticerebral antibodies in functional psychoses

Anticerebral antibodies to rabbit brain were investigated by the indirect immunofluorescence method in the sera of 44 schizophrenics and 52 depressives diagnosed according to DSM-III-R, and of 54 healthy volunteers. Four types of staining pattern were observed: type A (nerve cells), type B (blood vessels), type C (nuclei), and type D (glial cells); 34.1% of schizophrenics (27.3% after the absorption with rabbit liver acetone powder) showed type A, as compared with 3.8% (1.9% after the absorption) of depressives and with none of the controls.

Biological measures and cellular immunological function in depressed psychiatric inpatients

Thirty depressed psychiatric inpatients, including 18 with a diagnosis of major depression, and 25 hospital staff controls were compared with respect to cellular immune function--that is, mitogen responsiveness to concanavalin A (con A), phytohemagglutinin (PHA), and pokeweed mitogen (PWM); natural killer cell (NK) activity; and T cell subsets, including helper/inducer T cells (CD4) and suppressor/cytotoxic cells (CD8). Only physically healthy subjects, who had not used psychoactive medications (except for low dose benzodiazepines) or other medications known to affect the immune system for at least 14 days, were included. Paired comparisons of the immune measures of patients with a DSM-III diagnosis of major depression (n = 18) with their controls demonstrated a statistically significant reduction of the patients' con A response. In addition, the patients with major depression had significantly lower con A and PHA responses than the combined patients with other forms of depression (atypical, dysthymic, or atypical bipolar). There was no indication that severity of depression, dexamethasone suppression test status, benzodiazepine use, or age accounted for the differences in immune function. A possibly important, unexpected finding was that antihistamine use was associated with lower immune function.

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.

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.

Alterations of nonspecific immunity in patients with common migraine

In 23 patients with common migraine (CM), immune responsiveness and frequency of immunocompetent cells were investigated. In particular, phagocytosis and killing of Candida albicans by polymorphs (PMNs) and monocytes were analyzed. Also, the percentages of CD3+, CD4+, CD8+, natural killer, and CD15+ cells were evaluated by direct immunofluorescence using specific monoclonal antibodies. The results showed deficits of phagocytosis or killing exhibited by PMNs and monocytes. These immunological findings are discussed in terms of perturbation of immune status in CM patients during migraine attacks.

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.

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.

CSF prostaglandin-E in agoraphobia with panic attacks

Prostaglandins are thought to act as neuromodulators of both central catecholamine and endocrine systems. Abnormalities of these systems have been described in affective disorders, in general, and in agoraphobia with panic attacks, in particular. This study measured basal prostaglandin-E (PGE) cerebrospinal fluid (CSF) levels in 20 patients with agoraphobia with panic attacks and 10 nonpsychiatric controls. In a subgroup of patients and controls, CSF levels of adrenocorticotrophic hormone (ACTH) and corticotropin-releasing factor (CRF) were also measured. There was no significant difference in CSF PGE levels between patients and controls. However, patients with higher depression scores had lower CSF PGE levels. CSF PGE levels tended to correlate with CSF ACTH, but not CSF CRF in the patient group, in general, and in the female patients, in particular. These findings do not support an abnormality in basal CNS PGE production in agoraphobia with panic attacks, but suggest further study of the PGE modulatory effect on the hypothalamic-pituitary-adrenal axis in this disorder.

Polyunsaturated fatty acids, prostaglandins, and schizophrenia

Psychotic disorders, particularly schizophrenia, are associated with clinical phenomena that can be explained by disturbances in polyunsaturated fatty acid and prostaglandin metabolism. Previous studies of PUFA, PG synthesis, PGE1 receptor activity and aggregation responses in platelets, and clinical treatment trials suggest a role for PGE in the pathophysiology of schizophrenia. Since a decrease in PGE1 activity can be associated with an increase of dopamine release, a deficiency of PGE1 is consistent with the dopamine hypothesis of schizophrenia. State-of-the-art assay and clinical trial methodology should clarify the role of PUFA metabolism in schizophrenia.

Diazepam inhibits phagocytosis and killing exerted by polymorphonuclear cells and monocytes from healthy donors. In vitro studies

The effect of a benzodiazepine (BDZ), diazepam on human polymorphonuclear cell (PMN) and monocyte phagocytosis and killing from healthy volunteers has been evaluated. Diazepam is able to inhibit in vitro both functions exerted by PMN and monocytes at 10(-5) and 10(-6) M concentrations/ 4 x 10(6) phagocytes. 10(-7) M concentration was not effective in all the instances. These results are discussed for their possible clinical implications, since previous studies have shown that in patients with phobic disorder there is evidence for reduced phagocytosis and killing capacities.

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.

Decreased mononuclear leukocyte TSH responsiveness in patients with major depression

A subgroup of individuals with major depressive disorder have an impaired thyrotropin (TSH) response to thyrotropin-releasing hormone (TRH). The molecular relationship between the mechanism of this "blunted" TSH response and depression is unknown. Numerous recent studies have characterized similarities and interactions between the immune and neuroendocrine systems. As the immune system both produces and responds to TSH, we utilized a peripheral blood leukocyte system to compare immunoreactive (ir)-TSH responsiveness in 10 adult patients (1 man, 9 women) with Research Diagnostic Criteria for major depressive disorder to that of 9 control subjects. All subjects had normal baseline serum TSH and T4 concentrations. Isolated mononuclear leukocytes were treated in vitro with either 0.5 micrograms/ml staphylococcal enterotoxin A (SEA), 50 micrograms/ml TRH, or no stimulant. After incubation, the cells were monitored for ir-TSH production by indirect immunofluorescence and reverse hemolytic plaque assay using antisera to TSH-beta. The culture supernates were analyzed by TSH radioimmunoassay. SEA- and TRH-treated cell cultures from depressed individuals had significantly fewer immunofluorescent positive cells, as well as significantly fewer and smaller plaques, than did similarly treated leukocytes from control subjects. The increase in supernatant ir-TSH was significantly less in TRH-treated cultures from depressed patients as compared to normals (p less than 0.05). These results suggest that examination of mononuclear leukocyte TSH production may reflect an altered state of neuroendocrine function and may thus be a useful marker for major depressive disorder.

Rapid antidepressant response to alprazolam in depressed patients with high catecholamine output and heterologous desensitization of platelet adenylate cyclase

The present study examined the relationship between 24-hr urinary catecholamine (norepinephrine and epinephrine) output and measures of platelet adenylate cyclase (AC) activity in depressed patients (n = 17) and control subjects (n = 10). In both groups, significant inverse correlations were observed when 24-hr urinary catecholamine levels were examined in relation to measures of both receptor-mediated (prostaglandin D2 and alpha 2-adrenergic) and postreceptor-mediated (NaF) platelet AC enzyme activities, suggesting that circulating catecholamines may regulate platelet AC by heterologous (agonist-nonspecific) desensitization of the AC enzyme complex. Depressed patients who had favorable antidepressant responses to alprazolam had significantly higher pretreatment urinary catecholamine output and lower receptor-mediated platelet AC enzyme activities than control subjects, whereas the nonresponders did not. After 8 days of treatment with alprazolam, urinary catecholamine levels declined significantly. In responders, receptor-mediated measures of platelet AC activity increased significantly by day 8 to values comparable to those in control subjects; but similar changes were not observed in nonresponders. Prior to treatment, responders showed a strict linear relationship between receptor-mediated (prostaglandin D2) and postreceptor-mediated (NaF) stimulation of platelet AC activity through the stimulatory guanine nucleotide regulatory protein (Ns), whereas nonresponders did not. This suggests the presence of two distinct coupling interactions between platelet prostaglandin D2 receptors and the stimulatory guanine nucleotide regulatory protein in responders and nonresponders to the antidepressant effects of alprazolam prior to treatment. The authors propose that catecholamines, possibly acting through prostaglandins, may regulate platelet AC enzyme activity by heterologous desensitization occurring through postreceptor mechanisms.

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.