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

The bidirectional relationship of depression and disturbances in B cell homeostasis: Double trouble

Major depressive disorder (MDD) is a recurrent, persistent, and debilitating neuropsychiatric syndrome with an increasing morbidity and mortality, representing the leading cause of disability worldwide. The dysregulation of immune systems (including innate and adaptive immune systems) has been identified as one of the key contributing factors in the progression of MDD. As the main force of the humoral immunity, B cells have an essential role in the defense against infections, antitumor immunity and autoimmune diseases. Several recent studies have suggested an intriguing connection between disturbances in B cell homeostasis and the pathogenesis of MDD, however, the B-cell-dependent mechanism of MDD remains largely unexplored compared to other immune cells. In this review, we provide an overview of how B cell abnormality regulates the progression of MMD and the potential consequence of the disruption of B cell homeostasis in patients with MDD. Abnormalities of B-cell homeostasis not only promote susceptibility to MDD, but also lead to an increased risk of developing infection, malignancy and autoimmune diseases in patients with MDD. A better understanding of the contribution of B cells underlying MDD would provide opportunities for identification of more targeted treatment approaches and might provide an overall therapeutic benefit to improve the long-term outcomes of patients with MDD.

Altered B Cell Homeostasis in Patients with Major Depressive Disorder and Normalization of CD5 Surface Expression on Regulatory B Cells in Treatment Responders

Pro-inflammatory activity and cell-mediated immune responses have been widely observed in patients with major depressive disorder (MDD). Besides their well-known function as antibody-producers, B cells play a key role in inflammatory responses by secreting pro- and anti-inflammatory factors. However, homeostasis of specific B cell subsets has not been comprehensively investigated in MDD. In this study, we characterized circulating B cells of distinct developmental steps including transitional, naïve-mature, antigen-experienced switched, and non-switched memory cells, plasmablasts and regulatory B cells by multi-parameter flow cytometry. In a 6-weeks follow-up, circulating B cells were monitored in a small group of therapy responders and non-responders. Frequencies of naïve lgD⁺CD27^- B cells, but not lgD⁺CD27⁺ memory B cells, were reduced in severely depressed patients as compared to healthy donors (HD) or mildly to moderately depressed patients. Specifically, B cells with immune-regulatory capacities such as CD1d⁺CD5⁺ B cells and CD24⁺CD38^hi transitional B cells were reduced in MDD. Also Bm1-Bm5 classification in MDD revealed reduced Bm2' cells comprising germinal center founder cells as well as transitional B cells. We further found that reduced CD5 surface expression on transitional B cells was associated with severe depression and normalized exclusively in clinical responders. This study demonstrates a compromised peripheral B cell compartment in MDD with a reduction in B cells exhibiting a regulatory phenotype. Recovery of CD5 surface expression on transitional B cells in clinical response, a molecule involved in activation and down-regulation of B cell responses, further points towards a B cell-dependent process in the pathogenesis of MDD.

Adolescent Substance Use & Psychopathology: Interactive Effects of Cortisol Reactivity and Emotion Regulation

How are emotional processes associated with the increased rates of substance use and psychological disorders commonly observed during adolescence? An index of emotion-related physiological arousal-cortisol reactivity-and subjective emotion regulation have both been independently linked to substance use and psychological difficulties among youth. The current study (N = 134 adolescents) sought to elucidate the interactive effects of cortisol reactivity following a stressful parent-child interaction task and self-reported emotion regulation ability on adolescents' substance use and externalizing and internalizing behavior problems. Results revealed that adolescents with low levels of cortisol reactivity and high emotion regulation difficulties were more likely to use substances, and also had the highest parent-reported symptoms of oppositional defiant disorder. With respect to internalizing symptoms, high emotion-related physiological reactivity coupled with high emotion regulation difficulties were associated with higher self-reported major depression symptoms among youth. Findings reveal that different profiles of HPA axis arousal and emotion regulation are associated with substance use and symptoms of psychopathology among adolescents.

Child abuse, disruptive behavior disorders, depression, and salivary cortisol levels among institutionalized and community-residing boys in Mongolia

INTRODUCTION

Hypothalamic-pituitary-adrenal (HPA) axis activity is related to childhood disruptive behavior disorders and to exposure to abuse and neglect. This study explores the relationship of diurnal salivary cortisol levels with oppositional defiant disorder (ODD) and caregiver attitudes toward physical punishment among boys in Mongolia.

METHODS

Salivary cortisol was collected in the home or institution 4 times daily for 4 days from 46 boys, aged 4-10 years, in Ulaanbaatar, Mongolia. Caregivers rated child disruptive behavior symptoms, attitudes toward physical punishment, and community violence exposures. Mixed effects models were used to estimate the association of psychopathology and caregiver attitudes with salivary cortisol levels.

RESULTS

Boys meeting criteria for ODD displayed consistently lower diurnal salivary cortisol levels compared to boys without ODD diagnoses. Controlling for ODD diagnosis, boys with depression showed higher cortisol levels throughout the day. No other diagnosis was associated with cortisol levels. Psychiatric diagnosis accounted for 17% of between individual variations in cortisol levels unexplained by the covariates. In a separate model, caregivers' beliefs regarding physical punishment accounted for 11% of between individual differences: boys with caregivers who stated physical punishment was necessary for discipline displayed hypocortisolism. Institutionalization did not associate with cortisol levels.

DISCUSSION

Salivary cortisol data from a non-Western naturalistic setting support an association of reduced basal HPA activity with disruptive behavior disorders and caregiver attitudes toward discipline. These findings suggest HPA functioning may be a reflection of or mediate disruptive behavior disorders in children across ethnic and cultural settings.

Preliminary Evidence for a Compromised T-Cell Compartment in Maltreated Children with Depression and Posttraumatic Stress Disorder

OBJECTIVE

Adverse childhood experiences, such as maltreatment, and affective disorders are associated with a proinflammatory state and/or variably compromised counts in lymphocyte subsets in adults. Animal models of social stress indicate that recent thymic emigrant cells (RTE), which maintain the T-cell compartment, are affected.

METHODS

In this study, we examined the association between lymphocyte subsets, and depression and posttraumatic stress disorder (PTSD) among 16 maltreated children (aged 6-17 years) 1-3 years after the intervention by the Child Protection Team and among 14 healthy age-matched controls. The participants completed psychological assessment and had blood drawn for fluorescent-activated cell sorting analysis.

RESULTS

Among maltreated children and adolescents, depression was associated with lower counts of RTEs and T-helper cells after controlling for age. We found additional trends and large effect sizes with regard to the percentages of these cells, as well as for related lymphocyte subsets. Similar effects were found for PTSD, i.e. lower counts of naïve T cells, which was also supported by a trend for their percentage. Compared to controls, maltreated participants with a clinical level of depression had decreased percentages of RTEs, with a similar trend for PTSD.

CONCLUSION

Limited by the nature of a pilot study and the small sample size, these preliminary findings of a compromised T-cell compartment related to psychiatric symptoms in maltreated children and adolescents need to be further studied; particularly the role of RTEs needs further evaluation.

Internalizing and externalizing behaviors predict elevated inflammatory markers in childhood

BACKGROUND

Children with behavior problems, such as internalizing or externalizing disorders, are at increased risk for poorer physical health in adulthood. Inflammation has been posited as a potential biological mediator underlying this association. However, it is unclear how early in development associations between behavior problems and inflammation may be detected, and whether associations are present for both internalizing and externalizing behaviors in pre-pubertal children.

METHODS

Using data from children in the Avon Longitudinal Study of Parents and Children, we examined associations between behavior problems at age 8 (assessed via the parent-report Strengths and Difficulties Questionnaire) and inflammatory markers assessed at age 10. Inflammatory markers included C-reactive protein (CRP; n=4069) and interleukin-6 (IL-6; n=4061). We further evaluated whether body mass index (BMI) mediated associations, and tested for potential reverse causality by considering whether age 10 inflammation was associated with changes from initial levels to age 12 behavior problems.

RESULTS

After adjusting for relevant covariates, age 8 externalizing behaviors were associated with elevated CRP at age 10, and age 8 internalizing and externalizing behaviors were associated with elevated IL-6 at age 10 (p's<0.05). We found no evidence that observed associations were mediated by BMI or that inflammatory markers at age 10 were associated with increased internalizing or externalizing behavior problems at age 12.

CONCLUSIONS

These findings document an association between behavior problems and elevated concentrations of CRP and IL-6 at 10 years. Heightened inflammation in childhood may be a pathway through which early behavior problems increase risk for adult chronic diseases.

Research review: the role of cytokines in depression in adolescents: a systematic review

BACKGROUND

While cytokines have been implicated in the pathophysiology of depression in adults, the potential role in younger age groups such as adolescents is less clear. This article therefore reviews the literature (a) to explore the relationship between cytokines and depression in adolescents, and (b) to examine how cytokines may be related to adolescent depression in the context of other neurobiological theories of depression.

METHOD

A systematic review of the scientific literature on the subject was conducted in February 2013, searching the Web of Knowledge, PubMed (Medline), PsycInfo and Cochrane electronic databases.

RESULTS

Eighteen studies were identified measuring both depression or depressive symptoms and cytokines or immune markers in adolescents. Adolescents with depression show age-specific characteristics of the immune and inflammatory system, specifically in NK cell activity and in pro-inflammatory cytokines (such as IL-1β and TNF-α). In addition, the role of cytokines in adolescent depression is influenced by neurodevelopment, hormonal changes, stress and trauma.

CONCLUSIONS

There may be differences in the neurobiology of adolescent major depressive disorder (MDD) compared with adult MDD. Increased understanding of the role of cytokines in adolescent MDD may lead to improved outcomes in the treatment of adolescent depression.

Associations among depression, perceived self-efficacy, and immune function and health in preadolescent children

Experimental animal studies and adult research consistently show that stress exposure and/or psychological symptoms are associated with poorer health and immune functioning. The application to children is not yet clear, however, and we lack developmental models for studies in this area. The objective of this paper was to test the hypothesis that self-reported self-efficacy and depression, two markers of psychological well-being in children, would predict immunity and rate of illnesses. The data are based on a prospective study of 141 healthy, normally developing children aged 7-13 years who were recruited from an ambulatory pediatric setting. Children completed self-efficacy and depression measures and had blood obtained for IL-6 plasma levels and natural killer cell functional assays on three occasions, 6 months apart. Parents maintained weekly child illness diaries over 1 year using a thermometer to record fever. Parent psychiatric symptoms and income were used as covariates. Results indicated that, across the three occasions of measurement collected over the 1-year period, higher perceived self-efficacy was significantly associated with lower plasma interleukin 6 concentrations. There was no overall main effect of depressive symptoms on immune measures; however, for older girls, higher depression was associated with elevated natural killer cell cytotoxicity and an increased rate of total illnesses and febrile illnesses. The findings provide some of the first evidence that psychological processes are associated with immunity and health in a normally developing sample of preadolescents. Furthermore, the pattern of results suggests a modified model of a link between psychological well-being and immunological processes in children. These results build on and expand research on the notion of allostatic load and develop a groundwork for developmental studies in this area.

Pituitary volume prospectively predicts internalizing symptoms in adolescence

BACKGROUND

Early adolescence is a critical time for the development of both internalizing and externalizing disorders. We aimed to investigate whether pituitary volume, an index of hypothalamic-pituitary-adrenal (HPA) axis function, represents a vulnerability factor for the emergence of internalizing and externalizing symptoms during adolescence using a prospective, longitudinal design.

METHODS

One hundred and fifty-five adolescents completed 3T structural magnetic resonance imaging (MRI), symptom rating scales and a diagnostic interview during early adolescence (M age 12.6 years, SD .5 years); symptom rating scales were re-administered approximately three years later (M age 15.2 years). The volume of the pituitary gland was estimated by manually delineating its structure on MR images. The degree to which pituitary volumes prospectively predicted change in internalizing and externalizing symptoms across the two time-points was assessed using hierarchal linear regression, after controlling for the influence of gender, age, pubertal stage and intracranial volume.

RESULTS

Larger pituitary volumes prospectively predicted an increase in internalizing, but not externalizing, symptoms from early adolescence to mid-adolescence.

CONCLUSIONS

This study provides the first evidence that increased pituitary volume might represent a specific vulnerability marker for the development of internalizing symptoms during early to mid-adolescence.

Concurrent and longitudinal associations of basal and diurnal cortisol with mental health symptoms in early adolescence

Recent biosocial theories postulate that both biological risk and the social context influence the development of mental health problems [Boyce and Ellis (2005) Development and Psychopathology, 17(2), 271-301]. Guided by this framework, we examined whether basal cortisol and its diurnal rhythm were associated with mental health symptoms in early adolescence. Because cross-sectional and longitudinal investigations sometimes reveal different cortisol-mental health associations, we examined the association both concurrently and longitudinally when children transition to middle school, a time which entails a major change in social context from single to multiple teachers, classrooms, and sets of classmates. Salivary cortisol was measured three times a day (waking, afternoon, and bedtime) across 3 days when adolescents were 5th graders. Mental health was measured when adolescents were in 5th and 7th grades, just before and after the transition to middle school. To deal with the substantial comorbidity of internalizing and externalizing symptoms at this developmental stage, mental health measures distinguished overall symptom severity from the preponderance of internalizing versus externalizing symptoms (i.e., directionality). A three-level Hierarchical Linear Model was used to extract basal cortisol and its diurnal rhythm separate from the day-to-day and within-the-day fluctuations in cortisol in response to daily experiences. Results were specific to symptom severity, suggesting that cortisol is a nonspecific risk factor for mental health symptoms in young adolescents. At 5th grade, low basal cortisol was associated with concurrent symptom severity. However, longitudinally, it was adolescents with high cortisol at 5th grade who were at risk for increasing mental health symptoms by 7th grade. Flat diurnal rhythms in 5th grade were related to levels of symptom severity at both 5th and 7th grades. Considering the change in social context, as defined by the transition to middle school, helped resolve seemingly inconsistent evidence that both hypo- and hyper-arousal were associated with mental health symptoms in early adolescence.

Immunity in adolescents with major depression

OBJECTIVE

The association between major depression (MD) and altered immunity appears to be age-related, with differing immune changes found in prepubertal children, young adults, and older adults. There is limited information concerning immunity in adolescents with MD.

METHOD

Thirty-six otherwise healthy medication-free adolescents (aged 14-20; 23 female) from a community sample, meeting Diagnostic Interview Schedule for Children DSM-III-R criteria for unipolar MD, were compared with 36 nondepressed adolescents matched by gender, age, and racial background. A battery of quantitative and functional immune measures was obtained.

RESULTS

MD adolescents had increased (p < .05) circulating lymphocytes and lymphocyte subsets; however, altered distribution of lymphocyte subsets was found only for activated T (HLA-DR+) cells (p < .004) and, possibly, natural killer (NK) (CD56+) cells (p < .06), each showing lower percentages in the MD adolescents. Concanavalin A (but not phytohemagglutinin or pokeweed mitogen) mitogen response was lower in the MD adolescents (p < .02). NK cell activity was elevated at higher effector-target ratios (p < .001), an effect not associated with the number of circulating CD56+ (NK) cells.

CONCLUSIONS

Depressed adolescents showed changes in immune measures that have been found to be altered in other MD groups, although the pattern of effects differs.

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.

Are child-, adolescent-, and adult-onset depression one and the same disorder?

This paper reviews prior research studies examining neurobiological correlates and treatment response of depression in children, adolescents, and adults. Although there are some similarities in research findings observed across the life cycle, both children and adolescents have been found to differ from depressed adults on measures of basal cortisol secretion, corticotropin stimulation post-corticotropin releasing hormone (CRH) infusion, response to several serotonergic probes, immunity indices, and efficacy of tricyclic medications. These differences are proposed to be due to 1) developmental factors, 2) stage of illness factors (e.g., number of episodes, total duration of illness), or 3) heterogeneity in clinical outcome (e.g., recurrent unipolar course vs. new-onset bipolar disorder). Relevant clinical and preclinical studies that provide support for these alternate explanations of the discrepant findings are reviewed, and directions for future research are discussed. To determine whether child-, adolescent-, and adult-onset depression represent the same condition, it is recommended that researchers 1) use the same neuroimaging paradigms in child, adolescent, and adult depressed cohorts; 2) carefully characterize subjects' stage of illness; and 3) conduct longitudinal clinical and repeat neurobiological assessments of patients of different ages at various stages of illness. In addition, careful attention to familial subtypes (e.g., depressive spectrum disorders vs. familial pure depressive disorders) and environmental factors (e.g., trauma history) are suggested for future investigations.

Epstein-Barr virus antibodies in whole blood spots: a minimally invasive method for assessing an aspect of cell-mediated immunity

OBJECTIVE

Study 1: Introduce and validate a method for measuring EBV p18-VCA antibodies in whole blood spots to provide a minimally invasive marker of cell-mediated immune function. Study 2: Apply this method to a large community-based study of psychopathology in children and adolescents.

METHODS

The EBV antibody method was evaluated through analysis of precision, reliability, stability, and comparisons with plasma and indirect immunofluorescence methods. The effects of life events on p18-VCA antibody level were considered in a subsample of 9, 11, and 13 year-old children participating in the Great Smoky Mountains Study in North Carolina. The subsample was stratified by age, sex, and degree of overall life strain.

RESULTS

Dried blood spots provided a convenient, sensitive, precise, and reliable method for measuring EBV p18-VCA antibody titer. Life events were positively associated with p18-VCA antibodies in girls but not in boys.

CONCLUSIONS

The validity of the blood spot EBV p18-VCA antibody assay, as well as the ease of sample collection, storage, and transportation, may provide an opportunity for psychoneuroimmunology to explore a wider range of stress models in larger, community-based studies.

Major depressive disorder is associated with elevated monocyte counts

One of the most consistently reported findings in depression has been leucocytosis. In 33 in-patients with major depressive disorder, we assessed white blood cell count (WBC) and lymphocyte subsets four times over a period of 6 weeks. The control group consisted of 44 healthy subjects. Shortly after admission, we detected significant increases in the numbers of leucocytes, granulocytes, platelets and monocytes in the depressed patients. Patients who recovered well during hospitalization showed a decrease in monocyte counts, whereas those with slower clinical improvement had significantly higher monocyte counts than the control group. This longitudinal study demonstrates that monocytes may play a role in the acute phase of depression and could provide an explanation for immunological dysfunction in depressive states.

Cellular immunity in depressed, conduct disorder, and normal adolescents: role of adverse life events

OBJECTIVE

To determine whether adolescents with major depressive disorder have disturbances in their cellular immunity and to study whether the immunological changes detected are specific to depression or are general responses to stress.

METHOD

Twenty subjects with major depressive disorder, 17 nondepressed subjects with conduct disorder, and 17 normal adolescents were recruited. Subjects were assessed with a clinical interview for DSM-III-R and a modified version of the Coddington Life Events Checklist. Blood samples were drawn for total white blood cells, lymphocytes subsets, natural killer cell activity, lymphocyte proliferation response to phytohemagglutinin, and cortisol plasma levels.

RESULTS

Overall, there were no significant between-group differences in any of the cellular immune measurements. Natural killer cell activity was significantly negatively correlated with past year and lifetime adverse life events across all effector-target cell ratios. Controlling for diagnoses and socioeconomic status yielded similar results. There were no significant effects of age, sex, race, sleep, nutrition, cigarette use, menstrual cycle, or cortisol on any of the immunological variables.

CONCLUSIONS

In this sample of adolescents, we found that independent of the diagnoses and socioeconomic status, increases in adverse life events were associated with low natural killer cell activity.

Investigations of the cellular immunity during depression and the free interval: evidence for an immune activation in affective psychosis

1. Results of investigations of the immune function in affective disorders are conflicting. Some authors described an immune suppression, others an immune activation in major depression. The authors performed a study of cellular immunity in the MDD subtype endogenous depression. 23 patients suffering from endogenous depression were investigated during the depressive state, the results were compared with a group of 14 patients during the free interval and 51 healthy controls. 2. The lymphocyte proliferation after incubation with diphtheria- and tetanus toxoid, mainly stimulating T-cells, was reduced but after incubation with an antigen-cocktail, stimulating both, T- and B-cells, was increased in patients during depression and during the free interval compared to controls. 3. The CD3(+)- and CD4(+)-cells were significantly enhanced in both groups of patients while the CD8(+)-cells showed no differences to the controls. The ratio CD4+/CD8+ was increased in patients, too, as described in some autoimmune disorders. 4. The suppressor cell activity was significantly reduced in the PWM-assay and in the PHA-assay. The mixed lymphocyte culture showed a tendency to reduced suppressor cell activity as well. 5. The results point to an immune activation and to a disturbed control of the proliferative activity in affective psychosis. A T-cell related defect, not compensated by an increased number of CD3+- and CD4+ -cells is discussed. 6. From our point of view, the conflicting results of psychoneuroimmunological investigations in depressive disorders may be related to etiologically different subgroups of depression. The diagnostic category of MDD is possibly one of the traps in psychoneuroimmunology.

Psychoneuroendocrinological and immunological parameters in cancer patients: involvement of stress and depression

Plasma noradrenaline (NA), adrenaline (A), dopamine (DA), platelet serotonin (pS), free serotonin (fS), cortisol (CRT), growth hormone (GH), peripheral blood lymphocytes (lymph), lymphocyte subpopulations (LSS) and CD4/CD8 ratio were serially assessed in 50 non-medicated, advanced cancer patients (spontaneous evolution) and in age- and sex-paired controls. Clonidine tests and psychiatric evaluations were also serially performed. Patients showing long symptomless periods had all normal values except for raised pS, whereas those who remained free of symptoms for only a short time had raised NA, A and CRT, plus lowered pS values. Further increases in NA, A and CRT, plus additional increases in DA and fS, occurred during exacerbation periods, during which times reductions in lymph, LSS and NK also were observed. Patients in terminal stages showed maximal decreases of all neurotransmitters and immunological parameters; only DA and fS remained raised. Psychiatric interviews performed simultaneously with the clonidine tests revealed a low incidence of moderate depression during symptomless periods and no depression during exacerbation periods. Several significant positive and negative correlations between neurotransmitters and immunological parameters were found during exacerbation periods. Pain, although not intense, and other symptoms required occasional administration of low doses of non-opiate analgesics.