Multi-analyte profile analysis of plasma immune proteins: altered expression of peripheral immune factors is associated with neuropsychiatric symptom severity in adults with and without chronic hepatitis C virus infection

Neuroimmune modulation in liver pathophysiology

The liver, the largest organ in the human body, plays a multifaceted role in digestion, coagulation, synthesis, metabolism, detoxification, and immune defense. Changes in liver function often coincide with disruptions in both the central and peripheral nervous systems. The intricate interplay between the nervous and immune systems is vital for maintaining tissue balance and combating diseases. Signaling molecules and pathways, including cytokines, inflammatory mediators, neuropeptides, neurotransmitters, chemoreceptors, and neural pathways, facilitate this complex communication. They establish feedback loops among diverse immune cell populations and the central, peripheral, sympathetic, parasympathetic, and enteric nervous systems within the liver. In this concise review, we provide an overview of the structural and compositional aspects of the hepatic neural and immune systems. We further explore the molecular mechanisms and pathways that govern neuroimmune communication, highlighting their significance in liver pathology. Finally, we summarize the current clinical implications of therapeutic approaches targeting neuroimmune interactions and present prospects for future research in this area.

Impact of interleukin-1β single nucleotide polymorphisms and depressive symptoms in individuals with chronic viral hepatitis

Elevated levels of interleukin 1β (IL-1β) have been identified in patients with chronic viral hepatitis and have been associated with depressive symptoms. Given the high prevalence of depression in this patient population, this study sought to explore the potential influence of IL-1β genetic variations on the severity of depressive symptoms. In a cohort of 181 Taiwanese patients with chronic viral hepatitis, we investigated the impact of five common IL-1β single nucleotide polymorphisms (SNPs), including rs16944, rs1143627, rs1143630, rs1143643, and rs3136558, on depressive symptoms using the Beck's Depression Inventory-II. Additionally, we analyzed the primary domains of IL-1β-related depressive symptoms according to Beck's six symptom categories of depression. Our analysis revealed significant associations between depressive symptoms and three intronic IL-1β SNPs. After controlling for age, sex, marital status, and education level, patients with the rs1143630 GG, rs1143643 CC, and rs3136558 AA genotypes demonstrated higher severity of depressive symptoms in the domains of indecision (p = 0.004), agitation (p = 0.001), and feelings of punishment (p = 0.005), respectively, compared to rs1143630 GA+AA, rs1143643 CT, and rs3136558 AG+GG genotypes. According to Beck's categorization, these symptoms can be classified into three dimensions: disturbances in emotion regulation, energy, and cognition. Our findings demonstrate the association between IL-1β polymorphisms and depressive symptoms and suggest a potential underlying mechanism for specific depressive symptoms within the chronic viral hepatitis population. These insights could improve our understanding and treatment of depressive symptoms in individuals with viral hepatitis.

Inflammatory and mental health sequelae of COVID-19

The COVID-19 pandemic has caused significant negative consequences to mental health. Increased inflammatory factors and neuropsychiatric symptoms, such as cognitive impairment ("brain fog"), depression, and anxiety are associated with long COVID [post-acute sequelae of SARS-CoV-2 infection (PASC), termed neuro-PASC]. The present study sought to examine the role of inflammatory factors as predictors of neuropsychiatric symptom severity in the context of COVID-19. Adults (n = 52) who tested negative or positive for COVID-19 were asked to complete self-report questionnaires and to provide blood samples for multiplex immunoassays. Participants who tested negative for COVID-19 were assessed at baseline and at a follow-up study visit (∼4 weeks later). Individuals without COVID-19 reported significantly lower PHQ-4 scores at the follow-up visit, as compared to baseline (p = 0.03; 95% CI-1.67 to -0.084). Individuals who tested positive for COVID-19 and experienced neuro-PASC had PHQ-4 scores in the moderate range. The majority of people with neuro-PASC reported experiencing brain fog (70% vs. 30%). Those with more severe COVID-19 had significantly higher PHQ-4 scores, as compared to those with mild disease (p = 0.008; 95% CI 1.32 to 7.97). Changes in neuropsychiatric symptom severity were accompanied by alterations in immune factors, particularly monokine induced by gamma interferon (IFN-γ) (MIG, a. k.a. CXCL9). These findings add to the growing evidence supporting the usefulness of circulating MIG levels as a biomarker reflecting IFN-γ production, which is important because individuals with neuro-PASC have elevated IFN-γ responses to internal SARS-CoV-2 proteins.

Role of hepatitis c virus in hepatocellular carcinoma and neurological disorders: an overview

The hepatitis C virus (HCV) causes serious issues, affecting 71 million people globally. The most common manifestations range from chronic hepatitis to liver cirrhosis, leading to hepatocellular carcinoma. Many mechanisms are known to play an important role in HCV-induced HCC. The interaction of viral proteins with host cells results in oxidative stress damage, liver inflammation, and irregularities in signaling pathways. These results in the activation of oncogenes and metabolic disturbances, liver fibrosis, and angiogenesis. Additionally, some non-coding RNAs (ncRNAs) and toll-like receptors have been identified and play a significant role in HCC development. This virus is also associated with impairment of the central nervous system, resulting in acute or sub-acute encephalopathy and inflammatory disorders. Neurological disorders are associated with the inflammatory responses of many cells, including microglia and astrocytes. Additionally, there are many other extrahepatic manifestations, including neurological disorders such as depression and fatigue, in 50% of infected patients. These manifestations include neuro-invasion, immune-mediated damage, neurotransmitter alterations, sensory-motor polyneuropathy, sensitivity loss, weakness of the leg, and cryoglobulinemia, which significantly results in a reduced quality of life. HCV infection may be improved using an appropriate diagnosis and direct antiviral therapy for sustained virological response. However, the success of therapy depends on the symptoms and organ damage, diagnosis, and therapeutic strategies applied. Some published reports have discussed that HCV is associated with both HCC and neurological disorders. Additionally, it has also been observed that individuals with HCC also develop neurological disorders compared with individuals with HCV alone. This review aims to provide an overview of the latest information about the relationship between HCV-induced HCC and their role in neurological disorders. Additionally, we have also discussed the progress made in the diagnosis, physio-pathological mechanisms, and strong antiviral therapies developed for HCV infection and HCC, as well as the latest advancements made in the study of the neurological disorders associated with HCV infection.

Impact of direct-acting antiviral regimens on hepatic and extrahepatic manifestations of hepatitis C virus infection

Hepatitis C virus (HCV) is a common cause of liver disease and is associated with various extrahepatic manifestations (EHMs). This mini-review outlines the currently available treatments for HCV infection and their prognostic effect on hepatic manifestations and EHMs. Direct-acting antiviral (DAA) regimens are considered pan-genotypic as they achieve a sustained virological response (SVR) > 85% after 12 wk through all the major HCV genotypes, with high percentages of SVR even in advanced fibrosis and cirrhosis. The risk factors for DAA failure include old males, cirrhosis, and the presence of resistance-associated substitutions (RAS) in the region targeted by the received DAAs. The effectiveness of DAA regimens is reduced in HCV genotype 3 with baseline RAS like A30K, Y93H, and P53del. Moreover, the European Association for the Study of the Liver recommended the identification of baseline RAS for HCV genotype 1a. The higher rate of hepatocellular carcinoma (HCC) after DAA therapy may be related to the fact that DAA regimens are offered to patients with advanced liver fibrosis and cirrhosis, where interferon was contraindicated to those patients. The change in the growth of pre-existing subclinical, undetectable HCC upon DAA treatment might be also a cause. Furthermore, after DAA therapy, the T cell-dependent immune response is much weaker upon HCV clearance, and the down-regulation of TNF-α or the elevated neutrophil to lymphocyte ratio might increase the risk of HCC. DAAs can result in reactivation of hepatitis B virus (HBV) in HCV co-infected patients. DAAs are effective in treating HCV-associated mixed cryoglobulinemia, with clinical and immunological responses, and have rapid and high effectiveness in thrombocytopenia. DAAs improve insulin resistance in 90% of patients, increase glomerular filtration rate, and decrease proteinuria, hematuria and articular manifestations. HCV clearance by DAAs allows a significant improvement in atherosclerosis and metabolic and immunological conditions, with a reduction of major cardiovascular events. They also improve physical function, fatigue, cognitive impairment, and quality of life. Early therapeutic approach with DAAs is recommended as it cure many of the EHMs that are still in a reversible stage and can prevent others that can develop due to delayed treatment.

Gut-derived systemic inflammation as a driver of depression in chronic liver disease

Depression and chronic liver disease (CLD) are important causes of disability, morbidity and mortality worldwide and their prevalence continues to rise. The rate of depression in CLD is high compared to that of the general population and is comparable to the increased rates observed in other medical comorbidities and chronic inflammatory conditions. Notably, a comorbid diagnosis of depression has a detrimental effect on outcomes in cirrhosis. Systemic inflammation is pivotal in cirrhosis-associated immune dysfunction - a phenomenon present in advanced CLD (cirrhosis) and implicated in the development of complications, organ failure, disease progression, increased infection rates and poor outcome. The presence of systemic inflammation is also well-documented in a cohort of patients with depression; peripheral cytokine signals can result in neuroinflammation, behavioural change and depressive symptoms via neural mechanisms, cerebral endothelial cell and circumventricular organ signalling, and peripheral immune cell-to-brain signalling. Gut dysbiosis has been observed in both patients with cirrhosis and depression. It leads to intestinal barrier dysfunction resulting in increased bacterial translocation, in turn activating circulating immune cells, leading to cytokine production and systemic inflammation. A perturbed gut-liver-brain axis may therefore explain the high rates of depression in patients with cirrhosis. The underlying mechanisms explaining the critical relationship between depression and cirrhosis remain to be fully elucidated. Several other psychosocial and biological factors are likely to be involved, and therefore the cause is probably multifactorial. However, the role of the dysfunctional gut-liver-brain axis as a driver of gut-derived systemic inflammation requires further exploration and consideration as a target for the treatment of depression in patients with cirrhosis.

Neurological and psychiatric effects of hepatitis C virus infection

Hepatitis C virus (HCV) infection is widespread and affects 71 million people worldwide. Although hepatic manifestations are the most frequent, ranging from chronic hepatitis to cirrhosis and hepatocellular carcinoma, it is also associated with several extrahepatic manifestations. Infected patients may present non-specific neurological symptoms, regardless of the presence of liver cirrhosis. Several pathogenetic mechanisms underlying neurological symptoms have been hypothesized: neuroinvasion, immune-mediated damage, neurotransmitter alterations and cryoglobulinemia. Alterations of the central nervous system include cerebral vasculopathy, acute or subacute encephalopathy and inflammatory disorders. HCV infection may be responsible for neuropathies, of which the most frequent form is symmetrical axonal sensory or sensory-motor polyneuropathy which causes loss of leg sensitivity and weakness. Up to 50% of patients with HCV infection may experience cognitive decline and psychological disorders, such as depression and fatigue. HCV associated neurocognitive disorder is independent of the presence of liver cirrhosis and affects different domains than in patients with hepatic encephalopathy. It can be studied using specific tests that mainly explore executive functions, verbal learning and verbal recall. These disorders significantly reduce the quality of life. The new antiviral therapies improve the extrahepatic symptoms of HCV infection and their success depends on the achievement of sustained virological response. However, the effect of therapy may differ depending on the type of organ involved; neurological symptoms can be irreversible if there is organic liver damage. The aim of this review is to provide a critical overview of physiopathological mechanisms, diagnostic and therapeutic strategies of the neurological and psychiatric effects of HCV infection.

Only partial improvement in health-related quality of life after treatment of chronic hepatitis C virus infection with direct acting antivirals in a real-world setting-results from the German Hepatitis C-Registry (DHC-R)

Improvement of health-related quality of life (HRQoL) is frequently reported as a benefit when treating hepatitis C virus infection (HCV) with direct acting antivirals (DAA). As most of the available data were obtained from clinical trials, limited generalizability to the real-world population might exist. This study aimed to investigate the impact of DAA therapy on changes in HRQoL in a real-world setting. HRQoL of 1180 participants of the German Hepatitis C-Registry was assessed by Short-Form 36 (SF-36) questionnaires. Scores at post-treatment weeks 12-24 (FU12/24) were compared to baseline (BL). Changes of ≥2.5 in mental and physical component summary scores (MCS and PCS) were defined as a minimal clinical important difference (MCID). Potential predictors of HRQoL changes were analysed. Overall, a statistically significant increase in HRQoL after DAA therapy was observed, that was robust among various subgroups. However, roughly half of all patients failed to achieve a clinically important improvement in MCS and PCS. Low MCS (p < .001, OR = 0.925) and PCS (p < .001, OR = 0.899) BL levels were identified as predictors for achieving a clinically important improvement. In contrast, presence of fatigue (p = .023, OR = 1.518), increased GPT levels (p = .005, OR = 0.626) and RBV containing therapy regimens (p = .001, OR = 1.692) were associated with a clinically important decline in HRQoL after DAA therapy. In conclusion, DAA treatment is associated with an overall increase of HRQoL in HCV-infected patients. Nevertheless, roughly half of the patients fail to achieve a clinically important improvement. Especially patients with a low HRQoL seem to benefit most from the modern therapeutic options.

Natural History of Hepatic and Extrahepatic Hepatitis C Virus Diseases and Impact of Interferon-Free HCV Therapy

The hepatitis C virus (HCV) infects 71.1 million persons and causes 400,000 deaths annually worldwide. HCV mostly infects the liver, causing acute and chronic necroinflammatory damage, which may progress toward cirrhosis and hepatocellular carcinoma. In addition, HCV has been associated with several extrahepatic manifestations. The advent of safe and effective direct-acting antivirals (DAAs) has made the dream of eliminating this public health scourge feasible in the medium term. Prospective studies using DAA-based regimens have shown the benefit of HCV clearance in terms of both liver- and non-liver-related mortality.

Neuroinvasion and cognitive impairment in comorbid alcohol dependence and chronic viral infection: An initial investigation

Viruses that invade the central nervous system (CNS) can cause neuropsychiatric impairments. Similarly, chronic alcohol exposure can induce inflammatory responses that alter brain function. However, the effects of a chronic viral infection and comorbid alcohol use on neuroinflammation and behavior are not well-defined. We investigated the role of heavy alcohol intake in regulating inflammatory responses and behavioral signs of cognitive impairments in mice infected with lymphocytic choriomeningitis virus (LCMV) clone 13. LCMV-infected mice exposed to alcohol had increased peripheral inflammation and impaired cognitive function (as indicated by performance on the novel object recognition test). Initial findings suggest that brain region-specific dysregulation of microglial response to viral infection may contribute to cognitive impairments in the context of heavy alcohol use.

Expert opinion on managing chronic HCV in patients with neuropsychiatric manifestations

Neurological manifestations of HCV infection appear to be under-recognized in clinical practice despite the majority of HCV-infected patients experiencing symptoms such as fatigue, depression and cognitive dysfunction. There is also growing evidence for a link between HCV infection and an increased risk of Parkinson's disease. The mechanism underpinning the association between HCV and these neuropsychiatric syndromes still requires further investigation. Here we review the pre-clinical and clinical evidence for a link between HCV and effects on the central nervous system leading to neuropsychiatric syndromes. Lastly, we describe how improvements in neuropsychiatric manifestations of HCV following treatment have been observed, which is subsequently reflected in an overall improvement in health-related quality of life.

Association of chronic inflammation and perceived stress with abnormal functional connectivity in brain areas involved with interoception in hepatitis C patients

BACKGROUND

Sickness behavioral changes elicited by inflammation may become prolonged and dysfunctional in patients with chronic disease, such as chronic hepatitis C (CHC). Neuroimaging studies show that the basal ganglia and insula are sensitive to systemic inflammation.

AIM

To elucidate the clinical and neurobiological aspects of prolonged illnesses in patients with CHC.

METHODS

Thirty-five CHC patients not treated with interferon-α or other antiviral therapy, and 30 control subjects matched for age and sex, were evaluated for perceived stress (perceived stress scale; PSS), depression (PHQ-9), fatigue and irritability through a visual analog scale (VAS), as well as serum levels of interleukin-6 (IL-6), prostaglandin E₂ (PGE₂) and oxidative stress markers. Functional MRI was performed, measuring resting-state functional connectivity using a region-of-interest (seed)-based approach focusing on the bilateral insula, subgenual anterior cingulate cortex and bilateral putamen. Between-group differences in functional connectivity patterns were assessed with two-sample t-tests, while the associations between symptoms, inflammatory markers and functional connectivity patterns were analyzed with multiple regression analyses.

RESULTS

CHC patients had higher PSS, PHQ-9 and VAS scores for fatigue and irritability, as well as increased IL-6 levels, PGE₂ concentrations and antioxidant system activation compared to controls. PSS scores positively correlated with functional connectivity between the right anterior insula and right putamen, whereas PHQ-9 scores correlated with functional connectivity between most of the seeds and the right anterior insula. PGE₂ (positively) and IL-6 (negatively) correlated with functional connectivity between the right anterior insula and right caudate nucleus and between the right ventral putamen and right putamen/globus pallidus. PGE₂ and PSS scores accounted for 46% of the variance in functional connectivity between the anterior insula and putamen.

CONCLUSIONS

CHC patients exhibited increased perceived stress and depressive symptoms, which were associated with changes in inflammatory marker levels and in functional connectivity between the insula and putamen, areas involved in interoceptive integration, emotional awareness, and orientation of motivational state.

Reduced CXCL1/GRO chemokine plasma levels are a possible biomarker of elderly depression

BACKGROUND

Depression is the single largest contributor to non-fatal health loss worldwide. A role of inflammation in major depressive disorder (MDD) was suggested, and we sought to determine if cytokine levels predict the severity of depressive symptomatology or distinguish MDD patients from healthy controls (HCs).

METHODS

The severity of depressive symptoms and cognitive impairment were assessed by the Korean version of the Geriatric Depression Scale (GDS-K) and Mini-Mental State Examination (MMSE-KC) in 152 elderly subjects (76 with MDD). Plasma levels of 28 cytokines were measured and analysed as continuous predictors or dichotomized using the median value. The association between individual cytokines, MDD risk and depressive symptoms severity was investigated using multiple logistic and linear regressions that included the relevant covariates. A Cytokine Weighted Score (CWS) was calculated by weighting cytokines according to previously reported effect sizes on MDD risk. Sensitivity analyses were performed excluding subjects with significant cognitive impairment.

RESULTS

CXCL10/IP-10 levels were higher in subjects with MDD vs. HCs while the opposite was observed for CXCL1/GRO. Only the second association survived after adjusting for possible confounders and excluding subjects with severe cognitive impairment. Using dichotomized cytokine levels, CXCL1/GRO and TNF-α were negatively associated with MDD. The CWS was also negatively associated with MDD. Cytokine levels did not predict the severity of depressive symptoms.

LIMITATIONS

Our cross-sectional approach was not able to longitudinally evaluate any temporal fluctuations in the considered cytokine levels.

CONCLUSIONS

This study found significantly lower CXCL1/GRO chemokine plasma levels in elderly subjects with MDD compared to HCs.

Functional MRI and delay discounting in patients infected with hepatitis C

Hepatitis C virus-infected (HCV+) adults evidence increased rates of psychiatric and cognitive difficulties. This is the first study to use functional magnetic resonance imaging (fMRI) to examine brain activation in untreated HCV+ adults. To determine whether, relative to non-infected controls (CTLs), HCV+ adults exhibit differences in brain activation during a delay discounting task (DDT), a measure of one's tendency to choose smaller immediate rewards over larger delayed rewards-one aspect of impulsivity. Twenty adults with HCV and 26 CTLs completed an fMRI protocol during the DDT. Mixed effects regression analyses of hard versus easy trials of the DDT showed that, compared with CTLs, the HCV+ group exhibited less activation in the left lateral occipital gyrus, precuneus, and superior frontal gyrus. There were also significant interactive effects for hard-easy contrasts in the bilateral medial frontal gyrus, left insula, left precuneus, left inferior parietal lobule, and right temporal occipital gyrus; the CTL group evidenced a positive relationship between impulsivity and activation, while the HCV+ group exhibited a negative relationship. Within the HCV+ group, those with high viral load chose immediate rewards more often than those with low viral load, regardless of choice difficulty; those with low viral load chose immediate rewards more often on hard choices relative to easy choices. Results show that HCV+ patients exhibit greater impulsive behavior when presented with difficult choices, and impulsivity is negatively related to activation in regions important for cognitive control. Thus, interventions that decrease impulsive choice may be warranted with some HCV+ patients.

Systemic inflammation and immune cell phenotypes are associated with neuro-psychiatric symptoms in patients with chronic inflammatory liver diseases

BACKGROUND & AIMS

Chronic inflammatory liver diseases are frequently associated with neuropsychiatric and cognitive dysfunctions. We hypothesized that symptomatic patients may show altered levels of soluble inflammatory mediators (SIMs) as well as changes in immune cell phenotypes.

METHODS

A comprehensive immune-phenotyping including investigation of 50 SIMs as well as ex-vivo phenotypes of NK-cells, CD3+, CD4+, CD8+ and regulatory T cells in 40 patients with viral and autoimmune chronic liver diseases was performed. The patients' cognitive functions were assessed using an extensive battery of neuropsychological testing.

RESULTS AND CONCLUSION

Overall, our data indicate that while SIMs are significantly up-regulated, NK- and T-cells are less-activated in patients with neuropsychiatric symptoms accompanying chronic inflammatory liver diseases compared to patients without these symptoms. Moreover, HCV patients showed a unique pattern of immune alterations as compared to patients with HBV, autoimmune hepatitis and primary biliary cirrhosis. These findings hint towards potential mechanisms explaining these symptoms in patients with chronic liver diseases.

Anti-cytokine agents for anhedonia: targeting inflammation and the immune system to treat dimensional disturbances in depression

The etiology of mood disorders is mechanistically heterogeneous, underscoring the need for a dimensional approach to identify and develop targeted treatments in psychiatry. Accumulating evidence implicates inflammation as an important contributor to the pathophysiology of depression and presents the immune system as a viable therapeutic target that may be more proximate to the pathogenic nexus of brain-based disorders in specific subpopulations. Anhedonia is a transdiagnostic (e.g. Parkinson's disease, diabetes mellitus, rheumatic diseases), yet specific, and clinically relevant symptom dimension subserved by well-characterized neurobiological and neurophysiological substrates of the positive valence systems (PVS). Brain circuits, nodes, and networks, as well as cellular and molecular pathways (e.g. dopaminergic transmission; excitotoxicity; synaptic plasticity), subserving anhedonia are preferentially affected by inflammatory processes. To our knowledge, no published randomized, controlled clinical trial in populations with mood disorders has, to date, primarily sought to determine the effects of an anti-inflammatory agent on PVS functions or pathophysiology. Three ongoing clinical trials aim to investigate the effects of anti-TNF-alpha biologic infliximab on measures of anhedonia [ClinicalTrials.gov identifier: NCT02363738], motivational behavior and circuitry [ClinicalTrials.gov identifier: NCT03006393], and glutamatergic changes in the basal ganglia [ClinicalTrials.gov identifier: NCT03004443] in clinical populations with unipolar or bipolar depression. Positive results would further instantiate the relevance of inflammatory processes and the immune system in the pathophysiology of mood disorders and provide the impetus to develop scalable treatments targeting inflammation and the immune system to mitigate transdiagnostic, dimensional disturbances in brain-based disorders.

S100B and Inflammatory Cytokine Levels in Blood as Potential Markers of Blood-Brain Barrier Damage and Psychiatric Impairment in Comorbid Hepatitis C Viral Infection and Alcohol Use Disorder

BACKGROUND

Hepatitis C virus (HCV) infection and alcohol use disorder (AUD) both adversely affect the immune system resulting in alterations in immune cell signaling and inflammatory processes. The aim of this study was to investigate how comorbid AUD contributes to abnormalities in inflammatory mediators and psychiatric impairments in adults with HCV.

METHODS

Alcohol use, mood, and inflammatory factors were evaluated at 3 time points (baseline, week 4, and week 12) in Veterans with HCV, with (n = 42) and without (n = 13) comorbid AUD. Peripheral indices of immune activation, blood-brain barrier (BBB) damage (S100 calcium-binding protein B [S100B]), liver function, and viral load were measured using immunoassays and polymerase chain reaction assays.

RESULTS

Comorbid AUD was associated with increased symptoms of depression and anxiety, elevated levels of liver enzymes, and altered expression of inflammatory factors. Alcohol consumption was positively correlated with the severity of psychiatric symptoms. Univariate analysis identified significant group differences in interleukin (IL)-8 (p = 0.006), IL-10 (p = 0.03), and S100B (p = 0.048), with increased levels in participants with AUD, which persisted over time despite reductions in alcohol use and no significant change in HCV viral load. Statistically significant effects of study group or time were not found for the other immune factors assessed. Exploratory receiver operating characteristic curve analysis evaluated the ability of IL-8, IL-10, and S100B to differentiate between levels of alcohol consumption and generated biomarker cutoff values used to identify low risk and unhealthy alcohol use groups.

CONCLUSIONS

These results demonstrate that HCV and comorbid AUD are associated with greater psychiatric impairments, potentially resulting from increased inflammation, dysregulated cytokine expression, and compromised BBB function. Alcohol-induced BBB damage may increase the risk of neuropathological consequences within the context of chronic HCV infection.

Depression, fatigue and neurocognitive deficits in chronic hepatitis C

Patients with chronic hepatitis C virus (HCV) infection experience a range of symptoms including depression, fatigue and neurocognitive deficits, impairing quality of life. Depression, in particular, may be reactive to increased psychosocial stress, and the physical symptoms of advanced HCV or associated comorbidities. However, even patients at an early stage of HCV infection, with minimal hepatic inflammation or comorbidities, report more depressive symptoms and fatigue than the general population. Similarly, specific neurocognitive deficits occur in early stage HCV infection and are independent of the presence of depression or encephalopathy. Therefore, intracerebral neurobiological changes associated with HCV may potentially explain these symptoms. These changes may arise from infiltration of the brain by peripherally induced cytokines, as well as direct neuropathic effects of HCV viral particles penetrating the blood-brain barrier. These phenomena parallel those reported in human immunodeficiency virus (HIV) infection. HCV-associated intracerebral changes include upregulated inflammatory responses, altered neurotransmitter levels, hormonal dysregulation, and release of neurotoxic substances. These may subsequently lead to abnormal neuronal conduction and function in areas of the brain governing affective responses, emotional processing, motivation, attention and concentration. Although direct-acting antiviral medications lead to high rates of HCV clearance, intracerebral changes may not be subsequently reversed and symptoms of depression, fatigue and neurocognitive deficits may persist. There is an ongoing role for multidisciplinary care and pharmacotherapy to manage these symptoms in HCV patients. Furthermore, there may be opportunities for future therapies to specifically target and ameliorate HCV-associated intracerebral changes.

Chronic Hepatitis C Virus Infection and Depression

Hepatitis C virus (HCV) infection is a systemic disease with hepatic and extrahepatic manifestations, including neuropsychiatric conditions. Depression is a frequent disorder, which has been reported in one-third of patients with HCV infection and has an estimated prevalence of 1.5 to 4.0 times higher than that observed in patients with chronic hepatitis B virus infection or the general population. HCV seems to play a direct and indirect role in the development of depression. Impaired quality of life and increasing health care costs have been reported for patients with HCV infection with depression. Treatment-induced HCV clearance has been associated with improvement of depression and quality of life.

Parallel Effects of Methamphetamine on Anxiety and CCL3 in Humans and a Genetic Mouse Model of High Methamphetamine Intake

BACKGROUND

Methamphetamine (MA) abuse causes immune dysfunction and neuropsychiatric impairment. The mechanisms underlying these deficits remain unidentified.

METHODS

The effects of MA on anxiety-like behavior and immune function were investigated in mice selectively bred to voluntarily consume high amounts of MA [i.e., MA high drinking (MAHDR) mice]. MA (or saline) was administered to mice using a chronic (14-day), binge-like model. Performance in the elevated zero maze (EZM) was determined 5 days after the last MA dose to examine anxiety-like behavior. Cytokine and chemokine expressions were measured in the hippocampus using quantitative polymerase chain reaction (qPCR). Human studies were also conducted to evaluate symptoms of anxiety using the General Anxiety Disorder-7 Scale in adults with and without a history of MA dependence. Plasma samples collected from human research participants were used for confirmatory analysis of murine qPCR results using an enzyme-linked immunosorbent assay.

RESULTS

During early remission from MA, MAHDR mice exhibited increased anxiety-like behavior on the EZM and reduced expression of chemokine (C-C motif) ligand 3 (ccl3) in the hippocampus relative to saline-treated mice. Human adults actively dependent on MA and those in early remission had elevated symptoms of anxiety as well as reductions in plasma levels of CCL3, relative to adults with no history of MA abuse.

CONCLUSIONS

The results highlight the complex effects of MA on immune and behavioral function and suggest that alterations in CCL3 signaling may contribute to the mood impairments observed during remission from MA addiction.

Hepatitis C infection: A multi-faceted systemic disease with clinical, patient reported and economic consequences

Hepatitis C virus infection (HCV) affects approximately 170-200 million individuals globally. HCV is one of the primary causes of hepatocellular carcinoma (HCC) and cirrhosis and has been identified as the leading indication for liver transplantation in most Western countries. Because HCV is a systemic disease with hepatic, extrahepatic, economic and patient reported consequences, it is important for healthcare practitioners to understand the comprehensive and multi-faceted picture of this disease. In this context, it is important to fully appreciate the impact of HCV on the individual patient and the society. With the recent advent of the new generation of direct antiviral agents, the long standing goal of eradicating HCV in most infected patients has been accomplished. Therefore, now more than ever, it is critical to assess the total benefits of sustained virological response in a comprehensive manner. This should not be limited to the clinical benefits of HCV cure, but also to account for the improvement of patient reported health and economic outcomes of HCV cure. It is only through this comprehensive approach to HCV and its treatment that we will understand the full impact of this disease and the tremendous gains that have been achieved with the new antiviral regimens.

Deep sequencing of hepatitis C virus reveals genetic compartmentalization in cerebrospinal fluid from cognitively impaired patients

BACKGROUND & AIMS

Hepatitis C virus (HCV) causes neuropsychiatric impairment and fatigue with recent studies suggesting HCV invasion of the central nervous system (CNS). Our previous finding that endothelial cells from the blood-brain barrier support HCV infection warrants further investigation to elucidate whether the CNS can serve as a reservoir for independent HCV evolution.

METHODS

Cerebrospinal fluid (CSF) and plasma from six HCV-infected patients without liver disease or co-morbidities together with plasma from six healthy subjects were profiled for markers of immune activation and viral quasispecies measured by deep sequencing. Unsupervised data analyses were used to identify any associations between cytokine activation markers and clinical outcomes.

RESULTS

Four of six HCV-infected patients showed significant evidence of cognitive dysfunction and fatigue. Deep sequencing revealed independent viral evolution within the CNS of two cognitively impaired patients. Principal component analysis of peripheral cytokines demonstrated that individuals without cognitive impairment clustered together while a distinct cytokine pattern emerged with patients exhibiting cognitive dysfunction and fatigue.

CONCLUSIONS

Deep sequencing demonstrated unique viral variants in the CSF of two cognitively impaired patients consistent with CNS replication or sequestration. Meanwhile, compartmentalization was absent in infected patients with no neurocognitive impairment. Examination of cytokine profiles in HCV-infected patients with cognitive dysfunction revealed elevated peripheral cytokine levels resulting in a distinct cytokine profile that may be related to cognitive impairment or viral penetration into the CNS. Further studies to determine the significance of unique HCV variants within the CNS are warranted.

Serum Beta-2 Microglobulin: a Possible Marker for Disease Progression in Egyptian Patients with Chronic HCV Related Liver Diseases

BACKGROUND

Egypt has the highest prevalence of HCV infection in the world (~14.7%). Around 10-15% of HCV-infected persons will advance to cirrhosis within the first 20 years. The incidence of HCC is expected to grow in the next two decades, largely due to HCV related cirrhosis, and detection of HCC at an early stage is critical for a favorable clinical outcome. No simple reliable non-invasive marker has been available till now. B2M, a non-glycosylated polypeptide composed of 99 amino acids, is one of the components of HLA class I molecules on the surfaces of all nucleated cells. It has been reported that the level of serum B2M is elevated in patients with chronic hepatitis C and HCV-related HCC when compared to HCV-negative patients or healthy donors. Determining the clinical utility of serum β2M as a marker for disease progression in Egyptian patients with HCV related chronic hepatitis, cirrhosis and hepatocellular carcinoma was the aim of the present study.

MATERIALS AND METHODS

In this analytical cross sectional study 92 participants were included in 4 equal groups: Group (1) non cirrhotic chronic HCV; Group (2) HCV related liver cirrhosis; Group (3) HCC on top of HCV,; and Group (4) healthy controls. History taking, clinical examination, routine labs and abdominal ultrasound were conducted for all patients, PCR and Metavir scores for group (1) patients, and triphasic CT abdomen and AFP for Group (3) patients. β2M levels were measured in serum with a fully-automated IMX system.

RESULTS

The mean serum B2M level of Group (1) was 4.25 ± 1.48 μg/ml., Group (2) was 7.48 ± 3.04, Group (3) was 6.62 ± 2.49 and Group (4) was 1.62 ± 0.63. Serum B2M levels were significantly higher in diseased than control group (p<0.01) being significantly higher in cirrhosis (7.48 ± 3.04) and HCC groups (6.62 ± 2.49) than the HCV group (4.25 ± 1.48) (p<0.01). There was a significant correlation between B2M Level and ALK, total and direct bilirubin and INR (p<0.05), and a significant inverse correlation between B2M level and albumin, total proteins, HB and WBCS values (p<0.05). There was no significant correlation between B2M level and viral load or Metavir score, largest tumour size or AFP (p>0.05). The best B2M cut-off for HCV diagnosis was 2.6 with a sensitivity of 100%, a specificity of 92%, a positive predictive value (PPV) of 97% and a negative predictive value (NPV) of 100%. The best B2M cut-off for HCC diagnosis was 4.55 which yielded sensitivity, specificity, positive predictive value, negative predictive values of 74%, 62%, 39.5, 87.8% respectively (p-value <0.01) while best cut-off for cirrhosis was 4.9, with sensitivity 74 % and specificity 74%. The sensitivity for HCC diagnosis increased upon B2M and AFP combined estimation to 91%, specificity to 79%, NPV to 95% and accuracy to 83%.

CONCLUSIONS

Serum B2M level is elevated in HCV related chronic liver diseases and may be used as a marker for HCV disease progression towards cirrhosis and carcinoma.

Hepatitis C virus infection, and neurological and psychiatric disorders - A review

An association between hepatitis C virus infection and neuropsychiatric symptoms has been proposed for some years. A variety of studies have been undertaken to assess the nature and severity of these symptoms, which range from fatigue and depression to defects in attention and verbal reasoning. There is evidence of mild neurocognitive impairment in some patients with HCV infection, which is not fully attributable to liver dysfunction or psychosocial factors. Further evidence of a biological cerebral effect has arisen from studies using magnetic resonance spectroscopy; metabolic abnormalities correlate with cognitive dysfunction and resemble the patterns of neuroinflammation that have been described in HIV infection. Recent research has suggested that, in common with HIV infection, HCV may cross the blood brain barrier leading to neuroinflammation. Brain microvascular endothelial cells, astrocytes and microglia may be minor replication sites for HCV. Importantly, patient reported outcomes improve following successful antiviral therapy. Further research is required to elucidate the molecular basis for HCV entry and replication in the brain, and to clarify implications and recommendations for treatment.

Alcohol intake alters immune responses and promotes CNS viral persistence in mice

Chronic hepatitis C virus (HCV) infection leads to progressive liver disease and is associated with a variety of extrahepatic effects, including central nervous system (CNS) damage and neuropsychiatric impairments. Alcohol abuse can exacerbate these adverse effects on brain and behavior, but the molecular mechanisms are not well understood. This study investigated the role of alcohol in regulating viral persistence and CNS immunopathology in mice infected with lymphocytic choriomeningitis virus (LCMV), a model for HCV infections in humans. Female and male BALB/c mice (n=94) were exposed to alcohol (ethanol; EtOH) and water (or water only) using a two-bottle choice paradigm, followed one week later by infection with either LCMV clone 13 (causes chronic infection similar to chronic HCV), LCMV Armstrong (causes acute infection), or vehicle. Mice were monitored for 60days post-infection and continued to receive 24-h access to EtOH and water. Animals infected with LCMV clone 13 drank more EtOH, as compared to those with an acute or no viral infection. Six weeks after infection with LCMV clone 13, mice with EtOH exposure evidenced higher serum viral titers, as compared to mice without EtOH exposure. EtOH intake was also associated with reductions in virus-specific CD8(+) T cell frequencies (particularly CD11a(hi) subsets) and evidence of persistent CNS viremia in chronically infected mice. These findings support the hypothesis that EtOH use and chronic viral infection can result in combined toxic effects accelerating CNS damage and neuropsychiatric dysfunction and suggest that examining the role of EtOH in regulating viral persistence and CNS immunopathology in mice infected with LCMV can lead to a more comprehensive understanding of comorbid alcohol use disorder and chronic viral infection.

Effect of Moderate Exercise on Serum Interferon-Gamma and Interleukin-17 Levels in the Morphine Withdrawal Period

Background

Drug addiction triggers the infliction of a variety of diseases. Various subjects have indicated that during the withdrawal syndrome period, the immune system is weakened.

Objectives

This study aimed to investigate the changes in serum levels of interferon-gamma (IFN-γ) and interleukin-17 (IL-17) during the morphine withdrawal syndrome induced by 8 weeks of moderate exercise and their effects on the immune system function.

Materials and Methods

Twenty-four male Wistar rats (220 ± 10 g) were divided into four groups (n = 6): healthy control (HC), addicted control (AC), healthy trained (HT), and addicted trained (AT) groups. AC and AT groups were made addicted to morphine sulfate (0.4 mg/mL) in 21 days. To ensure their dependence on morphine, naloxone (3 mg/kg, i.p.) was injected into the body of a number of the rats. HT and AT groups were made to run on a treadmill 5 days per week for 8 weeks while time and speed gradually increased. Both prior to the exercises and 24 hours after the last training session, blood samples were collected from all the animals, and serum IFN-γ and IL-17 serum levels were measured using the ELISA method. This research was performed at the Bu-Ali Sina University, Hamadan, Iran.

Results

After 8 weeks of exercise, a significant increase was observed in the serum IFN-γ level in the HT group (251.17 ± 13.045) in comparison with the HC group (234 ± 12.884) (P = 0.045). Furthermore, the serum IFN-γ level in the AT group (218.33 ± 5.164) in comparison to the AC group (190.67 ± 8.477) showed a significant increase (P = 0.000). In addition, the serum level of IFN-γ in the HT group showed a significant increase compared to the AT group (P = 0.000). After 8 weeks of exercise, there was a significant decrease in the serum IL-17 level in the HT group (22.67 ± 4.46) compared with the HC group (38.17 ± 7.68) (P = 0.005). In addition, a significant decrease was observed in serum IL-17 in the AT group (42.17 ± 7.41) in comparison with the AC group (57.17 ± 7.83) (P = 0.007). In addition, the serum IL-17 level in the HT group significantly decreased in comparison with the AT group (P = 0.001).

Conclusions

Moderate exercise for 8 weeks increased the IFN-γ and decreased the IL-17 serum levels in the morphine-dependent rats. For this reason, this type of exercise can improve the function of the immune system during morphine withdrawal syndrome.

A Follow-Up Study of 50 Chronic Hepatitis C Patients: Adiponectin as a Resilience Biomarker for Major Depression

OBJECTIVE

Major depression (MD) is a condition associated with both hepatitis C virus (HCV) infection and pegylated interferon (IFN)-α treatment. IFN induces a depressive syndrome that is associated with an inflammatory profile. We aimed to investigate whether there is any specific alteration in plasma biomarkers associated with MD.

METHODS

HCV-monoinfected patients, with and without IFN treatment, were followed up for 18 months and went through structured psychiatric evaluation. We assessed plasma levels of brain-derived neurotrophic factor, tumor necrosis factor (TNF) and its soluble type 1 and type 2 receptors (sTNFR1 and sTNFR2, respectively), and adipokines (adiponectin, leptin and resistin) using ELISA.

RESULTS

Among the 50 patients included in the study, 14 were treated with IFN during the follow-up. Being older, not married, presenting higher body mass index, higher liver inflammatory activity, lower baseline adiponectin levels and use of IFN were associated with MD development. Higher levels of sTNFR1 during IFN treatment were associated with sustained virological response. The lack of a control group without HCV infection did not allow any assumption of a biomarker change exclusively due to the infection itself.

CONCLUSION

Adiponectin may be a resilience biomarker for MD in HCV-infected patients.

Plasma Inflammatory Factors Are Associated with Anxiety, Depression, and Cognitive Problems in Adults with and without Methamphetamine Dependence: An Exploratory Protein Array Study

OBJECTIVES

It is hypothesized that immune factors influence addictive behaviors and contribute to relapse. The primary study objectives were to (1) compare neuropsychiatric symptoms across adults with active methamphetamine (MA) dependence, in early remission from MA dependence, and with no history of substance dependence, (2) determine whether active or recent MA dependence affects the expression of immune factors, and (3) evaluate the association between immune factor levels and neuropsychiatric symptoms.

METHODS

A cross-sectional study was conducted using between group comparisons and regression analyses to investigate associations among variables. Eighty-four adults were recruited into control (CTL) (n = 31), MA-active (n = 17), or MA-remission (n = 36) groups. Participants completed self-report measures of anxiety, depression, and memory complaints and objective tests of attention and executive function. Blood samples were collected, and a panel of immune factors was measured using multiplex technology.

RESULTS

Relative to CTLs, MA-dependent adults evidenced greater anxiety and depression during active use (p < 0.001) and remission (p < 0.007), and more attention, memory, and executive problems during remission (p < 0.01) but not active dependence. Regression analyses identified 10 immune factors (putatively associated with cytokine-cytokine receptor interactions) associated with anxiety, depression, and memory problems.

CONCLUSION

While psychiatric symptoms are present during active MA dependence and remission, at least some cognitive difficulties emerge only during remission. Altered expression of a network of immune factors contributes to neuropsychiatric symptom severity.

Inflammation, psychiatric symptoms, and opioid use are associated with pain and disability in patients with cirrhosis

BACKGROUND & AIMS

Cirrhosis is associated with significant pain and disability, the etiologies of which are poorly understood. We investigated whether the pain and disability in patients with cirrhosis are associated with systemic inflammation and psychiatric symptoms.

METHODS

In a prospective study, we recruited 193 patients with cirrhosis caused by hepatitis C virus infection, nonalcoholic steatohepatitis, or alcohol from the hepatology clinic at the University of Pittsburgh. Patients were assessed using the McGill Pain Questionnaire, the Hospital Anxiety and Depression Scale, the Pittsburgh Sleep Quality Index, and the Pain Disability Index. Serum samples were collected and markers of inflammation were measured using standardized Luminex assays (Milipore, St. Charles, MO). We evaluated factors associated with pain, pain-related disability, and chronic opioid use by using multivariable regression models.

RESULTS

Pain was reported by 79% of patients, pain-related disability was reported by 75%, and depression and/or anxiety was reported by 47%; the average Model for End-Stage Liver Disease score was 12 ± 5. Serum samples from 58% percent of patients had increased levels of C-reactive protein. Opioids were prescribed for 30% of patients with pain. In multivariate analysis, factors significantly associated with pain included younger age (odds ratio [OR]/y, 0.93; 95% confidence interval [CI], 0.90-0.99), serum level of interleukin 6 (OR per pg/L, 1.63; 95% CI, 1.09-2.58), Hospital Anxiety and Depression Scale score (OR/point, 1.14; 95% CI, 1.07-1.24), and etiology (hepatitis C virus infection vs alcohol: OR, 3.70; 95% CI, 1.27-11.11). Disability scores were related significantly to psychiatric symptoms (incidence rate ratio [IRR]/point, 1.04; 95% CI, 1.02-1.05), prescription opioid use (IRR, 1.49; 95% CI, 1.14-1.94), Model for End-Stage Liver Disease score (IRR/point, 1.02; 95% CI, 1.0001-1.05), level of C-reactive protein (IRR per mg/dL, 1.13; 95% CI, 1.02-1.24), and pain severity (IRR/point, 1.19; 95% CI, 1.08-1.32).

CONCLUSIONS

Pain and disability are common among patients with cirrhosis, and are associated with inflammation, psychiatric symptoms, and opioid use, which potentially are modifiable. Although opioids are used commonly to treat pain, psychiatric symptoms and inflammation also might be treatment targets in this population.

Chronic hepatitis C virus infection and neurological and psychiatric disorders: An overview

Hepatitis C virus (HCV) infection is considered a systemic disease because of involvement of other organs and tissues concomitantly with liver disease. Among the extrahepatic manifestations, neuropsychiatric disorders have been reported in up to 50% of chronic HCV infected patients. Both the central and peripheral nervous system may be involved with a wide variety of clinical manifestations. Main HCV-associated neurological conditions include cerebrovascular events, encephalopathy, myelitis, encephalomyelitis, and cognitive impairment, whereas “brain fog”, depression, anxiety, and fatigue are at the top of the list of psychiatric disorders. Moreover, HCV infection is known to cause both motor and sensory peripheral neuropathy in the context of mixed cryoglobulinemia, and has also been recently recognized as an independent risk factor for stroke. These extrahepatic manifestations are independent of severity of the underlying chronic liver disease and hepatic encephalopathy. The brain is a suitable site for HCV replication, where the virus may directly exert neurotoxicity; other mechanisms proposed to explain the pathogenesis of neuropsychiatric disorders in chronic HCV infection include derangement of metabolic pathways of infected cells, alterations in neurotransmitter circuits, autoimmune disorders, and cerebral or systemic inflammation. A pathogenic role for HCV is also suggested by improvement of neurological and psychiatric symptoms in patients achieving a sustained virologic response following interferon treatment; however, further ad hoc trials are needed to fully assess the impact of HCV infection and specific antiviral treatments on associated neuropsychiatric disorders.

A longitudinal study evaluating the effects of interferon-alpha therapy on cognitive and psychiatric function in adults with chronic hepatitis C

OBJECTIVE

To prospectively evaluate for changes in objective cognitive performance (attention, memory, and executive function) and psychiatric symptom severity (depression, anxiety, fatigue, and pain) in patients before, during and after interferon-alpha based therapy (IFN) for chronic hepatitis C virus infection (HCV).

METHODS

33 HCV+ adults were evaluated two months before IFN initiation (baseline), three months into IFN, and six months following IFN termination (IFN+ Group). 31 HCV+ adults who did not undergo IFN therapy were evaluated at baseline and six months later (IFN- Group). At each evaluation, participants completed the Neuropsychological Assessment Battery (NAB) Attention, Memory and Executive Functions Modules, the Beck Depression Inventory, Second Edition (BDI), Generalized Anxiety Disorder Inventory (GADI), Fatigue Severity Scale (FSS), and Brief Pain Inventory (BPI).

RESULTS

Compared with the IFN- Group, the IFN+ Group experienced significantly (p<0.050) increased symptoms of depression, anxiety, fatigue and pain during IFN therapy relative to baseline. In the IFN+ Group, psychiatric symptoms generally returned to baseline levels following IFN termination. Sustained viral response was associated with significantly lower depression and fatigue. No significant changes in cognitive performance were observed.

CONCLUSIONS

During IFN, patients with HCV evidence significantly increased psychiatric symptoms, including symptoms of depression, anxiety, fatigue and pain. These psychiatric symptoms are generally short-term and remit following IFN termination, with increased benefit if viral clearance is achieved. However, IFN is not associated with significant declines in objective cognitive performance during or following IFN.

Novel α-2-macroglobulin cleaved fragments as biomarkers of early liver fibrosis in patients with chronic hepatitis C

ABSTRACT 

Aim: Liver biopsy is considered the gold standard for the diagnosis and staging of hepatic fibrosis in patients with chronic hepatitis C and is now progressively replaced by noninvasive procedures. We aimed at improving α-2-macroglobulin diagnostic value for liver fibrosis by identifying new isoforms that may be specifically related to early stages of the pathology. Materials & methods: α-2-Macroglobulin isoforms were characterized in serum samples from patients with chronic hepatitis C and mild (F1) to moderate (F2) fibrosis by proteomic methods. Results: New biological 40 kDa C-terminal α-2-macroglobulin fragments were identified as potential biomarkers of early fibrosis (fold change = 1.55; p < 0.01). Conclusion: The serum concentration of α-2-macroglobulin fragments allows a better differentiation of F1 and F2 fibrosis stages than total α-2-macroglobulin isoforms.

Disrupted TH17/Treg balance in patients with chronic low back pain

Chronic low back pain (CLBP) is a leading cause of disability and costs in health care systems worldwide. Despite extensive research, the exact pathogenesis of CLBP, particularly the individual risk of chronification remains unclear. To investigate a possible role of the adaptive immune system in the pathophysiology of CLBP, we analyzed T cell related cytokine profiles, T cell related mRNA expression patterns and the distribution of T cell subsets in 37 patients suffering from nonspecific CLBP before and after multimodal therapy in comparison to 25 healthy controls. Serum patterns of marker cytokines were analyzed by Luminex technology, mRNA expression of cytokines and specific transcription factors was measured by real-time PCR, and distribution of TH1-, TH2-, TH17- and regulatory T cell (Tregs) subsets was determined by multicolor flow cytometry. We found that CLBP patients exhibit an increased number of anti-inflammatory Tregs, while pro-inflammatory TH17 cells are decreased, resulting in an altered TH17/Treg ratio. Accordingly, FoxP3 and TGF-β-mRNA expression was elevated, while expression of IL-23 was reduced. Serum cytokine analyses proved to be unsuitable to monitor the adaptive immune response in CLBP patients. We further show that even after successful therapy with lasting reduction of pain, T cell subset patterns remained altered after a follow-up period of 6 months. These findings suggest an involvement of TH17/Treg cells in the pathogenesis of CLBP and emphasize the importance of these cells in the crosstalk of pain and immune response.

Trial Registration

German Clinical Trial Register: Registration Trial DRKS00005954.