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

Abstract

Coronavirus Disease 2019 [COVID-19], caused by severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2], has rapidly evolved into a global health emergency. Neopterin [NPT], produced by macrophages when stimulated with interferon [IFN-]gamma, is an essential cytokine in the antiviral immune response. NPT has been used as a marker for the early assessment of disease severity in different diseases. The leading cause of NPT production is the pro-inflammatory cytokine IFN-. Macrophage activation has also been revealed to be linked with disease severity in SARS-CoV-2 patients. We demonstrate the importance of NPT in the pathogenesis of SARS-CoV-2 and suggest that targeting NPT in SARS-CoV-2 infection may be critical in the early prediction of disease progression and provision of timely management of infected individuals.

Keywords: COVID-19; Neopterin; Prognosis; SARS CoV-2.

Graphical abstract

Fig. 1

Biosynthesis of neopterin: IFN-γ activates GTP cyclo-hydrolase that further cleaves GTP to 7,8-dihydro-neopterin triphosphate, and phosphatases, in turn, change this intermediate to neopterin. Since humans lack PTPS, an enzyme that converts DHNTP into 5,6,7,8-tetra hydrobiopetrin, the DHNTP is only biosynthesized to neopterin. On the other hand, IFN-γ initiates tryptophan degradation to kynurenine by activating the IDO enzyme. Thus, there is a direct correlation between increased neopterin and tryptophan degradation.

Fig. 2

Zn can inhibit ACE2 expression by reducing sirtuin1.

Fig. 3

HOCI mechanism acting on pathogens.