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.