The NMDA-receptor antagonist ketamine has proven efficient in reducing symptoms of suicidality, although the mechanisms explaining this effect have not been detailed in psychiatric patients. Recent evidence points towards a low-grade inflammation in brains of suicide victims. Inflammation leads to production of quinolinic acid (QUIN) and kynurenic acid (KYNA), an agonist and antagonist of the glutamatergic N-methyl-D-aspartate (NMDA) receptor, respectively. We here measured QUIN and KYNA in the cerebrospinal fluid (CSF) of 64 medication-free suicide attempters and 36 controls, using gas chromatography mass spectrometry and high-performance liquid chromatography. We assessed the patients clinically using the Suicide Intent Scale and the Montgomery–Asberg Depression Rating Scale (MADRS). We found that QUIN, but not KYNA, was significantly elevated in the CSF of suicide attempters (P<0.001). As predicted, the increase in QUIN was associated with higher levels of CSF interleukin-6. Moreover, QUIN levels correlated with the total scores on Suicide Intent Scale. There was a significant decrease of QUIN in patients who came for follow-up lumbar punctures within 6 months after the suicide attempt. In summary, we here present clinical evidence of increased QUIN in the CSF of suicide attempters. An increased QUIN/KYNA quotient speaks in favor of an overall NMDA-receptor stimulation. The correlation between QUIN and the Suicide Intent Scale indicates that changes in glutamatergic neurotransmission could be specifically linked to suicidality. Our findings have important implications for the detection and specific treatment of suicidal patients, and might explain the observed remedial effects of ketamine.

Human dendritic cells (DCs) are a distinct but heterogeneous lineage of APCs operating as the link between innate and adaptive immune responses, with the function to either maintain tolerance or trigger immunity. The DC lineage consists of several subpopulations with unique phenotypes; however, their functional characteristics and transcriptional similarities remain largely unknown. To further characterize the phenotypes and transcriptomes of the subsets, we purified myeloid CD16+, blood DC Ag 1+ (BDCA1+), and BDCA3+ DC populations, as well as plasmacytoid CD123+ DCs, from tonsillar tissue and peripheral blood. Transcriptional profiling and hierarchical clustering visualized that BDCA1+ DCs clustered with BDCA3+ DCs, whereas CD16+ DCs and CD123+ DCs clustered as distinct populations in blood. Differential expression levels of chemokines, ILs, and pattern recognition receptors were demonstrated, which emphasize innate DC subset specialization. Even though highly BDCA1+ and BDCA3+ DC-specific gene expression was identified in blood, the BDCA1+ DCs and BDCA3+ DCs from tonsils displayed similar transcriptional activity, most likely due to the pathogenic or inflammatory maturational signals present in tonsillar tissues. Of note, plasmacytoid DCs displayed less plasticity in their transcriptional activity compared with myeloid DCs. The data demonstrated a functionally distinct association of each of the seven subsets based on their signatures, involving regulatory genes in adaptive and innate immunity.

Filter paper blood samples taken routinely from 100 239 newborn infants were radioimmunoassayed five years later for plasma thyrotrophin concentrations. In 32 cases (0 03%) these were found to be raised. Thirty one of these children were traced and subjected to follow up examination by a paediatrician and a psychologist.Of the 31 children, 15 were found to have been receiving treatment for congenital hypothyroidism since a median of 5 months of age (diagnosed group). Of the 16 others, seven children were found to have raised serum thyrotrophin concentrations and were classified as hypothyroid (undiagnosed group). The remaining nine children were euthyroid.Children in the diagnosed group had a mean Griffiths developmental quotient of 87 (control value 103; p <0 01), and five out of 13 showed impaired neurological development. Of the remainder, those in the undiagnosed group had a mean developmental quotient of 100 and those in the euthyroid group a mean developmental quotient of 107.In this study achieving a detection rate of congenital hypothyroidism of one in 3000 in a neonatal screening

BackgroundDendritic cells (DCs) comprise heterogeneous populations of cells, which act as central orchestrators of the immune response. Applicability of primary DCs is restricted due to their scarcity and therefore DC models are commonly employed in DC-based immunotherapy strategies and in vitro tests assessing DC function. However, the interrelationship between the individual in vitro DC models and their relative resemblance to specific primary DC populations remain elusive.ObjectiveTo describe and assess functionality and applicability of the available in vitro DC models by using a genome-wide transcriptional approach.MethodsTranscriptional profiling was performed with four commonly used in vitro DC models (MUTZ-3-DCs, monocyte-derived DCs, CD34-derived DCs and Langerhans cells (LCs)) and nine primary DC populations (dermal DCs, LCs, blood and tonsillar CD123+, CD1c+ and CD141+ DCs, and blood CD16+ DCs).ResultsPrincipal Component Analysis showed that transcriptional profiles of each in vitro DC model most closely resembled CD1c+ and CD141+ tonsillar myeloid DCs (mDCs) among primary DC populations. Thus, additional differentiation factors may be required to generate model DCs that more closely resemble other primary DC populations. Also, no model DC stood out in terms of primary DC resemblance. Nevertheless, hierarchical clustering showed clusters of differentially expressed genes among individual DC models as well as primary DC populations. Furthermore, model DCs were shown to differentially express immunologically relevant transcripts and transcriptional signatures identified for each model DC included several immune-associated transcripts.ConclusionThe unique transcriptional profiles of in vitro DC models suggest distinct functionality in immune applications. The presented results will aid in the selection of an appropriate DC model for in vitro assays and assist development of DC-based immunotherapy.

Several studies suggest a role for kynurenic acid (KYNA) in the pathophysiology of schizophrenia. It has been proposed that increased brain KYNA levels in schizophrenia result from a pathological shift in the kynurenine pathway toward enhanced KYNA formation, away from the other branch of the pathway leading to quinolinic acid (QUIN). Here we investigate the levels of QUIN in cerebrospinal fluid (CSF) of patients with schizophrenia and healthy controls, and relate those to CSF levels of KYNA and other kynurenine metabolites from the same individuals. CSF QUIN levels from stable outpatients treated with olanzapine (n = 22) and those of controls (n = 26) were analyzed using liquid chromatography-mass spectrometry. No difference in CSF QUIN levels between patients and controls was observed (20.6 ± 1.5 nM vs. 18.2 ± 1.1 nM, P = 0.36). CSF QUIN was positively correlated to CSF kynurenine and CSF KYNA in patients but not in controls. The CSF QUIN/KYNA ratio was lower in patients than in controls (P = 0.027). In summary, the present study offers support for an over-activated and imbalanced kynurenine pathway, favoring the production of KYNA over QUIN in patients with schizophrenia.

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IntroductionThe role of immune activation in schizophrenia has received increasing interest in recent years. Epidemiological studies have shown that infections and autoimmune diseases are clin ic ally important risk factors for the development of schizo phrenia. [1][2][3] Furthermore, a recent study integrating results from a meta analysis of genome wide association studies in schizophrenia found that the most significant changes were observed in genetic loci related to the immune system. 4 Also, patients with schizophrenia show microglial activation, as re vealed by positron emission tomography. 5,6 Further, postmor tem studies using messenger RNA (mRNA) expression or im munohistochemical detection have shown increased levels of immune related compounds. 7-9 A number of investigations have focused on cytokines, but these studies have not yielded a unanimous picture, possibly because of a number of con founding factors, such as smoking and dietary habits, body mass index (BMI), type and duration of antipsychotic treat ment and drug abuse -all factors potentially affecting the Background: Accumulating evidence indicates that schizophrenia is associated with brain immune activation. While a number of reports suggest increased cytokine levels in patients with schizophrenia, many of these studies have been limited by their focus on peripheral cytokines or confounded by various antipsychotic treatments. Here, well-characterized patients with schizophrenia, all receiving olanzapine treatment, and healthy volunteers were analyzed with regard to cerebrospinal fluid (CSF) levels of cytokines. We correlated the CSF cytokine levels to previously analyzed metabolites of the kynurenine (KYN) pathway. Methods: We analyzed the CSF from patients and controls using electrochemiluminescence detection with regard to cytokines. Cell culture media from human cortical astrocytes were ana lyzed for KYN and kynurenic acid (KYNA) using high-pressure liquid chromatography or liquid chromatography/mass spectrometry. Results: We included 23 patients and 37 controls in our study. Patients with schizophrenia had increased CSF levels of interleukin (IL)-6 compared with healthy volunteers. In patients, we also observed a positive correlation between IL-6 and the tryptophan:KYNA ratio, indicating that IL-6 activates the KYN pathway. In line with this, application of IL-6 to cultured human astrocytes increased cell medium concentration of KYNA. Limitations: The CSF samples had been frozen and thawed twice before analysis of cytokines. Median age differed between patients and controls. When appropriate, all present analyses were adjusted for age. Conclusion: We have shown that IL-6, KYN and KYNA are elevated in patients with chronic schizophrenia, strengthening the idea of brain immune activation in patients with this disease. Our concurrent cell culture and clinical findings suggest that IL-6 induces the KYN pathway, leading to increased production of the N-methyl-d-aspartate receptor antagonist KYNA in patients with schizophrenia.

Human 6-sulfo LacNac-positive (slan) cells have been subject to a paradigm debate. They have previously been classified as a distinct dendritic cell (DC) subset. However, evidence has emerged that they may be more related to monocytes than to DCs. To gain deeper insight into the functional specialization of slan cells, we have compared them with both conventional myeloid DC subsets (CD1c and CD141) in human peripheral blood (PB). With the use of genome-wide transcriptional profiling, as well as functional tests, we clearly show that slan cells form a distinct, non-DC-like population. They cluster away from both DC subsets, and their gene-expression profile evidently suggests involvement in distinct inflammatory processes. An extensive transcriptional meta-analysis confirmed the relationship of slan cells with the monocytic compartment rather than with DCs. From a functional perspective, their ability to prime CD4 and CD8 T cells is relatively low. Combined with the finding that "antigen presentation by MHC class II" is at the top of under-represented pathways in slan cells, this points to a minimal role in directing adaptive T cell immunity. Rather, the higher expression levels of complement receptors on their cell surface, together with their high secretion of IL-1β and IL-6, imply a specific role in innate inflammatory processes, which is consistent with their recent identification as non-classical monocytes. This study extends our knowledge on DC/monocyte subset biology under steady-state conditions and contributes to our understanding of their role in immune-mediated diseases and their potential use in immunotherapeutic strategies.