Formation of neopterin, a biomarker of the activated human immune system, is linked with tryptophan (TRP) and phenylalanine (PHE) metabolism. To obtain normal values, in this study, serum concentrations of neopterin as well as of TRP, PHE and their respective metabolites kynurenine (KYN) and tyrosine (TYR) were investigated in 100 successive blood donor serum specimens from the University Clinics of Innsbruck, Austria. In addition, nitrite concentrations were determined. Donors had passed anamnestic examination at entry and were therefore considered as healthy. The mean age of participants was 49±11.4 (mean±SD) years; 18% were older than 60 years. Both genders were included in the analysis. Neopterin concentrations measured by enzyme-linked immunosorbent assay were 5.9±1.6 nmol/L (mean±SD). Levels of amino acids and metabolites were determined by HPLC. Mean KYN and TRP concentrations were 1.78±0.42 μmol/L and 67.4±10.2 μmol/L, respectively. KYN to TRP ratio (KYN/TRP), an estimate for the activity of tryptophan-degrading enzyme indoleamine 2,3-dioxygenase, was 26.7±6.2 μmol/mmol. Mean PHE and TYR concentrations were 65.2±11.1 μmol/L and 90.6±22.9 μmol/L. PHE to TYR ratio (PHE/TYR), an estimate for the activity of PHE-converting enzyme phenylalanine hydroxylase, was 0.75±0.14 μmol/μmol. Nitrite concentrations, estimated by Griess-Ilosvay reagent, were 44.9±32.0 μmol/L. Males were taller and heavier than females (both p<0.01), but body mass index did not differ. Males presented with significantly higher TRP and TYR concentrations than females (both p<0.05). There existed significant correlations between neopterin and KYN (rs=0.368), KYN/TRP (rs=0.453), TYR (rs=–0.267; all p<0.01) and PHE/TYR (rs=0.236; p<0.05) concentrations. Data indicate that also in a population of healthy individuals an association exists between “low-grade” immune activation as is indicated by slightly higher neopterin concentrations and biochemical alterations in the amino acid metabolism. Although minor, such changes may interfere with psychoneuroimmunological regulatory networks and thus be of clinical relevance.

Objectives: An HPLC method was developed to quantify serum concentrations of phenylalanine and tyrosine simultaneously using fluorescence detection without derivatization.Methods: Serum protein is precipitated with trichloroacetic acid, 0.015 mM dihydrogen-phosphate solution is used for separation on reversed-phase C-18 material, and acetonitrile is avoided. Both amino acids are monitored utilizing their natural fluorescence at 210 nm excitation and 302 nm emission wavelengths.Results: One analytical run is completed within 7 min. Lower detection limit for Phe and Tyr is 0.3 mu M. Comparison of the new method with a classical HPLC method for total amino acids and using UV-absorption detection reveals a highly significant relationship for Phe and Tyr.Conclusion: The new HPLC method allows rapid and very sensitive measurement of phenylalanine and tyrosine concentrations. (C) 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

AbstractBackground:Acute virus infections are indicated by increased serum neopterin concentrations. Testing of blood donations for increased neopterin was introduced in the Austrian Tyrol in 1986 and throughout Austria in 1994 to improve the safety of blood transfusions. Radioimmunoassay (RIA) was the first available test, and the 98th percentile for neopterin concentrations from 76,500 donations was defined as the cut-off threshold, excluding donations with neopterin ≥10 nmol/L. When ELISAs were introduced on fully automated test systems to measure neopterin concentrations, results were generally higher and the cut-off was adjusted up to 12 nmol/L.Methods:In early 2006, new equipment (Hamilton Microlab Star®pipettor+Dade Behring ELISA Processor III, BEP III®) became available which monitors sample and reagent volumes for each uptake and dispense, and takes the viscosity of the fluids into account. Using this system, the performance of neopterin determinations was evaluated over 21 months and compared to earlier data.Results:When the new apparatuses were introduced, an immediate decrease in mean neopterin concentrations and the percentage of samples with neopterin concentrations ≥10 nmol/L was observed. The 55,516 measurements performed in 2007 showed a mean value of 5.5 nmol/L. Neopterin in 680 donations (1.23%) were ≥10 nmol/L.Conclusions:The new Hamilton diluter increased the accuracy of the neopterin test procedure. Results are now identical with those of RIA and ELISA when run in a semi-automated manner. Differences in pipetting performance of standards and samples are considered as one possible explanation for the earlier discrepancies seen with the automated apparatus.Clin Chem Lab Med 2010;48:373–7.

Serum neopterin concentrations were determined in 20,000 blood donations. For the 400 donations with neopterin concentrations above the 98 th percentile and another 1200 donations with neopterin concentrations in the lower range, results of human parvovirus (HPV) B19 tests were compared. Infectious specimens were identified by dot blot hybridization assay and polymerase chain reaction (PCR) that used the outer primers and detected 1 pg of HPV B19 DNA, corresponding to approximately 10(5) copies of the genome, in the specimens and by a nested PCR that detected 1-10 fg of DNA, corresponding to 10(2)-10(3) copies of the genome. Of 400 specimens with neopterin concentrations > or =12 nmol/L (98th percentile, current cutoff), 10 tested positive by dot blot hybridization assay (9 of these were confirmed by nested PCR). Among 1200 specimens with low neopterin concentrations (<12 nmol/L), no specimen containing HPV B19 DNA was detected. These findings suggest an association between elevated neopterin concentrations and HPV B19 infectivity.

In Austria serum neopterin measurement was introduced as an additional unspecific screening marker for the detection of routinely unscreened viral infections in blood donations in 1994. This study was performed to test for associations between serum neopterin concentrations in blood donations and cytomegalovirus infections of the donors. All consecutive blood donations from volunteer blood donors collected during 1 year were incorporated into the study. Serum neopterin concentrations were measured by enzyme-linked immunosorbent assay (ELISA), and each donation of donors with CMV seronegativity or unknown CMV status was also screened for CMV antibodies by CMV IgG/IgM antibody ELISA. Data of donors who had two or more donations within this period were retrospectively analyzed for CMV seroconversions. CMV seroconversion was defined as a change in the donor's CMV status from antibody negative to positive. Frozen, stored plasma samples of the matching donors were tested for CMV IgM antibodies to confirm seroconversion. CMV seroconversions were classified by antibody patterns. In total, 56,068 consecutive blood donations were given by 44,427 volunteer donors. Among these, 9,105 had more than one donation during the observation period, and 4,329 (47.5%) out of these repeated donors were initially CMV antibody negative, of whom 36 were recruited as candidates for CMV seroconversion; 20 conversions were confirmed. All early infections ( n=8) were associated with neopterin concentrations of more than 13 nmol/l (98th percentile of all donations = 12.1 nmol/l) and all donations were excluded from transfusion solely on the basis of their elevated neopterin level. In addition, 17% of late and carrier states ( n=12) showed elevated neopterin concentrations. Acute CMV infections among blood donors presented with elevated serum neopterin concentrations even before CMV IgG/IgM antibodies were detectable.

Neopterin, a product of interferon-γ-activated monocytes/macrophages is a sensitive indicator of cell-mediated immune activation (1). In humans, increased concentrations of neopterin in serum and urine have been found during allograft rejection episodes and in various malignant disorders, autoimmune diseases, and viral infections, including HIV type 1 (HIV-1) (2)(3)(4)(5)(6)(7)(8). To improve the safety of blood donations, additional neopterin testing of blood donations became mandatory for all Austrian blood-transfusion services in addition to testing for HIV-1 and -2 antibodies, hepatitis C virus (HCV) antibodies, hepatitis B virus (HBV) surface antigen, alanine aminotransferase (ALT), and Treponema pallidum antibodies (9). In the Austrian Tyrol, ∼900 000 voluntary blood donations have been routinely screened for increased neopterin concentrations since 1986. According to the results of previous studies, the cutoff for neopterin concentrations was set to the 98th percentile, thus tolerating a donation loss of 2% (9). Although the behavior of neopterin concentrations during the course of acute viral infections, for example, is well known, there are fewer data regarding the association of neopterin concentrations and physiologic findings in a healthy population. In this study, we looked for associations between neopterin concentrations and other laboratory tests that are routinely performed on blood donations at our institute. Associations between neopterin concentrations and physiologic conditions of blood donors obtained during the blood-donation procedure were also investigated. Blood samples from 1156 consecutive blood donors from the Austrian Tyrol (693 males and 463 females) were collected in January 2001. A questionnaire was administered, which asked about current smoking habits, medical conditions, and use of medications. Of the blood donors, 262 (22.7%) reported being smokers (range of cigarettes smoked daily, 1–50), 56 (4.8%) were taking antihypertensive drugs, and 52 (4.5%) reported using antiinflammatory drugs, such as acetylsalicylic acid. …

Neopterin is released from human monocyte-derived macrophages preferentially upon stimulation with the Thlcell cytokine interferon-γ. In humans, increased concentrations of neopterin in serum and urine have been found in viral infections including human immunodeficiency virus type 1, various malignant disorders, autoimmune diseases and during allograft rejection episodes. In order to find additional parameters which might influence neopterin production, serum neopterin concentrations of 1156 blood donors were compared with other parameters routinely determined in blood transfusion. There existed correlations between serum neopterin concentration and blood donors' age (Spearman's rank correlation: rs = 0.259, ρ <0.0001), arterial diastolic blood pressure (rs 0.132, ρ <0.0001) and body mass index (rs = 0.084, ρ <0.01). Serum neopterin concentrations were lower in smokers compared to nonsmokers (Mann-Whitney test, ρ <0.0001). The data demonstrate that higher neopterin concentrations are associated with older age, higher diastolic blood pressure and higher body mass index, whereas lower neopterin concentrations are found in smokers compared to nonsmokers. It is assumed that immunopathogenetic pathways underlie these relationships, but the exact background of these associations still needs to be resolved.

BACKGROUND. The efficacy and success of a screening program for prostate cancer in young and healthy asymptomatic volunteers are described.METHODS. In the present study, prostate specific antigen (PSA) samples obtained from 2,272 males (aged 40-65 years) who donated blood at the local Red Cross Blood Bank were evaluated. Two groups of donors were distinguished, which were investigated in different ways. Group 1 comprised individuals aged 40-49 years (n = 568), while group 2 consisted of males aged 50-65 years (n = 1,704). Volunteers in group 2 who had PSA levels greater than 4 ng/ml (n = 302) were referred for ultrasound guided biopsy irrespective of findings on digital rectal examination (DRE). In group 2, individuals with PSA levels exceeding 4 ng/ml and positive DRE findings biopsy specimen was ordered (n = 2). In patients with unremarkable findings on DRE, serum PSA was determined 1 year later and in case of more than 20% increase in the PSA level biopsy was obtained under ultrasound guidance.RESULTS. The biopsy specimen yielded prostatic carcinoma in 58 patients in group 1. As a screening test, serum PSA determination was superior to digital rectal examination. On digital palpation only 2 presented with abnormal prostates. These 58 patients underwent radical prostatectomy and histological examination revealed organ-confined disease in all but 8. In group 2, in 4 of 12 males the biopsy specimen yielded prostatic carcinoma.CONCLUSIONS. This study shows that PSA measurement in blood donors is a useful method for recruiting screening volunteers, and therefore represents an additional possibility for early detection of prostate cancer in asymptomatic younger males. Furthermore, it represents an effective tool for following relatively young patients known to have a significant risk of prostate cancer. (C) 1997 Wiley-Liss, Inc.

Das Glykoprotein PSA, exklusiv von Prostataepithelzellen produziert, hat eine Reihe von Applikationen im Management bei Männern mit Prostatakarzinom. Es ist heute durchaus bekannt, daß erhöhtes prostataspezifisches Antigen mit der Präsenz eines Prostatakarzinoms einhergeht, jedoch gibt es bislang kaum Berichte über PSA als Firstline-Screeningtest zur Früherkennung von Prostatakarzinomen.

A high percentage of HIV-1-infected infants and children in Romania are coinfected with hepatitis B virus. Little information is available on the impact of concurrent hepatitis B infection on the course of HIV-1 infection. We conducted a prospective cohort study over 1 year in a group of 68 HIV-1-infected infants and children to determine whether hepatitis B surface antigenemia, neopterin, and beta 2-microglobulin (B2M) predicted death. Among the 44 hepatitis B surface antigen-positive (HBsAg+) subjects at enrollment, 13 (30%) died during 1 year of follow-up. In comparison, two of 24 (8%) HBsAg-negative subjects died (RR = 7.7; p = 0.05). Higher initial serum concentrations of neopterin and B2M were negatively associated with survival. After stratifying by baseline clinical evidence of HIV-related disease, survival was negatively associated with HBsAg+ status (p = 0.04) in 33 children in stage P-2, adjusting for age, serum neopterin, and serum B2M levels. The results of this study suggest that serum neopterin is a marker for severity of clinical illness and that HBsAg+ status increases the mortality rate among children with clinical evidence of HIV infection.

6-D-eiythm-Neopterin is synthesized in significantly in- creased amounts by human macrophages upon activation by v-interferon. Neopterin has been used as a marker for cellular immune activation in various diseases (1). Mea- surement of neopterin is possible by high-performance liq- uid chromatography (HPLC) or by radioimmunoassay (RIA) (2-4). More recently, enzyme-linked immunosorbant assays (ELISAs) of neopterin have been described (5-8). Neopterin measurement can be used to screen blood do- nors for presence of infections in a global sense, because increased neopterin concentrations in blood or urine are an early and sensitive indicator for the presence of a broad panel of infectious diseases. In the Austrian Tyrol, neo- pterin has been screened for routinely in each blood sample donated by voluntary blood donors since 1986, with the rationale of providing improved safety for the recipient of blood donations (9). Recently, all Austrian blood-banking

Journal Article Commercial enzyme-linked immunosorbent assay for neopterin detection in blood donations compared with RIA and HPLC Get access P Mayersbach, P Mayersbach Centr. Inst. Blood Transfusion and Immunol., Univ. Hospital, Innsbruck, Austria Search for other works by this author on: Oxford Academic Google Scholar R Augustin, R Augustin Centr. Inst. Blood Transfusion and Immunol., Univ. Hospital, Innsbruck, Austria Search for other works by this author on: Oxford Academic Google Scholar H Schennach, H Schennach Centr. Inst. Blood Transfusion and Immunol., Univ. Hospital, Innsbruck, Austria Search for other works by this author on: Oxford Academic Google Scholar D Schönitzer, D Schönitzer Centr. Inst. Blood Transfusion and Immunol., Univ. Hospital, Innsbruck, Austria Search for other works by this author on: Oxford Academic Google Scholar E R Werner, E R Werner Centr. Inst. Blood Transfusion and Immunol., Univ. Hospital, Innsbruck, Austria Search for other works by this author on: Oxford Academic Google Scholar H Wachter, H Wachter Centr. Inst. Blood Transfusion and Immunol., Univ. Hospital, Innsbruck, Austria Search for other works by this author on: Oxford Academic Google Scholar G Reibnegger G Reibnegger Centr. Inst. Blood Transfusion and Immunol., Univ. Hospital, Innsbruck, Austria Search for other works by this author on: Oxford Academic Google Scholar Clinical Chemistry, Volume 40, Issue 2, 1 February 1994, Pages 265–266, https://doi.org/10.1093/clinchem/40.2.265 Published: 01 February 1994

Summary We have evaluated a new commercially available enzyme-linked immunorsorbant assay for neopterin :or its suitability in the context of screening of voluntary blood donors. The assay was performed on 1040 consecutive blood donors, and compared with radioimmunoassay and. in a fraction of 142 donors . . : Iso with high performance liquid chromatography. On repetitive assays of all donations showing a concentration exceeding 8.0 nmol/L in the initial assay. three of the radioimmunoassay results were identified as gross outliers. No such gross outliers were detected for the enzyme-linked immunosorbant assay. RegarJing the reproducibility of results exceeding a cut-off limit of \0 nmol/L neopterin. the enzyme-linked ;mmunosorbant assay was better than the radioimmunoassay. Moreover. the enzyme-linked immunosorbant assay was slightly superior to radioimmunoassay when both tests were compared with high performance liquid chromatography (based on linear regression analysis. evaluation of frequencies of concentrations bant assay was slightly superior to radioimmunoassay when both tests were compared with high performance liquid chromatography (based on linear regression analysis. evaluation of frequencies of concentrations rations. Its slight superiority compared to the conventional radioimmunoassay likely results from the higher degree of automatization employed.

Journal Article Increased prevalence of IgM antibodies to Epstein-Barr virus and parvovirus B19 in blood donations with above-normal neopterin Get access H Schennach, H Schennach Central Inst. for Blood Transfusion and Immunol., Univ. Hosp., Innsbruck, Austria Search for other works by this author on: Oxford Academic Google Scholar P Mayersbach, P Mayersbach Central Inst. for Blood Transfusion and Immunol., Univ. Hosp., Innsbruck, Austria Search for other works by this author on: Oxford Academic Google Scholar D Schönitzer, D Schönitzer Central Inst. for Blood Transfusion and Immunol., Univ. Hosp., Innsbruck, Austria Search for other works by this author on: Oxford Academic Google Scholar D Fuchs, D Fuchs Central Inst. for Blood Transfusion and Immunol., Univ. Hosp., Innsbruck, Austria Search for other works by this author on: Oxford Academic Google Scholar H Wachter, H Wachter Central Inst. for Blood Transfusion and Immunol., Univ. Hosp., Innsbruck, Austria Search for other works by this author on: Oxford Academic Google Scholar G Reibnegger G Reibnegger Central Inst. for Blood Transfusion and Immunol., Univ. Hosp., Innsbruck, Austria Search for other works by this author on: Oxford Academic Google Scholar Clinical Chemistry, Volume 40, Issue 11, 1 November 1994, Pages 2104–2105, https://doi.org/10.1093/clinchem/40.11.2104 Published: 01 November 1994

Human endogenous retrovirus (HERV) K is present in about 50 copies in the human genome and transcription of HERV-K has previously been detected in several tumor cell lines as well as in peripheral blood lymphocytes from healthy donors. By means of immunoblotting we investigated the presence of antibodies recognizing recombinant HERV-K-envelope outer membrane constructs in different serum collectives. A total of 12.6% of sera obtained from normal blood donors was found positive. In serum collectives from breast carcinoma patients, HIV-1-positive individuals, and persons with cytomegalovirus infections no significant difference from the normal blood donor serum collective could be observed. Only a group of persons with a repeatedly raised serum neopterin concentration (> 10 nmol/liter) of unknown cause (HIV and hepatitis B and C virus infections were excluded) showed a significant higher percentage of HERV-K-outer membrane envelope-positive sera (21%). Furthermore we could observe a parallel HIV-1/HERV-K seroconversion, which probably is not due to an HIV-1/HERV-K-outer membrane envelope cross-reactivity. Possible implications of these findings are discussed.

Serologic markers of immune activation, neopterin and beta-2-microglobulin (B2M), have been shown to predict progressive human immunodeficiency virus type 1 (HIV-1) disease based on cohort studies in adults. Both parameters appear also to be valuable in distinguishing HIV-1 infants with progressive disease from asymptomatic infants and HIV-1 seronegative infants. In a cross-sectional study we examined the utility of neopterin and B2M testing in 135 infants of an orphanage in Romania, 69 of the infants (51%) were found to be HIV-1 antibody seropositive; 95% of the 135 infants were either hepatitis B virus (HBV) antigen or antibody seropositive. In the HIV-1 seronegative infants B2M was higher in those with HBV antigenaemia. Serum neopterin and B2M concentrations were higher in HIV-1 seropositive than in seronegative infants (p = 7 x 10(-12) and 1 x 10(-6)). Children with CDC stage P2 had only slightly higher neopterin and B2M values as compared to stage P1 (P = 0.04 and 0.08). Our study indicates that measurement of neopterin and B2M is useful to monitor HIV-1 infection, particularly in areas where laboratory facilities are limited. Both parameters continue to be associated with HIV-1 infection even when there is a high background rate of other infections.