Serum neopterin, beta2-microglobulin, soluble interleukin-2 receptors, and immunoglobulin levels in healthy adolescents

Influence of ethnicity on biochemical markers of health and disease in the CALIPER cohort of healthy children and adolescents

Background Accurate pediatric reference intervals (RIs) for laboratory tests determined in a healthy pediatric population are essential for correct laboratory test interpretation and clinical decision-making. In pediatrics, RIs require partitioning by age and/or sex; however, the need for partitioning based on ethnicity is unclear. Here, we assessed the influence of ethnicity on biomarker concentrations in the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) cohort of healthy children and adolescents and compared the results with the National Health and Nutrition Examination Survey (NHANES). Methods A total of 52 biomarkers were measured in a multiethnic population of 846-1179 healthy children (aged 5 to <19 years) upon informed consent. Biomarker concentrations were retrospectively compared between four major ethnic groups (i.e. Black, Caucasian, East Asian, and South Asian, determined by parental ethnicity). Retrospective results were verified prospectively using an additional 500 healthy pediatric samples with equal sample size across ethnicities. Ethnic-specific differences were assessed based on statistical significance and biological and analytical variations. Appropriate age-, sex-, and ethnic-specific RIs were calculated. Results Ethnic-specific differences were not observed for 34 biomarkers examined in the retrospective analysis, while 18 demonstrated statistically significant ethnic differences. Among these, seven analytes demonstrated ethnic-specific differences in the prospective analysis: vitamin D, amylase, ferritin, follicle-stimulating hormone (FSH), immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM). Analysis of select NHANES data confirmed CALIPER findings. Conclusions This is the first comprehensive Canadian pediatric study examining ethnic-specific differences in common biomarkers. While the majority of biomarkers did not require ethnic partitioning, ethnic-specific RIs were established for seven biomarkers showing marked differences. Further studies in other populations are needed to confirm our findings.

Juvenile Arthritis Patients Suffering from Chronic Inflammation Have Increased Activity of Both IDO and GTP-CH1 Pathways But Decreased BH4 Efficacy: Implications for Well-Being, Including Fatigue, Cognitive Impairment, Anxiety, and Depression

Juvenile idiopathic arthritis (JIA) represents joint inflammation with an unknown cause that starts before the age of 16, resulting in stiff and painful joints. In addition, JIA patients often report symptoms of sickness behavior. Recent animal studies suggest that proinflammatory cytokines produce sickness behavior by increasing the activity of indoleamine-2,3-dioxygenase (IDO) and guanosinetriphosphate⁻cyclohydrolase-1 (GTP⁻CH1). Here, it is hypothesized that inflammation in JIA patients enhances the enzymatic activity of IDO and GTP-CH1 and decreases the co-factor tetrahydrobiopterin (BH4). These compounds play a crucial role in the synthesis and metabolism of neurotransmitters. The aim of our study was to reveal whether inflammation affects both the GTP-CH1 and IDO pathway in JIA patients. Serum samples were collected from twenty-four JIA patients. In these samples, the concentrations of tryptophan (TRP), kynurenine (KYN), tyrosine (TYR), neopterin, and phenylalanine (PHE) were measured. An HPLC method with electrochemical detection was developed to quantify tryptophan, kynurenine, and tyrosine. Neopterin and phenylalanine were quantified by ELISA. The KYN/TRP ratio was measured as an index of IDO activity, while the PHE/TYR ratio was measured as an index of BH4 activity. Neopterin concentrations were used as an indirect measure of GTP-CH1 activity. JIA patients with high disease activity showed higher levels of both neopterin and kynurenine, and a higher ratio of both KYN/TRP and PHE/TYR and lower tryptophan levels than clinically inactive patients. Altogether, these data support our hypothesis that inflammation increases the enzymatic activity of both IDO and GTP-CH1 but decreases the efficacy of the co-factor BH4. In the future, animal studies are needed to investigate whether inflammation-induced changes in these enzymatic pathways and co-factor BH4 lower the levels of the brain neurotransmitters glutamate, noradrenaline, dopamine, serotonin, and melatonin, and consequently, whether they may affect fatigue, cognition, anxiety, and depression. Understanding of these complex neuroimmune interactions provides new possibilities for Pharma-Food interventions to improve the quality of life of patients suffering from chronic inflammation.

The Use of Neopterin as a Noninvasive Marker in Monitoring Diseases in Wild Chimpanzees

Pathogen analysis in wild great apes is both time- and resource-consuming. Therefore, we examined the potential use of urinary neopterin, a sensitive marker of cell-mediated immune system activation, as a disease marker and unspecific screening tool to facilitate informed pathogen analysis in great ape health monitoring. To test this, urinary neopterin was correlated to other disease markers such as sickness behaviors, fever, and urine parameters. Seasonal variation in urinary neopterin levels was investigated as well. The study encompassed noninvasively collected longitudinal data of young wild chimpanzees from the Taï National Park, Côte d´Ivoire. Relationships between disease markers were examined using a linear mixed model and a case study approach. Seasonal variation in urinary neopterin was tested using a linear mixed model. While the linear mixed model found no obvious relationship between urinary neopterin levels and other disease markers, the case study approach revealed a pattern resembling those found in humans. Urinary neopterin levels indicated seasonal immune system activation peaking in times of low ambient temperatures. We suggest the use of urinary neopterin as an unspecific screening tool in great ape health monitoring to identify relevant samples, individuals, and time periods for selective pathogen analysis and zoonotic risk assessment.

Validation of a Method for the Assessment of Urinary Neopterin Levels to Monitor Health Status in Non-human-primate Species

Determining individual health status is of great importance for a better understanding of life history trade-offs between growth, reproduction, and maintenance. However, existing immunological methods are invasive and therefore not suitable for investigating health status in wild populations. Thus, there is an urgent need for non-invasive methods to assess the immune status of animals. Neopterin is involved in the cell-mediated pathway of the immune response (Th1–type), secreted during the activation of monocytes and macrophages. We investigated if urinary neopterin could serve as a biomarker of health status in bonobos and chimpanzees. First, we performed a chemical validation of a commercial neopterin enzyme immune assay (EIA) for bonobo and chimpanzee urine. We then examined if urinary neopterin levels in bonobos increase during the acute period of respiratory infections. We found that neopterin levels can be reliably measured in urine of the two species with a commercial EIA. Stability experiments revealed considerable changes in urinary neopterin levels in relation to multiple freeze–thaw cycles and extended exposure to room temperature. Exposure to sunlight led to a degradation of urinary neopterin, whereas sample storage up to 2 years did not affect urinary neopterin levels. There was no detectable diurnal variation in neopterin levels, and levels remained very stable across several days in healthy individuals. While urinary neopterin levels were independent of sex, non-adult individuals had higher urinary neopterin levels than adults. Most importantly, there was a significant increase in urinary neopterin levels during a period of respiratory infection. Our results demonstrate that regular urine sample collection would allow for the monitoring of individual health status and disease progression with minimal disturbance of the subjects. In combination with behavioral, life history, and endocrinological parameters, the method can be used to investigate questions related to immunocompetence handicaps or life history trade-offs.

Human breast milk concentration of neopterin at various stages of lactation and during a single feeding

The aim of this work was to determine the physiological level of neopterin in human breast milk, and to study its variability depending on the duration of a single feeding and the lactation stage. Breast milk samples from 74 women were collected between 2 and 4 days after delivery, and at 15, 30, and 90 days after delivery. Additionally, breast milk samples from eight women were collected before and after 7 and 15 min of breastfeeding. The concentration of neopterin in breast milk was determined by an immunoenzymatic assay. The range of breast milk neopterin concentration at various stages of lactation amounted to 15.4–19.2 nmol/L at 2–4 days after delivery, 20.2–23.0 nmol/L at day 15, 20.8–24.5 nmol/L at day 30, and 16.9–20.4 nmol/L at day 90. The level of neopterin 2–4 days after delivery was significantly lower than that at days 15 and 30; moreover, the concentration of neopterin at day 30 was significantly higher than that at day 90. No significant differences were documented between neopterin concentrations at various phases of a single feeding. While the breast milk concentration of neopterin changes depending on the stage of lactation, it remains stable throughout a single feeding.

Evaluation of the serum levels of soluble IL-2 receptor and endothelin-1 in children with Crimean-Congo hemorrhagic fever

We aimed to assess the association between serum levels of soluble IL-2 receptor (sIL-2r) and endothelin-1 and severe infection in children with Crimean-Congo hemorrhagic fever (CCHF). Fifty-two patients under 18 years of age with a laboratory- confirmed diagnosis of CCHF and 38 healthy controls were enrolled in the study. Patients were classified into two groups based on disease severity (severe group and non-severe group). The sIL-2r and endothelin-1 levels were observed to be significantly higher in patients with severe CCHF compared with those with non-severe CCHF and the control group (p < 0.05). In addition, those with non-severe CCHF were also found to have a significantly higher sIL-2r level relative to the control group (p < 0.001). Although there was a positive correlation between sIL-2r and endothelin-1 levels, serum levels of both sIL-2r and endothelin-1 were negatively correlated with the platelets count. In children with CCHF, serum levels of sIL-2r and endothelin-1 were increased, and this increase is related to the severity of the disease. In this study, we concluded through prognosis that serum levels of sIL-2r and endothelin-1 might be related, and that hemophagocytic lymphohistiocytosis and endothelial injury might contribute to a pathogenesis of the disease.

The clinical and biochemical parameters in relation to the serum neopterin levels in Indian children and adolescents

INTRODUCTION

An adverse pattern of blood lipids and cardiovascular abnormalities starts in obese children during childhood and neopterin serves as a marker for cardiovascular disease. Unfortunately, the data for children and adolescents, particularly, in the Indian population, are scarce. The present study aimed at evaluating the levels of serum neopterin in obese and overweight children and adolescents of the Indian population.

METHODS

The study groups included 296 school going children and adolescents. (96 obese and 97 overweight subjects were compared with 103 normal controls who were aged between 10-17 years). The anthropometric variables, the lipid profile, the fasting serum glucose which was analyzed by using an autoanalyzer and the serum neopterin levels were assayed by HPLC (Shimazdu) by using the method of Palfrey et al., 1993. The serum insulin levels were measured by using ELISA kits.

RESULTS

The serum neopterin levels (nmol/l) were elevated significantly in the obese (7.4±1.4) and overweight (6.4±0.8) (p<0.001) children and adolescents than in the controls (4.9±0.9). The serum neopterin levels showed a positive correlation with the BMI (r=0.79), WHR (r=0.5), systolic (r=0.44) and diastolic blood pressures (r= 0.25), insulin (r=0.57), HOMAIR (r=0.55), total cholesterol (r=0.35), triglycerides (r=0.20) and LDL-C (r=0.27) and they showed a negative correlation with HDL-C (r=-0.15) and fasting glucose (r= -0.3).

CONCLUSION

This study revealed a good relationship between serum neopterin and the anthropometric and biochemical parameters. We, therefore, aim to conduct regular camps at schools to counsel and advise the identified overweight and obese children to go for physical exercise and a balanced diet. The implementation of preventive measures from early childhood will have far reaching benefits, as even the prevalence of other obesity related disorders could decline.

Proteomic analyses of human plasma: Venus versus Mars

BACKGROUND

Plasma is vital for the resuscitation of injured patients and to restore necessary procoagulants, especially Factors (F)II, FV, FVII, FX, and FXIII; however, female plasma has been implicated in the majority of transfusion-related acute lung injury (TRALI) cases and male-only plasma transfusion regimens have significantly decreased the incidence of TRALI. Little is known about the human plasma proteome, and no comparisons have been made between male and female plasma; therefore, we hypothesize that there are significant differences between plasma from male and female donors.

STUDY DESIGN AND METHODS

Five units of fresh-frozen plasma each were collected from nulliparous female donors and male donors, and the proteome was analyzed by depleting the 14 most common proteins by immunoaffinity columns followed by protein separation by one dimension gel electrophoresis, tryptic digestion of the proteins, analysis of the peptides by liquid chromatography-tandem mass spectrometry, and identification employing human protein sequence databases.

RESULTS

Female plasma versus male plasma contained pregnancy zone protein (419- to 580-fold), FV (twofold), α(1)-antitrypsin (twofold), β(2) -microglobulin (twofold), and Complement Factors H and C4B (1.5- to 2-fold) at significantly higher concentrations than males and males contained significant increases in Fc-binding protein (twofold), protein Z-dependent protease inhibitor (twofold), phosphatidylinositol glycan-specific phospholipase (fourfold), protein S-100 (threefold), and transgelin-2 (14-fold) versus females (p < 0.005). The increases in FV, α(1)-antitrypsin, and β(2)-microglobulin were confirmed by an activity assay or immunoblots.

CONCLUSION

We conclude that there are proteomic differences between male and female plasma, which could be exploited to improve clinical outcomes in transfused patients.

Neuroendocrine-immune aspects of accelerated aging in rheumatoid arthritis

The normal process of aging brings about changes in immune function, hormonal status, overall metabolism, and enhanced occurrence of neuropsychiatric disorders. These alterations are also evident at an accelerating pace in chronic inflammatory diseases. Treatment with immunosuppressive therapeutics is often not sufficiently effective. Treating neuroendocrine-immune alterations to regain homeostasis might enhance remission inducing and maintaining effects. This paper summarizes the phenomena related to normal aging and related to chronic inflammatory disease. Furthermore, a multimodal concept is being proposed to control more effectively chronic inflammatory disease on a neuroendocrine-immune basis.

Diurnal and sleep-wake dependent variations of soluble TNF- and IL-2 receptors in healthy volunteers

There is very little published information on the diurnal variation of cytokines and their receptors, in healthy individuals during normal sleep-wake patterns or during sustained wakefulness. The aim of the current investigation was to characterize concentrations of soluble tumor necrosis factor receptors (sTNF-Rs) and interleukin-2 receptor (sIL-2R) during normal sleep and wakefulness, as well as during a 24 h vigil. Plasma levels of the sTNF-R p55, sTNF-R p75, and sIL-2R did not differ significantly between nocturnal sleep and nocturnal wakefulness. Rhythmic analysis (2-h intervals) revealed significant diurnal variations for both sTNF-R p55 and sTNF-R p75, but not levels of sIL-2R. Diurnal variations of both sTNF-Rs were characterized by a single cosine curve with an average peak near 06:00 h in the morning. This peak occurred well before that of cortisol, and fluctuated inversely with the diurnal rhythm of temperature. These diurnal variations in sTNF-Rs levels are consistent with the hypothesis that the TNF system plays a role in normal diurnal temperature regulation.

Purine, kynurenine, neopterin and lipid peroxidation levels in inflammatory bowel disease

The kynurenine metabolites of tryptophan may be involved in the regulation of neuronal activity and thus gut motility and secretion. We have now performed a pilot study to measure serum concentrations of purines and kynurenines in patients with mild inflammatory bowel disease, as well as in sex- and age-matched control subjects. For some analyses, the patients were subdivided into subgroups of those with Crohn's disease and those with ulcerative colitis. The analyses indicated an increased activity in one branch of the kynurenine pathway. While there was no demonstrable difference in neopterin levels in either of the patient groups compared with controls, indicating that the disorders were in an inactive quiescent phase, both groups showed significantly higher levels of lipid peroxidation products. This suggests the presence of increased oxidative stress even during relative disease inactivity. The increased level of kynurenic acid may represent either a compensatory response to elevated activation of enteric neurones or a primary abnormality which induces a compensatory increase in gut activity. In either case, the data may indicate a role for kynurenine modulation of glutamate receptors in the symptoms of inflammatory bowel disease.

Measurement of cytokines in clinical samples using immunoassays: problems and pitfalls

With the explosion in interest in cytokines and an increasing understanding of their possible involvement in the pathogenesis of many diseases, the number of studies measuring cytokines in body fluids has increased markedly over the last 5 to 10 years. However, it is readily apparent from the literature that the level of awareness of the many factors that can potentially influence the results obtained is very low. Such factors are likely to contribute considerably to the disparities seen among similar types of study. These include assay properties such as standardization and specificity, type of sample and sample handling, and many biological influences such as age, sex, ethnic background, and diurnal rhythmicity. Clearly, it is not possible to control for all these factors, but a minimum evaluation of assays should be carried out as described, including recovery and parallelity studies using relevant samples and the establishment of reproducibility and normal healthy population levels. An awareness of these factors, which is the purpose of this review, may hopefully lead to an improvement in the quality of studies incorporating the measurement of cytokines in clinical samples and should aid in the interpretation of the data.