Panic disorder and immunity: few effects on circulating lymphocytes, mitogen response, and NK cell activity

Blood transcriptome analysis suggests an indirect molecular association of early life adversities and adult social anxiety disorder by immune-related signal transduction

Social anxiety disorder (SAD) is a psychiatric disorder characterized by severe fear in social situations and avoidance of these. Multiple genetic as well as environmental factors contribute to the etiopathology of SAD. One of the main risk factors for SAD is stress, especially during early periods of life (early life adversity; ELA). ELA leads to structural and regulatory alterations contributing to disease vulnerability. This includes the dysregulation of the immune response. However, the molecular link between ELA and the risk for SAD in adulthood remains largely unclear. Evidence is emerging that long-lasting changes of gene expression patterns play an important role in the biological mechanisms linking ELA and SAD. Therefore, we conducted a transcriptome study of SAD and ELA performing RNA sequencing in peripheral blood samples. Analyzing differential gene expression between individuals suffering from SAD with high or low levels of ELA and healthy individuals with high or low levels of ELA, 13 significantly differentially expressed genes (DEGs) were identified with respect to SAD while no significant differences in expression were identified with respect to ELA. The most significantly expressed gene was MAPK3 (p = 0.003) being upregulated in the SAD group compared to control individuals. In contrary, weighted gene co-expression network analysis (WGCNA) identified only modules significantly associated with ELA (p ≤ 0.05), not with SAD. Furthermore, analyzing interaction networks of the genes from the ELA-associated modules and the SAD-related MAPK3 revealed complex interactions of those genes. Gene functional enrichment analyses indicate a role of signal transduction pathways as well as inflammatory responses supporting an involvement of the immune system in the association of ELA and SAD. In conclusion, we did not identify a direct molecular link between ELA and adult SAD by transcriptional changes. However, our data indicate an indirect association of ELA and SAD mediated by the interaction of genes involved in immune-related signal transduction.

Blood-Based miRNA Biomarkers as Correlates of Brain-Based miRNA Expression

The use of easily accessible peripheral samples, such as blood or saliva, to investigate neurological and neuropsychiatric disorders is well-established in genetic and epigenetic research, but the pathological implications of such biomarkers are not easily discerned. To better understand the relationship between peripheral blood- and brain-based epigenetic activity, we conducted a pilot study on captive baboons (Papio hamadryas) to investigate correlations between miRNA expression in peripheral blood mononuclear cells (PBMCs) and 14 different cortical and subcortical brain regions, represented by two study groups comprised of 4 and 6 animals. Using next-generation sequencing, we identified 362 miRNAs expressed at ≥ 10 read counts in 80% or more of the brain samples analyzed. Nominally significant pairwise correlations (one-sided P < 0.05) between peripheral blood and mean brain expression levels of individual miRNAs were observed for 39 and 44 miRNAs in each group. When miRNA expression levels were averaged for tissue type across animals within the groups, Spearman's rank correlations between PBMCs and the brain regions are all highly significant (r _s = 0.47-0.57; P < 2.2 × 10^-16), although pairwise correlations among the brain regions are markedly stronger (r _s = 0.86-0.99). Principal component analysis revealed differentiation in miRNA expression between peripheral blood and the brain regions for the first component (accounting for ∼75% of variance). Linear mixed effects modeling attributed most of the variance in expression to differences between miRNAs (>70%), with non-significant 7.5% and 13.1% assigned to differences between blood and brain-based samples in the two study groups. Hierarchical UPGMA clustering revealed a major co-expression branch in both study groups, comprised of miRNAs globally upregulated in blood relative to the brain samples, exhibiting an enrichment of miRNAs expressed in immune cells (CD14+, CD15+, CD19+, CD3+, and CD56 + leukocytes) among the top blood-brain correlates, with the gene MYC, encoding a master transcription factor that regulates angiogenesis and neural stem cell activation, representing the most prevalent miRNA target. Although some differentiation was observed between tissue types, these preliminary findings reveal wider correlated patterns between blood- and brain-expressed miRNAs, suggesting the potential utility of blood-based miRNA profiling for investigating by proxy certain miRNA activity in the brain, with implications for neuroinflammatory and c-Myc-mediated processes.

DNA-methylation dynamics across short-term, exposure-containing CBT in patients with panic disorder

Interaction of genetic predispositions and environmental factors via epigenetic mechanisms have been hypothesized to play a central role in Panic Disorder (PD) aetiology and therapy. Cognitive Behavioral Therapy (CBT), including exposure interventions, belong to the most efficient treatments of PD although its biological mechanism of action remains unknown. For the first time, we explored the dynamics and magnitude of DNA-methylation and immune cell-type composition during CBT (n = 38) and the therapeutic exposure intervention (n = 21) to unravel their biological correlates and identify possible biomarkers of therapy success. We report transient regulation of the CD4 + T-Cells, Natural Killers cells, Granulocytes during exposure and a significant change in the proportions of CD4 + T cells, CD8 + T cells and B-Cells and Granulocytes during therapy. In an epigenome-wide association study we identified cg01586609 located in a CpG island and annotated to the serotonin receptor 3 A (HTR3A) to be differentially methylated during fear exposure and regulated at gene expression level with significant differences between remitters and non-remitters (p = 0.028). We moreover report cg01699630 annotated to ARG1 to undergo long lasting methylation changes during therapy (paired t test, genome-wide adj.p value = 0.02). This study reports the first data-driven biological candidates for epigenetically mediated effects of acute fear exposure and CBT in PD patients. Our results provide evidence of changes in the serotonin receptor 3 A methylation and expression during fear exposure associated with different long-term CBT trajectories and outcome, making it a possible candidate in the search of markers for therapy success. Finally, our results add to a growing body of evidence showing immune system changes associated with PD.

Altered immune phenotype and DNA methylation in panic disorder

Background

Multiple studies have related psychiatric disorders and immune alterations. Panic disorder (PD) has been linked with changes in leukocytes distributions in several small studies using different methods for immune characterization. Additionally, alterations in the methylation of repetitive DNA elements, such as LINE-1, have been associated with mental disorders. Here, we use peripheral blood DNA methylation data from two studies and an updated DNA methylation deconvolution library to investigate the relation of leukocyte proportions and methylation status of repetitive elements in 133 patients with panic disorder compared with 118 controls.

Methods and results

We used DNA methylation data to deconvolute leukocyte cell-type proportions and to infer LINE-1 element methylation comparing PD cases and controls. We also identified differentially methylated CpGs associated with PD using an epigenome-wide association study approach (EWAS), with models adjusting for sex, age, and cell-type proportions. Individuals with PD had a lower proportion of CD8T cells (OR: 0.86, 95% CI: 0.78–0.96, P-adj = 0.030) when adjusting for age, sex, and study compared with controls. Also, PD cases had significantly lower LINE-1 repetitive element methylation than controls (P < 0.001). The EWAS identified 61 differentially methylated CpGs (58 hypo- and 3 hypermethylated) in PD (Bonferroni adjusted P < 1.33 × 10^–7).

Conclusions

These results suggest that those with panic disorder have changes to their immune system and dysregulation of repeat elements relative to controls.

Peripheral Biomarkers in DSM-5 Anxiety Disorders: An Updated Overview

Anxiety disorders are prevalent and highly disabling mental disorders. In recent years, intensive efforts focused on the search for potential neuroimaging, genetic, and peripheral biomarkers in order to better understand the pathophysiology of these disorders, support their diagnosis, and characterize the treatment response. Of note, peripheral blood biomarkers, as surrogates for the central nervous system, represent a promising instrument to characterize psychiatric disorders, although their role has not been extensively applied to clinical practice. In this report, the state of the art on peripheral biomarkers of DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th edition) Anxiety Disorders is presented, in order to examine their role in the pathogenesis of these conditions and their potential application for diagnosis and treatment. Available data on the cerebrospinal fluid and blood-based biomarkers related to neurotransmitters, neuropeptides, the hypothalamic-pituitary-adrenal axis, neurotrophic factors, and the inflammation and immune system are reviewed. Despite the wide scientific literature and the promising results in the field, only a few of the proposed peripheral biomarkers have been defined as a specific diagnostic instrument or have been identified as a guide in the treatment response to DSM-5 Anxiety Disorders. Therefore, further investigations are needed to provide new biological insights into the pathogenesis of anxiety disorders, to help in their diagnosis, and to tailor a treatment.

Biological markers for anxiety disorders, OCD and PTSD: A consensus statement. Part II: Neurochemistry, neurophysiology and neurocognition

OBJECTIVE

Biomarkers are defined as anatomical, biochemical or physiological traits that are specific to certain disorders or syndromes. The objective of this paper is to summarise the current knowledge of biomarkers for anxiety disorders, obsessive-compulsive disorder (OCD) and posttraumatic stress disorder (PTSD).

METHODS

Findings in biomarker research were reviewed by a task force of international experts in the field, consisting of members of the World Federation of Societies for Biological Psychiatry Task Force on Biological Markers and of the European College of Neuropsychopharmacology Anxiety Disorders Research Network.

RESULTS

The present article (Part II) summarises findings on potential biomarkers in neurochemistry (neurotransmitters such as serotonin, norepinephrine, dopamine or GABA, neuropeptides such as cholecystokinin, neurokinins, atrial natriuretic peptide, or oxytocin, the HPA axis, neurotrophic factors such as NGF and BDNF, immunology and CO2 hypersensitivity), neurophysiology (EEG, heart rate variability) and neurocognition. The accompanying paper (Part I) focuses on neuroimaging and genetics.

CONCLUSIONS

Although at present, none of the putative biomarkers is sufficient and specific as a diagnostic tool, an abundance of high quality research has accumulated that should improve our understanding of the neurobiological causes of anxiety disorders, OCD and PTSD.

Epigenome-wide association study of DNA methylation in panic disorder

Background

Panic disorder (PD) is considered to be a multifactorial disorder emerging from interactions among multiple genetic and environmental factors. To date, although genetic studies reported several susceptibility genes with PD, few of them were replicated and the pathogenesis of PD remains to be clarified. Epigenetics is considered to play an important role in etiology of complex traits and diseases, and DNA methylation is one of the major forms of epigenetic modifications. In this study, we performed an epigenome-wide association study of PD using DNA methylation arrays so as to investigate the possibility that different levels of DNA methylation might be associated with PD.

Methods

The DNA methylation levels of CpG sites across the genome were examined with genomic DNA samples (PD, N = 48, control, N = 48) extracted from peripheral blood. Methylation arrays were used for the analysis. β values, which represent the levels of DNA methylation, were normalized via an appropriate pipeline. Then, β values were converted to M values via the logit transformation for epigenome-wide association study. The relationship between each DNA methylation site and PD was assessed by linear regression analysis with adjustments for the effects of leukocyte subsets.

Results

Forty CpG sites showed significant association with PD at 5% FDR correction, though the differences of the DNA methylation levels were relatively small. Most of the significant CpG sites (37/40 CpG sites) were located in or around CpG islands. Many of the significant CpG sites (27/40 CpG sites) were located upstream of genes, and all such CpG sites with the exception of two were hypomethylated in PD subjects. A pathway analysis on the genes annotated to the significant CpG sites identified several pathways, including “positive regulation of lymphocyte activation.”

Conclusions

Although future studies with larger number of samples are necessary to confirm the small DNA methylation abnormalities associated with PD, there is a possibility that several CpG sites might be associated, together as a group, with PD.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-016-0307-1) contains supplementary material, which is available to authorized users.

Recurrence of Panic Attacks after Influenza Vaccination: Two Case Reports

Human influenza is a contagious respiratory illness caused by the influenza virus. The influenza vaccination is recommended annually, but several adverse effects related to allergic reactions have been reported. Panic attacks are also known to occur, but no case of a panic attack adverse effect has been reported in South Korea. We present two cases of panic disorder patients whose symptoms were aggravated by the influenza vaccination. We assumed that dysregulation of T-lymphocytes in panic disorder patients could have a role in activating various kinds of cytokines and chemokines, which then can lead to panic attack aggravation.

Immune-related pathways including HLA-DRB1(∗)13:02 are associated with panic disorder

Panic disorder (PD) is an anxiety disorder characterized by panic attacks and anticipatory anxiety. Both genetic and environmental factors are thought to trigger PD onset. Previously, we performed a genome-wide association study (GWAS) for PD and focused on candidate SNPs with the lowest P values. However, there seemed to be a number of polymorphisms which did not reach genome-wide significance threshold due to their low allele frequencies and odds ratios, even though they were truly involved in pathogenesis. Therefore we performed pathway analyses in order to overcome the limitations of conventional single-marker analysis and identify associated SNPs with modest effects. Each pathway analysis indicated that pathways related to immunity showed the strongest association with PD (DAVID, P=2.08×10(-6); i-GSEA4GWAS, P<10(-3); ICSNPathway, P<10(-3)). Based on the results of pathway analyses and the previously performed GWAS for PD, we focused on and investigated HLA-B and HLA-DRB1 as candidate susceptibility genes for PD. We typed HLA-B and HLA-DRB1 in 744 subjects with PD and 1418 control subjects. Patients with PD were significantly more likely to carry HLA-DRB1(∗)13:02 (P=2.50×10(-4), odds ratio=1.54). Our study provided initial evidence that HLA-DRB1(∗)13:02 and genes involved in immune-related pathways are associated with PD. Future studies are necessary to confirm these results and clarify the underlying mechanisms causing PD.

Comparison of superoxide dismutase, glutathione peroxidase and adenosine deaminase activities between respiratory and nocturnal subtypes of patients with panic disorder

OBJECTIVE

There is mounting evidence indicating that oxidative and inflammatory processes may have an important role in the pathogenesis of panic disorder (PD). PD is a heterogeneous disease, and panic attacks are divided according to the different symptom clusters as respiratory, nocturnal, non-fearful, cognitive, or vestibular subtypes. The aim of this study was to compare whole-blood and serum superoxide dismutase (SOD), glutathione peroxidase and adenosine deaminase activities in PD patients with/without nocturnal, respiratory subtypes and healthy subjects.

METHODS

The study was conducted including 60 patients with PD and 30 healthy control subjects. The Panic Attack Symptom Checklist, Panic and Agoraphobia Scale, Hamilton Depression Rating Scale and Hamilton Anxiety Rating Scale were administered to the patients. Biochemical analyses were performed after all the blood samples were collected.

RESULTS

We found that whole-blood SOD and glutathione peroxidase activities of patients were significantly lower and adenosine deaminase activities of patients were higher than those of healthy controls. There were no statistically significant differences between respiratory and nocturnal subtypes. In addition, there were no marked relationships between the duration of illness and panic-agoraphobia scores of patients with nocturnal subtypes. Hamilton Depression Rating Scale and Hamilton Anxiety Rating Scale scores of patients with the nocturnal subtype were markedly higher than those of patients without the nocturnal subtype.

CONCLUSION

The results suggest that oxidative and inflammatory processes may play a role in the pathophysiology of PD. These findings may support the idea that both nocturnal and respiratory subtypes of PD have different symptom clusters of the same disease.

Decreased IFN-γ and IL-12 levels in panic disorder

OBJECTIVE

The aim of this study is to assess the measures of proinflammatory cytokines in patients with panic disorder in comparison with the healthy subjects.

METHODS

Twenty three patients with panic disorder with or without agoraphobia and twenty three controls were recruited for the study. Plasma samples of all subjects were analyzed for TNF-α, IFN-γ, IL-1β, IL-2, IL-6, and IL-12 concentrations and NK-cell activity is measured in the peripheral blood samples of the subjects.

RESULTS

We found significant differences on the mean values of IL-12 (p=0.01) and IFN-γ (p=0.02) between the panic disorder and control groups. In a logistic regression analysis, IFN-γ values were significant statistical predictors of the presence of panic disorder (B=-0.07, SE=0.03, p=0.04).

CONCLUSION

The most important implication of our results is to suggest a relation between panic disorder and low levels of IFN-γ, compatible with the results of the animal studies showing that IFN-γ plays a role by acting to regulate the development of anxiety-like behaviors.

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.

Interleukin 10 family gene polymorphisms are not associated with major depressive disorder and panic disorder phenotypes

Genetic regulation of immune system and inflammatory response may be related to the pathogenesis and manifestations of mood and anxiety disorders. In the present study we examined a range of single-nucleotide polymorphisms (SNP) in chromosomal region 1q32, the locus of interleukin 10 (IL10) gene, in patients with major depressive disorder (n=312) and panic disorder (n=210), and matched healthy controls (n=356). We found no significant associations of the SNPs in IL10 family genes with either diagnostic group. Haplotype analysis revealed seven haplotype blocks, but their frequencies did not differ between patients and controls. Significant associations were detected for SNP rs1539243 in IKBKE (inhibitor of kappa light polypeptide gene enhancer in B-cells, kinase epsilon) gene showing different allelic and genotypic distributions in the total as well as in separate diagnostic groups as compared to controls. IKBKE emerged as a candidate for further studies of genetic factors associated with panic disorder and major depressive disorder.

Effects of venlafaxine and fluoxetine on lymphocyte subsets in patients with major depressive disorder: a flow cytometric analysis

BACKGROUND

Studies have yielded conflicting results concerning flow cytometric lymphocyte analyses in patients with depression. Data about the effect of antidepressants on lymphocyte subsets are also contradictory. The aim of this study was to determine effects of venlafaxine versus fluoxetine on lymphocyte subsets in depressive patients.

METHODS

Sixty-nine patients diagnosed with major depressive disorder (MDD) according to DSM-IV and 36 healthy controls are included in the study. Sixty-nine patients were randomized to take fluoxetine (FLX) (n=33) or venlafaxine (VEN) (n=36). Serum lymphocyte subsets included CD3, CD4, CD8, CD16/56, CD19, CD45, Anti-HLA-DR which were measured by flow cytometric analyses at baseline and 6 weeks after the start of treatment. The severity of depression was evaluated with Hamilton rating scale for depression.

RESULTS

At baseline, patients with MDD had significantly lower CD16/56 ratio and higher CD45 ratio compared to the controls. Although numerically higher in the VEN treated patients, treatment response rates between the FLX (53%) and the VEN (75%) groups were not different statistically. CD45 values decreased significantly in the VEN group at the end of the 6 week treatment period whereas no difference was observed in the FLX group. By the 6th week, treatment responders showed a significantly higher CD16/56 ratio than non-responders. Baseline severity of depression and anxiety was positively correlated with baseline CD45 ratio and negatively correlated with baseline CD16/56 ratio. We did not observe consistent changes in the absolute number of circulating B or T cells, nor in the helper/inducer (CD4) or suppressor/cytotoxic (CD8) subsets.

CONCLUSIONS

CD16/56 was lower in patients with MDD and increased in treatment responders at 6th week. CD45 ratio was higher in patients with MDD than healthy subjects; it decreased with antidepressant treatment and was positively correlated with the severity of depression. Antidepressant treatment contributes to immune regulation in patients with major depressive disorder.

Effects of experimental panic on neuroimmunological functioning

OBJECTIVE

Psychoimmunological research in panic disorder (PD) so far focussed on single time point evaluation in resting conditions. No robust evidence for changes in the immune system was found using this method. However, PD is characterized by the occurrence of unexpected panic attacks (PAs). The current research focuses on cytokine and acute phase protein (APP) levels and mitogen-induced cytokine secretion following 35% CO(2) inhalation-induced panic.

METHODS

Eighteen PD patients and 18 matched healthy control subjects underwent both a placebo and a 35% CO(2) inhalation on separate days. Blood samples for cytokine and APP determination were taken before and after the inhalation. In addition to serum determination, whole blood samples were cultured and stimulated with mitogens for assessment of the functional capacity of the immune system.

RESULTS

The 35% CO(2) inhalation induced significantly higher levels of anxiety in PD patients as compared to the control subjects, but no differences in immune parameters were found, either in basal conditions or after experimental panic induction.

CONCLUSION

In our sample we do not find any changes in serum levels or functional capacity of several immunological parameters in the experimentally provoked PAs. Similar results have been found in social phobia, whereas in other affective disorders such as depression and posttraumatic stress disorder, immune changes are evident. Changes seem to coincide with alterations in hypothalamic-pituitary-adrenal (HPA) axis function. Therefore, the bidirectional communication pathway between the immune system and the HPA axis might play a role in some affective disorders, but it does not specifically seem to be involved in the etiology of PD.

Natural Killer T cells in patients with major depressive disorder

CD56 (Natural Killer T) cells showed a significant negative correlation with depressive symptom scale scores in acute and unmedicated patients with major depressive disorder. Decreased CD56 cells may reflect the severity of depressive symptoms but not the severity of anxiety symptoms in major depression.

Lymphocyte subsets and mood states in panic disorder patients

This study was conducted to examine lymphocyte subset counts and mood states in panic disorder patients. Twenty patients with panic disorder and 20 age- and gender-matched normal healthy subjects were recruited for the study. We used the Spielberger State (STAIS) & Trait (STAIT) Anxiety Inventory, Hamilton Depression Rating scale (HAMD) and Hamilton Anxiety Rating scale (HAMA) to measure mood states in all subjects. Lymphocyte subsets counts were made by flow cytometry. Panic patients showed significantly higher scores for anxiety and depression than normal subjects. Panic patients showed no differences in terms of the numbers of immune cells, as compared with normal healthy subjects, other than a lower proportion of T suppressor cells and a higher T helper cell/T suppressor cell ratio. HAMA and STAIS scores were common factors that could predict T cell numbers and proportions, T helper cell numbers, and natural killer cell proportions in panic disorder patients. We suggest that anxiety levels are related to the T-cell population in panic disorder patients and that quantitative immune differences may reflect altered immunity in this disorder.

Changes in lymphocyte subsets after short-term pharmacotherapy in patients with panic disorder

Panic disorder is associated with a high frequency of comorbid immunological diseases, such as allergies and asthma, although the psychoneuroimmunology of panic disorder is relatively unexplored. The objective of this study was to determine whether panic patients have different immunological findings compared with normal healthy subjects and whether changes in immune function are associated with short-term pharmacotherapy. We also examined whether immunological variables were associated with clinical severity and serum catecholamine levels. Patients with panic disorder (n=26) and healthy control subjects (n=26) were recruited for this study. All patients were treated with paroxetine for 3 months. We measured the lymphocyte subsets, psychopathological characteristics and serum catecholamine (norepinephrine and epinephrine) levels. Panic patients did not differ initially from control subjects in peripheral lymphocyte phenotypic markers. After drug therapy, however, percentages of circulating CD3+, CD4+ and CD8+ T lymphocytes were significantly increased, while the percentage of CD19+ B lymphocytes was significantly decreased in the patients. The difference in the percentage of CD8+ T lymphocytes before and after treatment was negatively correlated with pretreatment Global Clinical Impression scores. The lymphocyte subsets were not significantly associated with serum catecholamine levels in panic patients. In conclusion, panic patients showed increased CD3+, CD4+ and CD8+ T lymphocyte proportions and a decreased B lymphocyte proportion after 3 months of drug therapy. This finding suggests that pharmacological treatment may affect immune function in panic patients.

Immune parameters in patients with anxiety or depression during psychotherapy

BACKGROUND

Numerous studies have described distinctive immunological findings in patients with depression. In contrast, only very little is known about the possible influence of anxiety disorders on the immune system. It is also unknown whether treatment with psychotherapy alone has any influence on immunological variations in patients with psychiatric disorders.

METHODS

We measured immunological and psychological parameters in patients with minor depression (N=10) or anxiety disorder (N=13) over an 8-week course of inpatient psychotherapy. Data for patients and a group of healthy controls (N=11) were recorded three times in 4-week intervals. A FACS analysis revealed the composition of lymphocyte subpopulations. The production of reactive oxygen species (ROS) by phagocytes was analyzed using lucigenin-enhanced chemiluminescence.

RESULTS

On admission, patients with anxiety disorder showed a markedly elevated ratio of CD4(+) (T helper) versus CD8(+) (T suppressor/cytotoxic) lymphocytes compared to healthy controls (P<0.001) and minor depressives (P<0.01). The increased ratio in patients with anxiety disorder could mainly be attributed to a reduced count in CD8(+) T cells compared to healthy controls (P<0.01) and depressives (P<0.05). There were no differences between patients with depression and healthy controls with respect to the CD4(+)/CD8(+) ratio. We did not observe any differences in the production of ROS by phagocytes in patients compared to healthy controls. The CD4(+)/CD8(+) ratio remained elevated in patients with anxiety disorders during the following 8 weeks. There were no significant changes in this parameter over the course of the inpatient treatment.

LIMITATIONS

As a pilot study on the immune status in patients with anxiety disorders, the study's main limitation is the relatively low number of patients observed.

CONCLUSIONS

In this study we demonstrated for the first time marked immunological changes in patients with anxiety disorders. In addition, our results provide preliminary evidence that these immunological variations are not reversible by an 8-week course of inpatient psychotherapy alone.

Neuroimmunological parameters in panic disorder

BACKGROUND

The interaction between immune cells, neurotransmitters and the neuroendocrinological systems plays a role in affective disorders, especially depression. Although panic disorder (PD) shares a lot of features with depression, it is clearly a distinct disorder. Reports on immunological parameters in PD don't provide a clear picture of the immunological status of PD patients. This can partly be attributed to methodological differences between studies and small patient groups.

OBJECTIVE

The present study aims to assemble all studies on immunological parameters in PD in order to combine all available data to gain a broader perspective on this matter.

METHOD

PubMed was searched for studies describing immunological parameters in PD patients without comorbid disorders or medication use. All studies had to include a healthy control group and the outcome measures had to be shared by at least one other study.

RESULTS

Fourteen articles were found. Although the T-lymphocytic branch and the innate immune system were normal, the B-lymphocytic branch showed some differences between PD patients and healthy controls. B-cell counts were increased in PD patients, which was underlined by increased human leucocyte antigen (HLA)-DR counts and increased immunoglobulin A levels. However, B-cell activity following mitogen stimulation was normal.

CONCLUSIONS

PD patients show increased B-cell numbers. The finding that B-cell activity is not increased can possibly be attributed to functional exhaustion of these cells. The meaning of this finding remains unclear, although it may be potentially important in affective disorders as the same has been found in depression.