Neopterin is generated and released in increased amounts by macrophages upon activation by interferon-γ during Th1-type immune response. The potential usefulness of neopterin in early prognostic information of dengue virus infection was investigated.

Neopterin concentrations were determined in serum samples from 110 dengue fever (DF) patients. The neopterin levels were compared with those in 50 measles and 40 influenza patients; 155 healthy blood donors served as controls.

In acute sera of DF patients mean neopterin concentration was 48.2nmol/L, which was higher than that in patients with measles (mean: 36.3nmol/L) and influenza (18.8nmol/L) and in healthy controls (6.7nmol/L; P<0.001). In the patients with confirmed DF, an early neopterin elevation was detected already at the first day after the onset of symptoms and rose to a maximum level of 54.3nmol/L 4days after the onset. Higher increase of neopterin level in DF patients was associated with longer duration of fever and thus predicted the clinical course of the disease.

Neopterin concentrations were found significantly higher in DF patients compared with healthy controls and also with other viral infections (P<0.001) and may allow early assessment of the severity of DF.