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.

Hypermethylation of FOXP3 Promoter and Premature Aging of the Immune System in Female Patients with Panic Disorder?

Immunological abnormalities associated with pathological conditions, such as higher infection rates, inflammatory diseases, cancer or cardiovascular events are common in patients with panic disorder. In the present study, T cell receptor excision circles (TRECs), Forkhead-Box-Protein P3 gene (FOXP3) methylation of regulatory T cells (Tregs) and relative telomere lengths (RTLs) were investigated in a total and subsamples of 131 patients with panic disorder as compared to 131 age- and sex-matched healthy controls in order to test for a potential dysfunction and premature aging of the immune system in anxiety disorders. Significantly lower TRECs (p = 0.004) as well as significant hypermethylation of the FOXP3 promoter region (p = 0.005) were observed in female (but not in male) patients with panic disorder as compared to healthy controls. No difference in relative telomere length was discerned between patients and controls, but significantly shorter telomeres in females, smokers and older persons within the patient group. The presently observed reduced TRECs in panic disorder patients and FOXP3 hypermethylation in female patients with panic disorder potentially reflect impaired thymus and immunosuppressive Treg function, which might partly account for the known increased morbidity and mortality of anxiety disorders conferred by e.g. cancer and cardiovascular disorders.

The G allele in IL-10-1082 G/A may have a role in lowering the susceptibility to panic disorder in female patients.

BACKGROUND: Immune system activation is involved in the pathophysiology of panic disorder (PD). We investigated INF-γ+874 A/T, TNF-α-308 G/A, and IL-10-1082 G/A single nucleotide polymorphisms (SNPs) to determine their association with PD. METHOD: This study enroled 135 PD patients and 135 healthy controls. INF-γ+874 A/T (rs2430561), TNF-α-308 G/A (rs1800629), and IL-10-1082 G/A (rs1800896) were genotyped. RESULTS: There were no differences in genotypes or allele frequencies between the patient and control groups, regardless of accompanying agoraphobia. However, for female patients, the G allele frequency in IL-10 SNP was higher in the control group than in the patient group. Additionally, the female control group had a higher frequency of the A/G and G/G genotype in the IL-10 SNP than the female patient group. CONCLUSION: We suggest that the G allele in IL-10-1082 G/A might have a role in reducing the manifestations of PD in female patients. Further studies are needed to extend and confirm our findings.

Bipolar and panic disorders may be associated with hereditary defects in the innate immune system.

BACKGROUND: Mannan-binding lectin (MBL) and mannan-binding lectin-associated serine protease-2 (MASP-2) represent important arms of the innate immune system, and different deficiencies may result in infections or autoimmune diseases. Both bipolar and panic disorders are associated with increased inflammatory response, infections and mutual comorbidity. However, associations with MBL, MASP-2 or the gene, MBL2, coding for MBL, have not been investigated thoroughly. METHODS: One hundred patients with bipolar disorder, 100 with panic disorder and 349 controls were included. Serum concentrations of MBL and MASP-2 were measured and seven single nucleotide polymorphisms (SNPs) influencing these concentrations were genotyped. Disease association with genetic markers and serum levels were investigated. RESULTS: In panic disorder, we observed a large proportion (30%) of MBL deficient (<100ng/ml) individuals and significantly lower levels of MBL and MASP-2 plus association with the MBL2 YA two-marker haplotype. Bipolar disorder was associated with the MBL2 LXPA haplotype and lower MASP-2 levels. LIMITATIONS: No information on course or severity of disorders was included, and only MBL and MASP-2 were measured, excluding other components from the complement pathway. Restrictions defined by ethnical committees preclude information of control׳s ethnic origin. CONCLUSIONS: Significant differences in MBL and MASP-2 concentrations were observed between cohorts, especially an intriguing finding associating panic disorder with MBL deficiency. These differences could not be fully explained by allele or haplotype frequency variations. Since MBL deficiency is highly heterogeneous and associated with both infectious and autoimmune states, more research is needed to identify which complement pathway components could be associated with bipolar respectively panic disorder.

Immunoglobulin levels in panic disorder patients.

The study was conducted to evaluate the serum immunoglobulin levels in patients suffering from panic disorder and to assess the relationship between the changes of immunoglobulin levels and the socioeconomic parameters, as well as nutritional status. 54 panic patients were randomly selected from the Department of Psychiatry, Bangabandhu Sheikh Mujib Medical University (BSMMU) and Dhaka Medical College Hospital, Bangladesh. Fifty two, age and gender matched healthy volunteers (42 males and 10 females, mean age of 30 ± 6 yrs) were also enrolled in this study. Immunoglobulin levels were measured by turbidimetry method using immunoglobulin kits. It was found that the mean serum immunoglobulin concentrations of IgG, IgM and IgA of panic disorder patients were 0.999±0.26 (g/L), 0.1±0.028 (g/L) and 0.194±0.066 (g/L) respectively whereas the values were 1.24± 0.39 ( g/L ), 0.096±0.022 ( g/L) , 0.194±0.053 (g/L) in healthy volunteers. IgG level in panic disorder patient was found significantly (p <0.05) lower than that of the controls but the change in concentration of IgM and IgA were not significant (p=0.497, p=0.962). Socioeconomic data reveals that most of the patients were from lower income group and educated. BMI (Mean±SD) of the patients (22.62 ± 3.74 kg/m2) and controls (23.74 ± 2.71 kg/m2) were well within the normal range. From correlative analysis it has been found that income has significant effect (p=0 .047) on the change of the serum IgG level in panic disorder patient and it was also been justified by the regression analysis (p=0.049). This finding may play a key role in the diagnosis and treatment of the panic disorder patients. Further studies have been suggested with a large number of populations to confirm these findings.

Broad spectrum of cytokine abnormalities in panic disorder and posttraumatic stress disorder.

BACKGROUND: Proinflammatory cytokines have been reported to be elevated in individuals experiencing chronic stress as well as in those with major depressive disorder. Much less is known about cytokines in anxiety disorders such as posttraumatic stress disorder (PTSD) and panic disorder (PD). We hypothesized that PD and PTSD would be associated with a generalized proinflammatory cytokine signature. METHOD: We utilized Luminex technology to examine 20 cytokines and chemokines in serum from 48 well-characterized individuals with a primary DSM-IV PD or PTSD diagnosis, and 48 age- and gender-matched healthy controls. We conservatively employed a Bonferroni correction for multiple testing (alpha=.05/20=.0025). RESULTS: Individuals with primary PTSD or PD had significantly elevated median peripheral cytokine levels for 18 of 20 different cytokines compared to age- and gender-matched healthy controls (all P<.0025). To assess for the presence of a generalized proinflammatory state, we also examined the proportion of subjects with detectable levels of at least six of nine common proinflammatory cytokines and chemokines (IL-6, IL-1alpha, IL-1beta, IL-8, MCP-1, MIP-1alpha, Eotaxin, GM-CSF, and IFN-alpha). For men and women, 87% of anxiety patients had six or more detectable levels of these proinflammatory cytokines, compared with only 25% of controls (Fisher's Exact Test (FET) P=.000). Confirmatory analysis of the subset of individuals without current psychiatric medication use or comorbid depression was of comparable significance. CONCLUSIONS: These findings suggest that a generalized inflammatory state may be present in individuals with PD or PTSD.

Effects of experimentally induced panic attacks on neuroimmunological markers.

Since little is known concerning regulation of immunological parameters in rapid changing psychiatric states like panic attacks, we measured cytokines at different time points in healthy subjects, which underwent experimental panic induction using the CCK-4 paradigm. Apart from a challenge related IL-6 increase, we could not observe any changes of neuroimmunological markers in relation to acute anxiety with regard to time and group. Herein we conducted for the first time a new approach to immunological research in panic disorder, suggesting immune changes are more related to long term disease stress.

[Levels of adenosine deaminase and dipeptidyl peptidase IV in patients with panic disorder]. / Panik bozuklugunda adenozin deaminaz ve dipeptidil peptidaz IV enzim düzeyleri.

OBJECTIVE: Adenosine deaminase and dipeptidyl peptidase IV are enzymes connected to T cells that play an important role in immune system functioning. In this study, in order to understand the immune processes in panic disorder, we determined the serum levels of adenosine deaminase and dipeptidyl peptidase IV in medication-free panic disorder patients and compared them to those of healthy controls. METHOD: Enzymes levels were determined in blood samples of 24 healthy controls and 33 panic disorder patients diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders-IV that were medication free during the previous month and medically healthy. RESULTS: Levels of both enzymes were significantly higher in panic disorder patients than in the controls (P<0.001 for adenosine deaminase and P<0.05 for dipeptidyl peptidase IV). The levels of the enzymes did not correlate with sociodemographic variables, duration of the disorder, presence of agoraphobia, presence of stressors, number of panic attack symptoms, and Hamilton depression and anxiety rating scale scores. In addition, the 2 enzymes? levels did not correlate with each other. There was a correlation between Hamilton anxiety rating scale score and the number of panic attack symptoms (P<0.001); however, Hamilton anxiety rating scale scores were not correlated with the other variables. CONCLUSION: Our results suggest that there may be a primary or secondary impaired immune state in the course of panic disorder, as there is in many other psychiatric disorders, such as major depression. Future studies with larger samples are needed to clarify the relationship between the immune system and panic 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.

Psychiatric presentation of voltage-gated potassium channel antibody-associated encephalopathy. Case report.

Voltage-gated potassium channel antibody encephalopathy, a rare cause of limbic encephalopathy, typically presents with memory impairment and seizures. Psychiatric symptoms have not been emphasised in the literature. Here we describe a 58-year-old man who presented with panic attacks and psychogenic non-epileptic seizures and, later on, developed delusions and hallucinations and then confusion. He was found to have antibodies to voltage-gated potassium channels. Treatment with immuno-modulatory therapy resulted in almost complete recovery.

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.

Reduced anxiety level by therapeutic interventions and cell-mediated immunity in panic disorder patients.

OBJECTIVE: This study examined the relationship between reduced anxiety level by therapeutic interventions and cell-mediated immunity (CMI) in patients with panic disorder. METHODS: The subjects consisted of 42 patients with panic disorder and 42 normal gender- and age-matched controls. Among the patients, 21 were randomly assigned to a combined treatment of cognitive-behavioral therapy and the benzodiazepine antianxiety agent ethyl loflazepate (2 mg daily), and 21 were assigned to the antianxiety agent only. The treatment lasted for 6 weeks. Cell-mediated immune function was measured by the lymphocyte proliferative response to phytohemagglutinin (PHA) and interleukin-2 (IL-2) production. The anxiety level was assessed by the Hamilton Rating Scale for Anxiety and the anxiety subscale of the Symptom Checklist-90 Revised. RESULTS: Prior to treatment, the panic disorder patients had significantly lower IL-2 production and blastogenic response to PHA than the normal controls. However, no significant differences in CMI were found between the pretreatment and posttreatment period in either the patient group receiving medication only or the combined treatment group, though after treatment, patients were significantly less anxious than before treatment in both intervention groups. The delta change (posttreatment value minus pretreatment value) in the self-reported anxiety level was significantly associated with the delta change in the blastogenic response in the combined treatment group. CONCLUSION: These findings suggest that panic disorder may be associated with decreased CMI, and the reduced level of self-reported anxiety in the patients who underwent combined therapeutic intervention is likely to increase the blastogenic response. Further studies are needed to evaluate the long-term effects of treatment on immune function.

Stress regulates the lymphocyte homing receptor CD62L (L-selectin).

Based on a previous study showing that panic disorder patients had increased expression of na ve phenotype lymphocytes (CD45RA+ and CD62L+), increased plasma cortisol, as well as decreased interleukin-2 (IL-2) producion, we hypothesized that changes in the percentage of expression of these lymphocyte surface molecules could be related to the substances released by the hypothalamic-pituitary-adrenal (HPA) axis and possibly associated to panic disorder (cortisol, IL-2, serotonin and epinephrine). In order to study the altered expression, blood mononuclear cells of normal volunteers were stimulated with mitogen, in the presence of dexamethasone, IL-2, serotonin and epinephrin. CD62L is decreased by IL-2 in vitro. Serotonin and epinephrine did not promote changes in the expression of these surface molecules. The results of the ex vivo study are in agreement with a previous clinical study with panic patients. It could be suggested that stress is responsible for certain immunologic dysfunctions and new studies should be conducted.

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

Altered immune measures are commonly found in major depression (MD), however, less is known about the immune system in anxiety disorders. We examined quantitative and functional in vitro immune measures in patients with panic disorder (PD), which is often comorbid with MD. Fourteen otherwise healthy medication-free adults (ages 23-49; 11 female) meeting SCID-UP DSM-IIIR criteria for PD with agoraphobia and without current MD, were compared with 14 subjects free of PD, MD, or other major psychiatric disorders, matched by gender, age, and racial background. PD was associated with decreased percentage (p<.03) and total (p<.03) circulating CD19+ B lymphocytes, but no differences in other enumerative lymphocyte measures. Mitogen responses (Con A, PHA, PWM) did not differ except for possibly decreased PHA in PD (p<.06). NK cell activity did not differ between PD and control subjects. The few immune measure changes in PD contrast with those found in MD, providing further evidence for the specificity of immune changes in psychiatric disorders.

Cell-surface expression of L-selectin (CD62L) by blood lymphocytes: correlates with affective parameters and severity of panic disorder.

The surface immune phenotype of peripheral blood lymphocytes (PBL) was examined in 30 patients meeting DSM-III-R criteria for panic disorder and in 10 normal controls by immunostaining and cytofluorimetry. Patients with panic disorder and controls showed comparable numbers of PBL and no differences in the percentages of blood T-cells, B-cells, or NK-cells. The PBL in panic disorder patients showed a trend toward enrichment for "naive" CD45RA+ T-lymphocytes (35.0 +/- 7.6 vs. 28.7 +/- 9.8, P = 0.09) and significant enrichment for cells expressing CD62L (L-selectin, 22.9 +/- 5.9 vs. 14.6 +/- 6.3, P = 0.002), a lymphocyte homing receptor that mediates binding to lymph node endothelium. Increased expression of CD62L correlated directly with the global severity of illness, Hamilton Anxiety (HAM-A) and Hamilton Depression (HAM-D) scores. Although in the normal range, plasma cortisol levels were significantly increased in patients with panic disorder (P = 0.003) with respect to controls and correlated with the expression of CD62L by PBL. We conclude that the peripheral blood in panic disorder shows phenotypic changes that may reflect diminished cell activation in vivo.

Cytokine production in panic disorder patients.

Based on findings that stress and anxiety may modulate immune function, we compared the production of interleukin-2 (IL-2) and interleukin-3 (IL-3) by peripheral blood mononuclear cells between 24 patients with nonmajor depressed panic disorders, 9 with agoraphobia and 15 without, and 19 healthy volunteers. No differences in the production of these cytokines was noted between the patients with panic disorders and the volunteers or between the patients with and without agoraphobia. However, in the patients, a negative correlation was found for interleukin-3 production with severity of state anxiety, but not with trait anxiety or depression. This finding indicates that interleukin-3 levels may be sensitive to the presence of anxiety and stress.

Plasma anti-serotonin and serotonin anti-idiotypic antibodies are elevated in panic disorder.

The psychoneuroimmunology of panic disorder is relatively unexplored. Alterations within brain stress systems that secondarily influence the immune system have been documented. A recent report indicated elevations of serotonin (5-HT) and ganglioside antibodies in patients with primary fibromyalgia, a condition with documented associations with panic disorder. In line with our interest in dysregulated 5-HT systems in panic disorder (PD), we wished to assess if antibodies directed at the 5-HT system were elevated in patients with PD in comparison to healthy volunteers. Sixty-three patients with panic disorder and 26 healthy volunteers were diagnosed by the SCID. Employing ELISA, we measured anti-5-HT and 5-HT anti-idiotypic antibodies (which are directed at 5-HT receptors). To include all subjects in one experiment, three different batches were run during the ELISA. Plasma serotonin anti-idiotypic antibodies: there was a significant group effect [patients > controls (p = .007)] and batch effect but no interaction. The mean effect size for the three batches was .76. Following Z-score transformation of each separate batch and then combining all scores, patients demonstrated significantly elevated levels of plasma serotonin anti-idiotypic antibodies. Neither sex nor age as covariates affected the significance of the results. There was a strong correlation between anti-serotonin antibody and serotonin anti-idiotypic antibody measures. Plasma anti-serotonin antibodies: there was a significant diagnosis effect [patients > controls (p = .037)]. Mean effect size for the three batches was .52. Upon Z-score transformation, there was a diagnosis effect with antibody elevations in patients. Covaried for sex and age, the result falls below significance to trend levels. The data raise the possibility that psychoimmune dysfunction, specifically related to the 5-HT system, may be present in PD. Potential interruption of 5-HT neurotransmission through autoimmune mechanisms may be of pathophysiologic significance in certain patients with panic disorder. It remains to be demonstrated if the peripheral autoimmunity is representative of CNS 5-HT neuronal alterations. Replication appears warranted.

Plasma levels of tumor necrosis factor-alpha in patients with panic disorder: effect of alprazolam therapy.

Plasma concentrations of tumor necrosis factor-alpha (TNF-alpha) were measured in 10 outpatients with panic disorder, twice (at a 48-h interval) before and twice on days 30-32 of treatment with alprazolam (2-2.5 mg/day), and twice in 10 age- and sex-matched healthy controls. TNF-alpha concentrations did not differ in patients and control subjects, either before therapy or at days 30-32 of therapy. In five patients before therapy, and in three of them after therapy, TNF-alpha values were higher than the maximal concentrations of the cytokine in controls.

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

BACKGROUND: Although the relationship between stress and immune function is an area of active investigation, there have been few reports studying the relationship between anxiety disorders and the immune system. METHODS: This study employs flow cytometry to measure circulating lymphocyte phenotypic markers in 20 medication-free patients with panic disorder, 33 medication-free patients with generalized social phobia, and 32 healthy controls. RESULTS: Both patients with panic disorder and patients with social phobia had increased CD16 (natural killer) cell numbers. Panic disorder patients also had increased numbers of CD19 cells (B lymphocytes), human leukocyte antigen (HLA)-DR-presenting cells, and more cells with the combination of HLA-DR and CD19 surface markers (B lymphocytes with HLA-DR on their surface). CONCLUSIONS: These preliminary data suggest that subjects with panic disorder may have alterations in circulating lymphocyte profiles.