The importance of neopterin in COVID-19: The prognostic value and relation with the disease severity

Evaluation of serum neopterin levels in severe COVID-19 patients: An observational study

In patients with coronavirus disease (COVID-19), a massive inflammatory response is a significant cause of morbidity and mortality. Inflammatory markers are prognostic indicators of disease severity and the ultimate clinical outcome. Several studies have demonstrated a correlation between serum levels of neopterin, which can be an immune system marker, disease severity, and poor outcomes in COVID-19 patients. Our study aimed to determine the diagnostic significance of neopterin in conjunction with routinely measured inflammatory markers in patients with severe COVID-19. Serum neopterin, C-reactive protein (CRP), albumin levels, and complete blood count were determined in 39 patients with severe COVID-19 and 30 healthy individuals. Demographic characteristics, serum neopterin levels, and other laboratory data were compared between patients and healthy volunteers and statistically analyzed. High neopterin levels were observed in patients with severe COVID-19 compared to healthy volunteers. Furthermore, albumin levels were decreased, while CRP levels were increased in patients, statistically significantly. Also, positive correlations were shown between serum neopterin levels and serum CRP levels, while negative correlations were shown between serum neopterin levels and serum albumin levels. Systemic inflammation markers, CRP/albumin ratio, neutrophil/lymphocyte ratio, and platelet/lymphocyte ratio were significantly higher, while lymphocyte/monocyte ratio was also significantly lower in patients with severe COVID-19 than in healthy volunteers. However, serum neopterin levels were not linked to the CRP/albumin ratio, the neutrophil/lymphocyte ratio, or the platelet/lymphocyte ratio. On the other hand, they were linked negatively to the lymphocyte/monocyte ratio. Our findings highlight the association between high neopterin levels and patients with severe COVID-19. Neopterin is correlated with traditional inflammatory biomarkers and may indicate general immune and inflammatory activation in patients with severe COVID-19.

Neopterin and kynurenine in serum and urine as prognostic biomarkers in hospitalized patients with delta and omicron variant SARS-CoV-2 infection

OBJECTIVES

Currently, no biomarker or scoring system could clearly identify patients at risk of progression to a severe coronavirus disease (COVID)-19. Even in patients with known risk factors, the fulminant course cannot be predicted with certainty. Analysis of commonly determined clinical parameters (frailty score, age, or body mass index) together with routine biomarkers of host response (C-reactive protein and viral nucleocapsid protein) in combination with new biomarkers neopterin, kynurenine, and tryptophan, could aid in predicting the patient outcome.

METHODS

In 2021 and 2022, urine and serum samples were prospectively collected on 1st to 4th day after hospital admission in 108 consecutive COVID-19 patients hospitalized at the University Hospital Hradec Králové, Czech Republic. Delta and omicron virus variants were studied. Neopterin, kynurenine and tryptophan were determined by liquid chromatography.

RESULTS

A significant correlation was observed between urinary and serum biomarker concentrations. Urinary and serum neopterin, kynurenine and kynurenine/tryptophan ratio were significantly (p≤0.05) higher in patients who subsequently needed oxygen therapy vs. patients without oxygen therapy. These parameters were also significantly increased in patients who died during the hospitalization compared to survivors. Complex equations have been derived using the investigated biomarkers and other clinical or laboratory parameters to predict the risk of subsequent oxygen therapy or death during hospitalization.

CONCLUSIONS

Present data demonstrate that neopterin, kynurenine and kynurenine/tryptophan ratio in the serum or in the urine represent promising biomarkers in the management of COVID-19 that may help to guide important therapeutic decisions.

The usability of neopterin in determining disease course in COVID-19

OBJECTIVES

To investigate the usability of neopterin in demonstrating the progression of COVID-19. As a result of uncontrolled activation of COVID-19 monocytes and macrophages, IFN gamma increases and the resulting inflammatory response causes organ damage. IFN released from T cells causes an increase in gamma neopterin levels. Therefore, measurement of neopterin levels can be used to indicate immune system activation and disease progression.

METHODS

The study was carried out prospectively in two different centers. The patients were divided into two groups (mild-moderate and severe) and clinical, laboratory, imaging findings and neopterin levels at hospitalization were compared.

RESULTS

100 patients were included in our study, 41 of these patients were male. Forty-six patients were identified as severe COVID-19. C-reactive protein, lymphocyte count, fibrinogen, D dimers, lactate dehydrogenase, procalcitonin, troponin and neopterin levels were significant in indicating disease severity. (p<0.05). In ROC analysis, 0.642 for neopterin, 0.698 C-reactive protein, 0.331 lymphocyte count, 0.679 procalcitonin, 0.633 fibrinogen, 0.667 D dimers, 0.655 troponin and 0.706 lactate dehydrogenase were detected and these values were significant.

CONCLUSION

In our study, neopterin was detected as an important indicator in determining the course of COVID-19.

Neopterin, the Cell-Mediated Immune Response Biomarker, in Inflammatory Periodontal Diseases: A Narrative Review of a More than Fifty Years Old Biomarker

Neopterin is a biomarker of the activation of cellular immunity. The purpose of this review is to summarise neopterin metabolism, methods of its detection, and its role in inflammation, focusing on periodontal inflammatory diseases. This derivative of guanosine is a non-enzymatic product of 7,8-dihydroneopterin oxidation caused by free radicals which protect activated macrophages from oxidative stress. Various methods, usually based on enzyme-linked immunosorbent essay, high-performance liquid chromatography, or radioimmunoassay were developed for the isolation of neopterin. A wide spectrum of diseases and conditions are known to affect neopterin levels, including cardiovascular, bacterial, viral, and degenerative diseases, as well as malignant tumours. Neopterin levels were found to increase in subjects with periodontitis, especially when the oral fluid and gingival crevicular fluid were evaluated. These findings confirm the role of activated macrophages and cellular immunity in periodontal inflammatory diseases. The gingival crevicular fluid and the oral fluid appear to be the most valuable biologic fluids for the evaluation of neopterin levels in periodontitis. For gingival crevicular fluid, neopterin can be determined as the concentration or the so-called total amount. Nonsurgical periodontal treatment was associated with a decrease in neopterin levels, but an increase was also reported, suggesting the possible role of macrophages in the resolution of the periodontal lesion.

Evidence, detailed characterization and clinical context of complement activation in acute multisystem inflammatory syndrome in children

Multisystem inflammatory syndrome in children (MIS-C) is a rare, life-threatening complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. MIS-C develops with high fever, marked inflammation and shock-like picture several weeks after exposure to, or mild infection with SARS-CoV-2. Deep immune profiling identified activated macrophages, neutrophils, B-plasmablasts and CD8 + T cells as key determinants of pathogenesis together with multiple inflammatory markers. The disease rapidly responds to intravenous immunoglobulin (IVIG) treatment with clear changes of immune features. Here we present the results of a comprehensive analysis of the complement system in the context of MIS-C activity and describe characteristic changes during IVIG treatment. We show that activation markers of the classical, alternative and terminal pathways are highly elevated, that the activation is largely independent of anti-SARS-CoV-2 humoral immune response, but is strongly associated with markers of macrophage activation. Decrease of complement activation is closely associated with rapid improvement of MIS-C after IVIG treatment.

Immunopterin: A prospective therapy and preventative to fight COVID-19?

Background

The authors explore the therapeutic and prophylactic efficacies of Immunopterin (calcium pterin-6-carboxylate chelate) against coronavirus colds and as a therapy against COVID-19.

Methods

To determine Immunopterin’s therapeutic efficacy against colds and flus, a 5-year observational study was conducted with 34 subjects who took Immunopterin when feeling symptoms of a cold or flu. The mean sample cold recovery time was compared to the US population mean. A review of the Moheno (2014) 2-year observational study was conducted to evaluate the prophylactic efficacy of Immunopterin against colds. Early COVID-19 case studies, treated with Immunopterin, were collected to explore Immunopterin’s efficacy as a therapeutic and prophylactic against COVID19 disease.

Results

The mean cold recovery time for the therapeutic sample in the cold/flu observational study was 30 h compared to the US population mean of 168 h (N = 34; p < 0.001). Subjects taking prophylactic Immunopterin reported 0% incidences of colds and flus (N = 31). Immunopterin successfully treated four confirmed COVID-19 subjects. A fifth clinical nurse case study demonstrates COVID-19 prevention.

Conclusions

The therapeutic and prophylactic efficacies of Immunopterin against coronavirus colds, along with reported cross-reactivity between coronavirus colds and SARS-CoV-2 strongly suggest Immunopterin can act as a therapy and preventative against COVID- 19 infection associated disease.