Kinetics of dengue virus NS1 protein in dengue 4-confirmed adult patients.

In this work, the presence of NS1 protein as a possible early marker of dengue infection was studied in serum samples from confirmed adult patients with a primary and secondary dengue 4 infection. A total of 209 serum samples collected from day 2 up to day 7 of fever onset from 71 patients were tested by Platelia NS1 antigen capture ELISA kit (BioRad, Marnes-la-Coquette, France), and the results were compared with those obtained by capture antidengue virus IgM (MAC)-ELISA and ELISA inhibition method tests. The 83.3% of primary cases and 96.4% of secondary cases were NS1 positive. The kinetics of NS1 protein showed the highest values in optical density mean ratio or in percentage of positives between days 2 and 4. The results obtained in this study show the utility of the NS1 protein as a virologic early marker of dengue infection. Prospective studies should be carried out to confirm its utility as a prognostic marker of severe illness.