Plasma interleukin-1 beta and tumor necrosis factor concentrations in obsessive-compulsive disorders

Obsessive-Compulsive Disorder, PANDAS, and Tourette Syndrome: Immuno-inflammatory Disorders

In the last years, much focus has been given to the possible role of inflammatory and immunologic alterations in the pathophysiology of obsessive-compulsive disorder (OCD) and some related conditions, such as pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS) and Tourette syndrome (TS). Although the matter is intriguing, the available data are still controversial and/or limited. Therefore, the aim of this chapter was at reviewing and commenting on the literature on possible dysfunctions of inflammatory and immune system processes in OCD, PANDAS, and TS.This narrative review was carried out through searching PubMed and Google Scholar for English language papers from January 1985 to December 31, 2021.The data gathered up to now would suggest that the mechanisms involved might be heterogeneous according to the age of the patients and the disorder examined. Indeed, PANDAS seem more related to infections triggering autoimmunity not necessarily following group A beta-hemolytic streptococcal (GABHS) infection, as supposed in the past. Autoimmunity seems also important in TS, if coupled with an individual vulnerability that can be genetic and/or environmental. The data in adult OCD, albeit scattered and sometimes obtained in small samples of patients, would indicate that immune system and inflammatory processes are involved in the pathophysiology of the disorder. However, it is still unclear to conclude whether they are primary or secondary phenomena.In conclusion, taken together, the current findings pave that way towards novel and promising domains to explore the pathophysiology of OCD and related disorders, as well towards the development of innovative therapeutic strategy beyond current pharmacological paradigms.

Novel inflammatory targets for immunotherapies in pediatric patients with trichotillomania

Immune dysregulation may be important in the etiology of obsessive-compulsive and related disordersandbody-focusedrepetitivebehaviors, such as Trichotillomania (TTM). The role of inflammation and inflammatory markers in TTM has received relatively little attention. This study was aimed to determine the expression levels of inflammatory markers (i.e. IL-1β, IL-1α, IL-4, IL-6, IL-17, TNF-α and TGF-β) in peripheral blood mononuclear cells of children with TTM and healthy controls and to evaluate their association with clinical variables. Seventy-seven patients with TTM and 107 healthy controls were enrolled in the study. Peripheral blood was collected in standardized conditions. The mean age of patients and controls did not differ significantly (10.8 ± 4.4 and 12.0 ± 3.2 years; respectively). The majority of patients with TTM and controls were females (n = 55, 71.4 % and n = 55, 51.4 %; respectively); with a greater preponderance of females among TTM. Patients with TTM had significantly elevated expression levels of TNF-α, IL-6 and IL-17 compared to controls. However, the expression level of IL-4 was significantly reduced in TTM patients compared to controls. Accordingly, we found a pro-inflammatory state in TTM and those findings may suggest novel treatment options for TTM and further, cross-disciplinary studies focusing on neuro- inflammation in TTM conducted on larger samples are needed.

The Glutamate and the Immune Systems: New Targets for the Pharmacological Treatment of OCD

BACKGROUND

In the last decades the pharmacological treatment of obsessivecompulsive disorder (OCD) has been significantly promoted by the effectiveness of selective serotonin (5-HT) reuptake inhibitors (SSRIs) and the subsequent development of the 5-HT hypothesis of OCD. However, since a large majority of patients (between 40% and 60 %) do not respond to SSRIs or strategies based on the modulation of the 5-HT system, it is now essential to search for other possible therapeutic targets.

AIMS

The aim of this paper was to review current literature through a PubMed and Google Scholar search of novel hypotheses and related compounds for the treatment of OCD, with a special focus on the glutammate and the immune systems.

DISCUSSION

The literature indicates that glutamate, the main excitatory neurotransmitter, might play an important role in the pathophysiology of OCD. In addition, a series of clinical studies also supports the potential efficacy of drugs modulating the glutamate system. The role of the immune system alterations in OCD in both children and adults needs to be more deeply elucidated. In children, a subtype of OCD has been widely described resulting from infections driven by group A streptococcus β-hemolitic and belonging to the so-called "pediatric autoimmune neuropsychiatric disorders associated with streptococcus" (PANDAS). In adults, available findings are meager and controversial, although interesting.

CONCLUSION

The glutamate and the immune systems represent two intriguing topics of research that hold promise for the development of open novel treatment strategies in OCD.

Blood levels of interleukin-1 beta, interleukin-6 and tumor necrosis factor-alpha and cognitive functions in patients with obsessive compulsive disorder

BACKGROUND

Cognitive dysfunction and immune system disorders are two actual issues for the patients with Obsessive Compulsive Disorder (OCD). The cognitive dysfunctions have been considered to substantial part of clinical phenomenon of OCD but exploration of various etiopathogenesis of cognitive dysfunction is needed. Immune dysfuncion has been implicated to be important part of pathopysiology of OCD and different lines of evidence suggests immune abnormalities in OCD. But whether these immune changes are traits of disease or secondary to clinical burden of the disease such as cognitive dysfunctions has not been determined. Data regarding relation between the cognitive dysfunctions and immune system disorders in OCD is unsatisfied. In this study we aimed to investigate the relation of blood levels of interleukin 1-beta (IL-1ß), interleukin-6 (IL-6) and Tumor Necrosis Factor-α (TNF-α) with various neurocognitive functions in patients with OCD in comparison with its autogenous/reactive subtypes and healthy controls. Further exploration of the effects of various clinical variables on cognitive functioning in patients with OCD and additional investigation of whether the cognitive dysfunction associated with this disorder differs from or overlap with that in other anxiety disorders are needed.

METHODS

Forty-two patient with OCD and 45 age, sex and educational level matched healthy control were enrolled in the study. The diagnosis of OCD was made with Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Yale- Brown Obsessive-Compulsive Scale, Beck Anxiety and Depression Inventory Scales were administered. Neuropsychological test battery including Wisconsin Card Sorting Test (WCST), Trail Making Test A and B (TMT-A, TMT-B) were used for evaluation of the patients and healthy control. The plasma of interleukin-1beta (IL-1ß), interleukin-6 (IL-6), Tumor Necrosis Factor-Alpha (TNF-α) of both groups were measured with ELISA kits.

RESULTS

Blood levels of IL-1ß, IL-6 and TNF-α were significantly higher in patients with OCD than the healthy control. There was significant difference in IL-1ß, IL-6 but not in TNF-α between autogenous/reactive subtypes and healthy controls. TNF-α is positively correlated with TMT-A, TMT-B and Stroop Test Part 5, negatively correlated with immediate memory, verbal learning, interference effect, immediate recall, delayed recall and recognition in RAVLT. IL-1ß was positively correlated with TMT-A score. IL-6 was positively correlated with scores of TMT-A, TMT-B. IL-6 was negatively correlated with immediate memory, verbal learning, interference effect, immediate recall and delayed recall in RAVLT, positively correlated with number of perseverative error and negatively correlated with the number of categories completed in WCST.

CONCLUSION

This is the first study that investigates the relation of IL- 1ß, IL-6 and TNF-α levels with cognitive functions in OCD. There may be a contribution to pathogenesis of OCD and subtypes then new choices for treatment might be developed. Moreover, uncovering the effect of cytokine blood levels on cognitive function of OCD, new data concerning etiopathogenesis and further treatment choices can be gained.

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.

IL-1β, IL-6, TNF- α and CRP in Elderly Patients with Depression or Alzheimer's disease: Systematic Review and Meta-Analysis

We carried out systematic review and meta-analysis to evaluate whether peripheral levels of pro-inflammatory markers including Interleukin-1 beta (IL-1β), Interleukin-6 (IL-6), Tumor Necrosis Factor-α (TNF- α) and C-Reactive Protein (CRP) are significantly higher in elderly with depression and Alzheimer's disease. We searched Pubmed, PsycINFO and Embase, and thirty-four relevant studies (2609 with Depression, 1645 with Alzheimer's disease and 14363 Controls) were included. Compared with controls, IL-1β (pooled standardized mean difference [SMD]: 0.642; 95% confidence interval [CI]: 0.078-1.206; significant heterogeneity: I2 = 86.28%) and IL-6 (pooled SMD: 0.377; 95% CI: 0.156-0.598; significant heterogeneity: I2 = 88.75%) were significantly elevated in depression. There was no difference in TNF-α (p = 0.351) and CRP (p = 0.05) between those with depression and controls. Compared with controls, IL-1β (pooled SMD: 1.37, 95% CI: 0.06-2.68, significant heterogeneity: I2 = 96.01%) was significantly elevated in Alzheimer's disease. There were no differences in IL-6 (p = 0.138), TNF-α (p = 0.451) and CRP (p = 0.07) between elderly with Alzheimer's disease and controls. After Bonferroni adjustment, only IL-6 remained significantly higher in depression. Elderly with depression have higher IL-6 than controls, while those with Alzheimer's disease did not have higher peripheral inflammatory markers.

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.

Immune system and obsessive-compulsive disorder

BACKGROUND

Recently, much attention has been devoted to the possible alterations of the immune system in obsessive-compulsive disorder (OCD). Therefore, the aim of this paper was to review the current literature on the relationships between OCD and immune system.

METHODS

A PubMed and Google Scholar search was performed with specific keywords.

RESULTS

In the childhood, much emphasis has been given to the relationship between group A Streptococcus (GAS) infection and the development of a group of clinical syndromes characterized by neuropsychiatric symptoms known as "pediatric autoimmune neuropsychiatric disorders associated with streptococcus" (PANDAS). However, more recently, PANDAS has been reconsidered and evolved towards pediatric acute-onset neuropsychiatric syndrome (PANS) and/or Childhood Acute Neuropsychiatric Syndrome (CANS) all characterized by the presence of typical of OCD symptoms and tics. In adult OCD patients, different immunological parameters have been described to differ from those of healthy control subjects, although a few numbers of studies were carred out and most of them performed in small samples.

CONCLUSIONS

Although the exact relationships between OCD and immune processes are still unclear, available literature supports their role in the pathophysiology of OCD, while providing a fascinating hint for possible immunotherapeutic treatments in OCD.

Association between TNF-α-238G/A gene polymorphism and OCD susceptibility: A meta-analysis

BACKGROUND

Tumor necrosis factor-alpha (TNF-α) is an important cytokine and has been reported to be associated with the pathogenesis of many autoimmune and inflammatory diseases. TNF-α gene is located on a region that has been found to be associated with obsessive-compulsive disorder (OCD). We performed this meta-analysis to assess the relationship between susceptibility to OCD and the TNF-α-238G/A gene polymorphism.

METHODS

An extensive search of the available literature on the association between the susceptibility to OCD and the TNF gene polymorphism was conducted by searching PubMed, Web of Knowledge, Embase, Chinese Web of Knowledge, Wanfang, and Chongqing VIP database. The database was searched up to December 2016 and includes language of English and/or Chinese with the keywords of "obsessive-compulsive disorder" or "OCD," polymorphism or variant or mutation, "tumor necrosis factor" or "TNF" or "cytokine." The association between TNF-α-238G/A gene polymorphism and the susceptibility of OCD was anticipated by odds ratio (OR) with the corresponding 95% confidence interval (95% CI).

RESULTS

Four studies including 435 cases and 1073 controls were incorporated in our meta-analysis. In general, TNF-α-238G/A gene polymorphism might lead to a decreased risk of OCD susceptibility (G vs A genotype model: OR = 1.01, 95% CI = 0.37-2.77, P = .981; GG vs AA+AG model: OR = 0.93, 95% CI = 0.37-2.36, P = .879; GG+AG vs AA model: OR = 0.22, 95% CI = 0.06-0.73, P = .014; GG vs AA model: OR = 0.21, 95% CI = 0.06-0.71, P = .012; AG vs AA model: OR = 0.29, 95% CI = 0.07-1.16, P = .081; GG+AA vs AG model: OR = 1.17, 95% CI = 0.55-2.51, P = .683).

CONCLUSION

TNF-α-238G/A gene polymorphism might lead to a decreased risk of OCD susceptibility.

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.

Neuroinflammation and psychiatric illness

Multiple lines of evidence support the pathogenic role of neuroinflammation in psychiatric illness. While systemic autoimmune diseases are well-documented causes of neuropsychiatric disorders, synaptic autoimmune encephalitides with psychotic symptoms often go under-recognized. Parallel to the link between psychiatric symptoms and autoimmunity in autoimmune diseases, neuroimmunological abnormalities occur in classical psychiatric disorders (for example, major depressive, bipolar, schizophrenia, and obsessive-compulsive disorders). Investigations into the pathophysiology of these conditions traditionally stressed dysregulation of the glutamatergic and monoaminergic systems, but the mechanisms causing these neurotransmitter abnormalities remained elusive. We review the link between autoimmunity and neuropsychiatric disorders, and the human and experimental evidence supporting the pathogenic role of neuroinflammation in selected classical psychiatric disorders. Understanding how psychosocial, genetic, immunological and neurotransmitter systems interact can reveal pathogenic clues and help target new preventive and symptomatic therapies.

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.

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: the disease-avoidance emotion and its dysfunctions

This review analyses the accumulating evidence from psychological, psychophysiological, neurobiological and cognitive studies suggesting that the disease-avoidance emotion of disgust is a predominant emotion experienced in a number of psychopathologies. Current evidence suggests that disgust is significantly related to small animal phobias (particularly spider phobia), blood-injection-injury phobia and obsessive-compulsive disorder contamination fears, and these are all disorders that have primary disgust elicitors as a significant component of their psychopathology. Disgust propensity and sensitivity are also significantly associated with measures of a number of other psychopathologies, including eating disorders, sexual dysfunctions, hypochondriasis, height phobia, claustrophobia, separation anxiety, agoraphobia and symptoms of schizophrenia--even though many of these psychopathologies do not share the disease-avoidance functionality that characterizes disgust. There is accumulating evidence that disgust does represent an important vulnerability factor for many of these psychopathologies, but when disgust-relevant psychopathologies do meet the criteria required for clinical diagnosis, they are characterized by significant levels of both disgust and fear/anxiety. Finally, it has been argued that disgust may also facilitate anxiety and distress across a broad range of psychopathologies through its involvement in more complex human emotions such as shame and guilt, and through its effect as a negative affect emotion generating threat-interpretation biases.

Altered monocyte activation markers in Tourette's syndrome: a case-control study

BACKGROUND

Infections and immunological processes are likely to be involved in the pathogenesis of Tourette's syndrome (TS). To determine possible common underlying immunological mechanisms, we focused on innate immunity and studied markers of inflammation, monocytes, and monocyte-derived cytokines.

METHODS

In a cross-sectional study, we used current methods to determine the number of monocytes and levels of C-reactive protein (CRP) in 46 children, adolescents, and adult patients suffering from TS and in 43 healthy controls matched for age and sex. Tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), soluble CD14 (sCD14), IL1-receptor antagonist (IL1-ra), and serum neopterin were detected by immunoassays.

RESULTS

We found that CRP and neopterin levels and the number of monocytes were significantly higher in TS patients than in healthy controls. Serum concentrations of TNF-alpha, sIL1-ra, and sCD14 were significantly lower in TS patients. All measured values were within normal ranges and often close to detection limits.

CONCLUSIONS

The present results point to a monocyte dysregulation in TS. This possible dysbalance in innate immunity could predispose to infections or autoimmune reactions.

The role of interleukin (IL)-17 in anxiety and depression of patients with rheumatoid arthritis

BACKGROUND

Pro-inflammatory cytokines are found to be elevated in patients with anxiety and depression but whether their serum levels are related to anxiety and depression is unknown. We used rheumatoid arthritis (RA) as an inflammatory disease model to explore such relationships.

METHODS

Eighteen RA patients and 18 healthy controls matched for age and gender were assessed for the severity of anxiety and depression with the hospital anxiety and depression scale (HADS). Disease activity of RA and pain were assessed by the Disease Activity Scale (DAS-2)8 and visual analogue scale of pain, respectively. Serum pro-inflammatory cytokine levels, including tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-17 were determined by enzyme-linked immunosorbant assay. The differences in cytokine levels between RA patients and healthy controls, as well as within the RA group with and without anxiety and depression, were compared by using the Mann-Whitney U-test. The correlations between anxiety, depression and pro-inflammatory cytokines were explored by Spearman's rank correlation. Multiple linear regression was used to adjust for DAS-28 and pain.

RESULTS

Serum TNF-α, IL-6 and IL-17 levels were significantly higher in RA patients than those of healthy subjects (P < 0.001, P = 0.012 and P = 0.016, respectively). Within the RA group, serum IL-17 level was significantly higher in those with anxiety than those without (P = 0.044). Additionally, IL-17 level was positively correlated with the severity of anxiety, even after adjustment for DAS-28 and pain.

CONCLUSION

Serum IL-17 was elevated in RA patients, especially in those with anxiety. In addition, IL-17 level was independently associated with higher anxiety score.

Neopterin and biopterin as biomarkers of immune system activation associated with castration in piglets

Recent reports have shown that stressful situations may affect the production of unconjugated pterins (neopterin and biopterin). The aim of the study was to investigate the effect of castration on neopterin and biopterin plasma concentrations in piglets, using 2 groups of 12 piglets allocated to castrated and uncastrated (control) groups. Pterin concentrations were determined by HPLC with fluorescence detection. Blood samples were also analzyed for leukocyte profiles and plasma cortisol concentrations. A time × treatment interaction (P < 0.05) was detected for neopterin concentrations, such that neopterin was greater (P < 0.01) at 1 h after surgery in castrated piglets compared with precastration concentrations, and neopterin was greater (P = 0.05) in castrated than in control piglets at 1 h. Castration had no effect on biopterin concentration (P > 0.1). Time effects (P < 0.05) for neutrophil and lymphocyte concentrations and neutrophil-to-lymphocyte ratios were found. A time × treatment interaction (P < 0.01) was detected for plasma cortisol concentrations, such that cortisol was greater (P < 0.01) at 1 and 24 h after surgery in castrated piglets compared with precastration concentrations and was greater (P < 0.01) in castrated than in control piglets at 1 and 24 h. This study showed that castration activated the immune system of piglets as demonstrated by an increase in plasma neopterin concentrations.

Lipopolysaccharide-induced cytokine production in obsessive-compulsive disorder and generalized social anxiety disorder

The immune system is implicated in the pathophysiology of various psychiatric disorders. In anxiety disorders such as obsessive-compulsive disorder (OCD) and generalized social anxiety disorder (GSAD), immunological findings are equivocal and sparse. In this study, we investigated the lipopolysaccharide (LPS)- stimulated cytokine levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-8 (IL-8) by peripheral blood leukocytes in 26 OCD patients, 26 GSAD patients, and 52 healthy controls. We found that leukocytes of OCD patients produced less IL-6 compared with matched controls, whereas no cytokine differences were found between GSAD patients and matched controls. When both patient groups were compared, a trend toward lower IL-6 levels in OCD patients was observed. This supports the idea of immunological involvement in the pathophysiology of OCD and suggests that GSAD and OCD might be different in immunological respect.

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.

Streptococcal upper respiratory tract infections and psychosocial stress predict future tic and obsessive-compulsive symptom severity in children and adolescents with Tourette syndrome and obsessive-compulsive disorder

BACKGROUND

One goal of this prospective longitudinal study was to identify new group A beta-hemolytic streptococcal infections (GABHS) in children and adolescents with Tourette syndrome (TS) and/or obsessive-compulsive disorder (OCD) compared with healthy control subjects. We then examined the power of GABHS infections and measures of psychosocial stress to predict future tic, obsessive-compulsive (OC), and depressive symptom severity.

METHODS

Consecutive ratings of tic, OC, and depressive symptom severity were obtained for 45 cases and 41 matched control subjects over a 2-year period. Clinical raters were blinded to the results of laboratory tests. Laboratory personnel were blinded to case or control status and clinical ratings. Structural equation modeling for unbalanced repeated measures was used to assess the sequence of new GABHS infections and psychosocial stress and their impact on future symptom severity.

RESULTS

Increases in tic and OC symptom severity did not occur after every new GABHS infection. However, the structural equation model found that these newly diagnosed infections were predictive of modest increases in future tic and OC symptom severity but did not predict future depressive symptom severity. In addition, the inclusion of new infections in the model greatly enhanced, by a factor of three, the power of psychosocial stress in predicting future tic and OC symptom severity.

CONCLUSIONS

Our data suggest that a minority of children with TS and early-onset OCD were sensitive to antecedent GABHS infections. These infections also enhanced the predictive power of current psychosocial stress on future tic and OC symptom severity.

Immunopathogenic mechanisms in tourette syndrome: A critical review

Tourette syndrome (TS) has a multifactorial etiology, in which genetic, environmental, immunological and hormonal factors interact to establish vulnerability. This review: (i) summarizes research exploring the exposure of TS patients to immune-activating environmental factors, and (ii) focuses on recent findings supporting a role of the innate and adaptive immune systems in the pathogenesis of TS and related disorders. A higher exposure prior to disease onset to group A beta-haemolytic streptococcal (GABHS) infections in children with tics and obsessive-compulsive (OC) symptoms has been documented, although their influence upon the course of disease remains uncertain. Increased activation of immune responses in TS is suggested by changes in gene expression profiles of peripheral immune cells, relative frequency of lymphocyte subpopulations, and synthesis of immune effector molecules. Increased activity of cell-mediated mechanisms is suggested by the increased expression of genes controlling natural killer and cytotoxic T cells, increased plasma levels of some pro-inflammatory cytokines which correlate with disease severity, and increased synthesis of antineuronal antibodies. Important methodological differences might account for some inconsistency among results of studies addressing autoantibodies in TS. Finally, a general predisposition to autoimmune responses in TS patients is indicated by the reduced frequency of regulatory T cells, which induce tolerance towards self-antigens. Although the pathogenic role of immune activation in TS has not been definitively proven, a pathophysiological model is proposed to explain the possible effect of immunity upon dopamine transmission regulation and the generation of tics.

A cytokine study in children and adolescents with Tourette's disorder

BACKGROUND

While immune system dysregulation has been postulated to play a role in Tourette's disorder (TD), most research has focused on the hypothesis of an autoimmune process similar to rheumatic fever. This study examined the potential role of cytokines, modulators of the immune system. We hypothesized that children with TD would have increased levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-12, IL-1 beta and IL-6, and decreased IL-2. We also explored whether comorbid obsessive compulsive disorder (OCD) had an effect on the cytokine profile of TD patients.

METHOD

Thirty-two children and adolescents with TD (27 males, ages 7-18 years), 17 with comorbid OCD (14 males), and 16 healthy comparison subjects (7 males, ages 9-19), were enrolled. Plasma cytokines were examined using an enzyme-linked immunosorbent assay. The Mann-Whitney and binary logistic regression tests were used to compare the groups.

RESULTS

Only patients with comorbid OCD (TD+OCD; n=17) had significantly elevated IL-12 plasma levels compared to controls (2.73+/-5.12 pg/ml vs. 0.55+/-0.88 pg/ml, rank statistic=222.5; p<0.04). IL-2 was significantly higher in the TD+OCD subgroup compared to the non-OCD TD subgroup (0.74+/-0.29 pg/ml vs. 0.49+/-0.24 pg/ml, rank statistics=108.5; p<0.03). There were no other significant cytokine differences between groups.

CONCLUSIONS

Findings suggest a role for IL-12 and IL-2 in TD, and that the TD+OCD subgroup may involve different neuroimmunological functions than the TD-OCD subgroup. Larger studies with medication-free patients should follow.

A preliminary study of cytokines in suicidal and nonsuicidal adolescents with major depression

BACKGROUND

Increased systemic cytokine levels, modulators of the immune system, have been repeatedly documented in adult and adolescent major depressive disorder (MDD). This preliminary study extends this work to test the role of cytokines in suicidal symptomatology in adolescent MDD. Hypotheses were that acutely suicidal depressed adolescents would have: (1) increased plasma levels of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and IL-1beta, and (2) a proinflammatory/antiinflammatory cytokine imbalance (indexed by plasma IFN-gamma/IL-4), compared to nonsuicidal depressed adolescents and healthy controls.

METHODS

Twelve suicidal adolescents with MDD (7 females [58%]; 5 medication-free/naïve), 18 nonsuicidal adolescents with MDD (12 females [67%]; 8 medication-free/naïve), and 15 controls (8 females [53%]) were enrolled. MDD had to be of at least 6 weeks duration, with a minimum severity score of 40 on the Children's Depression Rating Scale-Revised. Plasma cytokines were examined using enzyme-linked immunosorbent assays. Nonparametric tests were used to compare subject groups.

RESULTS

Unexpectedly, suicidal adolescents with MDD had significantly decreased plasma TNF-alpha concentrations compared to nonsuicidal adolescents with MDD (1.33 +/- 2.95 pg/mL versus 30.9 +/- 110.9 pg/mL; p = 0.03). IFN-gamma was increased in both suicidal and nonsuicidal adolescents with MDD compared to controls (2.14 +/- 6.22 and 4.20 +/- 14.48 versus 0.37 +/- 0.64; p < 0.02, p = 0.005). Findings remained evident when controlled for age and gender.

CONCLUSIONS

Our preliminary findings suggest that immune system dysregulation may be associated with suicidal symptomatology in adolescent MDD. These findings should be replicated in larger samples with medication-free adolescents.

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.

TNF-alpha polymorphisms are associated with obsessive-compulsive disorder

INTRODUCTION

Several lines of evidence support an immunologic involvement in obsessive-compulsive disorder (OCD): the increased prevalence of OCD in patients with rheumatic fever (RF), and the aggregation of obsessive-compulsive spectrum disorders among relatives of RF probands. Tumor necrosis factor alpha is a proinflammatory cytokine involved in RF and other autoimmune diseases. Polymorphisms in the promoter region of the TNFA gene have been associated with RF. Given the association between OCD and RF, the goal of the present study was to investigate a possible association between polymorphisms within the promoter region of TNFA and OCD.

MATERIALS AND METHODS

Two polymorphisms were investigated: -308 G/A and -238 G/A. The allelic and genotypic frequencies of these polymorphisms were examined in 111 patients who fulfilled DSM-IV criteria for OCD and compared with the frequencies in 250 controls.

RESULTS

Significant associations were observed between both polymorphisms and OCD. For -238 G/A, an association between the A allele and OCD was observed (chi(2)=12.05, p=0.0005). A significant association was also observed between the A allele of the -308 G/A polymorphism and OCD (chi(2)=7.09, p=0.007). Finally, a haplotype consisting of genotypes of these two markers was also examined. Significant association was observed for the A-A haplotype (p=0.0099 after correcting for multiple testing).

DISCUSSION

There is association between the -308 G/A and -238 G/A TNFA polymorphisms and OCD in our Brazilian sample. However, these results need to be replicated in larger samples collected from different populations.

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.

Tourette's syndrome: clinical features, pathophysiology, and therapeutic approaches

Tourette's syndrome (TS) is a disorder characterized by simple and complex motor tics, vocal tics, and frequently obsessive-compulsive symptoms, its onset occurs before the age of 21. Typically, TS shows a waxing and waning course, but a chronification of the tics, even during later life, is often observed, TS mainly occurs in boys, and shows genetic heritability with differing penetrance. The pathological mechanism is still unclear. Neuroanatomical and neuroimaging studies, as well as effective treatment using antipsychotics, suggest that a disturbance of the dopaminergic system in the basal ganglia plays an important role in the pathogenesis of TS, Several possibly causative mechanisms of the disturbed dopaminergic neurotransmission are discussed, with the main emphasis on the-infection-triggered- inflammatory immune process, Extrapyramidal movement disorders are known to occur as a symptom of poststreptococcal disease, such as in Sydenham's chorea. Cases of childhood TS are proposed to be caused by such a post-streptococcal mechanism, being part of a spectrum of childhood neurobehavioral disorders termed pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (PANDAS), The overlap between TS and PANDAS is discussed, and a critical view of the PANDAS concept is presenter], The therapeutic implications of the different pathological mechanisms are described, taking into consideration not only the acute or chronic natures of different infections, but also an autoimmune process, Moreover, therapeutic strategies using typical and atypical antipsychotics, and also experimental therapies such as repetitive transcranial magnetic stimulation and deep brain stimulation, are critically discussed.

Immune variations in bipolar disorder: phasic differences

OBJECTIVES

To characterize the immunological variations of patients with a bipolar disorder (BD) diagnosis in manic (BDm) and depressive (BDd) phases, by the quantification of the serum levels of interleukin (IL)-1beta, -2, -4, -6 and tumor necrosis factor alpha (TNF-alpha).

METHODS

Twenty physically healthy patients with a BD type I diagnosis and 33 matched controls were studied, after giving informed consent. The inclusion criteria included at least three weeks without any kind of psychopharmacological treatment, Young Mania Rating Scale score > or =20 for BDm (n = 10) and Hamilton Depression Rating Scale score > or =21 for BDd patients (n = 10). Exclusion criteria included any infectious diseases, allergies or any other kind of medical illness that required treatment with immunosuppressors, as well as any other diagnosis in Axis I. Physical and laboratory examinations were performed to rule out any clinical illness. Enzyme-linked immunosorbent assay (ELISA) was used to analyze the serum cytokines concentration.

RESULTS

BD patients, when compared to controls, showed significant differences (p < or = 0.05) in the serum levels of the measured cytokines. The sub-group of BDd patients showed an increase in IL-6 and TNF-alpha, as well as a decrease in IL-2 concentration. The BDm sub-group, on the other hand, showed an increase in TNF-alpha and IL-4 values, with a low concentration of IL-1 and IL-2. The comparison between both sub-groups suggests that there is a distinctive cytokine pattern for the specific phases of the disorder: for mania, we found a high IL-4 and low IL-1beta and IL-6 concentration, while in the depressive phase, the inverse pattern was found.

CONCLUSIONS

Our results show the existence of phasic differences in the serum levels of cytokines in BD.

Neopterin levels and dexamethasone suppression test in obsessive-compulsive disorder

Neopterin, a biopterin precursor that is released by macrophages, is an important immunological marker in psychiatric disorders. It has been reported that glucocorticoids may cause suppression of cell-mediated immunity and consequently result in decreased neopterin levels. In the present study, we evaluated whether dexamethasone suppression test (DST) and neopterin findings were associated with pure obsessive-compulsive disorder (OCD) patients (OCD-D group) and the concomitant OCD and depression (OCD+D group). The sample comprised 44 patients with OCD (27 with OCD-D and 17 with OCD+D) and 30 control subjects. There was significantly higher DST nonsuppression in the OCD+D group than in the OCD-D group. With regard to mean neopterin levels, there was no significant difference between the OCD-D group and the control group, but there was a statistically significant difference between the OCD+D group and the control group. The OCD+D group had significantly lower neopterin levels than the 20 OCD-D group. We suggest that this distinction may reflect the fact that glucocorticoids can lead to suppression of cell-mediated immunity and consequently can result in decreased neopterin levels. In conclusion, our results suggest that not the OCD-D group had normal neopterin levels and DST results, and also that OCD may be a heterogeneous subtype characterized by some biological indicators or anxiety and affective disorders.

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.

Increased serum levels of interleukin-12 and tumor necrosis factor-alpha in Tourette's syndrome

BACKGROUND

The hypothesis that common infections can modulate the onset and course of tic disorders and early-onset obsessive-compulsive disorder (OCD) in pediatric populations is longstanding. To date, most investigations have focused on the hypothesis of molecular mimicry and humoral immune responses. This study was carried out to investigate whether cytokines associated with the innate immune response or T cell activation were altered under baseline conditions and during periods of symptom exacerbation.

METHODS

Forty-six patients with Tourette's syndrome and/or early-onset OCD, aged 7-17 years, and 31 age-matched control subjects participated in a prospective longitudinal study. Ratings of clinical severity and serum were collected at regular intervals, and serum concentrations of 10 cytokines were measured repeatedly.

RESULTS

Interleukin-12 and tumor necrosis factor alpha concentrations at baseline were elevated in patients compared with control subjects. Both of these markers were further increased during periods of symptom exacerbation.

CONCLUSIONS

These findings suggest that symptom exacerbations are associated with an inflammatory process propagated by systemic and local cytokine synthesis that might involve the central nervous system. We conclude that, in the future, longitudinal studies of children with neuropsychiatric disorders should examine the involvement of innate and T cell immunity.

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.

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.

Therapeutic relevance of altered cytokine expression

Cytokines and their receptors have numerous physiological functions. Altered concentrations of these mediators are associated with various afflictions. For example, over-expression of cytokines has been associated with altered drug concentrations and activity. Greater concentrations of cardiovascular drugs have been observed in humans and laboratory animals with various types of inflammatory disorders compared to healthy controls. Interestingly, the observed higher concentrations of drugs such as propranolol and verapamil have not been associated with increased effects. Indeed, reduced response to these cardiovascular drugs is observed, suggestive of cytokine-mediated downregulation of receptors. Increased cytokine concentrations have also been associated with decreased response to drugs used in treatment of other disorders such as AIDS, asthma and psychiatric diseases. This reduced response to drug in the presence of altered cytokine concentrations is especially relevant to the elderly population which has a greater incidence of multiple diseases and elevated concentrations of various cytokines compared to younger individuals. Furthermore, inflammatory conditions and their accompanied increased over-expression of cytokines are suggested to be the main determinants of therapeutic failure in myocardial infarction and angina. Therefore, altered cytokine concentrations may influence therapeutic outcomes of pharmacotherapy and result in treatment failure.

Association between -G308A tumor necrosis factor alpha gene polymorphism and schizophrenia

Dysregulation of the inflammatory response system has been linked to pathophysiology of schizophrenia. Evidence of immune activation has derived from the detection of abnormal levels of proinflammatory cytokines and their receptors in peripheral blood and cerebrospinal fluid from schizophrenic patients. Cytokines are involved in normal CNS development as well as in the pathogenesis of many neuro-psychiatric disorders, acting directly on neural cells or modulating neurotransmitter and neuropeptide systems. In particular tumor necrosis factor alpha (TNFalpha), depending on its concentration, can exert both neurotrophic and neurotoxic effects and influence neural cell growth and proliferation. Moreover, TNFalpha gene is located on the small arm of chromosome 6 (6p21.1-21.3), a locus associated with genetic susceptibility to schizophrenia. We studied the distribution of -G308A TNFalpha gene polymorphism in 84 schizophrenic patients and in 138 healthy volunteers. This biallelic base exchange polymorphism directly affects TNFalpha plasma levels. Frequency of the TNF2(A) allele is significantly increased in schizophrenic patients as compared to controls (P = 0.0042). Genotype distribution is also significantly different (P = 0.0024). TNF2 homozygotes are represented only in the patient group (P = 0.002). These data suggest a potential role of TNFalpha as a candidate gene for susceptibility to schizophrenia and suggest that immune dysregulation in schizophrenic patients could also have a genetic component.

The cognitive-affective neuroscience of obsessive-compulsive disorder

There is substantial evidence that obsessive-compulsive disorder (OCD) is mediated by specific cortico-striatal- thalamic-cortical (CTSC) circuits. Here we discuss very recent publications that address the following questions: How does damage to CSTC circuitry come about?; What are the neurochemical systems involved in mediating this circuitry?; and What are the implications of such damage for understanding the pathogenesis and management of OCD? A cognitive-affective neuroscience perspective is helpful in advancing our understanding of the role of these circuits in OCD and the dysfunctional procedural strategies that appear to characterize this disorder. Furthermore, this model is becoming integrated with a range of data including brain imaging, genetic, immunologic, and neurochemical findings.

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.