Low serum tryptophan predicts higher mortality in cardiovascular disease.

Background: The essential amino acid tryptophan is required for protein synthesis and formation of the neurotransmitter serotonin and may exert immunoregulatory functions. An accelerated tryptophan breakdown rate is associated with inflammation and immune activation.

Materials And Methods: Serum concentrations of free tryptophan, neopterin and high-sensitivity C-reactive protein (hsCRP) were measured in 1196 patients with coronary artery disease (CAD) derived from the LUdwigshafen RIsk and Cardiovascular Health (LURIC) study.

Immune activation and inflammation in patients with cardiovascular disease are associated with higher phenylalanine to tyrosine ratios: the ludwigshafen risk and cardiovascular health study.

Higher serum neopterin is associated with increased mortality in patients with coronary artery disease (CAD). Preferentially Th1-type cytokine interferon- γ stimulates neopterin production by GTP cychlohydrolase I (GCH-I) in parallel in monocyte-derived macrophages and dendritic cells. In other cells, activation of GCH-I leads to the formation of 5,6,7,8-tetrahydrobiopterin (BH4), the necessary cofactor of amino acid hydroxylases like phenylalanine 4-hydroxylase (PAH).

Vitamin D deficiency parallels inflammation and immune activation, the Ludwigshafen Risk and Cardiovascular Health (LURIC) study.

Background: Low vitamin D concentrations are detected in patients suffering from various clinical conditions which are characterized also by inflammation and immune activation.We investigated whether vitamin D levels in patients with coronary artery disease (CAD) are related to markers of immune activation.

Methods: Serum concentrations of 25-hydroxyvitamin D[25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH) 2 D] and the immune activation markers neopterin and high sensitivity C-reactive protein (hsCRP) were measured in 2015 patients derived from the LUdwigshafen RIsk and Cardiovascular Health (LURIC) study, a cohort study among patients referred for coronary angiography.

Low serum zinc levels in patients undergoing coronary angiography correlate with immune activation and inflammation.

Introduction: Low serum zinc concentrations are associated with adverse outcomes. To explain this phenomenon we aimed to investigate whether low zinc levels are related to immune activation, renal function and coronary artery disease (CAD).

Methods: Serum concentrations of zinc and the immune activation markers neopterin and C-reactive protein (CRP) were measured in 2048 patients derived from the LUdwigshafen RIsk and Cardiovascular Health (LURIC) study, a cohort study among patients referred for coronary angiography.

Gliadin IgG antibodies and circulating immune complexes.

Objective: Circulating immune complexes (CICs) in blood are associated with autoimmune-diseases such as systemic lupus erythematosus, immune complex glomerulonephritis, rheumatoid arthritis and vasculitis. However, slightly increased serum concentrations of such CICs are sometimes also found in healthy individuals. The objective of the current study was to assess whether food antigens could play a role in the formation of CICs.

Inverse association between serum concentrations of neopterin and antioxidants in patients with and without angiographic coronary artery disease.

Neopterin is released from human monocyte-derived macrophages upon stimulation with interferon-gamma and is a sensitive indicator for cellular immune activation. Furthermore, reactive oxygen species (ROS) are produced in case of immune activation and inflammation. In a cross-sectional approach, plasma concentrations of neopterin and of antioxidant compounds and vitamins were compared in 1463 patients investigated by coronary angiography, which were recruited within the LUdwigshafen RIsk and Cardiovascular Health (LURIC) study.

Inverse association between serum selenium concentrations and parameters of immune activation in patients with cardiac disorders.

Background: As a component of the enzyme glutathione peroxidase, the essential trace element selenium contributes to the reduction of peroxides. Disturbed selenium availability may relate to an activated immune response. In humans, immune activation is reflected by increased neopterin production and accelerated tryptophan degradation, expressed as the kynurenine to tryptophan ratio (kyn/trp).

Decreased serum tryptophan concentration predicts poor prognosis in malignant melanoma patients.

Background: Indoleamine (2,3)-dioxygenase (IDO) catalyses the initial, rate-limiting step in the degradation of the essential amino acid tryptophan. Via tryptophan deprivation, IDO activity suppresses T cell proliferation and differentiation and is thought to be a fundamental immune escape mechanism for tumor cells.

Objective And Methods: To investigate the potential role of tryptophan degradation as a prognostic marker, serum tryptophan and kynurenine concentrations and the kynurenine-to-tryptophan ratio (kyn/trp) in 87 patients with malignant melanoma were compared to the course of the disease and to concentrations of the immune activation marker neopterin.

Association between neopterin in cord blood, urinary neopterin in early childhood and the development of atopic dermatitis, asthma and hay fever.

It is generally accepted that the increased prevalence of atopic disease is due to a disturbed balance of T-helper (Th)1/Th2-type immunity. Upon stimulation by the Th1-type cytokine interferon (IFN)-gamma, human monocytes/macrophages release large amounts of neopterin. Thus, the determination of neopterin concentrations is an indirect measure of the levels of IFN-gamma and allows us to monitor Th1-type immune response.

Neopterin concentrations in blood donors differ between AB0 blood group phenotypes.

Objectives: Neopterin is produced by human monocyte-derived macrophages upon stimulation with interferon-gamma and is therefore a sensitive indicator for cellular immune activation. Common factors like age, diastolic blood pressure, body mass index, or smoking habits were found to be associated with neopterin concentrations in humans.

Design And Methods: In order to find possible genetic determinants which might influence neopterin production, we investigated 8288 consecutive blood donors after exclusion of samples suspicious of infections.

Antioxidants may increase the probability of developing allergic diseases and asthma.

In addition to genetic predisposition, a lack of triggers for Th1 immune response like exposure to infections, endotoxins and dirt in childhood are supposed to be responsible for the higher incidence of allergic rhinitis and asthma (hygiene hypothesis). In vitro, beverages rich in antioxidants like green tea and wine were found to suppress formation of Th1-type cytokine interferon-gamma. Due to the existing cross-regulatory interplay between Th1- and Th2-type immune response, these beverages may thus slow-down Th1-type immune response and thereby favour an over-production of Th2-type cytokines.

Association of increased neopterin production with decreased humoral immunity in the elderly.

Tetanus toxoid (TT) antibodies of 447 adult persons aged 27-69 years were investigated and analyzed in relationship with the time span since the last vaccination against tetanus as well as the serum concentration of neopterin. Neopterin is a pteridine, which is produced by monocytes/macrophages upon stimulation with the type 1 T cell-derived cytokine interferon-gamma. There was an inverse correlation between serum neopterin and TT antibody concentrations (Spearman's rank correlation coefficient: r(s)=-0.