Sleep and pain: recent insights, mechanisms, and future directions in the investigation of this relationship.

Sleep disturbances and chronic pain are considered public health concerns. They are frequently associated, and the direction of its relationship and possible mechanisms underlying it are frequently debated. The exploration of the sleep-pain association is of great clinical interest to explore in order to steer potential therapeutic avenues, accommodate the patient's experience, and adapt the common practice of health professionals. In this review, the direction between sleep-pain in adult and pediatric populations will be discussed. Moreover, the possible mechanisms contributing to this relationship as endogenous pain modulation, inflammation, affect, mood and other states, the role of different endogenous substances (dopamine, orexin, melatonin, vitamin D) as well as other lesser known such as cyclic alternating pattern among others, will be explored. Finally, directions for future studies on this area will be discussed, opening up to the addition of tools such as brain imaging (e.g., fMRI), electrophysiology and non-invasive brain stimulation techniques. Such resources paired with artificial intelligence are key to personalized medicine management for patients facing pain and sleep interacting conditions.

Neuroimmunological antibody-mediated encephalitis and implications for diagnosis and therapy in neuropsychiatry.

The past decade has seen a surge of reports and investigations into cases of autoimmune-mediated encephalitis. The increasing recognition of these disorders is especially of relevance to the fields of neurology and psychiatry. Autoimmune encephalitis involves antibodies against synaptic receptors, neuronal cell surface proteins and intracellular targets. These disorders feature prominent symptoms of cognitive impairment and behavioural changes, often associated with the presence of seizures. Early in the clinical course, autoimmune encephalitis may manifest as psychiatric symptoms of psychosis and involve psychiatry as an initial point of contact. Although commonly associated with malignancy, these disorders can present in the absence of an inciting neoplasm. The identification of autoimmune encephalitis is of clinical importance as a large proportion of individuals experience a response to immunotherapy. This review focuses on the current state of knowledge on n-methyl-d-aspartate (NMDA) receptor-associated encephalitis and limbic encephalitis, the latter predominantly involving antibodies against the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor, the γ-aminobutyric acid (GABA)B receptor and leucine-rich glioma-inactivated 1 (LGI1) protein. In addition, we briefly describe anti-dopamine D2 receptor encephalitis. A summary of the literature will focus on common clinical presentations and course, diagnostic approaches and response to treatment. Since a substantial proportion of patients with autoimmune encephalitis exhibit symptoms of psychosis, the relevance of this disorder to theories of psychosis and schizophrenia will also be discussed.

Alexithymia and its relationships with inflammatory response mediated by IL-1 family members.

The major aim of this study is to provide a review of the research studies regarding the clinical link between alexithymia and interleukins (IL). We performed a search for the relevant literature by using search terms as "alexithymia" combined with "interleukin or IL". A total of 9 original research studies were identified and included. Alexithymia was found to be prevalent in inflammatory response and associated with inflammatory cytokines. Our review emphasized for the first time the relationships of alexithymia with inflammatory response mediated by IL-1 family members. Therefore, the screening of alexithymic traits and the administration of appropriate psychological and psychotherapeutical interventions should be integral parts of disease management programs. Supplying such interventions will probably help with prevention of the development of the disease and/or its exacerbation by improving the quality of life of alexithymic individuals.

Are the emergence of affective disturbances in neuropathic pain states contingent on supraspinal neuroinflammation?

Neuro-immune interactions contribute to the pathogenesis of neuropathic pain due to peripheral nerve injury. A large body of preclinical evidence supports the idea that the immune system acts to modulate the sensory symptoms of neuropathy at both peripheral and central nervous system sites. The potential involvement of neuro-immune interactions in the highly debilitating affective disturbances of neuropathic pain, such as depression, anhedonia, impaired cognition and reduced motivation has received little attention. This is surprising given the widely accepted view that sickness behaviour, depression, cognitive impairment and other neuropsychiatric conditions can arise from inflammatory mechanisms. Moreover, there is a set of well-described immune-to-brain transmission mechanisms that explain how peripheral inflammation can lead to supraspinal neuroinflammation. In the last 5years increasing evidence has emerged that peripheral nerve injury induces supraspinal changes in cytokine or chemokine expression and alters glial cell activity. In this systematic review, based on strong preclinical evidence, we advance the argument that the emergence of affective disturbances in neuropathic pain states are contingent on pro-inflammatory mediators in the interconnected hippocampal-medial prefrontal circuitry that subserve affective behaviours. We explore how dysregulation of inflammatory mediators in these networks may result in affective disturbances through a wide variety of neuromodulatory mechanisms. There are also promising results from clinical trials showing that anti-inflammatory agents have efficacy in the treatment of a variety of neuropsychiatric conditions including depression and appear suited to sub-groups of patients with elevated pro-inflammatory profiles. Thus, although further research is required, aggressively targeting supraspinal pro-inflammatory mediators at critical time-points in appropriate clinical populations is likely to be a novel avenue to treat debilitating affective disturbances in neuropathic conditions.

Alexithymia is linked to neurocognitive, psychological, neuroendocrine, and immune dysfunction in persons living with HIV.

The neuropathological changes resulting from Human Immunodeficiency Virus (HIV) infection may manifest in alexithymia (AL), a multidimensional trait characterized by impairments in the cognitive assimilation of feelings and emotions. A sample of 93 HIV survivors scoring high, i.e., ⩾74 on the 26-item Toronto Alexithymia Scale (TAS-26), were compared to 79 low AL (TAS-26⩽54) survivors on measures of neurocognitive, psychological, neuroendocrine and immune function. Neurocognitive function was evinced by a standardized test of psychomotor speed, cognitive flexibility and task switching ability, HIV Dementia and general cognitive status. Patients were also screened for levels of depression, anxiety and psychological stress. A 24-h urinary norepinephrine (NE) and cortisol (CORT) collection was taken; blood was drawn for T lymphocyte subset counts (CD4+CD3+) and HIV-1 viral load. Alexithymic patients exhibited higher levels of executive dysfunction, psychological distress, norepinephrine-to-cortisol (NE/CORT) ratio and viral load. Linear regression models accounting for sociodemographic and disease-related variables revealed two AL subscales, difficulties identifying and describing feelings, predicted and explained a significant proportion of variance in the outcome measures. Specifically, poorer executive task-switching/cognitive flexibility was associated with greater difficulty describing feelings; dysregulated autonomic response (high NE/CORT ratio) and depressive symptoms were predicted by difficulty identifying feelings; higher levels of anxiety and psychological stress were both predicted by greater difficulty describing and identifying feelings. Overall, the psychoneuroimmunological profile of alexithymia in HIV positive persons at mid-stage of infection suggests a greater vulnerability for disease progression.

Alexithymia and its relationships with acute phase proteins and cytokine release: an updated review.

The alexithymia construct is multidimensional and comprises several features: (a) difficulty in identifying and describing feelings, (b) difficulty in distinguishing feelings from the bodily sensations, (c) diminution of fantasy, and (d) concrete and poorly introspective thinking. Altered immune responses have been seen in some psychiatric disorders and several data suggest that analogous changes could also be observable in alexithymia. Hence, the aim of this review is to investigate the relationships between alexithymia and acute phase proteins and cytokines in psychiatric, psychosomatic and medical diseases. Several studies have reported an association between alexithymia and higher circulating levels of acute phase proteins, especially C-Reactive Protein. Moreover, in alexithymic subjects the pro-inflammatory and anti-inflammatory cytokine balance may be tuned toward a pro-inflammatory imbalance with a concomitant altered cell-mediated immunity. These findings may be consistent with the "“stress-alexithymia hypothesis"”. Therefore, the screening of alexithymic traits and the administration of appropriate psychological and psychotherapeutical interventions should be integral parts of disease management programs. Supplying such interventions will probably help with prevention of the development of the disease and/or its exacerbation by improving the quality of life of alexithymic individuals.

Cognitive and emotional abnormalities in systemic lupus erythematosus: evidence for amygdala dysfunction.

Systemic lupus erythematosus (SLE) is a multi-system autoimmune disorder characterized by the production of autoantibodies. Approximately 30-50 % of patients produce autoantibodies directed against N-Methyl-D-aspartic acid receptors (NMDARs). Once they have gained access to brain tissue, these autoantibodies bind to the NR2A subunit of the NMDARs and synergize with glutamate to cause excitatory, non-inflammatory cell death or alter neuron function. Both humans with SLE and animal models of SLE have shown structural and functional damage to the amygdala. The amygdala is a brain region important for processing the emotional relevance of stimuli in the environment. It also serves to modulate perception, attention, and memory to facilitate the processing and learning of relevant stimuli. Research has linked amygdala damage to deficits in emotional memory and emotional behavior. Individuals with SLE often exhibit emotional dysregulation, such as lability and depression; however, the behavioral impact of possible amygdala dysfunction has yet to be studied in this population. The purpose of this review is to 1) examine possible associations between SLE, anti-NMDAR antibodies, amygdala damage, and emotional processing deficits and 2) to identify the clinical, social, and treatment implications for individuals with SLE who suffer from deficits in emotional processing.

Detection of plasma autoantibodies to brain tissue in young children with and without autism spectrum disorders.

Autism spectrum disorders (ASDs) are characterized by impaired language and social skills, often with restricted interests and stereotyped behaviors. A previous investigation of blood plasma from children with ASDs (mean age=5½ years) demonstrated that 21% of samples contained autoantibodies that reacted intensely with GABAergic Golgi neurons of the cerebellum while no samples from non-sibling, typically developing children showed similar staining (Wills et al., 2009). In order to characterize the clinical features of children positive for these autoantibodies, we analyzed plasma samples from children enrolled in the Autism Phenome Project, a multidisciplinary project aimed at identifying subtypes of ASD. Plasma from male and female children (mean age=3.2 years) was analyzed immunohistochemically for the presence of autoantibodies using histological sections of macaque monkey brain. Immunoreactivity to cerebellar Golgi neurons and other presumed interneurons was observed for some samples but there was no difference in the rate of occurrence of these autoantibodies between children with ASD and their typically developing peers. Staining of neurons, punctate profiles in the molecular layer of the dentate gyrus, and neuronal nuclei were also observed. Taken together, 42% of controls and subjects with ASD demonstrated immunoreactivity to some neural element. Interestingly, children whose plasma reacted to brain tissue had scores on the Child Behavior Checklist (CBCL) that indicated increased behavioral and emotional problems. Children whose plasma was immunoreactive with neuronal cell bodies scored higher on multiple CBCL scales. These studies indicate that additional research into the genesis and prevalence of brain-directed autoantibodies is warranted.

Alexithymia and tissue inflammation.

BACKGROUND: Altered immune responses are seen in depression, and recent data suggest that similar changes could also be observable in alexithymia. We examined whether the inflammatory markers high-sensitivity C-reactive protein (hs-CRP) and interleukin (IL)-6 are independently related to alexithymia or its factors in a population-based sample. METHODS: This study formed a clinical part of the Kuopio Depression (KUDEP) general population study focusing on the mental health of a general population of adults aged 25-64 years (n = 308). Alexithymia was measured using the Toronto Alexithymia Scale (TAS-20), and depressive symptoms were assessed using the Beck Depression Inventory (BDI-21). RESULTS: The levels of IL-6 (in picograms per milliliter) and hs-CRP (in milligrams per liter) were significantly higher in alexithymic than in nonalexithymic subjects (IL-6 effect size, ES: 0.50; hs-CRP ES: 0.27). The BDI scores, hs-CRP and IL-6 explained 33.5% of the variation in TAS scores in the whole study population. According to logistic regression analysis, hs-CRP but not IL-6 increased the likelihood of belonging to the alexithymic group. This observation remained unaltered after additional adjustments for chronic inflammation-related disorders, the use of inflammation-modulating medications and depressive symptoms. CONCLUSIONS: Our findings suggest that the association between hs-CRP and alexithymia resembles that observed in depressed patients. It is, however, independent of depressive symptoms. These findings widen our view on the stress-alexithymia concept.

The relationship between alexithymia and circulating cytokine levels in subjects undergoing upper endoscopy.

OBJECTIVE: Despite emerging evidence suggesting a link between alexithymia and immune function, previous studies yielded contrasting results. The proposed link between alexithymia and immune function remains controversial as does the role, in this relationship, of anxiety, depression and subjective stress. The aim of the study is to investigate the possible association between alexithymia and circulating levels of cytokines in subjects awaiting an upper endoscopy, a stressful procedure, controlling for anxiety levels, depression and subjective stress. METHODS: Participants were recruited from among consecutive patients referred for routine diagnostic upper endoscopy. All participants completed the Toronto Alexithymia Scale (TAS-20), the Hospital Anxiety and Depression Scale, and the Stress-related Vulnerability Scale. Serum levels of IL-1ß, IL-4, IL-6, IL-10, TNF-α and IFN-γ were measured by ELISA. RESULTS: Of the 90 subjects initially approached, 68 completed the study. The TAS-20 identified 22 alexithymic and 36 non-alexithymic patients. ELISA detected significantly lower IL-4 and IL-6 concentrations in alexithymic than in non-alexithymic patients. According to multiple linear regression analysis, alexithymia predicted low IL-4 and IL-6 levels in the sample overall, independently of stress, anxiety, depression and other possible confounders. No between-group differences were found in serum levels of IFN-γ, IL-1ß, and TNF-α. CONCLUSION: These findings argue against an isolated shift towards pro-inflammatory or anti-inflammatory mediators and suggest that circulating cytokine profiles differ in alexithymic and non-alexithymic subjects.

Non-paraneoplastic limbic encephalitis associated with antibodies to potassium channels leading to bilateral hippocampal sclerosis in a pre-pubertal girl.

Limbic encephalitis (LE) is increasingly recognized as a precipitating factor of adult onset temporal lobe epilepsy frequently associated with bilateral hippocampal damage. So far, clinical data in children are rare and only comprise paraneoplastic forms of LE. We describe a 13-year-old pre-pubertal girl in whom non-paraneoplastic LE was diagnosed according to diagnostic criteria proposed by Bien and Elger (2007). The girl presented with a subacute syndrome comprising memory impairment, affective disturbances, and refractory temporal lobe seizures. Serial MRI scans demonstrated an initial temporo-medial swelling with T2/FLAIR signal increase progressing to bilateral hippocampal atrophy within seven months. Two years after onset of symptoms, antibodies to potassium channels were found to be slightly elevated. Immunosuppressive therapy with steroid-pulses was followed by a transient reduction of seizure frequency, even though this was started more than two years after onset of first symptoms. However, extended immunotherapy was refused by the patient's parents, so no full assessment of the treatment response was possible. In conclusion, this case shows that non-paraneoplastic LE leading to mesial temporal lobe epilepsy is not restricted to adult patients. The proposed diagnostic criteria therefore should be adapted for paediatric patients. Patients may profit from immunosuppressive therapy even when it is started at a late stage with already overt hippocampal sclerosis.

Stimulant use is associated with immune activation and depleted tryptophan among HIV-positive persons on anti-retroviral therapy.

Cocaine, crack, and methamphetamine are stimulants that promote autonomic nervous system activation. Although these stimulants may have immunomodulatory effects, relatively few studies have examined this possibility. The present cross-sectional investigation utilized baseline data from 127 HIV-positive individuals on anti-retroviral therapy (ART) that were enrolled in a randomized controlled trial. The goal of this study was to examine whether stimulant use is independently associated with immune activation and indices of tryptophan degradation. Forty-four participants reported using stimulants 2-3 times a month or more (i.e., monthly stimulant use) and a sub-set of these (n=27) reported using stimulants once a week or more (i.e., weekly stimulant use) during the past three months. These stimulant-using groups were compared to a group of participants who reported no stimulant use (n=83) during the past three months. Results indicated that individuals who reported either monthly or weekly stimulant use displayed elevated neopterin, a measure of immune activation. Those who reported weekly stimulant use also displayed a markedly elevated HIV viral load and lower tryptophan levels. Even after controlling for self-reported ART non-adherence, weekly stimulant use was independently associated with higher neopterin, elevated HIV viral load, and lower tryptophan. To our knowledge, this is the first study to observe that stimulant use may independently promote immune activation and tryptophan degradation among HIV-positive persons on ART. Further research is needed to replicate these findings and examine the plausible bio-behavioral pathways that may account for the effects of stimulant use on HIV disease markers and depleted tryptophan.

Type C coping, alexithymia, and heart rate reactivity are associated independently and differentially with specific immune mechanisms linked to HIV progression.

The maladaptive Type C coping style has been linked to disease progression in HIV and other immunologically mediated disorders. We hypothesized that strong Type C coping, higher levels of alexithymia, and greater cardiovascular (particularly heart rate) responses to, and prolonged recovery from stress would be associated with poorer functioning of immune parameters previously linked to HIV pathogenesis and progression: (1) antigen-stimulated production of the beta (beta)-chemokines MIP-1 alpha and MIP-1 beta, which bind to the HIV co-receptor CCR5 and block HIV entry into CD4(+) lymphocytes; and (2) antigen-stimulated production of the proinflammatory cytokine interleukin-6 (IL-6), which synergizes immune activation associated with HIV replication. We examined relations among psychological, cardiovascular, and immune variables in a baseline sample of 200 HIV-infected, predominantly African American outpatients attending an HIV primary care clinic in inner-city Baltimore. In regression analyses adjusted for CD4(+) count and age, strong Type C coping was associated with significantly higher IL-6 production, as predicted. The theoretically related construct of alexithymia was correlated with significantly lower stimulated production of HIV-inhibiting MIP-1 alpha. Independent of alexithymia, greater heart rate reactivity, and poorer heart rate recovery in response to experimental stressors were also significantly associated with lower production of MIP-1 alpha, adjusted for cardiovascular medications, methadone use, CD4(+) count, and age. These findings support our primary set of hypotheses that maladaptive Type C coping, alexithymia, and heart rate reactivity/recovery are associated with disturbances in two key immune parameters implicated in HIV pathogenesis. Our secondary hypothesis, that dysregulated heart rate reactivity may mediate the connections between Type C coping and/or alexithymia and IL-6/ MIP-1 alpha was not confirmed. The finding that Type C coping, alexithymia, and heart rate reactivity/recovery are associated independently and differentially with specific aspects of relevant immune functioning may reflect distinct biobehavioral pathways that contribute to HIV progression.

Association between burnout and circulating levels of pro- and anti-inflammatory cytokines in schoolteachers.

OBJECTIVE: The burnout syndrome has been associated with an increased risk of cardiovascular disease. The physiological mechanisms potentially involved in this link are underexplored. Knowing that a chronic low-grade systemic inflammatory state contributes to atherosclerosis, we investigated circulating cytokine levels in relation to burnout symptoms. METHODS: We studied 167 schoolteachers (median, 48 years; range, 23-63 years; 67% women) who completed the Maslach Burnout Inventory with its three subscales emotional exhaustion (EE), lack of accomplishment (LA), and depersonalization (DP). Levels of the proinflammatory cytokine tumor necrosis factor (TNF)-alpha and of the anti-inflammatory cytokines interleukin (IL)-4 and IL-10 were determined in fasting morning plasma samples. The TNF-alpha/IL-4 ratio and the TNF-alpha/IL-10 ratio were computed as two indices of increased inflammatory activity. Analyses were adjusted for demographic factors, medication, lifestyle factors (including sleep quality), metabolic factors, and symptoms of depression and anxiety. RESULTS: Higher levels of total burnout symptoms aggregating the EE, LA, and DP subscales independently predicted higher TNF-alpha levels (DeltaR(2)=.024, P=.046), lower IL-4 levels (DeltaR(2)=.021, P=.061), and a higher TNF-alpha/IL-4 ratio (DeltaR(2)=.040, P=.008). Higher levels of LA predicted decreased IL-4 levels (DeltaR(2)=.041, P=.008) and a higher TNF-alpha/IL-4 ratio (DeltaR(2)=.041, P=.007). The categorical dimensions of the various burnout scales (e.g., burnout yes vs. no) showed no independent relationship with any cytokine measure. CONCLUSION: Burnout was associated with increased systemic inflammation along a continuum of symptom severity rather than categorically. Given that low-grade systemic inflammation promotes atherosclerosis, our findings may provide one explanation for the increased cardiovascular risk previously observed in burned-out individuals.

Juvenile onset central nervous system folate deficiency and rheumatoid arthritis.

Isolated cerebral folate deficiency was detected in a 13-year-old girl with cognitive and motor difficulties and juvenile rheumatoid arthritis. Her serum contains autoantibodies that block membrane-bound folate receptors that are on the choroid plexus and diminish the uptake of folate into the spinal fluid. Whereas her serum folate exceeded 21 ng/mL, her spinal fluid contained 3.2 ng/mL of 5-methyltetrahydrofolate as a consequence of the autoantibodies diminishing the uptake of this folate.

Alexithymia and interleukin variations in somatoform disorder.

OBJECTIVE: The aim of the present study was to investigate if somatoform disorders (SFD) are associated with changes in the normal serum levels of important interleukins, and further, to establish if these changes are related to the presence and severity of alexithymia in patients with SFD. METHODS: Twenty-four unmedicated patients who met the International Classification of Diseases (ICD-10) diagnostic criteria for SFD completed the psychological questionnaire to assess alexithymia (Toronto Alexithymia Scale), symptom reporting (SCL-90-R) and diagnostic criteria for SFD (Screening for Somatoform Symptoms scale). Serum concentrations of soluble interleukin 2 receptor alpha (sIL-2 Ralpha), IL-4, IL-6, IL-10 and IL-12 were determined in patients with SFD and in 9 healthy subjects. RESULTS: In patients with SFD, serum levels of IL-6 (p < 0.001), IL-10 (p = 0.047) and immunoglobulin E (p = 0.045) were significantly increased in comparison with healthy controls. Additionally, a negative correlation was observed between the level of alexithymia ('total' Toronto Alexithymia Scale score) and the serum levels of sIL-2 Ralpha (r = -0.538) in SFD. CONCLUSIONS: Taken together, these results suggest that SFD, with clinically significant alexithymia, are associated with a reduction in Th1-mediated immune function and an increase in the activation of the Th2 immune function, indicated by the augmented serum levels of IL-6 and IL-10 and elevated immunoglobulin E.

Alexithymia and neuroendocrine-immune response in patients with autoimmune diseases: preliminary results on relationship between alexithymic construct and TNF-alpha levels.

Alexithymia is conceptualized as a disorder of emotion regulation mechanisms, which involves a dissociation of emotional and physical responses to life events and bodily sensations. Our results might suggest a possible relationship between the alexithymic construct and TNF levels in RA patients. These preliminary findings corroborate the integrated bidirectional interactions between neuropsychological mechanisms and the neuroendocrine-immune system in patients affected by autoimmune diseases and contribute to finding a common biological pathway linking alexithymia and autoimmune-inflammatory diseases.

Cytokine-associated emotional and cognitive disturbances in humans.

BACKGROUND: Infectious, autoimmune, and neurodegenerative diseases are associated with profound psychological disturbances. Studies in animals clearly demonstrate that cytokines mediate illness-associated behavioral changes. However, the mechanisms underlying the respective psychological alterations in humans have not been established yet. Therefore, we investigated the effects of low-dose endotoxemia, a well-established and safe model of host-defense activation, on emotional, cognitive, immunological, and endocrine parameters. METHODS: In a double-blind, crossover study, 20 healthy male volunteers completed psychological questionnaires and neuropsychological tests 1, 3, and 9 hours after intravenous injection of Salmonella abortus equi endotoxin (0.8 ng/kg) or saline in 2 experimental sessions. Blood samples were collected hourly, and rectal temperature and heart rate were monitored continuously. RESULTS: Endotoxin had no effects on physical sickness symptoms, blood pressure, or heart rate. Endotoxin caused a mild increase in rectal temperature (0.5 degrees C), and increased the circulating levels of tumor necrosis factor alpha (TNF-alpha), soluble TNF receptors, interleukin (IL)-6, IL-1 receptor antagonist, and cortisol. After endotoxin administration, the subjects showed a transient significant increase in the levels of anxiety (effect size [ES] = 0.55) and depressed mood (ES = 0.66). Verbal and nonverbal memory functions were significantly decreased (ES = 0.55 to 0.64). Significant positive correlations were found between cytokine secretion and endotoxin-induced anxiety (r = 0.49 to r = 0.60), depressed mood (r = 0.40 to r = 0.75), and decreases in memory performance (r = 0.46 to r = 0.68). CONCLUSIONS: In humans, a mild stimulation of the primary host defense has negative effects on emotional and memory functions, which are probably caused by cytokine release. Hence, cytokines represent a novel target for neuropsychopharmacological research.

Correlation between serum levels of interleukin-4 and alexithymia scores in healthy female subjects: preliminary findings.

OBJECTIVE: Some studies suggest that inaccuracy in recognizing and describing emotional states, combined with a highly descriptive mode of expression, as in alexithymia, may influence the immune response. We therefore investigated in healthy women the relationship between alexithymia and circulating levels of IL-1, IL-2 and IL-4. METHOD: Seventeen mentally and physically healthy women aged between 20 and 25 years completed psychological questionnaires to assess alexithymia (Toronto Alexithymia Scale: TAS) and depressed mood (Hospital Anxiety and Depression Scale: HAD). Serum concentrations of IL-1, IL-2 and IL-4 were measured by ELISA. RESULTS: We found a significant positive correlation between serum levels of IL-4 and TAS score (r = 0.55; p = 0.021) and between factor 1 of the TAS (difficulty in identifying feelings) and IL-4 (r = 0.57; p = 0.017) while serum IL-1 and IL-2 were not detected in ten and six patients, respectively. Although there was a significant correlation between age and IL-4 levels, a linear regression with BMI, age, depressed mood and TAS as independent variables showed that only alexithymia could predict significantly increased levels of IL-4. CONCLUSION: Alexithymia and difficulty in identifying feelings could be associated with increased levels of IL-4 which may result in chronic impairment of pro/anti-inflammatory cytokine balance with psychological and somatic consequences. Nevertheless, these intriguing findings would deserve replication and extension in a larger sample of subjects.

Negative affect, absorption, and immunity.

Relationships between the psychological characteristics absorption and neuroticism, and in vitro and in vivo measures of cell-mediated immunity were examined. Thirty-nine female subjects responded to questionnaires, donated blood for analysis of T-cell numbers, and were tested for delayed hypersensitivity skin responses. Consistent with the experimental hypothesis, subjects classified as repressors of negative affect (low absorption/low neuroticism), or extreme expressors of negative affect (high absorption/high neuroticism), showed lower immune responses than other groups of subjects. For the in vitro T-cell measures and the in vivo skin induration measures, there were also pervasive main effects of neuroticism, with subjects higher in neuroticism showing higher immunity than subjects lower in neuroticism.