Neopterin Concentrations In Patients Research Articles

Long-term significance of urinary neopterin in ovarian cancer: a study by the Austrian Association for Gynecologic Oncology (AGO)

Neopterin is produced by activated macrophages upon stimulation with interferon-γ (IFN-γ) and thus, elevated neopterin concentrations in patients indicate cellular inate immune response. Most studies in patients with malignant diseases found an association between higher neopterin concentrations and reduced survival and impaired prognosis. Nevertheless, neopterin is not a classical tumor marker since it is not produced by the cancer cells themselves. In a study conducted by the Austrian Gynecologic Oncology Group (AGO) in 114 patients with ovarian cystadenomas and 223 patients with invasive ovarian cancer, patients' urinary neopterin was determined before and after primary therapy. The relevance of neopterin in long-term median follow-up was assessed. Elevated levels (cut-off 250 µmol/mol creatinine) were found less frequently in women with benign ovarian cystadenomas (24%) than in patients with malignant disease (58%). After 10 years, only 57% of ovarian cancer patients with elevated urinary neopterin levels survived without disease progression following primary therapy when compared with 86% of women with normal levels (P < 0.001). Along with residual tumor, FIGO stage, age and histological type, neopterin was significantly associated with overall survival (OS) and progression-free survival (PFS). The median PFS was 52 and 12 months and the median OS was 81 and 24 months for patients with normal and elevated neopterin, respectively, P < 0.001. In a multivariate Cox regression analysis, only residual tumor, neopterin and age were independently associated with OS, while only residual tumor was predictive for PFS. Thirty patients with early-stage invasive ovarian cancer (FIGO I and II) were analyzed separately. Of 3 patients with elevated neopterin, 2 died of disease in contrast to 2 out of 27 patients with normal neopterin (P = 0.004). In ovarian cancer, the negative impact of elevated urinary neopterin levels indicates a detrimental effect of cancer-associated inflammatory reaction.

Salivary neopterin concentrations in patients with cancer of the oral cavity

Abstract Tumors of the oral cavity are relatively common malignancies with a poor prognosis. Use of both prognostic and predictive biomarkers in saliva represents one approach to improve the management of patients with these cancers. The aim of the present study was to measure salivary neopterin concentrations before and after surgery in patients with oropharyngeal cancer to assess potential use as a biomarker in clinical practice. Salivary neopterin concentration was determined before and after surgery in 16 patients treated for oropharyngeal cancer and compared with 15 healthy volunteers. Salivary neopterin concentrations were significantly higher in patients before surgery compared to the healthy controls. After the surgery, neopterin concentrations decreased significantly, and concentrations in patients and controls were comparable. A significant correlation was observed between the sum of the Community Periodontal Index of Treatment Needs values and salivary neopterin concentrations. In conclusion, tumor removal results in significant decrease of salivary neopterin concentrations. The use of salivary neopterin in diagnosis is compounded by an association with periodontal disease.

Systemic immune response and peripheral blood cell count in patients with a history of breast cancer

Abstract The aim of the present study was to evaluate the association between changes in peripheral blood cell count and neopterin concentrations in patients with a history of breast cancer. Peripheral blood cell count, serum ferritin, serum neopterin and urinary neopterin concentrations were determined in 61 patients with a history of breast cancer and 74 control subjects. Hemoglobin, relative lymphocyte count and absolute lymphocyte count were lower, and relative neutrophil count, ferritin and serum neopterin concentrations were significantly higher in breast cancer patients than in controls. Compared to controls, the difference in hemoglobin concentration was statistically significant only in patients with active disease. Significant negative correlations were observed between urinary neopterin and hemoglobin as well as between serum neopterin and relative lymphocyte counts in breast cancer patients. Increased ferritin concentrations were associated with a history of hypertension, but higher absolute lymphocyte counts were associated with hypertension only in subjects without history of cancer. In conclusion, in patients with a history of breast cancer, anemia is associated with disease activity and systemic immune activation. Ferritin concentrations are increased in subjects with hypertension.

Immune activation and inflammation increase the plasma phenylalanine-to-tyrosine ratio

Abstract The proinflammatory cytokine interferon (IFN) γ activates GTP-cyclohydrolase I. In turn, the production of neopterin in human monocytic cells and of 5,6,7,8-tetrahydrobiopterin (BH4) in other human cells and cells of other species is markedly upregulated. BH4 is cofactor for the biosynthesis of the neurotransmitters 5-hydroxytryptamine (serotonin) and the catecholamines dopamine, epinephrine (adrenaline), and norepinephrine (noradrenaline). The finding of increased neopterin concentrations in patients with viral infections, autoimmune syndromes, malignant tumors, and during treatment with specific cytokines corresponds well with its immunobiological background. However, there is no clear information about BH4 concentrations in these patients. Furthermore, higher blood phenylalanine (Phe)-to-tyrosine (Tyr) ratios have been described in patients with ovarian cancer, after multiple trauma and with sepsis, in patients with HIV-1 infection, in elderly individuals, and in patients with HCV infection under IFN-α therapy. Recent studies already showed that the alterations of Phe metabolism are associated with mood changes and depression. Results point to an impaired hydroxylation of Phe when the enzyme phenylalanine 4-hydroxylase (PAH) is less efficient. As the decrease of PAH activity might result from a diminished availability of BH4, the determination of the Phe/Tyr ratio may serve as an indirect measure of BH4 availability.

Effects of Inhalation Anesthetics on the Profile of Urinary Neopterin as an Immune Marker in Patients who Underwent Laparoscopic Cholecystectomy

Abstract It has been claimed that inhalational anesthetics affect many phases of immune response. Although, there are a lot of studies on the effects of widely used anaesthetic agents and methods on the immune system, there are only a few studies to show the effects by evaluation of neopterin concentrations as an important marker of cellular immunity. This study was done to evaluate possible effects of inhalation anesthetics, such as desflurane, isoflurane, and sevoflurane on the immune system by measuring urinary neopterin concentrations in patients who underwent laparoscopic cholecystectomy. The study is randomized, prospective and double blind. Urinary neopterin was measured in patients submitted to general anesthesia with either desflurane (n = 20) or isoflurane (n = 11), or sevoflurane (n = 13) in laparoscopic cholecystectomy. Urine samples were collected preoperatively, at 2nd and 24th hours post-operatively and the neopterin per creatinine concentrations were measured by using high-performance liquid chromatography. The preoperative neopterin levels were similar across the study groups. Variance analysis of repeated measures showed an effect of time (p &lt;0.05): Neopterin concentrations increased over time, but the effect of different anesthetics on neopterin was similar. The mean increases in neopterin concentrations were similar among all the applied anesthetics. In conclusion, this report shows changes of immune response by investigation of neopterin in urine samples during 24 hours in patients exposed to three different inhalational anesthetic agents sevoflurane, desflurane and isoflurane in laparoscopic cholecystectomy.

Cord blood and maternal serum neopterin concentrations in patients with pre-eclampsia

Pre-eclampsia is a syndrome characterized by hypertension and proteinuria. The aim of this study was to investigate neopterin concentrations in cord blood and maternal serum in patients with pre-eclampsia and a control group. Cord blood and maternal serum neopterin were measured in 21 patients with pre-eclampsia and in 27 control subjects. Neopterin concentrations were measured by high performance liquid chromatography. Cord blood neopterin concentrations were significantly increased in patients with pre-eclampsia compared to controls (54.3+/-16.8 vs. 43.4+/-8.5 nmol/L, p=0.011, respectively). Maternal serum neopterin (257.3+/-36.8 vs. 150.9+/-33.8 nmol/L, p<0.001) was also higher in patients with pre-eclampsia. Cord blood and maternal serum neopterin concentrations are higher in patients with pre-eclampsia. Maternal serum neopterin concentrations used may be used as a marker for the early diagnosis of pre-eclampsia.

Cerebrospinal Fluid Neopterin in Patients with Tumors and other Disorders

Abstract Increased urinary or serum concentrations of neopterin have been reported in cancer patients, but less is known about neopterin concentrations in cerebrospinal fluid (CSF). CSF neopterin was determined with radioimmunoassay in 64 patients. CSF neopterin concentrations in patients with tumors were significantly higher compared to patients with predominantly peripheral infections (Lyme borreliosis and herpes simplex infection) and no infectious, inflammatory or neoplastic disorder, and significantly lower compared to patients with meningitis or encephalitis. Among patients with tumors, CSF neopterin was significantly higher in patients with non- Hodgkin lymphoma (NHL) compared to other tumors. The difference between patients with tumors other than NHL and predominantly peripheral infections was of borderline significance, and a significant difference was observed between patients with tumors other than NHL and no disorder. CSF neopterin was significantly higher in patients with NHL compared to patients with predominantly peripheral infections, multiple sclerosis or polyneuropathy and no disorder, and no difference was evident compared to patients with meningitis or encephalitis. In conclusion, among patients with tumors, high CSF neopterin may suggest the diagnosis of NHL.

Persistent Intrathecal Immune Activation in HIV-1-Infected Individuals on Antiretroviral Therapy

Neopterin is a well-established marker of macrophage activation. The cerebrospinal fluid (CSF) neopterin levels are elevated in most HIV-1-infected individuals and decrease significantly after initiation of antiretroviral therapy (ART). Unexpectedly, CSF concentrations often remain mildly abnormal even in patients treated for a long time with suppressive ART. The aims of this study were to analyze if persistently elevated CSF neopterin levels were associated with the type of antiretroviral regimen or with low-level CSF HIV-1 concentrations and to evaluate if plasma HIV-1 RNA levels correlated to lingering CSF neopterin concentrations in patients with effective ART. One hundred fifty-seven chronically HIV-1-infected patients with stable ART for > or =6 months and no neurologic symptoms were included, and 193 HIV-1-infected patients without ART served as controls. Neopterin was analyzed with a radioimmunoassay or an enzyme-linked immunosorbent assay. HIV-1 RNA quantification was performed with the Roche Amplicor assay (version 1.5; Hoffman-La Roche, Basel, Switzerland). Two quantitative HIV-1 RNA assays with sensitivities < or =2.5 copies/mL were used in 40 samples. As anticipated, HIV-1 RNA and CSF neopterin levels were markedly lower in patients on ART compared with untreated controls. No significant difference in CSF neopterin concentrations was found between those treated with protease inhibitor- and nonnucleoside reverse transcriptase inhibitor-based regimens in combination with 2 nucleoside analogues. Subjects with CSF HIV-1 RNA loads <2.5 copies/mL had the lowest CSF neopterin levels. Plasma viral load had no impact on intrathecal immune activation in cases with CSF viral loads <50 copies/mL. The persistent intrathecal cell-mediated immune response was associated with CSF viral load but not with treatment regimen in individuals on ART.

Urinary Neopterin in Patients with Diabetes Mellitus and Foot Ulcers

Abstract Increased urinary or serum concentrations of neopterin have been reported in disorders associated with systemic immune activation, e.g. viral infections, cancer, or autoimmune diseases, but the data on neopterin concentrations in patients with diabetes mellitus are limited. The aim of the present study was to investigate urinary neopterin concentrations in patients with diabetes mellitus and with or without diabetic foot. Urinary neopterin was determined by high-performance liquid chromatography in 51 patients with diabetes mellitus, including 19 patients with diabetic foot, and 18 healthy controls. Neopterin concentrations were significantly increased in patients with diabetes mellitus compared to controls (mean ± standard deviation; 221 ± 149 vs. 139 ± 66 μmol/mol creatinine; Mann-Whitney U test, p = 0.003). Urinary neopterin concentrations in patients with or without diabetic foot were identical (224 ± 113 vs. 219 ± 169 μmol/mol creatinine). No significant difference was also observed between patients with type 1 and type 2 diabetes mellitus, between patients treated with insulin compared to patients not treated with insulin, patients with or without diabetic retinopathy, with or without diabetic neuropathy, with or without diabetic nephropathy, with or without ischemic heart disease, with or without ischemic disease of lower extremities, and with or without ischemic cerebrovascular disease. Atrend of higher neopterin concentrations was observed in patients with any complication of diabetes compared to no complications (234 ± 164 vs. 176 ± 73 μmol/mol creatinine), and compared to controls, urinary neopterin was significantly increased only in patients with complications. No significant correlation was observed between urinary neopterin and glycosylated hemoglobin (rs = - 0.14, p = 0.39) or the duration of diabetes (rs = 0.25, p = 0.09). In conclusion, present results demonstrate that urinary neopterin is increased in patients with diabetes mellitus. No differences were observed in urinary neopterin concentrations based on type of diabetes, therapy or presence of diabetic foot, and urinary neopterin did not correlate with the glycosylated hemoglobin levels or duration of diabetes. Increased urinary neopterin concentrations in patients with diabetes mellitus is associated with the presence of complications and may reflect systemic immune activation associated with atherosclerosis.

Neopterin, Catalase and Superoxide Dismutase in Females with Benign and Malignant Breast Tumors

Abstract The aim of the present study was to evaluate the relationship between the levels of neopterin among patients with benign and malignant breast disease and the relation with the stage of the malignant process. In this study, neopterin concentrations and enzyme activities of superoxide dismutase (SOD) and catalase (CAT) were determined in malign (n=30) and benign breast tumor patients (n=30) by high performance liquid chromatographic and spectrophotometric methods, respectively. Results were compared with a healthy control group (n=20). The correlations between neopterin, CAT and SOD were also evaluated in controls and patients. Urinary neopterin level of the control group was (mean value ± S.D.) 128.6 ± 64.6 μmol/mol creatinine. Neopterin concentrations in patients with breast malignancy were 153.6 ± 71.2 μmol/mol creatinine and 107.8 ± 32.1 μmol/mol creatinine in benign disorders patients. The mean neopterin level in the benign group was found to be statistically different from the malign tumor group (p = 0.039). SOD and CAT activities in controls were found as 3.57 ± 0.84 U/mg protein and 2.19 ± 0.20 U/mg protein, respectively. In patients with malignancy, the SOD activity was 3.84 ± 0.73 U/mg protein while CAT activity was 1.03 ± 0.13 U/mg protein. Patients with benign breast disorders, SOD activity was 4.09 ± 1.00 U/mg protein and CAT activity was 1.02 ± 0.18 U/mg protein. Whereas SOD activity did not differ between the groups of patients and controls, the mean catalase level in the control group was higher than in the benign and malign tumor groups (both p &lt;0.001). Urinary neopterin concentration seems to be an important and useful biomarker in diagnosis of breast tumors in clinical practice.

Gamma Interferon Is Dispensable for Neopterin Production In Vivo

Previous studies have indicated that neopterin is synthesized in vitro by human monocyte-derived macrophages and dendritic cells upon stimulation with gamma interferon (IFN-gamma). Neopterin production under specific conditions in vitro has also been obtained upon stimulation with IFN-alpha and/or IFN-beta. However, it is unknown if any IFN-gamma-independent neopterin synthesis is possible in vivo. In the present study we investigated the serum neopterin concentrations in patients affected by the syndrome of Mendelian susceptibility to mycobacterial disease (MSMD). Indeed, this syndrome is characterized by deeply impaired or absent IFN-gamma production or function due to severe mutations in molecules involved in IFN-gamma/interleukin-12 (IL-12)/IL-23-dependent pathway. Serum neopterin levels were measured by an enzyme-linked immunosorbent assay in 27 patients with MSMD. We found that serum neopterin levels are elevated in the complete absence of IFN-gamma activity due either to a complete deficiency of its receptor or to deleterious mutations of IL-12 or its receptor. These data clearly indicate that, as reported from in vitro studies, other stimuli are able to induce neopterin synthesis in vivo. Consequently, neopterin cannot be used as means of diagnosis of MSMD due to IFN-gamma-, IL-12-, and IL-23-dependent pathway defects.

Relationship between homocysteine and neopterin concentrations in patients with gynecological cancer

Elevated concentrations of vascular risk factor homocysteine have been described in patients with malignant diseases, and homocysteine was supposed to be useful as tumor marker. Likewise, elevated concentrations of Th1-type immune activation marker neopterin are frequently observed in patients suffering from cancer and serve as prognostic marker for the survival of patients. In this study, the relationship between homocysteine and neopterin concentrations was examined in 18 patients with gynecological cancer. Concentrations of homocysteine and cysteine were measured by HPLC in sera of patients, folic acid and vitamin B 12 levels were determined by radioimmunoassay, and neopterin concentrations were measured by ELISA. Median homocysteine concentration was 11.2 μM (interquartile range: 9.9–13.2 μM), 3 patients had levels higher than 15 μM, the upper limit of the normal range. Neopterin concentrations were increased in 13 patients (median: 11.6; 7.7–24.9 nM), cysteine (median: 234; 216–255 μM), folate (median: 7.8; 6.2–11.7 ng/ml) and vitamin B 12 (median: 352; 258–570 pg/ml) concentrations were all within reference ranges although rather at the lower side. Higher homocysteine concentrations correlated inversely with low folate concentrations ( r s=−0.605; P<0.01) and tended to be higher in patients with higher cysteine levels ( r s=0.457; P<0.06; Fig. 1). No correlation was found between homocysteine and immune activation marker neopterin, although the three patients with elevated homocysteine concentrations tended to have higher neopterin levels as well ( P<0.07). In conclusion, only a few patients with gynecological cancer present with elevated homocysteine concentrations and hyperhomocysteinemia seems only weakly related to immune activation phenomena, tumor cell proliferation probably is more important for the increase of homocysteine.

Elevated serum neopterin predicts future adverse cardiac events in patients with chronic stable angina pectoris

Serum levels of neopterin, an immune modulator secreted by activated macrophages, are elevated in patients with acute coronary syndromes compared with stable angina patients and control subjects. In unstable angina, serum neopterin levels correlate with the presence of vulnerable coronary stenosis, multiple complex coronary lesions, and patient outcome. The present study assessed the prognostic significance of raised serum neopterin concentrations in patients with stable angina pectoris. We carried out a 1-year follow-up prospective study in 297 patients with chronic stable chest pain undergoing diagnostic coronary angiography. The primary study endpoint was the composite of non-fatal myocardial infarction, unstable angina, and cardiac death. Fifty-one patients (17.2%) had adverse coronary events during follow-up. Mean serum neopterin levels were significantly higher in patients with events compared with those without (P=0.02). On multiple regression analysis, neopterin levels (P=0.021), severity of coronary artery disease (P=0.009), and a history of previous myocardial infarction (P=0.001) were independent predictors of adverse events. Serum neopterin is an independent predictor of major adverse coronary events in patients with chronic stable angina pectoris. This marker of macrophage activation may be useful for risk stratification in patients with chronic stable angina.

Urinary neopterin concentrations in patients with Balkan endemic nephropathy (BEN)

Balkan endemic nephropathy (BEN) is of great clinical importance in restricted areas of Bulgaria, Serbia, Croatia, Bosnia, Herzegovina, and Romania, since the etiology of BEN is still unknown. In urine samples from 48 patients (41 females and 7 males, aged 65.6 +/- 6.87 years) with BEN living in an endemic area of Vratza district, Bulgaria, neopterin concentrations were measured by high-pressure liquid chromatography (HPLC) and compared with other clinical and laboratory investigations, including creatinine, hemoglobin, and erythrocyte sedimentation rates (ESRs). Urinary neopterin concentrations were 263 +/- 128 (mean +/- SD; range, 78 to 786 micromol/mol creatinine), 24 (50%) of BEN patients presented with increased concentrations as compared to the established normal ranges. Average ESRs were increased (1 hour, 29.0 +/- 14.7 mm/hour) and hemoglobin was decreased (109.3 +/- 16.4 g/L). Hemoglobin correlated inversely with ESRs (rs = -0.787 and -0.780) and creatinine concentrations (r = -0.690, all P < 0.001), but not with neopterin concentrations. Neopterin concentrations also did not correlate with serum creatinine levels. There existed an age relationship of ESR, creatinine, and hemoglobin, but not of neopterin. Neopterin concentrations were slightly lower in five females with low titers of antibodies against local B1 hantavirus strain (P < 0.05). The findings can support an immune-mediated inflammatory process in the pathogenesis of BEN only in a subgroup of patients.

Immune Activation after Apicoectomy: Comparison between Patients with and without Prophylactic Antibiotic Therapy

Summary In humans neopterin concentrations represent a sensItive index of cell-mediated immune activation. In a previous study, we found significantly increasing neopterin concentrations in patients after dental extractions. In this study, we investigated whether prophylactic antibiotic treatment of patients influenced the course of neopterin levels in patients with apicoectomy. Urinary neopterin concentrations were monitored in 23 patients with apicoectomy in the front region. Urine samples were collected before and on days 1, 3, 5, 7, 9 after apicoectomy. Six patients received antibiotic therapy, 17 were without such treatment. We found that average neopterin concentrations increased preferentially in patients not treated with antibiotics whereas pateints treated with antibiotics showed only a moderate increase of neopterin levels which returned to normal within three days. We conclude that antibiotic treatment is able to reduce immune activation which is frequently seen in patients after apicoectomy, and we assume this maybe also true in patients after dental extractions. Most likely transient bacteraemia is the cause of immune activation in such patients. However, an inhibitory influence of antibiotics on cytokine cascades cannot be ruled out.

Increased Interferon-γ and Neopterin Concentrations in Patients with Acute Brucellosis

Journal Article Increased Interferon-γ and Neopterin Concentrations in Patients with Acute Brucellosis Get access A. Diez-Ruiz, A. Diez-Ruiz Search for other works by this author on: Oxford Academic PubMed Google Scholar M. Al-Amrani, M. Al-Amrani Search for other works by this author on: Oxford Academic PubMed Google Scholar G. Weiss, G. Weiss Search for other works by this author on: Oxford Academic PubMed Google Scholar F. Gutierrez-Gea, F. Gutierrez-Gea Search for other works by this author on: Oxford Academic PubMed Google Scholar H. Wachter, H. Wachter Search for other works by this author on: Oxford Academic PubMed Google Scholar D. Fuchs D. Fuchs Reprints or correspondence: Dr. Dietmar Fuchs, Institute for Medical Chemistry and Biochemistry, University of Innsbruck, Fritz Pregl Strasse 3, A-6020 Innsbruck, Austria. Search for other works by this author on: Oxford Academic PubMed Google Scholar The Journal of Infectious Diseases, Volume 167, Issue 2, February 1993, Pages 504–505, https://doi.org/10.1093/infdis/167.2.504 Published: 01 February 1993

Serum C-reactive protein and neopterin concentrations in patients with viral or bacterial infection.

Serum C-reactive protein and neopterin concentrations were measured in samples taken at an early stage in different types of infection to see whether the combination of markers could contribute to the diagnosis of infection and help distinguish between bacterial and viral infections, tuberculosis, and infections due to "other" pathogens. Both markers were significantly raised in all categories of infection compared with controls, and there were significant differences between the means of both markers when comparing several of the categories of infection. Only C-reactive protein concentrations in bacteraemic patients, however, were both sensitive and specific at distinguishing the type of infection. The additional use of neopterin estimation played only a minor part in increasing the specificity of diagnosis in tuberculosis and in viral infections. On the basis of this study it was not considered worth the time and expense of performing neopterin assays in addition to C-reactive protein estimations to differentiate viral from bacterial infection.

Urinary excretion of porphyrins is increased in patients with HIV-1 infection

Urine concentrations of total porphyrins and of porphyrin precursors, delta-aminolaevulinic acid and porphobilinogen, were analysed in the first-morning urine samples of 36 people with established HIV-1 infection. For comparison, we also analysed the urine samples of 26 healthy HIV-seronegative people. In patients with HIV-1 infection concentrations of total porphyrins were found to be significantly higher than in healthy controls. Furthermore, there was a close correlation between concentrations of total porphyrins and porphobilinogen and urine neopterin concentrations in patients. Our data indicate an association between chronic immune activation and altered porphyrin metabolism. The data may provide a rationale for the observation of acute porphyria in patients with HIV-1 infection.

Value of urinary neopterin in the differential diagnosis of bacterial and viral infections

Neopterin is released by stimulated macrophages. In this study we analyzed the diagnostic potential of urinary neopterin concentrations in patients with bacterial and viral infection. All but one of 17 patients with viral infection had increased urinary neopterin concentrations. Patients with bacterial urinary tract infection also showed increased neopterin concentrations, whereas patients with bacterial pneumonia had significantly lower neopterin levels. In addition, patients with acute bacterial pneumonia had lower neopterin levels than patients with protracted infection. A significant inverse correlation between urinary neopterin and hemoglobin concentrations was found. Neopterin concentrations could serve as a helpful additional marker of infectious diseases. Combined with other clinical and laboratory parameters it is a useful parameter for distinguishing between viral and bacterial origins of infection, as was shown by multivariate stepwise linear discriminant analysis.

Comparison of serum and urine neopterin concentrations in patients with HIV-1 infection

Urine and serum neopterin concentrations are now widely used to monitor patients with HIV-1 infection. However, there are no published studies comparing the levels in urine and serum, and relating both to the patients' immune status. Urine and serum neopterin concentrations correlated closely in our study population of 37 HIV-1 seropositive patients (34 homosexuals, 3 drug addicts) and 10 HIV-1 seronegative homosexuals. Our data further show that urine and serum neopterin concentrations correlate almost identically with the clinical and immunological presentation of HIV-1 infected individuals, as expressed by the Walter Reed Staging classification. In addition, there was no difference between the correlation of neopterin concentrations in either serum or urine with the Quetelet indices. It will depend on the clinical situation whether blood or urine sampling is preferred. Collection and handling of urine samples from HIV infected patients is less risky to health care personnel in HIV settings.