Psychoimmune investigation in obsessive-compulsive disorder: assays of plasma transferrin, IL-2 and IL-6 receptor, and IL-1 beta and IL-6 concentrations

Exploring the role of interleukin-1β and interleukin-6 in the pathophysiology of obsessive-compulsive disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) is a highly prevalent neuropsychiatric disorder. Recently, there has been a growing interest in investigating the association between pro-inflammatory cytokines and the pathogenesis of OCD. However, studies targeting interleukin-1β (IL-1β) and interleukin-6 (IL-6) in OCD are limited. Therefore, the present study aimed to explore the potential role of pro-inflammatory cytokines IL-1β and IL-6 in the pathophysiology and development of OCD.

METHODS

This study recruited 58 OCD patients and 30 age-sex-matched healthy controls (HCs). A qualified psychiatrist diagnosed OCD patients and assessed HCs based on the Diagnostic and Statistical Manual for Mental Health Disorders, 5th edition (DSM-5) criteria. We measured the severity of OCD using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). Serum IL-1β and IL-6 levels were measured using ELISA kits following the appropriate methods.

RESULTS

The results showed that serum IL-1β levels were significantly elevated in OCD patients compared to HCs (23.68±1.65 pg/ml vs. 15.75±1.02 pg/ml; p = 0.002). Similarly, OCD patients exhibited significantly higher serum IL-6 levels than HCs (44.97±0.73 pg/ml vs. 37.04±0.35 pg/ml; p<0.001). We observed both cytokines were positively correlated with the Y-BOCS scores in OCD patients (IL-1β: r = 0.380, p = 0.015; IL-6: r = 0.324, p = 0.026) which indicates their role in disease pathophysiology.

CONCLUSION

These results suggest that serum IL-1β and IL-6 levels may be associated with the pathophysiology of OCD. Also, these cytokines levels in blood samples can serve as early risk assessment tools for the development of OCD. We recommend further studies in a large and homogeneous population to support these findings.

Inflammation in obsessive-compulsive disorder: A literature review and hypothesis-based potential of transcranial photobiomodulation

Obsessive-compulsive disorder (OCD) is a disabling neuropsychiatric disorder that affects about 2%-3% of the global population. Despite the availability of several treatments, many patients with OCD do not respond adequately, highlighting the need for new therapeutic approaches. Recent studies have associated various inflammatory processes with the pathogenesis of OCD, including alterations in peripheral immune cells, alterations in cytokine levels, and neuroinflammation. These findings suggest that inflammation could be a promising target for intervention. Transcranial photobiomodulation (t-PBM) with near-infrared light is a noninvasive neuromodulation technique that has shown potential for several neuropsychiatric disorders. However, its efficacy in OCD remains to be fully explored. This study aimed to review the literature on inflammation in OCD, detailing associations with T-cell populations, monocytes, NLRP3 inflammasome components, microglial activation, and elevated proinflammatory cytokines such as TNF-α, CRP, IL-1β, and IL-6. We also examined the hypothesis-based potential of t-PBM in targeting these inflammatory pathways of OCD, focusing on mechanisms such as modulation of oxidative stress, regulation of immune cell function, reduction of proinflammatory cytokine levels, deactivation of neurotoxic microglia, and upregulation of BDNF gene expression. Our review suggests that t-PBM could be a promising, noninvasive intervention for OCD, with the potential to modulate underlying inflammatory processes. Future research should focus on randomized clinical trials to assess t-PBM's efficacy and optimal treatment parameters in OCD. Biomarker analyses and neuroimaging studies will be important in understanding the relationship between inflammatory modulation and OCD symptom improvement following t-PBM sessions.

The association between anxiety, traumatic stress, and obsessive-compulsive disorders and chronic inflammation: A systematic review and meta-analysis

BACKGROUND

Anxiety is characterized by prolonged preparation for real or perceived threat. This may manifest both as psychological and physiological activation, ultimately leading to greater risk for poor health. Chronic inflammation may play an integral role in this relationship, given the influential role that it has in chronic illness. The aim of this meta-analysis is to examine levels of chronic inflammation, measured by inflammatory cytokines and C-reactive protein, in people with anxiety disorders, PTSD (posttraumatic stress disorder), or obsessive-compulsive disorder compared to healthy controls. Several moderating variables, including specific diagnosis and depression comorbidity, were also assessed.

METHODS

Seventy six full-text articles were screened for eligibility with 41 studies ultimately included in analysis.

RESULTS

Results demonstrated a significant overall difference between healthy controls (HCs) and people with anxiety disorders in pro-inflammatory cytokines (P = 0.013, Hedge's g = -0.39), which appears to be largely driven by interleukin-1β (IL-1β; P = 0.009, Hedge's g = -0.50), IL-6 (P < 0.001, Hedge's g = -0.93), and tumor necrosis factor-α (P = 0.030, Hedge's g = -0.56). Moderation analyses revealed a moderating effect of diagnosis (P = 0.050), as only individuals with PTSD demonstrated differences in inflammation between HCs (P = 0.004, Hedge's g = -0.68).

CONCLUSIONS

These data demonstrate the association between inflammatory dysregulation and diagnoses associated with chronic, impactful, and severe anxiety and provides insight into the way that anxiety, and in particular PTSD, is related to certain inflammatory markers. In doing so, these findings may provide an initial step in disentangling the relationship between anxiety and basic health processes.

Immune Aberrations in Obsessive-Compulsive Disorder: a Systematic Review and Meta-analysis

Some lines of evidence have indicated that immune dysregulation could play a role in the pathophysiology of obsessive-compulsive disorder (OCD). However, results have been inconsistent across studies. Thus, a systematic review and meta-analysis of studies measuring immune mediators in participants with OCD compared to healthy controls (HC) was conducted. The PubMed/MEDLINE, PsycINFO, and EMBASE electronic databases were systematically searched from inception through June 21, 2018. Sixteen studies met inclusion criteria comprising data from 1001 participants (538 with OCD and 463 were HCs). Levels of TNF-α, IL-6, IL-1β, IL-4, IL-10, and interferon-γ did not significantly differ between participants with OCD and healthy controls. In addition, the ex vivo production of TNF-α and IL-6 by isolated macrophages did not significantly differ between participants with OCD and HCs. Nevertheless, included studies have varied in methodological quality with the enrollment of samples that differed regarding medication status, the proper matching of OCD participants and HCs, age groups, and the presence of psychiatric comorbidities. In conclusion, an association between immune dysregulation and OCD remains unproven. Future studies should consider enrolling larger and more homogeneous samples with OCD.

Individualized Immunological Data for Precise Classification of OCD Patients

Obsessive⁻compulsive disorder (OCD) affects about 2% of the general population, for which several etiological factors were identified. Important among these is immunological dysfunction. This review aims to show how immunology can inform specific etiological factors, and how distinguishing between these etiologies is important from a personalized treatment perspective. We found discrepancies concerning cytokines, raising the hypothesis of specific immunological etiological factors. Antibody studies support the existence of a potential autoimmune etiological factor. Infections may also provoke OCD symptoms, and therefore, could be considered as specific etiological factors with specific immunological impairments. Finally, we underline the importance of distinguishing between different etiological factors since some specific treatments already exist in the context of immunological factors for the improvement of classic treatments.

Cytokine, chemokine and BDNF levels in medication-free pediatric patients with obsessive-compulsive disorder

The aim of this study was to investigate whether the serum levels of IL-12, IL-17, TGFβ, TNF-alpha, sTNFR1, sTNFR2, IL-1β, CCL3, CCL24, CXCL8, and BDNF are associated with obsessive-compulsive disorder (OCD) in medication-free children. A total of 44 (22 boys/22 girls) medication-free children with OCD and 40 (23 boys/17 girls) healthy controls were included in this study. The severity of the OCD symptoms were assessed by the Children's Yale-Brown Obsessive-Compulsive Scale and the Maudsley Obsessive-Compulsive Inventory. The Children's Depression Inventory and the Screen for Child Anxiety-Related Emotional Disorders were applied to the children in order to determine depression and anxiety levels. IL-17, IL-12, TGF β, TNF-alpha, sTNFR1, sTNFR2, IL-1β, CCL3, CCL24, CXCL8, and BDNF levels were measured by enzyme-linked immunosorbent assay. Multivariate analysis of covariance (MANCOVA) revealed a significant main effect on both groups for the levels of serum cytokine, chemokine, and BDNF, an effect that was independent of severities of depression and anxiety [Pillai's Trace V = 0.371, F (11, 70) = 3.756, p < 0.001, hp² = 0.187]. Analysis of covariance (ANCOVA) indicated that serum TNF-alpha levels were significantly higher in the OCD group than in the control group (p < 0.001). In contrast, serum IL-12 levels were significantly lower in the OCD group than in the control group (p = 0.014). These findings suggest that TNF-alpha and IL-12 may play a role in the pathophysiology of OCD in children. The causal relationship between these proinflammatory cytokines and pediatric OCD requires further investigation.

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.

Plasma cytokine abnormalities in drug-naïve, comorbidity-free obsessive-compulsive disorder

Growing evidence in the last decade suggest significant role of immune alterations in the pathogenesis of obsessive-compulsive disorder (OCD). Cytokines, mediators of inflammation, alter the neurotransmitter concentration and result in a hyposerotonergic and hyperglutamatergic state implicated in pathogenesis of OCD. However, only few studies have examined cytokine abnormalities in OCD with inconsistent results possibly due to confounding effects of medications and comorbid anxiety-depression. We examined 20 comorbidity free, drug free OCD patients and 20 age and sex matched healthy controls. Clinical severity was assessed using Yale Brown Obsessive Compulsive Scale, Hamilton anxiety rating scale, Hamilton depression rating scale and Clinical Global Impression. Levels of different cytokines, Interleukin (IL)-2, IL-4, IL-6, IL-10, Tumor necrosis factor (TNF)-α and Interferon (IFN)-γ were assessed using Cytometric Bead Array. OCD patients had significantly greater plasma levels of IL-2, IL-4, IL-6, IL-10 and TNF-α levels than controls but not IFN-γ. Reanalysis of data with only drug naïve patients (excluding 4 drug free patients) did not alter the results. Presence of these abnormalities in drug-naïve patients suggests the possible role of cytokines in the pathogenesis of OCD. Study findings have potential clinical utility in development of novel therapeutic options targeting cytokine aberrations in OCD.

Association study between IL-1β-511 C/T polymorphism and obsessive-compulsive disorder (OCD) in Chinese Han population

AIM

This study investigated the potential association between Obsessive-Compulsive Disorder (OCD) and a functional polymorphism of IL-1beta-511 C/T in Chinese Han population.

METHODS

The authors genotyped the IL-1beta-511 C/T of 241 OCD patients and 444 healthy control subjects and then performed a case-control association analysis.

RESULTS

No difference was found in IL-1beta-511 C/T genotypic and allelic frequencies between OCD cases and controls (chi2 = 0.501, df = 2, P = 0.78 by genotype; chi2 = 0.487, df = 1, P = 0.49 by allele).

CONCLUSION

IL-1beta-511 polymorphism may not play a major role in the genetic predisposition to OCD in Chinese Han population. Given that this is an early investigation of this gene in OCD, further studies are required to draw firm conclusions.

How cigarette smoking may increase the risk of anxiety symptoms and anxiety disorders: a critical review of biological pathways

Multiple studies have demonstrated an association between cigarette smoking and increased anxiety symptoms or disorders, with early life exposures potentially predisposing to enhanced anxiety responses in later life. Explanatory models support a potential role for neurotransmitter systems, inflammation, oxidative and nitrosative stress, mitochondrial dysfunction, neurotrophins and neurogenesis, and epigenetic effects, in anxiety pathogenesis. All of these pathways are affected by exposure to cigarette smoke components, including nicotine and free radicals. This review critically examines and summarizes the literature exploring the role of these systems in increased anxiety and how exposure to cigarette smoke may contribute to this pathology at a biological level. Further, this review explores the effects of cigarette smoke on normal neurodevelopment and anxiety control, suggesting how exposure in early life (prenatal, infancy, and adolescence) may predispose to higher anxiety in later life. A large heterogenous literature was reviewed that detailed the association between cigarette smoking and anxiety symptoms and disorders with structural brain changes, inflammation, and cell-mediated immune markers, markers of oxidative and nitrosative stress, mitochondrial function, neurotransmitter systems, neurotrophins and neurogenesis. Some preliminary data were found for potential epigenetic effects. The literature provides some support for a potential interaction between cigarette smoking, anxiety symptoms and disorders, and the above pathways; however, limitations exist particularly in delineating causative effects. The literature also provides insight into potential effects of cigarette smoke, in particular nicotine, on neurodevelopment. The potential treatment implications of these findings are discussed in regards to future therapeutic targets for anxiety. The aforementioned pathways may help mediate increased anxiety seen in people who smoke. Further research into the specific actions of nicotine and other cigarette components on these pathways, and how these pathways interact, may provide insights that lead to new treatment for anxiety and a greater understanding of anxiety pathogenesis.

Exercising the worry away: how inflammation, oxidative and nitrogen stress mediates the beneficial effect of physical activity on anxiety disorder symptoms and behaviours

Regular physical activity exerts positive effects on anxiety disorder symptoms, although the biological mechanisms underpinning this effect are incompletely understood. Numerous lines of evidence support inflammation and oxidative and nitrogen stress (O&NS) as important in the pathogenesis of mood and anxiety disorders, and physical activity is known to influence these same pathways. This paper reviews the inter-relationships between anxiety disorders, physical activity and inflammation and O&NS, to explore whether modulation of inflammation and O&NS may in part underpin the positive effect of physical activity on anxiety disorders. Numerous studies support the notion that physical activity operates as an anti-inflammatory and anti-O&NS agent which potentially exerts positive effects on neuroplasticity, the expression of neurotrophins and normal neuronal functions. These effects may therefore influence the expression and evolution of anxiety disorders. Further exploration of this area may elicit a deeper understanding of the pathogenesis of anxiety disorders, and inform the development of integrated programmes including PA specifically suited to the treatment and prevention of anxiety disorders and symptoms.

Anti-purkinje cell and natural autoantibodies in a group of psychiatric patients. Evidences for a correlation with the psychopathological status

Phenomena of autoimmunity are frequent among psychiatric patients, but we don't know yet if they should be considered primary and linked to the pathophisiology of the disorder, or aspecific and associated to a general immune system activation. Paraneoplastic Cerebellar Degeneration (PCD) represents a well known model of specific autoimmunity. In order to better understand the abovementioned issues, we used this condition to compare a set of immune dysfunctions found in a group of psychiatric patients. For this reason we tested sera from 48 psychiatric patients (24 schizophrenics, 17 bipolars and 7 obsessive-compulsive), 22 PCD patients and 52 healthy controls for the presence of anti-Purkinje autoantibodies and of some natural autoantibodies (ANAs, AMAs, APCAs, ASMAs). Psychopatological status of the psychiatric patients was assessed with BPRS, SANS, SAPS, HAM-D, CGI-S. In the psychiatric group anti-Purkinje autoantibodies were identified in 11/48 (22,9%) patients, while they were present in 22/22 (100%) PCD patients and in 0/52 (0%) healthy controls. Among all anti-Purkinje autoantibody positive patients (in the PCD and psychiatric samples), only those belonging to the psychiatric sample, but not those with PCD, were frequently found positive also for natural autoantibodies, that are considered good markers of aspecific immune activation. In these patients, both anti-Purkinje and natural autoantibodies were found associated with acute/positive psychopathological symptoms. These results seem to point out that some phenomena of auto-immunity described in psychiatric patients could be aspecific, unrelated to the pathophysiology of the concomitant mental disorders and could be more frequent during phases of acute/positive symptoms.

A cytokine study of adult patients with obsessive-compulsive disorder

OBJECTIVES

We aimed to determine the plasma levels of cytokines in patients with obsessive-compulsive disorder (OCD) as compared with healthy controls and to investigate whether there is any association between their concentrations and OCD clinical and therapeutic features.

METHODS

Forty patients with OCD and 40 healthy controls had their plasmas assessed for a range of cytokines (tumor necrosis factor-α, or TNF-α), chemokines (CCL2, CCL3, CCL11, CCL24, CXCL8, CXCL9, CXCL10), and other mediators (TNF soluble receptors sTNFR1 and sTNFR2 and interleukin-1 receptor antagonist) by enzyme-linked immunosorbent assay. Patients with OCD were further examined with the Mini-International Neuropsychiatric Interview, the Obsessive-Compulsive Inventory-Revised, and the Beck Depression Inventory.

RESULTS

Compared with healthy controls, patients with OCD exhibited significantly increased plasma levels of CCL3, CXCL8, sTNFR1, and sTNFR2. Among patients with OCD, there was a positive correlation between relative antidepressant dose and sTNFr2 levels. Furthermore, although the levels of sTNFR1 correlated positively with the severity of washing symptoms, CCL24 levels correlated negatively with the severity of hoarding.

CONCLUSIONS

The levels of certain immune markers are increased in adult patients with OCD and seem to vary according to predominant symptoms dimensions. Other studies are required to establish whether our findings truly reflect immunologic dysfunction in OCD or are the result of other hidden confounding factors.

Systematic review of proinflammatory cytokines in obsessive-compulsive disorder

Several studies have examined levels of proinflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6. This meta-analysis was conducted to examine the association between obsessive-compulsive disorder (OCD) and plasma serum levels of proinflammatory cytokines. Twelve studies met inclusion criteria. The meta-analysis demonstrated a significant reduction in IL-1β levels in OCD. No significant difference in plasma levels of IL-6 or TNF-α was demonstrated. Stratified subgroup analysis revealed possible moderating effects of age and medication use on IL-6 levels. Studies including children on psychotropic medication had lower plasma IL-6 levels. Stratified subgroup analysis revealed a moderating effect of comorbid depression on TNF-α levels. Elevated TNF-α levels were reported in studies that included individuals with comorbid depression. Future studies examining immune function in OCD should adjust for potential confounding due to medication use and comorbid depression. Further studies assessing cerebrospinal fluid cytokine levels in OCD are also needed.

Disgust affects TNF-alpha, IL-6 and noradrenalin levels in patients with obsessive-compulsive disorder

Neurobiological research of obsessive-compulsive disorder (OCD) has rarely taken in account the context dependent evocation of obsessive-compulsive symptoms. To bypass this obstacle, this study investigated neurobiological parameters during a standardized disgust provocation paradigm in patients with OCD and healthy controls. Ten OCD patients and 10 healthy controls were exposed to 9 disgust related items using a standardized provocation paradigm. Catecholamines and cortisol in plasma and lipopolysaccharide (LPS) stimulated levels of TNF-alpha and IL-6 by peripheral leucocytes were assessed along with severity of obsessive-compulsive symptoms, disgust, and anxiety levels using Visual Analogue Scales prior, during and after a provocation paradigm. Noradrenalin levels increased, while LPS stimulated TNF-alpha and IL-6 by peripheral leucocytes decreased during exposure to disgust related objects in OCD patients but not in healthy controls. Cortisol levels were not affected by exposure neither in patients nor in controls, but overall cortisol levels of OCD patients were increased compared to controls. In conclusion, our data suggests that symptom provocation in OCD patients with contamination fear is accompanied by alterations in the immune and neuroendocrine systems but does not affect cortisol levels.

Normalisation of immune cell imbalance after pharmacological treatments of patients suffering from obsessive-compulsive disorder

Recent data have shown the presence of immunological alterations in adult patients suffering from obsessive-compulsive disorder (OCD). The objective of this study was to examine the possible effects of 12 months of treatment with different serotonergic drugs, such as clomipramine and selective serotonin reuptake inhibitors (SSRIs) on peripheral immunological cells of 18 OCD patients. Both the absolute number and percent of CD4+, CD8+, CD3+, CD19+ and CD56+ cells were measured in peripheral blood before and after treatment by means of a Facstar Flow Sorter apparatus. At baseline, all patients showed a significant increase of CD8+ and decrease of CD4+ lymphocytes when compared with a similar group of healthy control subjects; after the treatment, CD8+ and CD4+ cells, respectively, decreased and increased significantly, and the CD4+/CD8+ ratio increased, when compared with baseline values, in parallel with the clinical improvement. These data suggest that the alterations of immune cells reported in patients with OCD at baseline may be reverted by treatment with SRIs and should be considered a state-dependent marker, perhaps related to a condition of stress.

Pregnant women's cortisol is elevated with anxiety and depression - but only when comorbid

Elevated cortisol during pregnancy is associated with adverse birth outcomes and may alter fetal development and subsequent adult health. Numerous studies link elevated cortisol to depression and anxiety, but only a few have examined these relationships during pregnancy and in response to laboratory stressors. No studies have investigated the impact of comorbid anxiety and depression on cortisol during pregnancy. Salivary cortisol samples were collected twice before and once after a set of computer-based tasks (Stroop color-word matching task and either mental arithmetic or a controlled breathing task) from 180 pregnant women at approximately 36 weeks gestation. Based on psychiatric diagnoses, four groups of women were compared: 121 control, 16 depression, 34 anxiety, and 9 comorbid. Women also completed symptom and stress self-report scales. There was a significant main effect for maternal diagnosis on cortisol levels. Post hoc comparisons showed that comorbid subjects had higher salivary cortisol levels than controls, but subjects with only one diagnosis did not. Similar to cortisol, the comorbid subjects also had higher ratings on pregnancy-specific distress. Comorbidity during pregnancy, versus depression or an anxiety disorder alone, is uniquely associated with elevated cortisol and a negative evaluation of pregnancy. The potential impact of this combined psychiatric diagnosis on fetal development and future adult health needs further investigation.

Obsessive-compulsive disorder and immunology: a review

Interest in the possibility of an immune-mediated pathophysiology of obsessive-compulsive disorder and related disorders has increased. In the late 1980s, the National Institute of Mental Health reported an increase in obsessive-compulsive symptoms (OCS) in patients with Sydenham chorea (SC). Subsequently, a precipitating streptococcal infection in children with sudden onset of OCS but no chorea led to the coining of PANDAS (Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection). This association has furthered interest in biological measures for immune and genetic susceptibility in non-PANDAS obsessive-compulsive disorder patients (OCD). Furthermore, some studies are trying to demonstrate alterations of immune parameters in OCD patients, with few positive results. In this narrative review, our objective was to describe the immunologic findings in OCD, PANDAS, and their association with SC.

Plasma levels of tumor necrosis factor-alpha and interleukin-6 in obsessive compulsive disorder

Aim. Recent research implicated place of an immune mechanism in the pathophysiology of obsessive-compulsive disorder (OCD). Despite increasing evidence involvement of cytokine release in OCD, results of the studies are inconsistent. The aim of this study was to evaluate the plasma levels of the cytokines; tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in OCD patients. Methods. Plasma concentrations of TNF-α and IL-6 were measured in 31 drug-free outpatients with OCD, and 31-year age and sex-matched healthy controls. TNF-α and IL-6 concentrations in blood were determined by enzyme-linked immunosorbent assay (ELISA). Results. Both TNF-α and IL-6 levels showed statistically significant increases in OCD patients compared to controls (P < .000, P < .001, resp.). In addition, the age of onset was negatively correlated with TNF-α level (r = −.402, P = .025) and duration of illness was weakly correlated with IL-6 levels (r : .357; P : .048) in patients group. Conclusion. OCD patients showed increases in TNF-α and IL-6 levels compared to the healthy controls. This study provides evidence for alterations in the proinflamatory cytokines which suggest the involvement of the immune system in the pathophysiology of OCD.

Immunology of obsessive-compulsive disorder

Childhood OCD often develops into a chronic illness that lasts decades. Proof that some type of immunotherapy (such as antibiotic prophylaxis) could significantly reduce recurrence or exacerbation of symptoms of OC or tics would suggest a supportive role for immune triggers in the onset or worsening of these conditions and provide additional tools for improving outcome. The validity of PANDAS will continue to be questioned, however,because demonstrating a clear causation will be difficult on a background ofa common childhood illness. Along with the previously mentioned immuno-therapy study, validation of the PANDAS phenotype (broadly interpreted)would be advanced from new and continued research in the following areas: (1) prospective studies to identify infectious triggers in the onset and exacerbations of OCD spectrum disorders, (2) biological measures for immune and genetic susceptibility, and (3) large scale epidemiological studies demonstrating the relationship between infection and OCD spectrum disorders. The assimilation of these study results should allow for elucidation of the immune system's role in the onset and maintenance of OCD.

Decreased TNF-alpha and NK activity in obsessive-compulsive disorder

BACKGROUND

Accumulating evidence points towards the involvement of autoimmune mechanisms in the pathophysiology of some subgroups of obsessive-compulsive disorder (OCD). This study was carried out to investigate whether obsessive-compulsive disorder is associated with altered activity of the immune system, and whether these changes are related to particular clinical characteristics.

METHODS

Ex vivo production of TNF-alpha, IL-4, IL-6, IL-10, and IFN-gamma in whole blood cultures, and NK-cell activity and peripheral blood NK cell-, monocytes-, T-cell-, and B-cell- percentages were measured in 50 medication-free outpatients with OCD and 25 controls.

RESULTS

In OCD patients, we found a significant decrease in production of TNF-alpha (p < 0.0001) and NK-activity (p = 0.002) in comparison with controls. No significant differences were observed in the other immune variables. Patients with first-degree relatives with OCD had significant lower NK-activity than patients who had no relatives with OCD (p = 0.02), and patients with a childhood onset of OCD had significantly lower number of NK-cells than patients with a late onset (p= 0.003).

CONCLUSIONS

Changes in TNF-alpha and NK activity suggest a potential role of altered immune function in the pathophysiology of obsessive-compulsive disorder.

Plasma levels of soluble transferrin receptors and Clara cell protein (CC16) during bipolar mania and subsequent remission

Clara cell protein (CC16) and transferrin receptor (TfR) have been reported as possible biological markers for major depression and schizophrenia. However, the alternations of plasma TfR and CC16 levels and the influences of numerous clinical variables on them during bipolar mania are not sufficiently described. We investigated the immune function of 36 bipolar I, manic (DSM-IV) patients with Young Mania Rating Scale (YMRS) scores > or =26 as well as during the subsequent remission (YMRS < or =12) and age- and sex- matched healthy controls. The plasma TfR levels were increased during acute mania along with subsequent remission and were independent of medication status, individual variations, clinical and erythrocyte variables. Among inflammatory parameters and haematological variables, the plasma TfR levels merely had significant and negative relationship with the percentage of monocyte in circulating leukocyte counts despite of elevated plasma soluble interleukin-2 receptors levels during bipolar mania. The plasma levels of CC16 of bipolar patients did not significantly alter during acute mania, whereas smoking, body mass index, and co-existing psychotic features collectively contributed 42% of the plasma levels of CC16. We provide additional evidence to indicate the pathophysiological role of the immune systems in affective disorders. It is suggested that the elevation of plasma TfR levels might be a trait phenomenon in bipolar disorder.

Cerebrospinal fluid interleukin-6 in obsessive-compulsive disorder and trichotillomania

Recent studies have suggested that neuroimmune abnormalities may play an important role in the pathogenesis of obsessive-compulsive disorder (OCD) and related disorders. This study was undertaken to determine whether cerebrospinal fluid (CSF) concentrations of the proinflammatory cytokine interleukin (IL)-6 differ between OCD and trichotillomania patients and healthy control subjects. Lumbar puncture with a standardized procedure was performed on 26 patients with OCD and 9 with trichotillomania. All patients were drug-free and met DSM-IV criteria. Twenty-six age- and sex-matched healthy volunteers underwent the same procedure. CSF was assayed for IL-6 using a quantitative 'sandwich' enzyme immunoassay technique. Mean+/-S.D. CSF IL-6 levels did not differ between OCD patients (n=26) (2.4+/-1.1 pg/ml) and controls (n=26) (2.4+/-1.9 pg/ml) or between trichotillomania patients (n=9) (2.3+/-0.8 pg/ml) and their matched controls (n=14) (1.9+/-0.5 pg/ml). These findings fail to support speculation that ongoing immune activation may be causally involved in the pathogenesis of OCD or trichotillomania.

Differentiating primary pathophysiologic from secondary adaptational processes

The following manuscript is mainly conceptual in nature. It should be read with reservation since the relevance of its suggestions have yet to be proven. Basically it proposes two rules for the differentiation between primary illness-related pathophysiological vs. secondary adaptational processes. These rules may guide hypotheses generation for further research that is aimed at understanding psychiatric disorders and their shared and unshared mechanisms. For example, in the case of anxiety disorders and depression, it may be of interest to learn if their shared properties are of primary pathophysiological or secondary adaptational significance. We first present some historical observations on the development of the concept of "secondary adaptational processes." We assume such adaptational processes are generated by the organism in order to compensate for primary pathophysiological malfunction or impairment. Next, we propose rules that may enable the dissection of secondary adaptational from primary pathophysiological processes. We also discuss the possible implications of designing studies to sort out these processes, suggesting that the understanding of adaptational processes, may explain the effects of "placebo treatment." Finally we illustrate the application of these rules by two examples: a) amygdala activation, a biological alteration shared by anxiety disorders and major depression and b) elevated plasma soluble interleukin 2 receptor, an unshared property by anxiety disorders and major depression. Also, the first example relates to a biological perturbation associated with a primary pathophysiological mechanism, while the second represents a biological alteration associated with secondary adaptational processes.

Effects of symptomatic severity on elevation of plasma soluble interleukin-2 receptor in bipolar mania

BACKGROUND

Circulating soluble interleukin-2 receptors (sIL-2Rs) and soluble interleukin-6 receptors (sIL-6Rs) are stable immune measures. Elevated plasma sIL-2R levels are present in patients with schizophrenia, major depression, and bipolar mania, but not with minor psychiatric disorders. The increased plasma sIL-2R levels are state-dependent in bipolar mania. However, altered production of plasma sIL-6R and the effects of clinical characteristics on plasma sIL-6R and sIL-2R levels in bipolar disorder remains uncertain.

METHODS

Plasma sIL-2R and sIL-6R levels were measured in 31 Taiwanese bipolar manic (DSM-IV) patients with Young Mania Rating Scale (YMRS) scores of > or =26 as well as during the subsequent remission (YMRS< or =12), and equal numbers of age- and gender-matched healthy controls. The relationships of clinical variables such as age, age of onset, smoking, medication status, coexisting psychotic features, number of prior episodes, duration of illness, presence of depression before or following the manic episode, and manic severity to plasma sIL-2R and sIL-6R levels in acute mania along with remission were examined.

RESULTS

Plasma sIL-2R but not sIL-6R levels were significantly higher in acute mania than in subsequent remission (P<0.05) and controls (P<0.0005). In acute mania, the plasma sIL-2R levels were significantly correlated to YMRS scores (r=0.34, P<0.05). The remaining clinical variables had no effect on plasma sIL-2R and sIL-6R levels in acute mania or remission. There was a significantly positive relationship between the reduction of plasma sIL-2R levels from the acute to follow-up measurements (DeltasIL-2R) and symptomatic improvement of acute mania (DeltaYMRS) (r=0.61, P<0.001).

LIMITATIONS

Our sample included medicated and unmedicated patients in acute mania. The psychotropic medication may have divergent effects on the plasma sIL-2R levels in acute mania and subsequent remission.

CONCLUSIONS

Elevation of plasma sIL-2R but not sIL-6R levels in bipolar mania supports the idea that the immunomodulatory mechanism may vary in different psychotic disorders. In contrast to being a trait marker in schizophrenia and depressive disorder, plasma sIL-2R levels may be considered a biological indicator of manic severity in a group of bipolar affective patients.

Cytokines in de obsessief compulsieve stoornis en in anorexia nervosa: een overzicht

The alterations in the inflammatory response system (IRS) appear to be quite different between OCD and anorexia nervosa and are also different from the changes observed in major depression. In anorexia nervosa, there is some evidence for increased production of monocytic cytokines, i.e. tumor necrosis factor-α (TNFα) and interleukin-6 (IL-6), and decreased production of Th-1 like cytokines, i.e. IL-2 and IFNγ. In the same patients there are also signs of immunosuppression, e.g. lowered numbers of CD4 and CD8 T cells and increased production of transforming growth factor-beta (TGFβ). The increased production of monocytic cytokines may be the consequence of the hyponutritional status of those patients. The diminished production of the Th-1 like cytokines may be the consequence of at least four different factors: 1) the deficiency in nutritional factors; 2) neuroendocrine disorders, such as increased Cortisol production; 3) the increased TGFβ production; and 4) lower serum dipeptidyl peptidase activity. In OCD no consistent or specific alterations in the IRS are observed. There is no evidence that IRS activation may play a role in the pathophysiology of OCD and anorexia nervosa.

Immunological alterations in adult obsessive-compulsive disorder

BACKGROUND

Some recent findings suggest the involvement of autoimmune mechanisms in childhood onset of obsessive-compulsive disorder (OCD), on the basis of a parallel drawn with Sydenham's chorea, a manifestation of rheumatic fever. A monoclonal antibody called D8/D17 characterizing a B-lymphocyte antigen, present in almost all patients with rheumatic fever, has been found also in children affected by OCD, Tourette syndrome, and chronic tics to a greater degree than in healthy control subjects. The few observations of disturbances of some immunologic parameters in adult OCD patients, prompted the authors to investigate and compare subsets of peripheral immunological cells for differences in adult patients with OCD and healthy control subjects.

METHODS

Twenty patients suffering from OCD, with no comorbidity for other psychiatric disorders, were compared with a similar group of healthy control subjects. The immune subsets were measured by flow cytometry.

RESULTS

The CD8+ lymphocytes were significantly increased and CD4+ lymphocytes significantly decreased in OCD patients, while the other cells did not differ between the two groups. No correlation was found between immunologic and clinical parameters.

CONCLUSIONS

These data indicate that patients with adult OCD showed increased CD8+, i.e., suppressor T lymphocytes, and decreased CD4+, which identify helper T lymphocytes, as compared with a similar group of healthy control subjects. The findings appear peculiar to patients with OCD and are suggestive of an immunologic imbalance, which might be related to the stress deriving from the frustrating situation determined by the disorder itself.

Circulating lymphocyte subsets in obsessive compulsive disorder, major depression and normal controls

BACKGROUND

Obsessive compulsive disorder (OCD) shares several features with depressive illness (e.g., comorbidity, early escape from dexamethasone suppression, effectiveness of serotonergic pharmacotherapy). It was of interest to establish whether OCD, like major depression, was also associated with immune alterations, notably elevations of circulating natural killer (NK) cells.

METHOD

Circulating lymphocytes were determined from morning blood samples taken from OCD and major depressive patients, as well as from age- and sex-matched controls. Stress perception and coping styles were evaluated in order to assess whether such variables accompanied the NK alterations. Finally, in a subset of patients, symptoms of the illness, stress/coping, and circulating lymphocytes, were also evaluated following 12 weeks of antidepressant medication (serotonergic reuptake inhibitor).

RESULTS

The major depressive and OCD patients reported increased perception of day-to-day stresses, coupled with reliance on emotion focused coping styles. Moreover, circulating NK cells were elevated among male OCD and major depressive patients, whereas only a modest increase of NK cells was seen in female major depressives. Twelve weeks of medication alleviated depressive and OCD symptoms, and resulted in normalization of NK cells in the major depressives. However, in OCD patients the reduction of symptoms was not accompanied by significant variations of circulating NK cells.

CONCLUSIONS

Although major depression and OCD are both accompanied by elevated circulating NK cells, at least in males, normalization of NK cells following treatment was only evident in depression. The persistent elevations of NK cells among male OCD patients may reflect either a trait characteristic of the illness, or symptom reduction and not true remission.

LIMITATIONS

Although elevations of lymphocyte subsets in major depressive and OCD patients were observed, conclusions concerning immune status in OCD ought to be held in abeyance pending assessment of other indices of immune and cytokine functioning.

Reduced lymphocyte proliferation and interleukin-2 production in anxiety disorders

OBJECTIVE

The purpose of this study was to examine the effect of anxiety on cell-mediated immunity.

METHOD

The subjects consisted of 31 patients with anxiety disorders and 31 normal controls, who were gender-matched. Cell-mediated immune function was measured by the lymphocyte proliferative response to phytohemagglutinin (PHA), Interleukin-2 (IL-2) production, and natural killer cell activity (NKA). The extent of anxiety was assessed by the Hamilton rating scale for anxiety and the anxiety subscale of symptom checklist-90 revised (SCL-90-R).

RESULTS

The patients with anxiety disorders were significantly lower than the normal controls in lymphocyte proliferative response to PHA and IL-2 production. However, there was no significant difference in NKA between the two groups. Also, no significant correlation was found between the duration of illness or the degree of anxiety and each immune measure in patients with anxiety disorders.

CONCLUSIONS

The results suggest a reduced cell-mediated immune function in patients with anxiety disorders, compared with normal controls. These findings also imply that a variety of immune measures should be assessed at the same time in this kind of psychoneuroimmunology research. This would help elucidate the relationship between anxiety and immune function, which has been unclear in most previous research using a single immune measure.

Obsessive compulsive disorder: Opportunities within and beyond the serotonergic domain

Abnormality of the serotonin (5-hydroxytryptamine - 5-HT) system and particularly hypersensitivity of postsynaptic 5-HT receptors remained the leading hypothesis for the underlying pathophysiology of obsessive compulsive disorder (OCD) during the 1980s. A number of lines of evidence supported this serotonergic hypothesis, not least the treatment studies which demonstrated clearly and consistently that anti-obsessional efficacy was a function of serotonin re-uptake inhibition. Studies of markers and biological probes provided further evidence: platelet studies, for example, linked reductions in 5-HT activity with clinical response, and treatment response was correlated with decreased 5-hydroxyindolacetic acid (5-HIAA) levels within the cerebrospinal fluid of OCD patients. Added to this was the evidence from the behavioral or physiological responses observed following serotonergic challenge with the serotonin agonists meta-chlorophenylpiperazine, a compound with high affinity for 5-HT1A-, 5-HT1D- and 5-HT2C-receptors.

Components of biological variation in serum soluble transferrin receptor: relationships to serum iron, transferrin and ferritin concentrations, and immune and haematological variables

We investigated the components of biological variation in serum soluble transferrin receptor (TfR) in relation to serum iron, transferrin (Tf), ferritin, soluble interleukin-2 receptor (sIL-2R), sIL-6R, and number of erythrocytes, haemoglobin (Hb), haematocrit (Ht), mean corpuscular volume (MCV), mean cell haemoglobin (MCH), and erythrocyte distribution width (RDW). We took monthly blood samples during 1 calendar year from 26 healthy subjects for assay of the above variables. The estimated CVs for TfR were interindividual CVg = 20.8%, and intra-individual CVi = 13.6%; for Tf, CVg = 14.4% and CVi = 6.7%; for iron, CVg = 16.8% and CVi = 29.2%; and for ferritin, CVg = 71.1% and CVi = 26.5%. There was a statistically significant seasonal pattern in the four variables with significant annual, biannual and/or trimonthly rhythms, which were expressed as a group phenomenon. The peak-trough differences in the yearly variations, expressed as a percentage of the mean, were: for TfR, 11.7%; for iron, 39.2%; for Tf, 11.7%; and for ferritin, 29.3%. Up to 34.2% of the within-subject variability in TfR (which reflects changes over time) could be explained by the regression on iron, ferritin, Tf, sIL-2R, sIL-6R and MCH values. Up to 67.2% of the between-subject variability in TfR (which reflects differences in the homeostatic setpoint during the study year) could be explained by the regression on gender, iron, Tf, and ferritin values.

Interleukin-6-(IL-6) plasma levels in depression and schizophrenia: comparison between the acute state and after remission

The concentration of cytokines such as Interleukin-6 (IL-6) has been reported to be elevated in depressed and schizophrenic patients and, in healthy persons, upon stress. Interleukin-6 plasma levels were determined in depressed (n = 12) and schizophrenic (n = 32) patients during the acute state of illness and after remission at approximately 8 weeks after admission and were compared with healthy controls (n = 12). Patients were diagnosed according to DSM-III-R by the Structured Clinical Interview (SCID). Severity of illness was assessed for depression by the Montgomery Asberg Depression Rating Scale (MADRS) and for schizophrenia by the Brief Psychiatric Rating Scale (BPRS). Interleukin-6 plasma concentrations were elevated during the acute state either of depression or of schizophrenia if compared to controls. After remission, IL-6 concentrations in depressed and in schizophrenic patients had decreased and did not differ significantly from controls. We hypothesize that the elevated IL-6 levels during the acute state of depression or schizophrenia may reflect an unspecific stress response.